Dissertations / Theses: 'Biosurfactant'

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Chen, Chien-Yen. "Biosurfactant production." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419243.

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Domingues, Patrícia Maia. "Isolation of estuarine biosurfactant-producing bacteria." Master's thesis, Universidade de Aveiro, 2011. http://hdl.handle.net/10773/7773.

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Mestrado em Biotecnologia
Bioremediation has proven to be an effective strategy in the recuperation of oil contaminated ecosystems. However most bacteria used in this processes, while being able to degrade a wide range of the oil hydrocarbons, have limited action due to the low water solubility of these compounds. Hence, a possible solution for this problem would be the use of biosurfactant-producing bacteria, since the presence of surfactants help improve the hydrocarbons dispersal, solubilization and bioavailability. The objective of this work was to assess the biotechnological potential of Ria de Aveiro estuarine system regarding the presence of hydrocarbonoclastic biosurfactant-producing bacteria and to evaluate different combinations of environmental inocula and carbon sources for the isolation of biosurfactants producing bacteria. Selective cultures (diesel, crude and paraffin) were prepared using inocula from different environmental matrixes: samples from the surface microlayer (SML), bulk estuarine sediments and sediments of the rhizosphere of Halimione portulacoides, a characteristic halophyte from the salt marshes of Ria de Aveiro. During the incubation period, the development of the selective cultures was assessed by quantification of colony forming units (CFU). The highest value of CFU was obtained in the crude-sediment culture, while the lowest value was found with the diesel-rhizosphere combination. The DGGE profiles of the 16s rRNA gene fragments of the total community DNA extracted at the end of the incubation of the selective cultures, show that communities were different in terms of structural diversity. The values of the Shannon-Weaver index of diversity indicate that the higher diversity was achieved in the selective cultures with paraffin as carbon source (2.5231), followed by the crude oil (2.2509), and diesel (1.6726) selective cultures. From the selective cultures, 111 presumably hydrocarbonoclastic isolates were obtained after isolation and purification. Of these, 66 were tested for biosurfactant production by the atomized oil assay, with positive results for 17 isolates (25.8%). The environmental matrix with best results was the SML water and diesel was the most effective carbon source. Having in consideration the high number of isolates obtained from the selective cultures and the percentage of biosurfactant producers, the estuarine system of Ria the Aveiro, and in particular the SML, can be regarded as an interesting seedbank for the prospection of hydrocarbonoclastic and biosurfactants producing bacteria. The SML microhabitat shows particularly high biotechnological potential for the isolation of bacterial strains with interesting properties for application in bioremediation strategies in coastal and estuarine areas.
A biorremediação é tida como uma possível estratégia na recuperação de ecossistemas contaminados com hidrocarbonetos. A aplicação eficaz desta tecnologia é, no entanto, muitas vezes limitada pela natureza hidrofóbica dos contaminantes. O recurso a estirpes bacterianas simultaneamente degradadoras de hidrocarbonetos e produtoras de biossurfactantes apresenta um enorme potencial na reciclagem de compostos hidrofóbicos. Assim, o objectivo deste trabalho consistiu em avaliar o potencial biotecnológico do sistema estuarino da Ria de Aveiro quanto à presença de bactérias hidrocarbonoclásticas produtoras de biossurfactantes e a avaliação de várias combinações de inóculos ambientais e fontes de carbono para a obtenção de isolados bacterianos de interesse. Para tal foram realizadas experiências em meios selectivos (diesel, crude e parafina) a partir de inóculos de diferentes matrizes ambientais: amostras da microcamada superficial (SML), sedimentos estuarinos e rizosfera de bancos de Halimione portulacoides, uma planta halófita dos sapais da Ria de Aveiro. O desenvolvimento da cultura ao longo do período de incubação foi avaliado pela contagem de unidades formadoras de colónias (CFUs). A cultura selectiva com maior teor de bactérias cultiváveis foi a de crude-sedimento e aquela em que a abundância bacteriana foi mais baixa foi a de diesel-rizosfera. A partir da análise dos perfis de DGGE dos fragmentos do gene 16s rRNA do DNA total extraído das culturas selectivas verificou-se que no fim do período de incubação, o grau de semelhança entre as comunidades bacterianas das culturas selectivas é relativamente baixo. Pelo índice de diversidade de Shannon-Weaver a maior diversidade estrutural das comunidades bacterianas encontra-se nas culturas selectivas de parafina (2,5231), seguidas das de crude (2.2509) e das de diesel (1.6727). Das culturas selectivas, foi obtido um conjunto de isolados que foi testado quanto à capacidade de produção de biossurfactantes pelo método atomized oil. De 66 isolados testados, 17 produziram resultado positivo (25,8%), sendo a água da SML a matriz ambiental com melhores resultados e o diesel a melhor fonte de carbono para o isolamento de bactérias produtoras de biossurfactantes. Tendo em conta o elevado número de isolados obtidos e a percentagem de produtores de biossurfactantes, pode concluir-se que na Ria de Aveiro, particularmente na SML, existem comunidades bacterianas adaptadas à utilização se substratos hidrofóbicos, com uma boa representação de produtores de biossurfactantes. Os resultados confirmam a perspectiva de que a SML da Ria de Aveiro é um microhabitat com elevado potencial biotecnológico para isolamento de estirpes de bactérias hidrocarbonoclásticas produtoras de biossurfactantes com promissoras aplicações em processos de biorremediação de regiões estuarinas e costeiras após contaminação acidental com hidrocarbonetos de petróleo.

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Bamara, Prosper. "Conversion of hydrocarbons to biosurfactants : an insight into the bioprocess optimisation of biosurfactant production using alkanes as inducers." Master's thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/5344.

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Surfactants are chemical compounds that are able to alter interfacial properties, particularly surface tension. When they are biologically produced, the term biosurfactant is used. One of the most important groups of biosurfactants is a family of chemical compounds known as glycolipids, whose structure consists of a sugar group and a lipid tail. Glycolipids are subdivided into three main groups: rhamnolipids, sophorolipids and trehalolipids, named following their sugar moieties, respectively rhamnose, trehalose and sophorose. Biosurfactants exhibit attractive advantages over chemical surfactants. Examples of these are biodegradability, low toxicity, and effectiveness at extreme temperature, pH and salinity. The objective of the present research project was, first, to investigate the potential of liquid aliphatic hydrocarbons to induce biosurfactant production by the bacterium Ps. aeruginosa 2Bf isolated based on its ability to metabolise alkanes. The second objective was to optimise biosurfactant production using alkanes as sole carbon and energy source, through optimising the mixing & aeration conditions, media conditions as well as provision of alkane, in a stirred tank batch reactor system. The final objective was to describe the biosurfactant formed. Experiments were organised in three major series: the exploratory shake flask based experiments, the bioreactor-based experiments to optimise biosurfactant production and characterise biokinetics and performance, and the biosurfactant characterisation experiments. Following review of a number of methods, microbial cell counts were selected as the most reproducible measure of biomass formation in the presence of alkanes. The presence of biosurfactant was quantified functionally in terms of the emulsification index and alteration of surface tension. Using a shake flask-based study, nitrogen source was investigated in terms of biomass and biosurfactant synthesis. Four pre-selected nitrogen sources were tested in order to select the best for bioreactor based study. These nitrogen sources consisted of specific combinations of three nitrogen compounds, NH4NO3, NaNO3 and (NH4)2SO4. During the study, long chain liquid n-alkanes were used as sole carbon source and the C/N ratio maintained at the value of 18.6 in mass terms. Results confirmed that both a combination of NO3 ' and NH4+ ions or a nitrogen source composed solely of NH4+ ions were suitable for biomass growth and biosurfactant production. (NH4)SO4 was used as the N-source of choice in the remainder of the study. While the C14-C17 alkanes cut was the carbon source of interest in the study, two pure alkanes, n-C12 and n-C16 were tested and compared to the C14-C17 blend. The C14-C17 fraction, sourced as an industrial byproduct, compared favourably as a carbon source with respect to hexadecane and dodecane. ii Biosurfactant production was not observed in Ps. aeruginosa 2Bf cultures where glucose was the sole carbon source and the bacteria were not previously exposed to linear alkanes. Using a mixed carbon source of glucose and alkane, or on pre-exposure of the bacteria to alkane, biosurfactant production was induced. Induction was optimised where alkane was the sole carbon source over a period of four sub-culture steps. In the quantitative optimisation of biosurfactant production through the bioreactor based study, mixing and aeration were optimised; agitation and aeration proved to be equally important, the first at intermediate rates, the second at lower rates. Their interaction, when maximum biomass was used as the variable for response, was found to be important for agitation rates up to 500 rpm. Beyond this range of agitation speed, the interaction between aeration and agitation became negligible. In the case of Eindex as the variable for response, similar results were obtained with regard to the impact of the interaction between aeration and agitation on the process. It was significant from lower to intermediate agitation rates, and negligible from intermediate to higher rates of agitation. Lower aeration rate was found to enhance the oxygen utilisation rate, while mass transfer was relatively favoured by high aeration rate. Regarding the emulsification power of the product, quantitative tests were carried out on culture suspension, supernatant prepared by centrifugation and supernatant prepared by centrifugation and filtration at 0.22Î¼m pore size filters. Results showed that some emulsification effect was lost through centrifugation and filtration. This loss of emulsification effect was more pronounced in the filtration case, thus showing that some biosurfactant was removed along some other material or substance through sticking on filter paper. Foam control was required, and two mechanical foam breakers were compared to anti-foam reagent. It was experimentally established that mechanical foam breakers are preferable to chemical anti-foam reagents. On comparing the two different mechanical foam breakers, the modified two blade paddle with three slits, FB-2, performed better than the simple two blade paddle foam breaker, FB-1. Further investigations showed that the interaction between type of foam control and agitation rate was negligible throughout the process. The Biosurfactant was characterised at the structural level and the antibiotic potential of Ps. aeruginosa 2Bf's biosurfactant was analysed. In addition to the thin layer chromatography, three different spectroscopic methods (mass, infrared & nuclear magnetic resonance) were used to study the chemical structure of the biosurfactant produced. Up to six rhamnolipid structures were tentatively identified with spectrometric analysis whereas only four to five structures could be detected with thin layer chromatography. Possession of an anti-microbial activity by the rhamnolipids produced was confirmed with the B. subtilis inhibition test.

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Shen, Hsin-Hui. "Neutron reflection study of the biosurfactant surfactin." Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491968.

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Three different deuterated surfactins were produced from the Bacillus sub/iUs strain, one perdeuterated, one with the four leucines perdeuterated, and one with everything except the four leucines perdeuterated. The neutron reflectivity profiles ofthese three samples in each of null reflecting water and D20 with a seventh profile of the protonated surfactin in D20 were measured under different pH values and ionic concentrations. This combination of different isotopic compositions made it possible to deduce the distribution of each type of iabelled fragment in the surfactin. The consistency of the three null water profiles showed how well defined the deuteration was in the three deuterated samples. The ball-like structure found for the surfactin at surfaces makes it more like a hydrophobic nanoparticle whose solubility in water is only maintained by the double charge. This is probably what makes it so surface active at such low concentrations and what contributes to its formation of very compact surface layers that are much thinner than observed for most conventional amphiphiles. The adsorbed structures of surfactin at all standard solid/liquid interfaces (silica/water, hydrophobic OTS/water, sapphire/water) at different pH conditions have also been investigated by neutron reflection. Surfactin is quite peculiar; it is basically a charged, or partially charged, hydrophobic ball and the general pattern ofadsorption are quite different from normal. anionic surfactants. The overall thickness of the surfactin is about 1.3 nm. The adsorption varies with different substrates and is dominated by hydrophobic and electrostatic interactions. Contrast variation plays an important role in increasing the sensitivity to bilayers and was utilized extensively in the study of the interaction of surfactin with phospholipids on the silicon/silica surface. The d31-DPPC-surfactin bilayer in D20 is a particularly favourable contrast among the four possibilities (h-DPPCID20, d31-DPPCID20, d62DPPC/ CmSi, and d7s-DPPC /CmSi) for the study of this system. It was found that surfactin disrupts and solubilizes phopsholipid bilayers. This happens when the concentration of surfactin in the bilayer is above a certain threshold and when surfactin micelles are present in the bulk solution. The solubilization rate is related to the bilayer coverage. More detailed studies have shown that the surfactin is eXclusively located in the outer leaflet of the bilayer when it starts to penetrate and in this, and some other features, the adsorption into bilayers resembles that of conventional non-ionic/anionic surfactant mixtures.

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Chen, Zixi. "Polyurethane-Based Biosurfactant Mimics as Antibiofilm Agents." University of Akron / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=akron1619217360880311.

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Jiménez, Peñalver Pedro. "Sophorolipids production by solid-state fermentation: from lab-scale to pilot plant." Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/458652.

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En aquest treball es proposa una tecnologia alternativa per a la producció de soforolípids (SLs), un tipus de biosurfactant, presentats com a alternativa als surfactants produïts químicament degut a la seva major eficiència i millor perfil mediambiental. En aquest treball s'han dut a terme dues estratègies per a millorar la relació de cost-eficiència dels SLs respecte als surfactants produïts químicament, que és el que determina la seva viabilitat econòmica. Ambdues estratègies estan basades en la producció de SLs mitjançant la fermentació en estat sòlid. La primera estratègia va consistir en el ús d’un residu de winterització (RW) amb l'objectiu de disminuir el preu dels substrats i, per tant, el cost final de producció dels SLs. Es va utilitzar melassa de sucre com a co-substrat i palla de blat com a suport inert. El procés va ser optimitzat en base al rati de substrats, la velocitat d’aeració i a la mida de l’inòcul a escala de 100-g, obtenint-se un rendiment de 0.261 g per g de substrat al dia 10. El procés optimitzat, va ser escalat satisfactòriament a un bioreactor de llit fix de 40-L, però posteriorment, es van observar problemes associats amb l'eliminació de calor durant l'escalat a un bioreactor de 100-L amb barreja intermitent. L'estructura química i les propietats interfacials de la barreja natural del SLs produït a partir del RW es va estudiar durant una estança al Rensselaer Polytechnic Institute (NY, USA). La segona estratègia consistí en l'ús de àcid esteàric (C18:0) per a l'obtenció de SLs amb una estructura específica que millori les propietats fisicoquímiques de la barreja natural de SLs i, per tant, la seva eficiència. Es va utilitzar melassa de sucre com a co-substrat i escuma de poliuretà com a suport inert. L'efecte de la densitat de l'escuma de poliuretà i la capacitat de retenció hídrica van ser avaluades i el procés va ser optimitzat en base al rati de substrats e inòcul, obtenint-se un rendiment final de 0.211 g de SLs per g de substrat. Els SLs produïts contenien elevades quantitats de SLs C18:0. Es van observar correlacions significatives entre el rendiment de SLs i l’oxigen consumit (COA). Això suggereix que el COA pot ser utilitzat com a mesura indirecta de la producció de SLs per a la monitorització en línea de processos de FES. Aquesta tesi representa el començament d'una nova línia d'investigació centrada en la producció de SLs per FES en el Grup de Investigació en Compostatge (GICOM) del Departament d’Enginyeria Química, Biològica i Ambiental de la Universitat Autònoma de Barcelona.
En este trabajo se propone una tecnología alternativa para producir soforolípidos (SLs), un tipo de biosurfactante, presentados como alternativa a los surfactantes producidos químicamente debido a su mayor eficiencia y mejor perfil medioambiental. En este trabajo se han explorado dos estrategias para mejorar la relación coste-eficiencia de los SLs respecto a los surfactantes producidos químicamente, que es lo que determina su viabilidad económica. Ambas estrategias están basadas en la producción de SLs mediante la fermentación en estado sólido (FES) de Starmerella bombicola. La primera estrategia consistió en el uso de un residuo de winterización (RW) con el fin de disminuir el precio de los sustratos. Se utilizó melaza de azúcar como co-sustrato y paja de trigo como soporte inerte. El proceso fue optimizado en base a la ratio de sustratos, la velocidad de aireación y el tamaño del inóculo a escala de 100-g obteniendo un rendimiento de 0.261 g de SLs por g de sustrato a día 10. El proceso fue escalado satisfactoriamente a un biorreactor de lecho fijo de 40-L, pero se observaron problemas asociados con la eliminación del calor durante el escalado a un biorreactor de 100-L. Los SLs producidos a partir del RW fueron caracterizados durante una estancia en el Rensselaer Polytechnic Institute (RPI) en NY, EEUU. La segunda estrategia consistió en el uso de ácido esteárico (C18:0) para obtener SLs con una estructura específica que mejore las propiedades fisicoquímicas de la mezcla natural de SLs y, por tanto, su eficiencia. Se utilizó melaza de azúcar como co-sustrato y espuma de poliuretano como soporte inerte. Se evaluó el efecto de la densidad de la espuma de poliuretano y la capacidad de retención hídrica y el proceso fue optimizado en base a la ratio de sustratos e inóculo obteniendo un rendimiento final de 0.211 g de SLs por g de sustrato. Los SLs producidos presentaron contenidos elevados de SLs diacetilados C18:0 acídico y lactónico. Se observaron correlaciones significativas entre el rendimiento de SLs y el oxígeno consumido (COA). Esto sugiere que el COA puede ser usado como medida indirecta de la producción de SLs para la monitorización on-line de procesos de FES. Esta tesis representa el comienzo de una nueva línea de investigación centrada en la producción de SLs por FES en el Grupo de Investigación en Compostaje (GICOM) del Departamento de Ingeniería Química, Biológica y Ambiental de la Universitat Autònoma de Barcelona.
This work proposes a potential alternative approach to produce sophorolipids (SLs), a type of biosurfactant, which are presented as an alternative to chemically-produced surfactants due to their higher efficiency and better environmental compatibility. Two strategies have been performed in this work to increase their cost-performance relative to petroleum based surfactants, which determines their commercial viability. Both are based in the production of SLs by the solid-state fermentation (SSF) of solid hydrophobic substrates by the yeast Starmerella bombicola. The first strategy was to use winterization oil cake (WOC), an oil cake that comes from the oil refining industry, to decrease the price of the substrates and, therefore, the final production costs of SLs. Sugar-beet molasses was used as co-substrate and wheat straw was chosen as inert support. The process was optimized in terms of substrates ratio, aeration rate and inoculum size at 0.5-L scale to obtain a yield of 0.261 g of SLs per g of substrate at day 10. The optimized process was successfully scale-up to a 40-L packed-bed bioreactor but problems associated with heat removal were found during the scale-up to a 100-L intermittently-mixed bioreactor. The chemical structure and interfacial properties of the SL natural mixture produced from the WOC were studied during a research stay at the Rensselaer Polytechnic Institute (RPI) in NY, USA. The second strategy consisted in the use of stearic acid (C18:0) to obtain SLs with a specific structure that improves the physicochemical properties of the SL natural mixture and, therefore, their performance. Sugar-beet molasses was used as co-substrate and polyurethane foam (PUF) functioned as inert support. The effect of PUF density and water holding capacity was assessed and the process was optimized in terms of substrate and inoculum ratio to obtain a final yield of 0.211 g of SLs per g of substrate. SLs produced herein had high contents of diacetylated acidic and lactonic C18:0 SLs. There were significant correlations between the SL yield and the oxygen consumed (COC). This suggests that the respiration parameter COC, can be used as an indirect measurement of the production of SLs for the on-line monitoring of SSF processes. This thesis represents the beginning of a new research line focused on the production of SLs by SSF in the Composting Research Group (GICOM) at the Department of Chemical, Biological and Environmental Engineering of the Universitat Autònoma de Barcelona.

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Weber, Andreas [Verfasser]. "Process Analysis of Biosurfactant Downstream Processing / Andreas Weber." München : Verlag Dr. Hut, 2014. http://d-nb.info/1063222281/34.

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Perfumo, Amedea. "Investigation of bacterial biosurfactant production for industrial use." Thesis, University of Ulster, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.554284.

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This study presents part of a multifaceted study of microbial biosurfactants and their industrial potential. The first step was the assembly of a microbial culture collection of a variety of biosurfactant-producing organisms with the choice of biosurfactant types informed by the industrial partner. The choice was based on two main criteria, the ease of product recovery and its final yield. Two groups of glycolipid biosurfactants were selected for further study: rhamnolipids produced by Pseudomonas aeruginosa and sophorolipids by Candida spp. Efforts to manipulate the biosurfactant chemical profiles by changing the cultivation media (carbon source in particular) and conditions in shake-flasks, demonstrated that there is only a limited possibility for changing the biosurfactant composition. This raised the question of the extent to which biosurfactant production is constrained by genetic determinants? To overcome the limitations of the flask-scale production, selected P. aeruginosa and Candida strains were used in bioreactors, and rhamnolipids and sophorolipids were synthesised in quantities sufficient for extraction and purification. The purified biosurfactants were used by the project partners for further characterisation and formulation in trial industrial products. Rhamnolipid yields were approximately 10 g/L whilst sophorolipid production exceeded 100 g/L. Detailed examination of the orcinol assay, which is widely used for the determination of rhamnolipid yields, showed that the method is flawed and provides an overestimate of yield when compared to quantification following extraction and purification. The culture approach had demonstrated the restricted possibilities for manipulating rhamnolipid production profile in P. aeruginosa and therefore a wider range of strains from different environmental niches were selected for genetic analysis. The aim of this part of the investigation was to establish the extent of natural gene variation which could be exploited for customised biosurfactant production. The comparative analysis of the rhl genes, coding the factors involved in rhamnolipid biosynthesis, was carried out on different P. aeruginosa strains isolated from water, soil and including pathogenic strains infecting cystic fibrosis patients. The extent of the gene sequence diversity resulted < 5%, which indicated that the rhl genes are conserved and are part of the core genome of P. aeruginosa. The single polymorphisms that occurred on the gene sequences, which gave rise to several variants, revealed no clear effect on the phenotype but appeared rather random. These variants showed also no specific correlation with different habitats. The analysis of the codon usage further supported the confidence in the highly conservative nature of the rhl genes. Most amino acids were encoded by highly preferred codons, some of which were selected upon the optimal translational efficiency, some others were instead determined by the high GC content of P. aeruginosa genome. On the whole, our data correlated well in showing that rhamnolipid biosurfactants produced by P. aeruginosa are conserved in their structure and profile as well in the genetic makeup. As involved in many important biological activities under a variety of environmental conditions, rhamnolipids developed as highly fit molecules. In the light of this, it appears that the likelihood that isolates of P. aeruginosa displaying unusual rhamnolipid profiles and features occurring naturally would be limited. Alternative routes for the development of industrially customised rhamnolipid biosurfactants are suggested as either the genetic manipulation of P. aeruginosa or the screening of rhamnolipid-producing organisms closely related.

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Urum, Kingsley. "Biosurfactant enhanced treatment of petroleum oil contaminated soils." Thesis, Heriot-Watt University, 2004. http://hdl.handle.net/10399/232.

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This thesis reports the experimental measurements on the ability of biological origin surfactants (i.e. biosurfactants - aescin, lecithin, rhamnolipid, saponin and tannin) on removing crude oil and a heavy fuel oil blend from various soils, through soil washing process. The greatest advantage of soil washing is that it is a physical means of separating oil from soil using water or surfactants without chemically modifying either the soil or the oil. The oil removal performance of the biosurfactants was evaluated against that of a well studied synthetic surfactant (sodium dodecyl sulphate, SDS) using water as a base case. For this purpose, different washing settings (i.e. test tubes, stirred flasks, packed column, and air bubble assisted stirred tank) were used to treat contaminated soils with high oil toxicity. The effects of operational parameters such as washing temperature (5 to 500C), washing time (1 to 20 minutes), concentration of surfactant solutions (0.004 to 0.5%-mass), volume of surfactant solution (5 to 20 cm3), flow rate (2 to 16 cm3/minutes), pore volume (10 to 70) and contamination history was investigated. The interaction of the surfactant solutions with the oil and soils was also investigated, which was used to explain the dominant mechanisms behind soil washing. The contaminated soils were prepared in the laboratory by mixing the oil and soils. Two different contamination cases were considered: weathered contamination in which freshly contaminated soils were subjected to heat treatment in a fan assisted oven (simulating weathering effect in the natural hot environments), and non-weathered contamination in which contaminated soils were not subjected to any heat treatment. The different washing techniques employed in this study yielded a novel and informative description on the selection of biosurfactants in the remediation of crude oil contaminated soils. This is believed to have major academic and industrial values for the treatment of (1) soil contaminated with oil, (2) sand produced with oil, (3) drill cuttings, (4) enhanced oil recovery, and (5) waste drilling mud and sludge from oil storage tank. In addition, the characterization of the biosurfactants in oil-water, soilwater and oil-soil systems give a general knowledge of their behaviour, which is important in the application for effective removal of oil from soil. Soil washing was found to have a considerable potential in removing oil from the different contaminated soils and results were comparable with those reported in literature. Oil removal by rhamnolipid was more effective than the other biosurfactants and water was effective at higher parameter levels. Further, biosurfactants can preferentially remove certain aromatic groups, which may be desirable for more rapid soil remediation. The rhamnolipid can be equally as efficient at removing oil from soil as SDS at a repeatability range of ± 6%. However, rhamnolipid have advantages over SDS beacuase the use of rhamnolipid will eliminate the need for removing surfactants from effluents as their release will not damage the environment due to their safe natures. Other surfactants (bio and/or synthetic) can be blended with rhamnolipid to achieve greater performance characteristics. In general, the stirred tank and air bubble assisted stirred tank reactors settings were more effective in removing oil from the weathered and the non-weathered contaminated soil samples. The most influential parameter on the oil removal was washing solution temperature with more than 80% of crude oil removal at 500C.

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Gidudu, Brian. "Biosurfactant Enhanced Bioelectrokinetic Remediation of Petrochemical Contaminated Soil." Diss., University of Pretoria, 2019. http://hdl.handle.net/2263/79238.

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Soil pollution in recent years has emerged as an issue of great environmental concern. Contamination of soil by improper disposal or spillage of petrochemicals and products containing petroleum hydrocarbons is one of such pollution cases highly reported. To remediate petroleum contaminated soil, A DC powered electrokinetic reactor was used with biosurfactants as an enhancement for the remediation process. To begin with, studies were made under voltage variations of 10 V and 30 V with an electrode spacing of 185 mm. Biosurfactant with its producing microbes and biosurfactant free cells were introduced in the soil chamber after which the reactor was left to run for 10 days under the electric field. The technology was able to achieve the highest oil recovery of 75.15 % from the soil in 96 hours at 30 V. With other factors remaining constant, the reactor was also operated under a constant voltage of 30 V with configurations of fixed electrodes spacings of 335 mm, 260 mm,185 mm and continuous approaching electrodes at 335 mm, 260 mm and 185 mm. The current in the electrolyte was highest with the least electrode distance of 185 mm. The increase in current led to a direct proportional increase in the electroosmotic flow towards the cathode leading to increased coalescence of the oil from the soil as compared to the other electrode distances. The analysis of the results showed reduction in the total carbon content in the soil with viable oil recovery rates for all the electrode distances with 185 mm being the most effective in both oil recovery and degradation. The reactor was further operated with amended biosurfactant concentrations of 28 g/L, 56 g/L and 84 g/L to enhance the recovery of oil from the soil and aid in biodegradation of the remaining oil by hydrocarbon degrading microbes. The highest oil recovery of 83.15 % was obtained with the biosurfactant concentration of 56 g/L showing that the hyper increase in concentration of the biosurfactants is not necessary to have an efficient process. In all experiments the microorganisms were able to survive under the electro-halo-thermal environment in the reactor and degraded the remaining hydrocarbons to acceptable amounts in the environment. The bacteria were however affected by the constantly changing pH in all experiments. The presence of biosurfactants was so significant in aiding oil recovery and increasing bioavailability of hydrocarbons to the microbes. Production of biosurfactants in the reactor followed up by kinetic suggestions of the processes in the bioelectrokinetic reactor should be studied in future.
Dissertation (MEng)--University of Pretoria, 2019.
Environmental Engineering
MEng
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Chiewpattanakul, Paramaporn. "Isolation and structure elucidation of biosurfactant from microorganism and its application model in drug delivery system." Thesis, Vandoeuvre-les-Nancy, INPL, 2010. http://www.theses.fr/2010INPL004N/document.

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Des microorganismes produisant des molécules tensioactives ont été isolés à partir d’échantillons de sols contaminés par des huiles, en provenance des provinces de Songkhla et Chiangmai (Thaïlande) et de Shianghai (Chine). Les différentes souches ont été sélectionnées de façon à obtenir les biosurfactants ayant les meilleures propriétés tensioactives et d’émulsification. Parmi 102 souches isolées, 6 microorganismes produisaient des biosurfactants. La souche SK80 a conduit aux meilleures propriétés tensioactives. Des observations morphologiques macroscopiques et microscopiques ont permis de caractériser la souche SK80. L’analyse de la séquence ARNr 28S indique que cette souche appartient à la famille Exophiala Dermatitidis. La composition du milieu de culture (source de carbone et d’azote) et les conditions de culture de ce microorganisme ont été adaptées de façon à obtenir des quantités importantes de biosurfactant. Des analyses spectroscopiques (RMN 1H, RMN 13C, COSY et de masse, APCI MS) ont révélé que ce biosurfactant était un monooléate de glycérol. La monomyristine a été choisie comme constituent synthétique modèle dans des études d’encapsulation. Deux méthodes de préparation, émulsion/évaporation de solvant, nanoprécipitation, ont été employées pour encapsuler la monomyristine dans des nanoparticules recouvertes de dextrane et dont le cœur était constitué de poly(acide lactique) ou de dextrane hydrophobisé. Les conditions d’encapsulation ont été variées afin de maximiser le rendement d’encapsulation et la stabilité colloïdale des particules
Biosurfactant producing microorganisms were isolated from oil contaminated soils collected from Songkhla and Chiangmai province, Thailand and Shianghai, China. Their culture broths were screened for obtaining biosurfactants with the highest surface activity and emulsification ability. Among 102 isolates, 6 microorganisms produced biosurfactants. The culture supernatant of SK80 strain exhibited the highest surface activity. SK80 was identified by macroscopic morphology, microscopic morphology and showed that it is a black mold. The 28S rRNA sequence homology analysis suggested that SK80 belongs to Exophiala dermatitidis. The composition of culture medium such as carbon source, nitrogen source, and culture condition of this microorganism was optimized to obtain high amounts of biosurfactant. 1H NMR, 13C NMR, COSY and Mass Spectrometer (APCI MS) results indicated that this biosurfactant was monoolein (oleoyl glycerol), a kind of monoacylglycerol. Monomyristin was chosen as a monoacylglycerol model to be synthesized and used as nanoparticle encapsulated drug. Two preparation methods, emulsion/solvent evaporation and nanoprecipitation, were used to encapsulate monomyristin in dextran-covered nanoparticles with poly(lactic acid) of hydrophobized dextran as the core material. Encapsulation conditions were optimized with regard to the yield encapsulation and the colloidal stability

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Ochsner, Urs Arnold. "Genetics and biochemistry of Pseudomonas aeruginosa rhamnolipid biosurfactant synthesis /." [S.l.] : [s.n.], 1993. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10401.

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Chen, Minglei. "Surface and solution properties of biosurfactant and surfactant mixtures." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.669970.

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Crosman, John T. "Enhanced biosurfactant production using synchronous cultures of Corynebacterium alkanolyticum." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0003/MQ44001.pdf.

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Iroakasi, Ogonnaya Ijeoma. "Characterisation, optimisation and environmental application of selected biosurfactant producers." Thesis, University of Aberdeen, 2012. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=192235.

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Biosurfactants are produced by a variety of microorganisms most of which are bacteria. Their ability to reduce surface and interfacial tensions makes them suitable for environmental applications where hydrophobic compounds are concerned. The biodegradability and lower toxicity of biosurfactants compared to chemical surfactants is ecologically valuable. Four biosurfactant producing bacteria (Alcanivorax borkumensis DSM 11573, Bacillus subtilis DSM 3256, Bacillus licheniformis RS1, and Rhodococcus ruber DSM 43338) were investigated in this study. Their growth and biosurfactant producing profiles were studied. The Bacillus species produced exogenous biosurfactants which were extracted and identified as surfactin and lichenysin. The other isolates produced cell bound biosurfactants and were therefore selected for augmentation in hydrocarbon degradation. Bacterial bioluminescent biosensor derived quantitative structure activity relationships were employed as a tool to validate the suitability of the extracted biosurfactants as solvents for ecotoxicity assessment of hydrophobic organic compounds. The relationships obtained in biosurfactants and water did not differ (p > 0.05) and suggests that the biosurfactants did not compromise the performance of the biosensors. Remediation of diesel hydrocarbons by degraders in the presence of Alcanivorax borkumensis or Rhodococcus ruber was tested. Degradation was 5 and 3 times more effective with respiration rates 20 and 5 times higher in the presence of A. borkumensis and R. ruber respectively. The effect of biosurfactants on bioactivity in historically contaminated soils was evaluated using the extracted lichenysin. Bioactivity was improved in the presence of the biosurfactant. Bioactivity was correlated to biodegradation of hydrocarbons in a crude oil impacted soil amended with degraders, biosurfactant producers and a chemical dispersant (p < 0.001). The lowest CFU counts for heterotrophs and degraders were observed for the chemical dispersant. The results from this study further highlight the value of biosurfactants for environmental application. Improvement in production is necessary to encourage widespread commercial application of biosurfactants.

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Winterburn, James. "Production of biosurfactant by fermentation with integral foam fractionation." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/production-of-biosurfactant-by-fermentation-with-integral-foam-fractionation(e4bd51dc-f31f-468a-81d4-d1a512d7b5a2).html.

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Biosurfactants are naturally occurring amphiphiles with potential for use as alternatives to traditional petrochemical and oleochemical surfactants. The unique properties of biosurfactants, including their biodegradability and tolerance of a wide range of temperature and pH, make their use in a range of novel applications attractive. Currently the wider ultilisation of biosurfactants is hindered by a lack of economically viable production routes, with downstream processing presenting a significant challenge. This thesis presents an investigation into the production of HFBII, a hydrophobin protein, using an adsorptive bubble separation technique called foam fractionation for in situ recovery of the biosurfactant. The effects of foaming on the production of HFBII by fermentation were investigated at two different scales. Foaming behaviour was characterised in standard terms of the product enrichment and recovery achieved. Additional specific attention was given to the rate at which foam, product and biomass overflowed from the fermentation system in order to assess the utility of foam fractionation for HFBII recovery. HFBII was expressed as an extracellular product during fed batch fermentations with a genetically modified strain of Saccharomyces cerevisiae, which were carried out with and without antifoam. In the presence of antifoam HFBII production is shown to be largely unaffected by process scale, with similar yields of HFBII on dry matter obtained. More variation in HFBII yield was observed between fermentations without antifoam. In fermentations without antifoam a maximum HFBII enrichment in the foam phase of 94.7 was measured with an overall enrichment of 54.6 at a recovery of 98.1%, leaving a residual HFBII concentration of 5.3 mg L-1 in the fermenter. It is also shown that uncontrolled foaming reduced the concentration of biomass in the fermenter vessel, affecting total production. This series of fermentation experiments illustrates the potential for the application of foam fractionation for efficient in situ recovery of HFBII, through simultaneous high enrichment and recovery which are greater than those reported for similar systems. After the suitability of foam fractionation was demonstrated a novel apparatus design was developed for continuously recovering extracellular biosurfactants from fermenters. The design allows for the operating conditions of the foam fractionation process, feed rate and airflow rate, to be chosen independently of the fermentation parameters. Optimal conditions can then be established for each process, such as the aeration rate required to meet the biological oxygen demand of the cell population. The recirculating foam fractionation process was tested on HFBII producing fermentations. It is shown that by using foam fractionation to strip HFBII from fermentation broth in situ the amount of uncontrolled overflowing from the fermenter was greatly reduced from 770.0 g to 44.8 g, compared to fermentations without foam fractionation. Through optimisation of the foam column operating conditions the proportion of dry matter retained in the fermenter was increased from 88% to 95%, in contrast to a dry matter retention of 66% for fermentation without the new design. With the integrated foam fractionation process a HFBII recovery of 70% was achieved at an enrichment of 6.6. This work demonstrates the utility of integrated foam fractionation in minimising uncontrolled foaming in fermenters whilst recovering an enriched product. This integrated production and separation process has the potential to facilitate improved biosurfactant production, currently a major barrier to their wider use.

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PUELLES, JHONATAN GERARDO SOTO. "HEMATITE FLOTATION USING A CRUDE BIOSURFACTANT EXTRACTED FROM RHODOCOCCUS OPACUS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=29688@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
FUNDAÇÃO DE APOIO À PESQUISA DO ESTADO DO RIO DE JANEIRO
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
BOLSA NOTA 10
A bioflotação é definida como um processo de separação, através do qual o mineral de interesse é flotado ou deprimido seletivamente, utilizando os reagentes de origem biológica, também conhecidos como bioreagentes. Estas substâncias são caracterizadas por possuírem uma química verde, seletividade e potencial para tratar a partículas finas. Neste sentido, o objetivo principal da pesquisa é a avaliação de um biosurfactante não refinado extraído da bactéria Rhodococcus opacus na flotação de hematita. Na primeira fase, foi desenvolvido um protocolo para a extração dos biosurfactantes intracelulares e aqueles associados a parede celular da bactéria. Mediante extração com etanol a 121 graus celsius e 2 atm, as substâncias anfifílicas foram liberadas e solubilizadas. A recuperação média de biosurfactante não refinado foi de 0,3 g por dm cubico. A caracterização por FTIR identificou grupos álcool (menos OH), cetona (C igual O) e cadeias de carbono saturadas e insaturadas. Que podem compor os mycolatas e trehalolipideos que são encontrados na parede celular da bacteria. Por estudos eletroforéticos encontrou-se umPIE de 7,5 e um PZC em torno de 7,6. Aplicando o modelo Gouy-Chapman e o modelo misto de Gouy Chapman e o capacitor de placas, foi possível estudar o efeito do biosurfactante no comportamento eletrostático das partículas de hematita. Predizendo como elas foram se tornando hidrofóbicas em valores de pH ácido e como sua flotabilidade diminuía em pH básicos, após interação com o biosurfactante. Finalmente, foi testado o biosurfactante e a própria bactéria em ensaios de microflotação de hematita, resultando o primeiro na melhora na flotabilidade de hematita. Os resultados mostraram uma boa afinidade e baixo consumo de reagente.
Bioflotation is defined as a separation process by which the mineral of interest is floated or depressed selectively, using reagents of biologic origin also known as bioreagents. These substances are characterized by their green chemistry, selectivity and potential to treat fine particles. Currently they are been studied with the expectative of substitute the synthetic reagents used in the mineral flotation processes. Between the diverse microorganisms, the hydrophobic bacteria Rhodococcus opacus has been studied as biofrother and biocollector in hematite flotation. In that sense, the research s principal objective is the assessment of the hematite floatability using a crude biosurfactant extracted from the bacteria Rhodococcus opacus and consequently determine its potential as an alternative against synthetic reagents or the bacteria itself. In a first stage, it was developed a protocol for the extraction of cell associated and intracellular biosurfactants from the bacteria. Throughout ethanol extraction at 121 degrees centigrade and 2 atm, the cell associated substances where released and solubilized. The average crude biosurfactant recovery was around 0.3 g per L of broth. Characterization by FTIR identified alcohol (minus OH) and ketone (C equal O) groups as well as saturated and unsaturated carbon chains. Which may compose the mycolates and trehalolopids that are found in the cellular wall of the genera Rhodococci. Electrophoretic studies of the hematite sample, before BS interaction, found an IEP around a pH of 7.5 and a PZC at pH 7.6. Applying the Guoy-Chapman model and the mixed model of Guoy Chapman and the plate capacitor, it was possible to study the effect of the biosurfactant onto the electrostatic behavior of the hematite particles. The model predicted the hydrophobicity of the modified hematite at acid pH. Finally it was tested the crude biosurfactant against the bacteria itself in microflotation tests, resulting the first one in an improved hematite floatability. The results showed a high affinity of the crude biosurfactant for hematite particles and relatively low reagent consumption.

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Ukwungwu, S. V. "Investigation into the impact of biosurfactant in heavy oil reservoirs." Thesis, University of Salford, 2017. http://usir.salford.ac.uk/43942/.

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Exploitation of oil resources in mature reservoirs is essential for meeting future energy demands. Despite the primary and secondary oil recovery, significant amount of residual oil is still left behind in the reservoir, necessitating tertiary recovery methods. These typically includes surfactant flooding, polymer flooding, Microbial Enhanced Oil Recovery (MEOR) etc. To exemplify the potential of microorganisms to degrade heavy crude oil to reduce its viscosity, is part of a process known as MEOR. In recent times surfactants produced by microbes have gained wider acceptability in the petroleum industry due to their low toxicity and ease with which they are naturally broken down in the environment. Petrochemical-based synthetic surfactants are currently used in substantial amounts to increase recovery of hydrocarbons, and these surfactants are more recalcitrant in the environment. The present study therefore, uses a technique to utilise microbes that will economically achieve a scale of Enhanced Oil Recovery (EOR) through biosurfactant production, lowering of interfacial tension (IFT) and contact angle, changes in rock wettability of sandstone grains and biosurfactant flooding. Three biosurfactants were produced under laboratory conditions, from three species of the genus bacillus using sucrose 3% (w/v) as their carbon source for growth and metabolism. These species produced biosurfactants of different specific activities that resulted in different impacts on IFT and contact angle. The biosurfactants produced are BS-1, BS-2 & BS-3. After applying the cell-free extracellular biosurfactants to the system, the results show that there is reduction in interfacial tension from 56.95 mN/m to 4.49 mN/m, 6.69 mN/m, and 10.94 mN/m. Also, the contact angle of the oil film was significantly reduced from 147.04° to 111.84°, when the cell-free extracellular biosurfactant (BS-2) was applied to the system. Qualitative wettability tests were also performed on the sandstone crushed rock samples, which shows that, the spent culture medium changes wettability of the grains to water-wet and intermediate-wet. It should be noted that the decomposition property of sucrose as a carbon source makes it eco-friendly for biosurfactant production. The biosurfactant flooding also found to have a recovery of 38% (an interval of nominally 8%) against 30% water flooding, due to the development of a water-wet state, which was achieved by flooding the core with 5PV of BS-2 supernatant solution. Economic analysis was also considered in determining the possible profitability of the corresponding MEOR method with addition of biosurfactant costs that were utilised during this study. The case study results of these analysis show that the cumulative cashflow, indicated a payback period of 2.54 years for a capital investment of $45.32 million, given a typical oil production of 2,720 barrel per day. Moreover, with this type of biosurfactant (BS-2) supernatant, it has become evident that there can be an enhance recovery in the heavy oil reservoir by changing the wettability of rock grains. This thus, provides new tools for use in EOR schemes that leads to promising environmental sustainability.

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Seyrig, Chloé. "Structures biosurfactant-biopolymère auto-assemblées capables de répondre aux stimuli." Electronic Thesis or Diss., Sorbonne université, 2021. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2021SORUS487.pdf.

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Les systèmes polymère-tensioactif ont de nombreuses applications dans la vie de tous les jours, mais leur origine pétrochimique est aujourd’hui controversée. Dans une démarche plus respectueuse de l’environnement, des systèmes biopolymère-biotensioactif seraient une alternative intéressante. Il existe en effet une grande famille de molécules biosourcées, certaines produites par fermentation microbienne, possédant un fort potentiel, cependant aujourd’hui limité, leur comportement en solution n’étant pas encore clairement établi. Le LCMCP a développé une expertise sur ce point, et le but de ces travaux de thèse est dans un premier temps d’étudier en conditions diluées le diagramme de phase de deux biotensioactifs dont l’auto-assemblage dépend du pH en présence de biopolymères. Il en résulte que des coacervats complexes sont formés à pH basique dans les deux cas (biotensioactifs sous forme micellaire), tandis qu’à pH acide l’interaction est soit perturbée quand le biotensioactif se réorganise en fibres, soit maintenue si celui-ci évolue vers une phase vésiculaire, donnant lieu à la formation de structures multilamellaires. Ces dernières se sont avérées prometteuses pour l’encapsulation de molécules modèles, notamment la curcumine, aux nombreuses applications thérapeutiques. Stables en milieu biologique, elles permettent le relargage de la curcumine qui peut exercer son activité, notamment anti-cancéreuse. Dans un deuxième temps, dans des conditions plus concentrées, les effets des différentes phases du biotensioactif sur les propriétés mécaniques de gels de biopolymère ont été étudiés. La phase fibrillaire renforce le gel d’une part, et le gel hybride possède des propriétés modulables en fonction du pH et/ou de la température d’autre part
Polymer-surfactant systems have many applications in everyday life, but their petrochemical origin is currently controversial. In a more environmentally friendly approach, biopolymer-biosurfactant systems would be an interesting alternative. Indeed, there exists a large family of biobased molecules, including ones produced by yeast fermentation, which possess a huge potential, however currently limited as their behavior in solution is not clearly established yet. LCMCP has developed an expertise on this point, and the goal of this work in first to study in dilute conditions the phase diagram of two biosurfactants of which self-assembly depends on pH, in presence of biopolymers. It results that complex coacervates are formed at basic pH in both cases (biosurfactants within their micellar state), while at acidic pH interaction is either disturbed when the biosurfactant reorganizes into fibers, or maintained if this one evolves towards a vesicular phase, forming multilamellar structures. These latter were found promising for the encapsulation of model drug molecules, especially curcumin which has various therapeutic applications. Stable in biological environment, they allow the release of curcumin which can exercise its activity, especially against cancer. Secondly, in more concentrated conditions, the effect of the different biosurfactant’s phases on the mechanical properties of biopolymer’s hydrogels were studied. The fibrillar phase reinforce the gel on a hand, and the hybrid gel possess properties which can be tuned by pH and/or temperature on another hand

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Lebron-Paler, Ariel. "Solution and Interfacial Characterization of Rhamnolipid Biosurfactant from P.aeruginosa ATCC 9027." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/193778.

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Rhamnolipid biosurfactants are investigated to determine their role in biological processes, and for discovery of novel, more biocompatible applications in areas related to medicine, agriculture, and environment. Fundamental understanding of the physical and chemical properties of rhamnolipids is needed. Thus, systematic studies on solution and interfacial properties on rhamnolipids from P.aeruginosa ATCC 9027 were undertaken. A purification protocol was developed and a thorough qualitative and quantitative speciation analysis was performed with high performance liquid chromatography-mass spectrometry (HPLC-MS), nuclear magnetic resonance (NMR) spectroscopy and HPLC with evaporative light scattering detection (ELSD). Acid-base properties of the mixture of 30 monorhamnolipid congeners, including both saturated and unsaturated species, were characterized at concentrations below and above the CMC at fixed ionic strength using potentiometry and attenuated total reflectance-Fourier transform infrared (ATRFTIR) spectroscopy. A pKₐ of 4.3 was found for concentrations below 50 μM and a pKₐ of 5.6 above 100 μM. The pKₐ is dictated by aggregation in solution. Molecular areas of monorhamnolid monolayers at the air-water interface are strongly influenced by protonation state, and increase from 31 to 109 Å²/molecule as pH increases from 4 to 8.5 and as ionic strength decreases. Adsorption isotherms of monorhamnolipids on γ-Al₂O₃ were investigated as a function of pH using ATR-FTIR spectroscopy and Frumkin model fits, from which K(ads) values of 1.20 (± 0.10) x 10⁵ M⁻¹ at pH 4.0, 2.14 (± 0.51) x 10⁴ M⁻¹ at pH 6.3 and 1.31 (± 0.09) x 10³ M⁻¹ at pH 8.6 were obtained. Interaction parameters were positive at all pH values. Cooperative adsorption is driven by hydrophobic interactions (physisorption) at any pH including hydrogen bonding and electrostatic interactions. Chemisorption was also observed at high pH values. Formation constants for monorhamnolipid-Pb²⁺ and monorhamnolipid-Cd²⁺ complexes were determined using differential pulse polarography in the low μM concentration range. A modified Lingane equation was developed to account for monorhamnolipid adsorption on the Hg surface. β values for adsorbed metal complexes are ~10^3.2 and ~10^0.8 for Pb²⁺ and Cd²⁺, respectively, compared to previously published β values of 10^8.58 and 10^6.89, respectively. Evidence for 1:1 and 2:1 monorhamnolipid-metal complexes was provided by electrospray ionization-mass spectrometry.

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Arroua, Boussad. "Caractérisation des interactions entre les bactéries de réservoirs pétroliers et les interfaces eau-hydrocarbures-roche." Thesis, Pau, 2016. http://www.theses.fr/2016PAUU3053/document.

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La récupération assistée des hydrocarbures par des microorganismes (MEOR) est une technologie potentiellement utilisable pour améliorer l’efficacité de l’extraction pétrolière. Cette technique utilise les capacités métaboliques de certaines souches bactériennes pour récupérer les huiles des réservoirs. Cependant, le manque de connaissances sur la physiologie et les activités métaboliques des microorganismes des réservoirs est un obstacle majeur pour le développement de cette approche. L’objectif de ce travail était d’étudier la physiologie des microorganismes indigènes de réservoirs pétroliers, en déterminant leurs capacités métaboliques, leurs conditions de croissances et leur positionnement taxonomique. Pour cela, trois activités physiologiques d’intérêt pour la MEOR : (1) la dégradation de l’hexadécane ;(2) la production de biosurfactant et (3) la formation de biofilm ont été évaluées sur 84 souches bactériens anaérobies isolées exclusivement de plusieurs réservoirs pétroliers. Ces isolats appartiennent à deux groupes métaboliques : les bactéries sulfato-réductrices (BSR) et les anaérobies fermentaires. Ainsi, cette prospection à donner une image de la diversité des souches de réservoirs possédant des activités appropriées pour la MEOR. Le séquençage et l’analyse phylogénétique du gène codant pour L’ARNr 16S a permet d’identifier deux nouvelles espèces bactériennes d’anaérobies fermentaires, SRL 4223 et SRL 4209 capables de produire des biosurfactants. Ainsi la caractérisation de ces deux isolats a révélé que la souche SRL 4223 présentait toutes les caractéristiques phénotypiques et génétiques autorisant sa classification un nouveau genre nommé Pleomorphochaeta caudata et que la souche SRL 4209 peut être affilié comme une nouvelle espèce de ce nouveau genre
The Microbial enhanced oil recovery (MEOR) is a potentially useful technology to improve the efficiency of oil extraction. This technique utilizes microorganisms and/or their metabolites (biosurfactants, polymers, biomass…etc.) to recover oil from reservoirs. However, the lack of basic knowledge about physiology and metabolic capacities of reservoir microorganisms is a major obstacle for the development of this approach. The objective of this work was to study the physiology of indigenous reservoir microorganisms by determining their metabolic capacities, their growth conditions and their taxonomic position. For this, three activities related to MEOR: (1) hexadecane degradation; (2) biofilm formation and (3) biosurfactant production were evaluated on 84 anaerobic bacterial strains isolated exclusively from several petroleum reservoirs. These isolates belong to two metabolic groups: sulfate-reducing bacteria (SRB) and anaerobic fermentative bacteria. This study gives a picture of the diversity of indigenous strains possessing proper activities for MEOR. Sequencing and phylogenetic analysis of 16S rRNA gene identified two new species of fermentative bacteria: SRL 4223 and SRL 4209, capable of producing biosurfactants. Characterization of these isolates revealed that the strain SRL 4223 had all the phenotypic and genetic characteristics allowing its classification as a new genus named Pleomorphochaeta caudata and the strain SRL 4209 was affiliated as a new species of this genus

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Davis, Daniel. "A study of nitrogen metabolism and lipopeptide biosurfactant production by Bacillus species." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394224.

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ROSARIO, LISA MARINHO DO. "BIOFLOTATION OF APATITE: COMPARATIVE ANALYSIS BETWEEN RHODOCOCCUS ERYTHROPOLIS STRAIN AND ITS BIOSURFACTANT." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2017. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=36393@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
O principal método de beneficiamento da rocha fosfática para concentração da apatita é a flotação. A flotação da apatita com baixo teor costuma utilizar surfactantes sintéticos, que apesar de caros apresentam boa seletividade. A fim de reduzir custo sem perder eficiência, surgiram pesquisas com o intuito de substituir estes surfactantes convencionais por biossurfactantes. Esta rota de bioprocessamento mineral revela-se atrativa sob o aspecto comercial, visto que além de apresentar baixo custo é ambientalmente aceitável, pois ao utilizar microrganismos não patogênicos cria-se uma nova classe de reagentes biodegradáveis, modificando o cenário da flotação convencional. Este trabalho tem como objetivo avaliar o uso da estirpe bacteriana Rhodococcus erythropolis e do biossurfactante extraído desta na bioflotação da apatita. Foram realizados ensaios de bioflotação utilizando tubo de Hallimond, na faixa de pH entre 3 e 11, faixa granulométrica da apatita entre 75 e 106 micrômetros, com solução de 10(-3)M de NaCl, diferentes concentrações dos biorreagentes e tempo de flotação igual a 2, 5 e 7 minutos. O biossurfactante apresentou melhor desempenho, quando comparado com a biomassa. Em todos os casos, observou-se um incremento da flotabilidade em valores de pH menor que 7, no entanto, a maior flotabilidade apresentou-se em pH igual a 4 com a utilização de 140 mg/L de biossurfactante.
The main method of processing phosphate rock, for apatite concentration, is flotation. The flotation of apatite with low content usually uses synthetic surfactants, which are expensive, but present good selectivity. In order to reduce costs without losing efficiency, research has emerged with the purpose of replacing these conventional surfactants by biosurfactants. This mineral bioprocessing route is attractive in the commercial aspect, since low cost and environmentally friendly, when using non-pathogenic microorganisms, creating a new class of biodegradable reagents and modifying the conventional flotation scenario. This work aims to evaluate the use of bacterial strain Rhodococcus erythropolis and the biosurfactant extracted from in apatite bioflotation. Bioflotation tests were performed using a Hallimond tube in the pH range of 3 to 11, apatite granulometric range between 75 and 106 micrometers in a solution of 10(-3)M NaCl, different concentrations of the bioreagents and flotation time equal to 2, 5 and 7 minutes. The biosurfactant presented better performance, recovering more apatite than the biomass. In all cases an increase in flotability was observed at pH bigger than 7, however, the highest flotability was at pH to be 4 with 140 mg/L of biosurfactant.

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Domingues, Patrícia Maia. "Subaquatic sediments as sources of hydrocarbonoclastic and biosurfactant producing facultative anaerobic bacteria." Doctoral thesis, Universidade de Aveiro, 2018. http://hdl.handle.net/10773/22847.

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Doutoramento em Engenharia Química
Actualmente são conhecidas poucas estirpes bacterianas capazes de produzir biossurfactantes (BSFs) em condições de microaerobiose ou anaerobiose. Estas bactérias têm um papel importante não só em processos naturais (ex. formação de biofilmes ou de hidratos de gás), como podem ter diversas aplicações biotecnológicas (ex. estratégias de biorremediação e aplicações industriais). As bactérias produtoras de BSFs em condições de limitação de oxigénio, com capacidade para degradar hidrocarbonetos são de particular interesse para estratégias de biorremediação de locais contaminados com hidrocarbonetos de petróleo (PHs) e na recuperação microbiana de petróleo (MEOR). Neste contexto, o objectivo deste trabalho foi o isolamento, identificação e a caracterização de bactérias anaeróbias ou anaeróbias facultativas produtoras de BSF e degradadoras de hidrocarbonetos (hidrocarbonoclásticas) na perspetiva da sua aplicação biotecnológica em condições de limitação de oxigénio. Foram escolhidos dois ambientes contaminados com PHs como potenciais fontes de bactérias hidrocarbonoclásticas produtoras de BSFs: vulcões de lama (MV) de mar profundo do Golfo de Cádis (Oceano Atlântico) e o sistema estuarino da Ria de Aveiro (Portugal). Foram preparadas culturas de enriquecimento com sedimentos subaquáticos recolhidos nestes dois habitats, como potenciais inóculos de bactérias anaeróbias facultativas. Um design experimental fatorial foi usado para testar o efeito do crude como fonte de carbono, e de nitrato e/ou sulfato, como aceitadores terminais de eletrões. De forma a melhor compreender a estrutura das comunidades bacterianas envolvidas na biodegradação de PHs nos MV do mar profundo procedeu-se à sequenciação do gene 16S rRNA das comunidades bacterianas de culturas de enriquecimento com sedimento de dois MVs, um activo e outro inactivo, e com ou sem adição de crude e/ou nitrato. Detetou-se uma diferenciação entre as comunidades dos dois MVs, independentemente dos suplementos a que as culturas foram expostas, sendo que Alphaproteobacteria e Bacilli predominaram nas culturas com sedimentos de MV activo e inactivo, respectivamente. De uma forma menos acentuada, tanto o nitrato como o crude afetaram a composição das comunidades bacterianas. Géneros de bactérias que só foram detectados nos ensaios com adição de crude (ex. Erythrobacteraceae no MV activo e Acidimicrobiale no MV inactivo) poderão ser usados como indicadores da presença de hidrocarbonetos de petróleo nestes habitats. A biodegradação de PHs nas culturas com crude foi avaliada por cromatografia gasosa acoplada a espectrometria de massa. De uma forma geral, as comunidades de culturas do MV activo foram capazes de degradar n-alcanos de tamanho inferior a C13 e compostos monoaromáticos, enquanto as comunidades do MV inactivo apresentaram a capacidade de metabolizar vários tipos de hidrocarbonetos aromáticos policíclicos. A presença de nitrato apenas afectou positivamente a biodegradação de alcanos, e não teve efeito ou foi mesmo inibitória da biodegradação de outros hidrocarbonetos. A partir de todas as culturas, com todos os tipos de sedimentos, dos MVs do Golfo de Cádis e do estuário da Ria de Aveiro, foi possível isolar-se um total de 13 isolados capazes de sobreviver exclusivamente com crude como fonte de carbono e produzir BSF em condições de aerobiose. Destas, apenas duas não foram capazes de produzir BSFs em anaerobiose. A sequenciação do gene 16S rRNA dos isolados permitiu identifica-los como pertencendo aos géneros Pseudomonas, Bacillus, Ochrobactrum, Brevundimonas, Psychrobacter, Staphylococcus, Marinobacter e Curtobacterium, a maioria dos quais não tinha ainda membros conhecidos como produtores de BSF em anaerobiose. Os resultados obtidos com este trabalho permitiram caracterizar melhor as comunidades envolvidas na degradação de PHs em MVs de mar profundo. Conseguiu-se ainda isolar e identificar estirpes, tanto de mar profundo como de ambiente estuarino, capazes de degradar PHs e produzir BSFs em condições de anaerobiose. Estas estirpes apresentam elevado potencial biotecnológico para aplicações como MEOR e biorremediação em ambientes com escassez de oxigénio.
So far, only few bacterial strains are known to produce biosurfactants (BSFs) under microaerobic or anaerobic conditions. However, these bacteria are not only involved in important natural processes (e.g. biofilm and gas hydrates formations) but can also be used in several biotechnological applications (e.g. bioremediation strategies and industrial applications). Bacteria able to produce BSFs under oxygen-limiting conditions that are also able to degrade hydrocarbons, are of particular interest to bioremediation strategies of sites contaminated with petroleum hydrocarbons (PHs) and microbial enhanced oil recovery (MEOR) strategies. In this context, this work aims at isolating, identifying, and characterizing BSF-producing and hydrocarbon-degrading (hydrocarbonoclastic) bacteria grown under anaerobic conditions, which can be used in biotechnological applications under oxygen limitation. Two environments contaminated with PHs were chosen as potential sources of hydrocarbonoclastic BSF-producing bacteria: deep-sea mud volcanos from the Gulf of Cadiz (Atlantic Ocean), and the estuarine system of Ria de Aveiro (Portugal). Enrichment cultures were prepared using subaquatic sediments from both sites, as potential sources of facultative anaerobic bacteria. A factorial experimental design was used to test the effect of crude oil as carbon source, and nitrate and/or sulfate, as terminal electron acceptors. Aiming at better understanding the structure of bacterial communities involved in PHs biodegradation at deep-sea MVs, sequencing of the 16S rRNA gene was performed for bacterial communities from cultures containing sediments from two MVs, active and inactive, and with or without crude oil and/or nitrate. A distinction between the communities of MVs with different activity, independent of the supplements was observed. Alphaproteobacteria and Bacilli were the predominant classes found in enrichment cultures inoculated with active and inactive MVs sediments, respectively. In a minor scale, nitrate and crude oil additions also affected the composition of bacterial communities. Therefore, genera that only appeared in cultures with crude oil. (e.g. Erythrobacteraceae in active MV cultures and Acidimicrobiale in inactive MV cultures) can be used as biosensors of the presence of PHs in these habitats. Biodegradation of PHs in cultures containing crude oil was assessed by gas chromatography coupled with mass spectrometry. Overall, communities from active MV cultures were able to degrade n-alkanes below C13 and monoaromatic hydrocarbons, while communities from inactive MV cultures presented the ability to metabolize several types of polycyclic aromatic hydrocarbons. The presence of nitrate only had a positive effect on the biodegradation of alkanes, and had no effect or even an inhibitory effect on the biodegradation of other hydrocarbons. A total of 13 isolates able to survive on crude as carbon source and produce BSF under aerobic conditions were obtained from all cultures either from sediments of the Gulf of Cadiz MVs or the estuarine system of Ria de Aveiro. Only two isolates failed to produce BSF under anaerobiosis. Sequencing of 16S rRNA gene was used to establish the identification of isolates as Pseudomonas, Bacillus, Ochrobactrum, Brevundimonas, Psychrobacter, Staphylococcus, Marinobacter and Curtobacterium. Most of these genera had never been described as able to produce BSFs under anaerobic conditions. The results obtained in this work allowed to better characterize the deep-sea communities involved in PHs degradation, as well as, to identify strains from deep-sea and estuarine sediments able to degrade PHs and produce BSFs under anaerobic conditions. These bacteria present high biotechnological potential for applications in oxygen-limiting environments, such as, MEOR and bioremediation of environments contaminated with PHs.

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25

Hogan, David E., and David E. Hogan. "Biosurfactant (Monorhamnolipid) Complexation of Metals and Applications for Aqueous Metalliferous Waste Remediation." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/623071.

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Biosurfactants are compounds that exhibit surface activity (e.g., reduce surface and interfacial tension) and are derived from natural, biological sources. They are considered green substances due to their natural derivation, biodegradability, and relatively low toxicity. Biosurfactants from multiple classes have been shown to interact with metals, and a review of these interactions is provided. Rhamnolipids produced by Pseudomonas aeruginosa are attracting attention for metal remediation applications. The purpose of this dissertation is to evaluate rhamnolipids' ability to complex rare earth elements, determine the environmental compatibility of novel rhamnolipid diastereomers, and assess the efficacy of rhamnolipid as a collector in ion flotation. Previous research shows rhamnolipids selectively bind elements of environmental concern over common soil and water cations, but there had been no examination of transition metals from the f-block of the periodic table. The f-block elements include the rare earth elements, which are a vital component of nearly every modern technology and subject to supply risk. The interaction between monorhamnolipids and the rare earth elements was investigated by determining conditional stability constants using a resin-based ion exchange method. For the 27 metals examined, the conditional stability constants could be divided into three groups, albeit somewhat subjectively: weakly, moderately, and strongly bound. UO22+, Eu3+, Nd3+, Tb3+, Dy3+, La3+, Cu2+, Al3+, Pb2+, Y3+, Pr3+, and Lu3+are strongly bound with conditional stability constants ranging from 9.82 to 8.20; Cd2+, In3+, Zn2+, Fe3+, Hg2+, and Ca2+ are moderately bound with stability constants ranging from 7.17 to 4.10; and Sr2+, Co2+, Ni2+, UO22+, Cs+, Ba2+, Mn2+, Mg2+, Rb+, and K+ are weakly bound with stability constants ranging from 3.95 to 0.96. The uranyl ion is reported twice due to the ion demonstrating two distinct binding regions. The conditional stability constants were demonstrated to be an effective predictor of metal removal order. The metal parameters of enthalpy of hydration and ionic charge to radius ratio were shown to be determinants of complexation strength. Naturally produced rhamnolipids are a mixture of congeners. Synthetic rhamnolipid synthesis has recently enabled production of four monorhamnolipid diastereomers of a single congener. The biodegradability, acute toxicity (Microtox assay), embryo toxicity (Zebrafish assay), and metal binding capacity of the diastereomers was investigated and compared to natural monorhamnolipid. Biodegradability testing showed all the diastereomers were inherently biodegradable. By the Microtox assay, all of the monorhamnolipids were categorized as slightly toxic by Environmental Protection Agency ecotoxicity categories. Out of 22 parameters tested, the zebrafish toxicity assay showed only diastereomer toxicity for the mortality parameter, except for diastereomer R,R which showed no toxic effects. All the monorhamnolipids interacted with both Cd2+ and Pb2+. Ion flotation is one possible technology for metal recovery and remediation of metal contaminated waters. Ion flotation utilizes charged surfactants to collect and concentrate non-surface active ions at the surface of an aerated solution. Rhamnolipid's suitability as a collector in ion flotation was investigated. A flotation column was designed to test monorhamnolipid efficacy as a collector. Monorhamnolipids form foams and effectively remove Cs+, Cd2+, and La3+ from solution. The efficacy of the flotation process relies on the collector:colligend ratio and valency of the colligend. Flotation of metal solutions showed a removal order of Cd2+>La3+>>Cs+ when the metals were present individually and mixed at equimolar concentrations. When mixed at order of magnitude different concentrations, the flotation order was Cd2+>>Cs+>>La3+. These studies show rhamnolipid has potential to be used for environmentally-compatible metal recovery and metalliferous water remediation, especially for the rare earth elements.

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26

Zhang, Lin. "Effects of Fatty Acid Substrates on Rhamnolipid (Biosurfactant) Biosynthesis and Congener Distribution." Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/203031.

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Rhamnolipids are surface-active molecules produced by Pseudomonas aeruginosa as congener mixtures. They are considered “green” alternatives to synthetic surfactants used in many applications. Optimizing yield and controlling congener distribution are necessary steps for successful commercialization. Studies have noted that vegetable oils, composed of a mixture of fatty acids, increase rhamnolipid yield. The physiological explanation for this is not yet understood. Furthermore the exact effects of various fatty acid components in the oils on rhamnolipid production have not been reported. The first part of the dissertation was to investigate rhamnolipid biosynthesis when fatty acid substrates are present. A combination of stable isotope tracing and gene expression assays were used to identify rhamnolipid lipid precursors and potential lipid metabolic pathways used in rhamnolipid synthesis. Result suggests that an octanoyl-CoA intermediate of β-oxidation is diverted from β-oxidation to de novo fatty acid synthesis via a “bypass route”, and is incorporated into either a 2-carbon or a 4 carbon β-ketoacyl- ACP, which can then be recognized by the RhlA enzyme for the biosynthesis of rhamnolipid lipid moiety. The second part of the dissertation focuses on studying how fatty acid substrates of different chain length (C₁₂ to C₂₂) and saturation (C(18:1) and C(18:2)) affect rhamnolipid yield, carbon conversion rate, and congener distribution. Results showed that stearic acid significantly increased rhamnolipid yield. A positive linear correlation between the mass percent of stearic acid used and the carbon conversion rate was observed. For all treatments, the RhaC₁₀C₁₀ was the most abundant and RhaC₁₀C(12:1) was the least abundant of the major congeners produced. However, the relative amounts of RhaC₁₀C₈ and RhaC₁₀C₁₂ congeners were dependent on several factors. In general, fatty acid substrates with relatively short chain length (C₁₂ and C₁₄), the unsaturated fatty acid C(18:2), and longer cultivation times resulted in a higher RhaC₁₀C₈/ RhaC₁₀C₁₂ ratio. The studies presented here demonstrate that the medium composition, in particular the organic substrate component, can affect rhamnolipid biosynthesis, yield, and congener distribution. Furthermore, this work presents evidence that C₁₈ fatty acids as co-substrates increase rhamnolipid yield by draining rhamnolipid intermediates directly from the β-oxidation pathway.

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27

Mpentshu, Yolanda Phelisa. "Biosurfactant producing biofilms for the enhancement of nitrification and subsequent aerobic denitrification." Thesis, Cape Peninsula University of Technology, 2018. http://hdl.handle.net/20.500.11838/2842.

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Thesis (Master of Engineering in Chemical Engineering)--Cape Peninsula University of Technology, 2018.
Wastewater treatment methods have always gravitated towards the use of biological methods for the treatment of domestic grey water. This has been proven to offer a series of advantages such as the reduction of pollution attributed to the use of synthetic chemicals; therefore, this decreases the requirement of further costly post primary treatment methods. Although such biological methods have been used for decades, their efficiency and sustainability has always been challenged by inhibitory toxicants which renders the systems redundant when these toxins are prevalent in high concentrations, culminating in the deactivation of biomass which facilitates the treatment. In most instances, this biomass is anaerobic sludge. Hence, the proposal to utilize biofilms which are ubiquitous and selfsustaining in nature. The use of engineered biofilms in wastewater treatment and their behaviour has been studied extensively, with current research studies focusing on reducing plant footprint, energy intensity and minimal usage of supplementary synthetic chemicals. An example of such processes include traditional nitrification and denitrification systems, which are currently developed as simultaneous nitrification and aerobic denitrification systems, i.e. in a single stage system, from the historical two stage systems. However, there is limited literature on biofilm robustness against a potpourri of toxicants commonly found in wastewater; particularly for total nitrogen removal systems such as simultaneous nitrification and denitrification (SND). This study was undertaken (aim) to assess the ability of biosurfactant producing biofilms in the removal of total nitrogen in the presence of toxicants, i.e. heavy metals and phenol, as biosurfactants have been proven to facilitate better mass transfer for pollutant mitigation. Unlike in conventional studies, the assessment of biosurfactant producers in total nitrogen removal was assessed in both planktonic and biofilm state. Since biofilms are known to have increased tolerance to toxic environmental conditions, they were developed thus engineered using microorganisms isolated from various sources, mainly waste material including wastewater as suggested in literature reviewed, to harness microorganisms’ possessing specified traits that can be developed when organisms are growing under strenuous environments whereby they are tolerant to toxic compounds. The assessment of these engineered biofilms involved the development from individual microorganisms to form biofilms in 1L batch reactors where the isolated microorganisms were grown in basal media containing immobilisation surfaces. The assessment of the total nitrogen efficiency was conducted using Erlenmeyer flasks (500mL) in a shaker incubator, with the biofilm TN removal efficiency being assessed in batch systems to ascertain simultaneous nitrification and denitrification rates even in the presence of heavy metals (Cu2+, Zn2+) and C6H5OH. Ambient temperature and dissolved oxygen conditions were kept constant throughout the duration of biofilm development with microorganisms (initially n = 20) being isolated for the initiation of biosurfactant studies which included screening. Results indicated that the engineered biofilms, constituted by biosurfactant producing organisms (n = 9), were consisiting of bacteria (97.19%), Protozoa (2.81%) and Archaea (0.1%) as identified using metagenomics methods. Some of the biosurfactant produced had the following functional group characteristics as determined by FTIR: -CH3-CH2, deformed NH, -CH3 amide bond, C-O, C=O, O-C-O of carboxylic acids, and C-O-C of polysaccharides. Other selected microorganisms (n = 5) tolerated maximum concentrations of the selected toxicants (Cu2+, Zn2+ and C6H5OH) of 2400 mg/L, 1800 mg/L and 850 mg/L, respectively. Enzyme analysis of the total nitrogen removal experiments indicated a higher nitrogen removal rate to be the Alcanigene sp. at 180 mg/L/h.

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Pinzon-Gamez, Neissa M. "Rhamnolipid Biosurfactant Production from Glycerol: New Methods of Analysis and Improved Denitrifying Fermentation." University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1257791610.

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29

Alves, Ana Rita da Rocha. "Increase of biosurfactant production by cocultivation of producing bacteria with biofilm forming strains." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/17798.

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Mestrado em Microbiologia
Os biossurfactantes (BSF) são compostos anfipáticos produzidos por uma vasta gama de microorganismos. São capazes de reduzir a tensão superficial e interfacial, bem como emulsificar e transportar substratos hidrofóbicos, regular a aderência de células a superficies e interferir com o desenvolvimento de biofilmes. Os BSF encontram aplicações nas mais diversas áreas, nomeadamente nas indústrias alimentar e do petróleo, no controle de biofilmes microbianos e na prevenção da biocorrosão, biofouling e desenvolvimento de biofilmes. são ainda usados como ingredientes em produtos terapêuticos, de cuidado pessoal e cosméticos. Os BSF representam uma alternativa vantajosa aos surfactantes químicos porque são menos tóxicos, mais biodegradáveis e estáveis em temperaturas e pH extremos. Contudo, a sua produção e aplicação é limitada devido pelo baixo rendimento do processo produtivo e pelos elevados custos de produção. Considerando que os BSF são metabolitos secundários, a hipótese de que a o co-cultivo com estirpes produtoras de biofilme (indutoras) estimula a síntese de BSF foi testada. Estirpes de Bacillus licheniformis e Pseudomonas sp produtoras de BSF foram co cultivadas com estirpes indutoras (Pseudomonas aeruginosa e Listeria innocua) de maneira a estimular a produção de surfactina e ramnolípidos, respetivamente. As culturas axénicas e co-culturas foram testadas quanto ao efeito tensioativo, pelo método do oil spray, cultivo em meio CTAB-azul de metileno e cultivo em meio agar de sangue. O método CPC-BTB foi usado para quantificação de surfatina e ramnolípidos, ambos surfactantes aniónicos, e o método de orcinol foi usado para a quantificação de ramnolípidos. O efeito das culturas e co-culturas na inibição de quorum sensing em Chromobacterium violaceum foi também avaliada. Os resultados do método CPC-BTB indicaram que a estimulação de produção de BSF em Pseudomonas #74 foi maior em co-cultura com L. innocua. Os resultados do teste do CTAB-azul de metileno indicaram que a produção de BSF em B. licheniformis foi mais estimulada em co-cultivo com P. aeruginosa. Não se verificaram diferenças significativas no efeito tensioativo avaliado pelos métodos do oil spray, colapso da gota cultivo emagar de sangue, nem pelo método quantitativo do orcinol. Os resultados indicam que o co-cultivo afecta a concentração de BSF, embora não existam diferenças no efeito tensioactivo, e que um maior rendimento de produção pode ser obtido através da seleção das estirpes indutoras adequadas.
Biosurfactants (BSF) are amphipathic compounds, produced by a vast range of microorganisms. They are able to reduce surface and interfacial tensions, as well as to emulsify and transport hydrophobic substrates, to regulate cell adherence to surfaces and to interfere biofilm development. BSF can have applications in diverse areas, such as petroleum and food industries, control of biofouling and biofilm development, and are also used as ingredients in therapeutic formulations, personal care products, and cosmetics. They represent an advantageous alternative to chemical surfactants because they less toxic, highly biodegradable and stable in extreme temperature and pH. However, mass production and application of BSF is still limited by the low production yield and high production costs. Considering that BSF are secondary metabolites, the hypothesis that cocultivation with biofilm-forming strains would induce BSF synthesis was tested. BSF producing strains of Bacillus licheniformis and Pseudomonas sp. were cultivated with inducing strains (Pseudomonas aeruginosa and Listeria innocua) as a way to stimulate the production of surfactin and rhamnolipids, respectively. Axenic cultures and co-cultures were tested as to the tensoactive effect by the oil spray method, cultivation in CTAB-methylene blue medium, cultivation in blood agar, and the drop collapse assay. The CPC-BTB method was used for the quantification of surfactin and rhamnolipids, both anionic surfactants, and the orcinol method for the quantification of rhamnolipids. Effect of the cultures and co-cultures in the quorum sensing inhibition in Chromobacterium violaceum culture was also evaluated. Results of the CPC-BTB test indicate that the stimulation of BSF production by Pseudomonas sp. was the highest in co-cultures with Listeria innocua. The results of the CTAB-methylene blue test indicate that BSF production in B. licheniformis was more stimulated by co-cultivation with P. aeruginosa. There were no significant differences in the tensoactive effect of the cell-free extracts as determined by oil spray, the drop-collapse test or by the blood-agar test. The results indicate that co-cultivation affects the concentration of BSF, although it does not have an effect in the tensioactive effect of the BSF, and that higher production yields can be attained by selecting convenient inducer strains.

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30

Bai, Guiyun 1964. "Biosurfactant-enhanced nonaqueous phase liquid (NAPL) removal and bacterial transport in porous media." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/282451.

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The well documented ineffectiveness of traditional pump-and-treat technology on the cleanup of non aqueous phase liquid (NAPL) contaminated sites has incurred an intensive research activities in improving the efficiency of NAPL removal from subsurface. Surfactant enhanced subsurface remediation has been proposed as one such option. In this dissertation, a series laboratory experiments were conducted to investigate the potential application of a microbially produced surfactant (biosurfactant) on NAPL removal and the effect on bacteria transport. Monorhamnolipid biosurfactant, produced by Pseudomonas aeruginosa ATCC 9027, was used in all the studies. Hexadecane was used as model NAPL to represent petroleum based products which are common NAPLs detected in contaminated sites. Results showed that rhamnolipid biosurfactant is effective in removing residual hexadecane from sandy soil. In the surfactant concentration tested in this study (40 to 1500 mg/L), mobilization of hexadecane is the main mechanism of the removal. In addition to displacement of hexadecane droplets from subsurface porous matrixes, dispersion or emulsification of hexadecane into surfactant solution also played an important role in hexadecane removal. The performance of this anionic rhamnolipid surfactant is greatly affected by the addition of electrolytes and the change of pH. Addition of Na⁺ and Mg²⁺ can significantly increase the solubilization capacity of rhamnolipid and reduce the interfacial tension between hexadecane and surfactant solution, while addition of Ca²⁺ has a competing effects of enhanced solubilization and Ca²⁺ induced rhamnolipid precipitation. Control of ionic strength and pH can be used to optimize surfactant systems to enhance the NAPL removal depending on the nature of NAPL (LNAPL or DNAPL). Addition of rhamnolipid can also enhance the transport of three bacterial cells with varying hydrophobicity, P. aeruginosa ATCC 9027, 27853, and 15442, by decreasing cell adsorption. This is because the adsorption of surfactant to the porous medium surface increases the surface negative charge density, hence the adsorption of bacteria to the surface is reduced. No significant influence of rhamnolipid on the bacteria surface properties is observed. The measured bacteria breakthrough curves were simulated by an advection-dispersion transport model incorporating two domain reversible sorption (instantaneous and rate-limited) and with two first order sink terms for irreversible sorption. Model simulation suggests that rhamnolipid mainly affects the irreversible sorption of cells.

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31

Ngwenya, Carol Zethu. "Enhanced biosurfactant production by Bacillus licheniformis stk 01 for hydrocarbons targeted for bioremediation." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2341.

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Thesis (MTech (Environmental Health))--Cape Peninsula University of Technology, 2016.
Environmental remediation of organic and inorganic contaminants such as hydrocarbons has been a research focus area of interest. Chemical surfactants have been extensively used for the remediation of contaminated sites for immobilisation of hydrocarbons from environmental matrices. The focus has been on the impact of chemical surfactants on the environment. These petroleum-based chemical surfactants have raised serious environmental concerns as: 1) they are toxic, 2) they deteriorate the environment owing to their non-biodegradability, 3) they are costly, and 4) most are not intended for environmental applications. As such, alternatives had to be found to mitigate concerns associated with the application of such synthetic surfactants in bioremediation. Biosurfactants produced by microorganisms are a potential alternative to these synthetic surfactants. They have minimal environmental impact, are biodegradable and can withstand extreme conditions. However, biosurfactants are associated with high production costs and low production yield. Currently, large-scale production of biosurfactants cannot be achieved. Most research focuses on improving production yield which will contribute to the reduction in production costs. A lichenysin lipopeptide biosurfactant producing Bacillus sp., which grew exclusively on Beta vulgaris agrowaste, was identified. The microorganism was found to be an effective emulsifier for high molecular weight hydrocarbons such as, lubricant oil and diesel. The aim of this study was to improve biosurfactant production yield from this Bacillus sp., including emulsification efficacy by optimising fermentation conditions by supplementing the broth with biocompatible nanoparticles synthesised using a green chemistry approach with B. vulgaris (B. vulgaris) extracts. This study also aimed at reducing production costs by using B. vulgaris agrowaste exclusively as the production medium, both for the biosurfactant and the nanoparticles.

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32

Bezza, Fisseha A. "Biosurfactant assisted bioremediation of petroleum and polycyclic aromatic hydrocarbons in aquatic and soil media." Thesis, University of Pretoria, 2016. http://hdl.handle.net/2263/61284.

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Petroleum hydrocarbons are organic pollutants of major concern due to their wide distribution, persistence, complex composition, and toxicity. They can bioaccumulate in food chains where they disrupt biochemical or physiological activities and can affect genetic integrity of many organisms, resulting in carcinogenesis, mutagenesis and impairment of reproductive capacity. Polycyclic aromatic hydrocarbons (PAHs) have been recognized as priority pollutants due to their carcinogenic, mutagenic and teratogenic properties. Bioremediation, which utilizes the metabolic versatility of microorganisms such as bacteria and fungi to degrade or detoxify hazardous wastes into harmless substances has been recognized as a sustainable, economic, environmentally friendly and versatile alternative for the remediation of many contaminated environments; however its effectiveness is limited by low bioavailability of nonaquous phase and soil-bound PAHs and petroleum hydrocarbons due to their low aqueous solubility, high hydrophobicity and strong sorption to soil. The purpose of this study was to investigate the PAHs and petroleum hydrocarbons bioavailability and subsequent biodegradation enhancement potential of biosurfactants. Biosurfactants have steadily gained increased significance in environmental applications such as bioremediation dueto several advantages over surfactants of chemical origin, such as biodegradability, environmental compatibility, low toxicity, high selectivity and specific activity at extreme temperature, pH and salinity. A series of experiments was designed to investigate the bioavailability and subsequent biodegradation enhancement potential of the biosurfactants produced by the bacterial strains Bacillus subtilis CN2, Ochrobactrum intermedium CN3, Paenibacillus dendritiformis CN5 and Bacillus cereus SPL_4 in liquid culture and soil microcosms with PAH-enriched microbial consortium from chronically contaminated sites. The biosurfactants exhibited a high level of thermal stability, tolerance to extreme levels of salinity and a positive effect for increasing pH. They were identified after Fourier Transform Infrared (FT-IR) spectrometry, Thin Layer Chromatography (TLC) and Liquid Chromatography/Tandem Mass Spectrometry (LC MS/MS) analyses. The biosurfactants physicochemical characterization displayed vast structural diversity and potent surface active properties of surface tension reduction and emulsion formation with a range of hydrocarbons. The lipopeptide biosurfactants produced by CN3 and CN2 enhanced degradations of used motor oil and petroleum sludge in liquid culture. In a shake flask pyrene degradation study, lipopeptide supplementations at 600 and 300 mg L-1 enhanced pyrene degradation to 83.5% and 67% respectively in 24 days compared to 16% degradation in its absence. However, degradation of pyrene was reduced to 57% as the lipopeptide supplementation was raised to 900 mg L 1. This demonstrates that the biodegradation of pyrene was found to increase with an increase in the lipopeptide concentration up to a threshold level. In a soil bioremedial study, microcosms supplemented with 0.2 and 0.6% (w/w) lipopeptide, 51.2% of 4-ring and 55% of 5- and 6-ring PAHs, 64.1% of 4-ring and 79% of 5- and 6-ring PAHs were removed respectively, compared to, 29% of 4-ring and 25.5% of 5- and 6-ring PAHs removal in the surfactant free control after 64 days of incubation. However, there was no statistically significant change in the degradation rates of low molecular weight PAHs in surfactant amended and surfactant free controls. The degradation of 5 and 6 ring PAHs was significantly enhanced (p < 0.05) in the higher surfactant dosage compared to the lower dosage. The results of this work demonstrated that the use of biosurfactants is a viable option to reduce clean-up time and for effective remediation of soil and aqueous media contaminated with polycyclic aromatic and petroleum hydrocarbons. The study demonstrated potential applications of microbial surfactants and provided an insight for further investigation of their large scale production for commercial applications.
Thesis (PhD)--University of Pretoria, 2016.
Chemical Engineering
PhD
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33

Cao, Shuyong. "Characterization of macrolactonization catalyzed by the excised thioesterase domain of biosurfactant lichenysin D synthetase /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?CHEM%202005%20CAO.

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OLIVERA, CARLOS ALBERTO CASTANEDA. "FLOTATION OF THE HEMATITE-QUARTZ SYSTEM USING THE SOLUBLE BIOSURFACTANT PRODUCED BY RHODOCOCCUS ERYTHROPOLIS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2018. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=36068@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
A busca por novos reagentes de baixa toxicidade e de alta biodegradabilidade tem sido estimulada. Como resultado, diversas pesquisas vêm desenvolvendo biorreagentes, dentre eles os biossurfactantes. Os biossurfactantes são moléculas de origem microbiana que possuem ação superficial. Essas moléculas, com propriedades anfifílicas, são produzidas biologicamente e têm aplicação em diversos setores industriais. Assim sendo, esta pesquisa teve como objetivo estudar a flotação do sistema hematita-quartzo utilizando o biossurfactante solúvel produzido por Rhodococcus erythropolis como biorreagente coletor. O biossurfactante (BS) foi caracterizado por análises químicas para determinar a percentagem de proteínas, carboidratos e lipídeos e, suas propriedades físico-químicas foram determinadas por tensão superficial e concentração micelar crítica (CMC). Os minerais e sua interação com o BS foram caracterizados por medições de potencial zeta, medidas de ângulo de contato e espectroscopia no infravermelho (FTIR) para determinar suas propriedades eletrocinéticas, hidrofobicidade e grupos funcionais, respectivamente. Os resultados de adsorção revelaram maior adsorção do biossurfactante na superfície de hematita do que na superfície de quartzo e, isto foi confirmado por analises FTIR e testes de microflotação. Os resultados de microflotação de hematita e de quartzo foram maiores em pH 3 e com concentração de BS de 100 mg/L, com recuperações em torno de 99,88 por cento e 31,05 por cento, respectivamente e, os mesmos foram analisados estatisticamente para obter uma função polinomial representativa da microflotação. Os testes de microflotação do sistema hematita-quartzo mostraram que o biossurfactante é mais seletivo com hematita do que quartzo. O estudo cinético mostrou que os dados experimentais da microflotação de hematita foram ajustados quanto ao modelo cinético de primeira ordem como ao modelo cinético de ordem fracionária, enquanto os dados experimentais da microflotação de quartzo foram ajustados ao modelo cinético de ordem fracionária. Finalmente, os resultados deste trabalho evidenciaram que a utilização do biossurfactante solúvel produzido por Rhodococcus erythropolis como reagente coletor no sistema hematita-quartzo foi viável, demonstrando o seu grande potencial e mostrando- se bastante promissor para uma futura aplicação na indústria da flotação mineral.
The search for new reagents of low toxicity and high biodegradability has been stimulated. As a result, several researches have been developing bioreagents, among them biosurfactants. Biosurfactants are molecules of microbial origin that have surface action. These molecules, with amphiphilic properties, are produced biologically and have application in various industrial sectors. Therefore, this research aimed to study the flotation of the hematite- quartz system using the soluble biosurfactant produced by Rhodococcus erythropolis as a collector bioreagent. The biosurfactant (BS) was characterized by chemical analysis to determine the percentage of proteins, carbohydrates and lipids and its physicochemical properties were determined by surface tension and critical micellar concentration (CMC). The minerals and their interaction with BS were characterized by measurements of zeta potential, contact angle measurements and infrared spectroscopy (FTIR) to determine their electrokinetic properties, hydrophobicity and functional groups, respectively. The adsorption results revealed higher adsorption of the biosurfactant onto the hematite surface than onto quartz surface and this was confirmed by FTIR analysis and microflotation tests. The results of hematite and quartz microflotation were higher at pH 3 and at the concentration of 100 mg/L, with recoveries around 99.88 percent and 31.05 percent, respectively, and they were analyzed statistically to obtain a polynomial function representative of microflotation. The microflotation tests of the hematite-quartz system showed that the biosurfactant is more selective with hematite than quartz. The kinetic study showed that the experimental data of hematite microflocation were adjusted to both the first order kinetic model and the kinetic model of non-integral order, while the experimental data of the quartz microflotation were adjusted to the kinetic model of non-integral order. Finally, the results of this work showed that the use of the soluble biosurfactant produced by Rhodococcus erythropolis as a collector reagent in the hematite-quartz system was feasible, demonstrating its great potential and showing quite promising for a future application in the mineral flotation industry.

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Bodour, Adria. "Approaches to assessing microbial communities in soil, two examples: Biosurfactant production and phenanthrene degradation." Diss., The University of Arizona, 2002. http://hdl.handle.net/10150/280136.

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This dissertation is concerned with studying aspects of the ecology of microorganisms from a functional perspective using different microbial populations in soils. In the first study, an investigation was done on the distribution of biosurfactant producing microorganisms. In the second study, temporal changes were observed in an indigenous phenanthrene degrading community following a long-term pulse of phenanthrene.

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Ochoa, Loza Francisco Javier 1956. "Physico-chemical factors affecting rhamnolipid (biosurfactant) application for removal of metal contaminants from soil." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282826.

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Contamination of soil and groundwater environments by toxic metals and organic compounds is of major concern because of the potential health hazard posed for humans. Remediation of such sites may require the addition of chemical agents that help in the mobilization of contaminants which are likely to be bound to solid surfaces. Surfactants are one of the agents proposed for addition to enhance the removal of soil-bound contaminants. In this dissertation, a series of laboratory experiments were conducted to investigate constraints to the potential application of a microbially produced surfactant (biosurfactant) for removal of metal contaminants from soil. The first part of the dissertation describes the measurement of stability constants and 13 metals including ten of the metals most frequently found in contaminated sites as well as three of the most common metal cations found in soil, Ca²⁺, Mg ²⁺, and K⁺. The second part of the dissertation describes a series of experiments designed to determine the interaction of the biosurfactant with soil matrix components including clays, metal oxides, and organic matter. The biosurfactant used in this research was monorhamnolipid produced by Pseudomonas aeruginosa ATCC 9027. A mixture of mono- and dirhamnolipid produced by P. aeruginosa UG2 was also used in some cases. Results showed that selectivity of the monorhamnolipid followed the order: Al³⁺ > Cu²⁺ > Pb²⁺ > Cd²⁺ > Zn²⁺ > Fe³⁺ > Hg ²⁺ > Ca²⁺ > Co²⁺ > Ni²⁺ > Mn²⁺ > Mg²⁺ > K⁺. These results suggest that monorhamnolipid binds common metal contaminants in preference over common soil cations such as Ca²⁺, Mg²⁺, and K⁺. Rhamnolipid was shown to bind to some soil constituents very strongly including hematite, illite, kaolinite, and montmorillonite. These results indicate that the effectiveness of rhamnolipid in soils with high amounts of iron oxide or clay may be limited due to extensive sorption. Finally, it was found that monorhamnolipid sorbed more strongly than a rhamnolipid mixture containing both monorhamnolipid and dirhamnolipid. This suggests that the use of a biosurfactant mixture may improve the effectiveness of rhamnolipid in the removal of organic and metal contaminants from soil.

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Domingos, Daniela Ferreira 1984. "Prospecção de biossurfactantes a partir de microbiota de manguezais = Prospection of biosurfactant from mangrove macrobiota." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/317333.

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Orientadores: Valéria Maia Merzel, Itamar Soares de Melo
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: O manguezal é um ambiente rico em diversidade microbiana, entretanto existem poucos estudos sobre esse tema no Brasil, tornando imperativo o conhecimento e a exploração de novos micro-organismos e seus metabólitos neste ecossistema. A prospecção da diversidade microbiana em ambientes pouco explorados, como os manguezais, potencializa as chances de sucesso na busca por novas moléculas bioativas, contribuindo para o desenvolvimento econômico e ambiental mais sustentável. Entretanto, sabemos que embora as técnicas de cultivo tenham sido aprimoradas e tenham permitido a recuperação in vitro de um número crescente de micro-organismos ainda não cultivados, nosso conhecimento sobre sua ecologia permanece insuficiente para cultivar a maioria deles. Neste contexto, as bibliotecas metagenômicas surgem como uma ferramenta poderosa para acessar de maneira mais abrangente a diversidade microbiana total em um dado ambiente, permitindo a análise e exploração de genes funcionais de membros da microbiota, principalmente de micro-organismos não-cultivados, e a descoberta de novos compostos bioativos. O objetivo geral desse trabalho foi a prospecção de biossurfactantes a partir de microbiota de manguezal utilizando uma abordagem polifásica. Para a abordagem independente-de-cultivo, foi construída uma biblioteca metagenômica de alto peso molecular a partir de sedimento de manguezal contaminado com petróleo. Os clones obtidos foram submetidos à triagem funcional e molecular para compostos com atividade biossurfactante. Três clones potencialmente produtores foram selecionados e submetidos ao sequenciamento fosmidial para a caracterização gênica dos insertos. Embora os clones apresentassem uma redução na tensão superficial, não foram identificados genes que pudessem estar envolvidos na síntese de algum biossurfactante. Os resultados obtidos revelaram que o uso da metagenômica funcional para a exploração metabólica de uma comunidade microbiana pode oferecer grandes limitações quando se trata de prospecção de biossurfactantes, cujos operons são muitas vezes maiores que 30-40 kb e podem conter elementos de regulação esparsos no genoma da bactéria selvagem. Na abordagem dependente-de-cultivo, foram selecionadas duas linhagens produtoras de biossurfactantes, Bacillus safensis CCMA-560 e Gordonia sp. CCMA-559, isoladas e testadas em estudo prévio. Através de planejamento experimental do tipo Plackett-Burman e Delineamento Composto Central Rotacional foi otimizada a produção do biossurfactante por essas linhagens. A pumolicidina produzida pelo B. safensis CCMA-560 foi caracterizada quimicamente, bem como a via metabólica responsável por sua produção. Este foi o primeiro trabalho a reportar a análise fisiológica, genética e química da produção de biossurfactante por representantes da espécie B. safensis
Abstract: Mangrove is an environment rich in microbial diversity, but little has been reported about it in Brazil, making the knowledge and exploitation of new microorganisms in mangroves an imperative issue. The prospection of microbial diversity in underexplored environments, such as mangroves, increses possibility of success in looking for new bioactive molecules, contributing to a more sustentable economy and environment. Although the cultivation techniques have been improved, allowing an increased number of yet uncultivated microorganisms to be able recuperated in vitro, our knowledge about their ecology is still insufficient to cultivate the majority of them. Therefore, the metagenomic library have emerged as a powerful tool to more widely access the overall microbial diversity in an environment, enabling the functional analyses of genes and the discovery of new bioactive compounds, mainly uncultured-microorganisms. The aim of the current work was the prospection of biosurfactant from mangrove microbiota through a polifasica approach. For the independent-cultivation approach, a metagenomic library of high molecular weight was constructed from mangrove sediment contaminated with oil. The clones were subjected to functional and molecular screening to identify biosurfactant activity. Three clones with the potential to procuce biosurfactant were selected, and the fosmid sequencing for genetic chatacterization of the insert was carried out. Although the clones showed the ability to reduce the surface tension, genes that may involved in biosurfactant synthesis were not identified. The results showed that using the functional metagenomic to explore metabolic pathways of microbial communities can have great limitation when in the prospection of biosurctants when the operon are larger then 30-40 kb and the genome of wild bacteria contains sparse regulation elements. For the dependent-cultivation approach, two strains that produce biosurfactant were selected: Bacillus safensis CCMA-560 and Gordonia sp. CCMA-559. They were isolated and tested in previous study. The biosurfactant production was opmized through the Placktt-Burman design and the Central Composite Design. The pumilacidin produced by B. safensis CCMA-560 was chemically characterized, and the metabolic pathway that is responsible for its production was genetically characterized. This work was the first report the physiologic, genetic, and chemical analysis on the biosurfactant production by the B. safensis strain
Doutorado
Genetica de Microorganismos
Doutora em Genética e Biologia Molecular

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Liu, Guansheng, Hua Zhong, Yongbing Jiang, Mark L. Brusseau, Jiesheng Huang, Liangsheng Shi, Zhifeng Liu, Yang Liu, and Guangming Zeng. "Effect of low-concentration rhamnolipid biosurfactant on P seudomonas aeruginosa transport in natural porous media." AMER GEOPHYSICAL UNION, 2017. http://hdl.handle.net/10150/623109.

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Enhanced transport of microbes in subsurface is a focus in bioaugmentation applications for remediation of groundwater. In this study, the effect of low-concentration monorhamnolipid biosurfactant on transport of Pseudomonas aeruginosa ATCC 9027 in natural porous media (silica sand and a sandy soil) with or without hexadecane as the nonaqueous phase liquids (NAPLs) was studied with miscible-displacement experiments using artificial groundwater as the background solution. Transport of two types of cells was investigated, glucose-grown and hexadecane-grown cells with lower and higher cell surface hydrophobicity (CSH), respectively. A clean-bed colloid deposition model was used to calculate deposition rate coefficients (k) for quantitative assessment on the effect of the rhamnolipid on the transport. In the absence of NAPLs, significant cell retention was observed in the sand (81% and 82% for glucose-grown and hexadecane-grown cells, respectively). Addition of low-concentration rhamnolipid enhanced cell transport, with 40 mg/L of rhamnolipid reducing retention to 50% and 60% for glucose-grown and hexadecane-grown cells, respectively. The k values for both glucose-grown and hexadecane-grown cells correlated linearly with rhamnolipid-dependent CSH quantitatively measured using a bacterial-adhesion-to-hydrocarbon method. Retention of cells by the soil was nearly complete (>99%). Forty milligrams per liter of rhamnolipid reduced the retention to 95%. The presence of NAPLs in the sand enhanced the retention of hexadecane-grown cells with higher CSH. Transport of cells in the presence of NAPLs was enhanced by rhamnolipid at all concentrations tested, and the relative enhancement was greater than in the absence of NAPLs. This study shows the importance of hydrophobic interaction on bacterial transport in natural porous media and the potential of using low-concentration rhamnolipid for facilitating cell transport in subsurface for bioaugmentation efforts.

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FRANZETTI, ANDREA. "Surface Active Compounds by Gordonia and their applications in environmental remediation." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2007. http://hdl.handle.net/10281/8056.

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This chapter reports the outline of the results presented in the next chapters. CHAPTER 2 deals with the isolation and the characterization of new SAC-producing strains. From a site, chronically contaminated by diesel fuel, three bacterial strains (M22, BS25 and BS29) belonging to the Gordonia genus were isolated. Results showed that those Gordonia strains were able to grow using a wide range of straight and branched aliphatic hydrocarbons as carbon and energy source and to produce at least two classes of surface-active compounds. Emulsifying agent(s) was released in the culture medium when bacteria grew both on hydrocarbons and water-soluble substrates. Cell-bound biosurfactant(s), that reduce the surface tension, was produced on hydrocarbons; however, its production was significantly lower on water soluble substrates. Solvent extraction and Thin Layer Chromatography analyses allowed us to classify the cell-bound biosurfactants as glycolipids and to confirm that the chemical nature of the extracellular bioemulsans is different. The relation among growth phase, surface-active compound production and cell-surface properties was analysed in kinetic experiments on hydrocarbons. Gordonia sp. BS29 synthesised, and released extracellularly, bioemulsan(s) during the exponential phase with n-hexadecane as carbon and energy source. The production of biosurfactant(s) started in the exponential phase and its concentration increased during the following linear growth. Furthermore, the adhesion of bacterial cells to hydrocarbons decreased during growth. Our results let to hypothesize a change in the mode by which Gordonia cells access the substrate during growth on hydrocarbons. The results reported in CHAPTER 3 deals with the evaluation of the application potentialities of the isolates and the biosynthesised SACs in environmental restoration technologies. Microbial amphiphiles and their producing strains can be use both as enhancers of biodegradation rate in bioremediation technologies of hydrocarbon contaminated soil and chemico-physical technologies of soil washing. The applicability of our strains and SACs were evaluated for the following applications: bioremediation of (i) aliphatic and (ii) aromatic hydrocarbon contaminated soil and (iii) washing of soil contaminated by crude oil. Microcosm bioremediation experiments were carried out and the effect of BS29 and M22 bioaugmentation and the bioemulsans on biodegradation rate and extent were evaluated also in comparison to the effect of the rhamnolipids, biosurfactants known for their capacities of enhancing bioremediation. Over time, the humidity was kept constant (25%) and the analyses of residual hydrocarbons, total microorganisms and hydrocarbon-degrading microorganisms were carried out. Hydrocarbon biodegradation data were analysed by Analysis of Variance (ANOVA) to compare the tested conditions with the control without any addition. The dependent variables for the comparison were the biodegradation rate and the residual concentration of each contaminant at the end of the experiments. The bioremediation results showed that the bioemulsan is able to effectively reduce final concentration of recalcitrant branched hydrocarbons even not at the same extent of rhamnolipids. Batch soil washing experiments were carried and we compared the effect of the BS29 bioemulsans with the ones of the sole water and a mixture of rhamnolipids (biosurfactant already experimented and used in soil washing techniques) on the removal of the pollutants from soil. Experimental Design Techniques were utilised for an efficient experiment planning and to evaluate the effect of the operational parameters on pollutants removal. The investigated factors were (i) the time of washing and (ii) the ratio between the volume of washing solution and the weight of soil. The use of a crude solution of the BS29 bioemulsans in different conditions resulted in a mean of crude oil removal of 43.1%, while the mean removal in rhamnolipid experiments was 50.8%. ANOVA test showed that both of them are significantly different (α=0.05) from the mean of sole water removal (19.5%). Furthermore, in bioemulsan experiments, a significant effect of time of washing was observed with a positive correlation with the extent of the oil removal. On the contrary, in the tested experimental conditions, neither the solution:soil ratio nor the time of washing significantly affects the removal in rhamnolipids experiments. The results obtained from the optimisation procedure for the maximisation of biosurfactant concentration in cultural broth are reported in CHAPTER 4. The optimisation process involved three consecutive steps. In the first step a two level 2(8-2) Fractional Factorial Design (FFD) was used to identify cultural factors that have a significant influence on biosurfactant(s) biosynthesis. Concentrations of inorganic phosphorous and sodium chloride were found as most important factors affecting yield of biosurfactant biosynthesis Then, on the selected factors, a steepest ascent procedure and a Central Composite Design (CCD) were applied to obtain a second order polynomial function which fitted the experimental data in the vicinity of the optimum. The factors taken into account were inorganic nutrients, such as phosphorous, ammonium and micronutrients, the carbon sources and the time of growth. With the optimised broth composition we obtained a more than 16-fold increase in the biosurfactant concentration compared to the normal BH broth, reaching a Critical Micelle Diluton (CMD) value (129.43 (95% confidence interval: 119.47 – 139.40)) among the highest in literature. In CHAPTER 5 the whole conclusions of the project are drawn and the perspectives for the future are put forward. CHAPTER 6 presents the results of the studies dealing with the ecology and the survival of thermophilic bacteria in cold soil environments. Population analysis of thermophiles in rainwater and air samples has shown distinct differences supporting the view that long distance global transport and deposition in rainwater are a possible source of replenishment of the soil thermophile populations.

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Bueno, Silvia Messias [UNESP]. "Bactérias produtoras de biossurfactantes: isolamento, produção, caracterização e comportamento num sistema modelo." Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/100904.

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Surfactantes são agentes ativos de superfície amplamente utilizados em vários setores industriais. Estas moléculas, com propriedades anfifílicas, são produzidas química ou biologicamente. A grande maioria dos surfactantes disponíveis comercialmente é sintetizada a partir de derivados do petróleo. Em vista de suas vantagens ecológicas, há um grande interesse comercial na substituição de surfactantes sintéticos por naturais. Nesta pesquisa, foram coletadas cinco amostras de solos contaminados e não contaminados por hidrocarbonetos designadas 1, 2, 3, 4 e 5 das quais foram isoladas vinte e oito colônias bacterianas pela técnica de diluição decimal em tubos de ensaio e plaqueamento em placas de Petri contendo meio PCA (Ágar Padrão para Contagem). As bactérias isoladas foram coradas pelo método de Gram para observação das características morfológicas. Destas, apenas treze apresentaram hemólise em placas de Ágar Sangue, o que indicou a presença de biossurfactante. Posteriormente, estas foram cultivadas em meio de produção contendo sais minerais e o caldo de cultura, sem a presença de células, foi utilizado para a determinação da tensão superficial e do índice de emulsificação. As oito bactérias cujos caldos (sem a presença de células) apresentaram diminuição de tensão superficial de no mínimo 20% e índice de emulsificação estável após 24 horas foram selecionadas para realização de testes bioquímicos para identificação. A análise dos resultados destes testes mostrou que as bactérias pertencem ao gênero Bacillus. Foi determinada a otimização da produção de biossurfactantes em caldo de fermentação utilizando diferentes pH (5,0; 6,0; 7,0 e 8,0), tempo de fermentação (48, 72 e 96 horas) e diferentes fontes de carbono (glicose, sacarose, manitol, frutose, glicose + frutose e caldo de cana) nas concentrações 1, 2, 3, 4 e 5%...
Surfactants are surface-active agents widely used in various industries. These molecules, with amphiphilic properties, are produced chemical or biologically. The vast majority of commercially available surfactants is synthesized from oil derivatives. In view of its environmental benefits, there is a large commercial interest in the replacement of natural by synthetic surfactants. In this survey, were collected five samples of contaminated and not contaminated soil by hydrocarbons designated 1, 2, 3, 4 and 5 which were isolated twenty-eight bacterial colonies by the technique of decimal dilution in test tubes, and plating in Petri dishes containing PCA medium (Plate Count Agar) The bacteria isolated were stained by the method of Gram for observation of morphological characteristics. Of these, only thirteen had haemolysis in blood agar plates, which indicated the presence of biosurfactant. Later, they were grown in a production medium containing minerals and the culture broth, without the presence of cells was used to determine the surface tension and the emulsification index. The eight bacteria whose broths (without the presence of cells) had reduction of surface tension of at least 20% and emulsification index stable after 24 hours were selected to carrying out biochemical test for identification. The results of these tests showed the bacteria belong to the genus Bacillus. It was determined the optimization of production of biosurfactants in fermentation broth using different pH (5.0, 6.0, 7.0 and 8.0), fermentation time (48, 72 and 96 hours) and different carbon sources (glucose, sucrose, mannitol, fructose, glucose + fructose and cane juice) at concentrations 1, 2, 3, 4 and 5%. The results showed that pH 5.0 and 7.0; time of 72 hours and fermentation of sucrose at low concentrations had the best production of biosurfactant. The 2C bacteria (Bacillus sp) isolated... (Complete abstract click electronic access below)

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Woods, Charles E. "Examination of the effects of biosurfactant concentration on natural gas hydrate formation in seafloor porous media." Master's thesis, Mississippi State : Mississippi State University, 2004. http://library.msstate.edu/etd/show.asp?etd=etd-07062004-202938.

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Soemo, Angela Renee. "Microenvironment of Monorhamnolipid Biosurfactant Aggregates and Monorhamnolipid Effects on Aqueous Dispersion Properties of Metal Oxide Nanoparticles." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/293563.

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The purpose of this dissertation was two-fold: 1) explore the micelle structure and microenvironment of monorhamnolipids (mRL), produced by Pseudomonas aeruginosa ATCC 9027, and their mixtures with synthetic surfactants in order to postulate possible applications of these materials in industrial products and 2) examine the effects of mRL on commercial metal oxide nanoparticle (NP) aqueous dispersion behavior to reveal the potential impact of microbial secondary metabolites on NP fate and transport in the environment. The mixing behavior of mRL with cetylpyridinium chloride (CPC) was measured using surface tensiometry. Electrostatics resulted in cooperative enhancement in mixture properties, but were not significant until α(CPC) ≥ 0.25. Steady-state and time resolved fluorescence quenching measurements in mRL micelles revealed that quenching proceeded via a combined static and dynamic mechanism. Static quenching was preferred in mRL illustrating the reactants form a globular micelle. Changing the structure of the reactants displayed changes in the degree and mechanism of quenching further supporting this aggregate model. Fluorescence measurements on mRL-Tween 20 micelles supported that a geometrically-driven shape transition occurs as mRL decreases. The corresponding decrease in probe lifetime indicated the polarity of the micelle was decreasing. Tween "sealed" the mRL micelles making them less susceptible to water penetration. The effect of mRL on metal oxide NP dispersions was evaluated on adsorption strength, NP aggregate size and stability, and zeta potential under different conditions. Silica NPs showed little adsorption of mRL and was impervious to all variables in altering the solution stable aggregate size. NP aggregate size decreased at very high mRL concentrations due to osmotic and electrosteric repulsions of mRL micelles in solution. Titania, despite expectations, indicated fairly low adsorption of mRL and displayed similar aggregate dispersion stability as that of silica. Spectroscopic investigations exposed that the commercial titania NPs were contaminated with silica altering NP surface properties. Zinc oxide (ZnO) dispersions were substantially affected by the adsorption of mRL. Without mRL, ZnO NPs were unstable independent of pH. The addition of mRL stabilized the ZnO dispersions and lowered the zeta potentials. Furthermore, mRL coating prevented the dissolution of ZnO, the major factor implicated in ZnO toxicity.

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Rodríguez, Gutiérrez Alejandra. "Producción, escalado y recuperación de soforolípidos mediante fermentación en estado sólido con la cepa Starmerella bombicola." Doctoral thesis, Universitat Autònoma de Barcelona, 2020. http://hdl.handle.net/10803/671303.

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El present treball representa la continuació a la línia de recerca per a la producció de soforolípids (SLs) per fermentació en estat sòlid (FES) que va ser inciada en nuna tesi aneterior. Els SLs són un tipus de surfactant biològic produït per microorganismes i representa una gran alternativa per a la substitució dels surfactants químics, els quals presenten una gran demanda. Els estudis es van realitzar per FES utilitzant com a substrats residus agroindustrials (residu de winterització de l’oli de gira-sol i melassa de remolatxa sucrera) i el llevat Starmerella bombicola. La primera etapa de la investigació va consistir en l’avaluació de 9 materials de diferent naturalesa (biològics i inerts) per a ser utilitzats com a suports per a la producció d’SLs per FES a una escala de 0.5 L. Els materials biològics (lignocel·lulòsics) van presentar millors resultats en comparació als materials inerts. La palla de blat (PT) va resultar ser el suport amb la major producció de SLs (0.20 gSL g-1MS), el qual va ser seleccionat per a la segona etapa relacionada a l’avaluació de la producció de SLs a escales més grans. Així mateix, es va comprovar que és possible produir SLs utilitzant altres residus anàlegs el residu de winterització, però, cal tenir en compte el contingut d’impureses dels mateixos i el procés de recuperació del compost per evitar les interferències d’aquestes mateixes en la qualitat final del producte. L’avaluació de l’escalat de la producció de SLs es va dur a terme en dos reactors de diferent grandària (22 i 100 L), on es va estudiar l’efecte de la temperatura durant el procés i la producció de SLs. Es va observar que mitjançant una temperatura ambient controlada i la implementació d’estratègies de ventilació la temperatura pot ser controlada. Així mateix, es va implementar un procés de diferents cicles d’esterilització que va permetre la reducció del creixement d’altres microorganismes dins el reactor, els quals podrien interferir en el procés metabòlic del llevat per produir SLs. Els resultats van demostrar que el llevat té la capacitat de produir SLs tot i que es modifiquin les seves condicions òptimes de temperatura. Finalment, com a part d’una estada de recerca que es va realitzar a l’Institut Tecnològic d’Estudis Superiors de Monterrey (ITESM) a Monterrey, Nuevo León, Mèxic, es van avaluar dos diferents tecnologies per a l’extracció i recuperació de SLs com a alternativa per a la substitució al mètode convencional amb acetat d’etil. Es van estudiar els sistemes de dues fases aquoses (ATPs) i l’extracció amb fluids supercrítics (FSC). L’extracció amb ATPs va permetre incrementar el rendiment de SLs de 0.20 a 0.34 gSL g-1MS mentre que amb FSC el rendiment va ser de 0.13 gSL g-1MS. Els resultats demostren que hi ha alternatives amigables amb el medi ambient i amb potencial per extreure SLs produïts a partir del procés de FES. Aquesta tesi representa un camí per explorar a més detall altres estratègies per a la producció, recuperació i purificació de SLs mitjançant FES i continuar amb la línia d’investigació que es va iniciar en el Grup de Recerca en Compostatge (GICOM) del Departament d’Enginyeria Química, Biològica i Ambiental de la Universitat Autònoma de Barcelona.
El presente trabajo representa la continuación a la línea de investigación iniciada en una tesis anterior, para la producción de soforolípidos (SLs) por fermentación en estado sólido (FES). Los SLs son un tipo de surfactante biológico producido por microorganismos y representa una gran alternativa para la sustitución de los surfactantes químicos, los cuales presentan una gran demanda. Los estudios se realizaron por FES utilizando como sustratos residuos agroindustriales (residuo de winterización del aceite de girasol y melaza de remolacha azucarera), y su fermentación por una cepa de la levadura Starmerella bombicola. La primera etapa de esta investigación consistió en la evaluación de 9 materiales de diferente naturaleza (biológicos e inertes) para ser utilizados como soportes para la producción de SLs por FES a una escala de 0.5 L. Los materiales biológicos (lignocelulósicos) presentaron mejores resultados en comparación a los materiales inertes. La paja de trigo (PT) resultó ser el soporte con la mayor producción de SLs (0.20 gSL g-1MS), el cual fue seleccionado para la segunda etapa relacionada a la evaluación de la producción de SLs a escalas mayores. Así mismo, se comprobó que es posible producir SLs utilizando otros residuos análogos al residuo de winterización, sin embargo, es necesario tomar en cuenta el contenido de impurezas de los mismos y el proceso de recuperación del compuesto para evitar las interferencias de estas mismas en la calidad final del producto. El escalamiento de la producción de SLs se llevó a cabo en dos reactores de diferente tamaño (22 y 100 L), en donde se estudió el efecto de la temperatura durante el proceso y la producción de SLs. Se observó que mediante una temperatura ambiente controlada y la implementación de estrategias de aireación la temperatura puede ser controlada. Así mismo, se implementó un proceso de diferentes ciclos de esterilización que permitió disminuir el crecimiento de otros microorganismos dentro del reactor, los cuales podrían interferir en el proceso metabólico de la levadura para producir SLs. Los resultados demostraron la levadura tiene la capacidad de producir SLs a pesar de que se modifiquen sus condiciones óptimas de temperatura. Finalmente, como parte de una estancia de investigación que se realizó en el Instituto Tecnológico de Estudios Superiores de Monterrey (ITESM) en Monterrey, Nuevo León México se evaluaron dos diferentes tecnologías para la extracción y recuperación de SLs como alternativa para la sustitución al método convencional con acetato de etilo, se estudiaron los sistemas de dos fases acuosas (ATPS) y la extracción con fluidos supercríticos (FSC). La extracción con ATPS permitió incrementar el rendimiento de SLs de 0.20 a 0.34 gSL g-1MS, mientras que con FSC el rendimiento fue de 0.13 gSL g-1MS. Los resultados demuestran que existen alternativas amigables con el medio ambiente y con potencial para extraer SLs producidos a partir del proceso de FES. Esta tesis representa un camino para explorar a mayor detalle otras estrategias para la producción, recuperación y purificación de SLs mediante FES y continuar con la línea de investigación que se inició en el Grupo de Investigación en Compostaje (GICOM) del Departamento de Ingeniería Química, Biológica y Ambiental de la Universitat Autònoma de Barcelona.
The present work represents the continuation of the research line for the production of sophorolipids (SLs) by solid state fermentation (FES), that was started in a previous PhD thesis. SLs are a type of biological surfactant produced by microorganisms and represent a great alternative for the substitution of chemical surfactants, which are in great demand. The studies were carried out by FES using agro-industrial residues (winterization oil cake and sugar beet molasses) as substrates, and its fermentation with the strain of yeast Starmerella bombicola. The first stage of this investigation consisted in the evaluation of 9 materials of different nature (biological and inert) to be used as supports for the production of SLs by FES at a 0.5 L scale. The biological materials (lignocellulosic) presented better results in comparison to inert materials. Wheat straw (PT) resulted the support with the highest production of SLs (0.20 gSL g-1MS), which was selected for the second stage related to the evaluation of the production of SLs at larger scales. Likewise, it was found that it is possible to produce SLs using other residues analogous to the winterization residue, however, it is necessary to take into account their impurity content and the compound recovery process to avoid their interferences in the final quality of the product. The scaling of the production of SLs was carried out in two reactors of different sizes (22 and 100 L), where the effect of temperature during the process and the production of SLs was studied. It was observed that through a controlled room temperature and the implementation of aeration strategies, the temperature can be controlled. Likewise, a process of different sterilization cycles was implemented that allowed the growth of other microorganisms within the reactor to be reduced, which could interfere in the metabolic process of the yeast to produce SLs. The results demonstrated that the yeast has the ability to produce SLs despite its optimal temperature conditions being modified. Finally, as part of a research stay that was carried out at the Instituto Tecnológico de Estudios Superiores de Monterrey (ITESM) in Monterrey, Nuevo León México, two different technologies for the extraction and recovery of SLs were evaluated as an alternative to replace the conventional method. with ethyl acetate, two phase aqueous systems (ATPS) and supercritical fluid extraction (FSC) were studied. Extraction with ATPS allowed to increase the performance of SLs from 0.20 to 0.34 gSL g-1MS, while with FSC the yield was 0.13 gSL g-1MS. The results show that there are environmentally friendly alternatives with the potential to extract SLs produced from the FES process. This thesis represents a way to explore in greater detail other strategies for the production, recovery and purification of SLs by means of FES and to continue with the line of research that began in the Composting Research Group (GICOM) of the Department of Chemical, Biological Engineering and Environmental of the Autonomous University of Barcelona.
Universitat Autònoma de Barcelona. Programa de Doctorat en Ciència i Tecnologia Ambientals

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Mano, Mario Cezar Rodrigues. "Estudo da recuperação, concentração e purificação de biossurfactante produzido por Bacillus subtilis." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256675.

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Orientador: Glaucia Maria Pastore
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: Biossurfactantes são compostos anfifílicos produzidos por microrganismos que possuem atividade superficial, ou seja, a capacidade de reduzir a tensão superficial e interfacial entre dois líquidos imiscíveis. Devido a suas características, esses compostos possuem uma ampla gama de potenciais utilizações que vão desde a indústria de alimentos, cosméticos, farmacêutica, petroquímica entre outras. O processo de recuperação e purificação de biossurfactantes é alvo de constantes aperfeiçoamentos, pois compreende, em alguns casos, até 60% do custo de produção dos mesmos. Alguns processos utilizados com mais freqüência para recuperação de biossurfactantes são as técnicas de fracionamento de espuma, precipitação e extração, além da ultrafiltração. O objetivo deste trabalho foi avaliar a viabilidade dos processos de ultrafiltração e diafiltração para recuperação e purificação de biossurfactantes produzidos por Bacillus subtilis. O processo foi conduzido com a produção de espuma via fermentação, que continha alta concentração de biossurfactantes. Após pré-tratamento, a espuma passou pelos processos de ultrafiltração e diafiltração, com parâmetros fixos e pré-estabelecidos. Os resultados da ultrafiltração mostram um aumento na concentração de biossurfactantes de 0,7 para aproximadamente 1,1 g/L, porém com um grau de pureza ainda abaixo de 50%. Já no processo de diafiltração, os resultados apontam para uma purificação de valores de pureza superiores a 50%. Uma análise final indica que ambos os processos, de concentração de biossurfactantes por ultrafiltração, e de purificação por diafiltração são viáveis e conseguem um bom rendimento, a custo baixo, sendo uma boa alternativa no ¿downstream¿ de tais produtos
Abstract: Biosurfactant are amphifilic compounds produced by microorganisms that have superficial activity, or capacities of reducing superficial and interfacial tension between two immiscible liquids. Besides these characteristics, this compound has a large utility, going since the food industry, cosmetic, pharmacy, petrochemical among others. The biosurfactant recovery and purification process is the target of constant improvements, because it means until 60% of total production cost. Some process used with more frequency for biosurfactant recovery are foam fractionation, precipitation and extraction, besides ultrafiltration. The aim of this work was to evaluate the viability of ultrafiltration and diafiltration process for Bacillus subtilis biosurfactant recovery and purification. The process was conduced with a foam production by aerobic fermentation, which contained high biosurfactant concentration. After pre-treatment, the foam passes to ultrafiltration and diafiltration process, with fixed and pre-established parameters. The ultrafiltration results show an increase in the biosurfactant concentration from 0,7 to approximately 1,1 g/L, but with a lower 50% purity level. In the diafiltration process already, the results show purity levels higher than 50%. Final analysis indicates in both, the biosurfactant concentration by ultrafiltration and the biosurfactant purification by diafiltration, viability and good yield, with low cost, it might be a good alternative in ¿downstream process¿ of such products
Mestrado
Mestre em Ciência de Alimentos

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Rosa, Célia Francisca Centeno da. "Avaliação da composição do meio de produção de ramnolipídios de Pseudomonas aeruginosa." reponame:Repositório Institucional da FURG, 2008. http://repositorio.furg.br/handle/1/2916.

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Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós-Graduação em Engenharia e Ciência de Alimentos, Escola de Química e Alimentos, 2008.
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A reação de transesterificação de óleos vegetais tem como produto principal o biodiesel, porém o glicerol que é subproduto desta reação pode ser transformado em resíduo devido ao aumento da produção deste biocombustível. Estudos revelam que o glicerol pode ser utilizado como substrato em processos fermentativos juntamente com microrganismos capazes de utilizá-lo como fonte de carbono. A bactéria Pseudomonas aeruginosa demonstra capacidade de assimilação de glicerol para produção de biossurfactantes, que são moléculas produzidas por microrganismos capazes de diminuir a tensão superficial. A maior vantagem de utilização dos biossurfactantes é a aceitabilidade ambiental já que são biodegradáveis e podem ser sintetizados a partir de fontes renováveis. Atualmente a maior aplicabilidade dos biossurfactantes está focada na biorremediação de poluentes, no entanto possui várias propriedades de interesse para inúmeras aplicações na agricultura, cosméticos, produtos farmacêuticos, detergentes, processamento de alimentos e outros. A maioria dos biossurfactantes são moléculas complexas e compreendem uma grande variedade de estruturas químicas, tais como:glicolipídios, lipopeptídios e lipoproteínas, biossurfactantes poliméricos, fosfolipídios, lipídios neutros e ácidos graxos. Dentre os glicolipídios, os mais estudados são os ramnolipídios, produzidos pela bactéria Pseudomonas aeruginosa. O presente trabalho teve como principal objetivo avaliar a composição do meio de produção para obtenção de ramnolipídio a partir da bactéria Pseudomonas aeruginosa LBM10 por fementação submersa, utilizando a técnica de planejamento experimental e análise de superfície de resposta. A cepa bacteriana, isolada de resíduos de pescado capturados na região costeira do sul do Brasil, foi utilizada para produção de ramnolipídio em meio mineral tendo o glicerol como única fonte de carbono. Foi realizado um planejamento completo central rotacional a fim de determinar a melhor condição de estudo, sendo as variáveis do planejamento a concentração de glicerol (13,2 a 46,8 g/L), a relação C/N (12,8 a 147,2) e a relação C/P (12,8 a 147,2), tendo-se como respostas a concentração de ramnolipídio, expressa como ramnose (g/L), índice de emulsificação (IE24, %), redução da tensão superficial (%) e os fatores de conversão de substrato em produto (YP/S), substrato em célula (YX/S) e célula em produto (YP/X). Os ensaios de fermentação foram realizados em incubadora rotatória a 30°C e 180 rpm, por um período de 144 h. De acordo com a validação dos modelos empíricos e análise das superfícies de respostas, a condição que permite obter maior produção de ramnolipídios (2,25 g/L) associada a um alto índice de emulsificação (65 %) é a que utiliza concentração de glicerol de 13,2 g/L, xv relação C/N de 12,8 e relação C/P na faixa de 40, apresentando YP/S de 0,26 g/g e redução da tensão superficial de 38,33 %.
The reaction of transesterification of vegetal oils has the biodiesel as main product. However, glycerol, the by-product of this reaction, can become an important feedstock with the increase in the production of this biofuel. Studies show that glycerol can be used as substrate in fermentatiion processes with microorganisms able to use it as carbon source. The bacteria Pseudomonas aeruginosa demonstrates capability of assimilation of glycerol for production of biosurfactants, which are molecules produced by microorganisms which reduce the surface tension. The most important advantage of biosurfactants is their ecological acceptance: they are biodegradable and can be produced from renewable substrates. Most work on biosurfactants applications has been focusing on bioremediation of pollutants however these microbial compounds exhibit a variety of useful properties for several applications in agriculture, cosmetics, pharmaceuticals, detergents, food processing and others. Most microbial surfactants are complex molecules, comprising a wide variety of chemical structures, such as glycolipids, lipopeptides and lipoprotein, polymeric biosurfactants, phospholipids, neutral lipids and fatty acids. Among glycolipid-type biosurfactants, rhamnolipids produced by Pseudomonas aeruginosa have been widely studied. The main objective of this work was to evaluate the culture medium for rhamnolipid production from Pseudomanas aeruginosa LBM10 by submerged fermentation using experimental design and surface response methodology. The strain, isolated from fish samples captured in a southern coastal zone in Brazil, was used to produce rhamnolipids using mineral media with glycerol as the only carbon source. A rotatable central composite design was used to establish the best medium composition. The parameters were: glycerol concentration (13.2 to 46.8 g/L), C/N ratio (12.8 to 147.2) and C/P ratio (12.8 to 147.2), and the responses were: rhamnolipid concentration, expressed as rhamnose (g/L), emulsification index (IE24, %), surface tension reduction (%) and yield factors YP/S, YX/S and YP/X. The fermentation assays were carried out in a rotary shaker at 30ºC and 180 rpm by 144 h. According to validation of the empirical models and response surfaces analysis, the condition that allows to get greater production of rhamnolipids (2.25 g/L) associate to high emulsification index (65 %) is that uses glycerol concentration of 13.2 g/L, C/N ratio of 12.8 and C/P ratio of 40, showing YP/S of 0.26 g/g and surface tension reduction of 38.33 %.

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Islam, Sanaiya. "Degradation of Ternary Mixture of Trihalomethanes in a Biotrickling Filter in the Presence of Biosurfactant and Fungi." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1584001114684329.

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Hentati, Dorra. "Isolement et caractérisation des bactéries marines hydrocarbonoclastes, production des biosurfactants et étude de la biodiversité microbienne au sein de trois ports de Sfax, Tunisie." Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTG064/document.

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La pollution des écosystèmes marins côtiers par les hydrocarbures, en particulier les HAPs, est un problème environnemental majeur. Le même constat est fait pour le littoral Sud de Sfax (Tunisie) dont la pollution presque généralisée menace sérieusement les ressources naturelles existantes dans la région. La caractérisation physico-chimique des échantillons marins prélevés à partir des trois ports (plaisance, commerce et pêche) de la ville de Sfax, prouve une contamination par des micropolluants organiques (hydrocarbures) et inorganiques (métaux) qui sont considérés comme des excellents traceurs de la pollution urbaine et industrielle et ils font partie des composés les plus toxiques étant donné leur faible biodégradation. La méthode d’empreinte moléculaire (PCR-SSCP) montre une dominance du domaine Bacteria suivie des Eucarya et des Archaea au sein des échantillons marins étudiés. Les analyses statistiques par le logiciel R ont montré l’absence de corrélation entre la communauté bactérienne identifiée par PCR-SSCP et les paramètres physico-chimiques étudiés.Dans une autre partie de travail, quatre souches bactériennes marines hydrocarbonoclastes ont été isolées et caractérisées sur les plans phénotypique et phylogénétique, après des enrichissements sur des HAPs et sur le pétrole brut: FLU5 de Bacillus stratosphericus, NAPH6 de Pseudomonas aeruginosa, PYR2 de Bacillus licheniformis isolées sur le fluoranthène, le naphtalène et le pyrène, respectivement, en présence de 30 g/l NaCl; et CO100 de Staphylococcus sp., isolée sur le pétrole brut, en présence de 100 g/l NaCl. Les analyses chromatographiques, GC-MS ou GC-FID, montrent les capacités biodégradatives intéressantes de ces composés récalcitrants par les bactéries isolées. En outre, ces quatre souches bactériennes, sont capables de produire des biosurfactants nommés BS-FLU5, BS-NAPH6, BS-PYR2 et BS-CO100, sur plusieurs sources de carbones, y compris l’huile de friture résiduelle, un substrat bon marché, minimisant ainsi le coût élevé de production de ces tensioactifs. Les analyses MALDI-TOF/MS, des biosurfactants BS-FLU5, BS-PYR2 et BS-CO100 purifiés, montrent qu’il s’agit des lipopeptides, les biosurfactants BS-NAPH6 sont de nature rhamnolipidique, sur la base des analyses FTIR. Ces quatre biosurfactants sont caractérisés par des propriétés tensiactives intéressantes : une faible CMC, une importante réduction de la tension de surface... Ils sont stables vis-à-vis d’une large gamme de pH, de température et de salinité. De plus, ces agents tensioactifs sont doués d’activité de remobilisation des hydrocarbures contenus dans des sols pollués par. Les biosurfactants BS-FLU5, BS-PYR2 et BS-CO100, présentent des activités anti-adhésives et anti-biofilms intéressantes contre des biofilms de certains microorganismes pathogènes. Par ailleurs, une propriété cicatrisante remarquable sur des plaies d’excision chez un modèle expérimental de rats de race Wistar, a été montrée par les quatre biosurfactants pour des concentrations de l’ordre de 5 et 10 mg/ml, en comparaison avec un cicatrisant de référence (CICAFLORA®). A noter que, l’évaluation de la cytotoxicité des biosurfactants étudiés, a montré qu’ils n’ont pas des effets toxiques sur des cellules rénales humaines HEK-239 à des concentrations jusqu’à 1000 µg/ml pour BS-FLU5 et BS-CO100 et jusqu’à 200 µg/ml pour BS-NAPH6 et BS-PYR2. La production des biosurfactants de la souche FLU5 à l’échelle pilote (deux fermenteurs de 20 et 100 litres, volume total), en présence d’un milieu économique, montre une augmentation des quantités des biosurfactants produits par rapport à l’échelle laboratoire (erlenmeyer, 1 litre). L’ensemble de ces résultats prometteurs, montrent que les souches marines isolées FLU5, NAPH6, PYR2 et CO100, ainsi que leurs biosurfactants demeurent d’intérêts biotechnologiques pour divers types d’applications, tels que la bioremédiation, l’agroalimentaire, la cosmétique
Pollution of coastal marine ecosystems by hydrocarbons, in particular polycyclic aromatic hydrocarbons (PAHs), is a major environmental problem. The South coast of Sfax (Tunisia) is an example of a polluted ecosystem subject to both urbanization and industrialization including the outfall of untreated domestic sewage and wastewaters, fishery activities, as well as ship traffic and boat pollution. The physico-chemical characterization of the seawater taken from three harbours (pleasure, commercial and fishing) of the city of Sfax, showed a heavy contamination by organic and inorganic micropollutants. These are excellent tracers of urban and industrial pollution, and they are among the most toxic compounds due to their low biodegradation.The molecular fingerprinting technique (PCR-SSCP) showed the dominance of the Bacteria domain followed by Eucarya and Archaea within the studied marine samples. Statistical analysis using the R software, showed that no correlation was identified between the bacterial community identified by PCR-SSCP and the studied physico-chemical parameters.In another part, four marine, aerobic and hydrocarbonoclastic strains: Bacillus stratosphericus FLU5, Pseudomonas aeruginosa NAPH6, Bacillus licheniformis PYR2, isolated after enrichments on fluoranthene, naphthalene and pyrene, respectively, and in the presence of 30 g/l NaCl. Strain Staphylococcus sp. CO100 was isolated after enrichment on crude oil, in the presence of 100 g/l. Chromatographic analysis (GC-MS or GC-FID), showed the interesting biodegradative capacities of these recalcitrant compounds by the isolated bacteria.Besides, these strains showed their capacity to produce efficient surface active agents BS-FLU5, BS-NAPH6, BS-PYR2 and BS-CO100, on several substrates and in particular the residual frying oil, which is a cheap and renewable carbon source alternative, thus minimizing the high cost of producing surfactants. The MALDI-TOF/MS analysis of the purified BS-FLU5, BS-PYR2 and BS-CO100 biosurfactants revealed that they are belonging to lipopeptide family. FTIR analysis showed the glycolipid nature, more precisely the rhamnolipid type, of biosurfactant BS-NAPH6.These four biosurfactants are characterized by interesting tensioactive properties (low CMC, important surface tension reduction...). Furthermore, these surface active agents showed interest stability against a broad range of pH, temperature and salinity. The application of these biosurfactants, in oil recovery, from hydrocarbons-contaminated soil, showed that they were more effective on the hydrocarbon-remobilization than some tested synthetic surfactants. The biosurfactants BS-FLU5, BS-PYR2 and BS-CO100, were found to have notable anti-adhesif and anti-biofilm activities, being able to prevent and eliminate the biofilm formation by pathogenic microorganisms. Moreover, the four tested biosurfactants showed an interesting healing activity, on the wound site in a rat model. They increased significantly the percentage of wound closure when compared to the untreated and CICAFLORA® (a reference pharmaceutical product) treated groups, using two different concentrations (5 and 10 mg/l). Interestingly, the evaluation of the cytotoxicity of the studied biosurfactants, showed that they have no toxic effects on human HEK-239 cells at concentrations up to 1000 μg/ml for BS-FLU5 and BS-CO100 and up to 200 μg/ml for BS-NAPH6 and BS-PYR2. An attempt to produce biosurfactant produce by strain FLU5 on a pilot-scale (fermentors of 20 and 100 liter, as total volume), using a cost-effective medium, was also performed. Preliminary results showed an increase in the quantities of biosurfactantsBS-FLU5 produced on a pilot-scale compared to the lab-scale (Erlenmeyer of 1 liter).These results highlight the interest for potential use of strains FLU5, NAPH6, PYR2 and CO100, as well as their biosurfactants, in a wide variety of industrial, environmental and biotechnological applications

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Bence, Keenan. "Bacterial production of antimicrobial biosurfactants by Bacillus subtilis." Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/17876.

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Thesis (MScEng)--Stellenbosch University, 2011.
ENGLISH ABSTRACT: Biosurfactants are microbially produced molecules that show excellent surface-active properties. Bacillus subtilis ATCC 21332 produces the biosurfactant, surfactin, which exhibits antimicrobial activity against bacteria as well as fungi. Although antimicrobial activity has been exhibited by a number of bacterially produced biosurfactants, notably the rhamnolipid from the pathogen Pseudomonas aeruginosa, the GRAS status B. subtilis makes the use of this organism preferable for large scale bioprocesses. The objectives of this study were to: (1) evaluate the effect of different nutrient conditions on growth and surfactin production; (2) evaluate the growth of B. subtilis ATCC 21332 and associated surfactin production on a hydrocarbon substrate; (3) evaluate the antimicrobial activity of surfactin against Mycobacterium aurum, and (4) to establish whether active growth of B. subtilis ATCC 21332 and associated surfactin production can be extended during fed-batch culture. B. subtilis ATCC 21332 was grown on low-nitrate; phosphate-limited and nutrient rich media with glucose as substrate during shake flask culture. Nitrate, phosphate, glucose and surfactin were quantified by HPLC analyses and growth via CDW and optical density measurements. Growth and surfactinproduction were further evaluated during shake flask cultureon a hydrocarbon substratereplacing the glucose in the nutrient rich medium with an equivalent amount of n-hexadecane. The antimicrobial activity was quantified by growth inhibition of M. aurum. Bioreactor batch and fed-batch studies were conducted to evaluate growth and surfactin production under controlled conditions. The fed-batch experiments included four constant dilution rate (D=0.40h-1; D=0.15h-1; D=0.10h-1 and D=0.05h-1) and two constant feed rate (F=0.40L/h and F=0.125L/h) fed-batch strategies. The nutrient rich medium was used for these experiments and also as the feed medium for fed-batch experiments. A CDW of 12.6 g/L was achieved in the nutrient rich medium during shake flask culture and was 2.5- and 1.6-fold higher than that achieved in the phosphate-limited medium and the lownitrate medium respectively. A surfactin concentration of 652 mg/L was achieved in the nutrient rich medium, while a maximum surfactin concentration of 730 mg/L was achieved in the phosphate-limited medium. A surfactin concentration of only 172 mg/L was achieved in the low-nitrate medium. Subsequently, growth and surfactin production were evaluated on n-hexadecane as sole carbon source. After inoculation, the CDW did not increase over a period of 119 h, which indicated that B. subtilis ATCC 21332 was unable to utilize n-hexadecane for growth and surfactin production. The maximum CDW (27 g/L) and maximum surfactin concentration (1737 mg/L) achieved in the bioreactor batch experiments were 2.1- and 2.6-fold higher respectively than that achieved in the nutrient rich medium during shake flask experiments. These results served as a benchmark for further fed-batch experiments. During the fed-batch phase of the D=0.40h-1 experiment, the biomass further increasedby 9 g/h, which was 3.5-, 3.1- and 5.3-fold higher compared to the fed-batch phases of the D=0.15h-1, D=0.10h-1 and D=0.05h-1 experiments respectively. Similarly, the biomass increased by 10.7 g/h during the fed-batch phase of the F=0.40L/h experiment, which was 4.6-fold higher than that of the F=0.125L/h experiment. The average rate of surfactin production was 633 mg/h during the fed-batch phase of the D=0.40h-1 experiment, 29.4-, 5.4- and 34.2-fold higher compared to the fed-batch phases of the D=0.15h-1, D=0.10h-1 and D=0.05h-1 experiments respectively. Analogously, the average rate of surfactin production (544 mg/h) of the F=0.40L/h experiment was 9.4 fold higher than that of the F=0.125L/h experiment. The antimicrobial assay showed that surfactin inhibits M. aurum growth. An inhibition zone diamater of 4mm was measured at a surfactin concentration of 208 mg/L, which linearly increased to 24mm at a surfactin concentration of 1662 mg/L. High feed flow rate strategies achieved higher rates of biomass increase and surfactin production and will thus decrease the production time required for large scale surfactin production.The antimicrobial activity of surfactin against M. aurum indicates that this biosurfactant has the potential to be used against M. tuberculosis, and as such has the potential to be used in the medical industry to reduce the spread of this, and other deadly diseases.
AFRIKAANSE OPSOMMING: Biosurfaktante is oppervlak-aktiewe molekules wat deur sekere mikro-organismes geproduseer word. Bacillus subtilis ATCC 21332produseer ‘n biosurfaktant genaamd surfactin, wat antimikrobiese eienskappe toon teen bakterieë sowel as fungi.Menige bakterieël geproduseerde biosurfaktante toon antimikrobiese eienskappe, vernaam die rhamnolipied van die patogeen Pseudomonas aeruginosa, maar die algemene veiligheids-status van B. subtilis gee voorkeur aan hierdie organisme vir grootskaalse bioprosesse. Die doelwitte van hierdie studie was: (1) om die effek van verskillende medium samestellings (in terme van voedingstowwe) ten opsigte van bakteriële seldigtheid en surfactin-produksie te evalueer; (2) om die bakteriële seldigtheid van B. subtilis ATCC 21332 en geassosieerde surfactin produksie vanaf ‘n alkaan-substraat te evalueer; (3) om die antimikrobiese aktiwiteit van surfactin teen Mycobacterium aurum te evalueer; (4) om vas te stel of die aktiewe groei van B. subtilis ATCC 21332 en geassosieerde surfactin-produksie gedurende voer-lot kultuur verleng kan word. B. subtilis ATCC 21332 was op lae-nitraat; fosfaat-beperkte en voedingstofryk-media met glukose as substraat in skudflesse gekultiveer. Nitraat, fosfaat, glukose en surfactin was deur hoëdruk vloeistofchromatografie gekwantifiseer en die seldigtheid deur middel van seldroëmassa en optiese digtheid metings. Verder was die groei van B. subtilis, en geassosieerde surfactin produksie, vanaf ‘n alkaan-substraat in skudflesse ge-evalueer deur die glukose in die voedingstofryke medium met ‘n ekwivalente hoeveelheid van n-heksadekaan te vervang. Die antimikrobiese aktiwiteit van surfactin was deur die geїnhibeerde groei van M. aurum gekwantifiseer. Bioreaktor lot en voer-lot studies was uitgevoer om die groei en surfactin produksie onder beheerde toestande te evalueer. Die voer-lot eksperimente het vier konstante verdunningstempos (D=0.40h-1; D=0.15h-1; D=0.10h-1 en D=0.05h-1) en twee konstante voertempos (F=0.40L/h and F=0.125L/h) ingesluit. Die voedingstofryke medium was vir hierdie eksperimente en ook as die voermedium vir dievoer-lot eksperimente gebruik. ‘n Seldigtheid van 12.6 g/L is bereik gedurende skudfleskultuur in die voedingstofryk-media en was 2.5- en 1.6-voud hoër as die seldigthede wat in die fosfaat-beperkte en lae-nitraat media bereik is. ‘n Surfactin konsentrasie van 652 mg/L is bereik in die voedingstofryke medium, terwyl ‘n maksimum surfactin konsentrasie van 730 mg/L in die fosfaat-beperkte medium bereik is. ‘n Surfactin konsentrasie van slegs 172 mg/L is in die lae-nitraat medium bereik.Hierna was bakteriële seldigtheid en surfactin produksie geuvalueer met slegs n-heksadekaan as die enigste koolstof bron. Die bakteriële seldigtheid het geen verandering getoon na inokulasie nie, wat aangedui het dat B. subtilis ATCC 21332 nie die vermoë beskik om n-heksadekaan vir groei en surfactin produksie te gebruik nie. Die maksimum seldigtheid (27 g/L) en maksimum surfactin konsentrasie (1737 mg/L) bereik in die bioreaktor lot eksperimente was 2.1- en 2.6-voud hoër onderskeidelik as dit bereik in die voedingstofryke medium gedurende skudfles eksperimente. Hierdie resultate dien as ‘n basis vir verdere voer-lot eksperimente. Gedurende die voer-lot fase van die D=0.40h-1 het die biomassa verder verhoog teen 9 g/h, wat 3.5-, 3.1- en 5.3-voud hoër was as dit van die D=0.15h-1, D=0.10h-1 en D=0.05h-1 eksperimente onderskeidelik. Die biomassa het soortgelyk tydens die voer-lot fase van die F=0.40L/h eksperiment teen 10.7 g/h verhoog, wat 4.6-voud hoër was as dit van die F=0.125L/h eksperiment. Die gemiddelde tempo van surfactin produksie was 633 mg/h gedurende die voer-lot fase van die D=0.40h-1 eksperiment, 29.4-, 5.4- en 34.2-voud hoër vergeleke met die voer-lot fases van die D=0.15h-1, D=0.10h-1en D=0.05h-1 eksperimente onderskeidelik. Die gemiddelde tempo van surfactin produksie (544 mg/L) was soortgelyk 9.4-voud hoër gedurende die voer-lot fase van die F=0.40L/h eksperimente, vergeleke met die die F=0.125L/h eksperiment. Die antimikrobiese toetse van surfactin teen M. aurum het positief getoets, wat aandui dat surfactin die groei van hierdie organisme inhibeer. ‘n Inhibisie sone deursnee van 4mm was gemeet teen ‘n surfactin konsentrasie van 208 mg/L, wat lineêr verhoog het tot 24 mm teen ‘n surfactin konsentrasie van 1662 mg/L. Hoë voertempo strategieë het hoër biomassa verhogingstempos en surfactin produksie tempos getoon en sal dus die produksietyd aansienlik verkort tydens grootskaalse surfactin produksie. Die antimikrobiese aktiwiteit van surfactin teen M. aurum toon dat hierdie biosurfaktant die vermoë het om gebruik te word teen M. tuberculosis. Daarom het surfactin die potensiaal om gebruik te word in die mediese industrie om die verspreiding van Tuberkulose, en ander dodelike patogene, te voorkom.

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49

Wang, Hui. "Interfacial and Solution Characterization of Rhamnolipid Biosurfactants and their Synthetic Analogues." Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/217062.

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Abstract:

Rhamnolipid (RL) biosurfactants have been considered "green" alternatives to synthetic surfactants. Here, systematic studies of monorhamnolipids (mRLs) and their synthetic analogues are performed to characterize their interfacial and solution behaviors as surfactants. Chemical structure-surface activity relationships of rhamnolipids were probed using surface tension measurements on RLs and a series of their synthetic analogues designed by "truncation modification." Based on our study on RLs and the rationally-designed RL analogues, the key structural factor responsible for the excellent surface activity performance of rhamnolipids is the presence of the rhamnose moiety in the headgroup. As a result, rhamnopyranosides (RhEs), the simplest surfactants with a rhamnose moiety in the headgroup, show surface activity comparable to the bioproduced mRLs. The purified mixture of mRLs harvested from Pseudomonas aeruginosa ATCC 9027 was mixed with a nonionic surfactant Tween-20 (TW) and studied by surface tension measurements at pH 8. The experimental values of CMC show deviation from the theoretical values predicted by ideal solution theory, which is hypothesized to be due to a shape change from rod-shaped to spherical as the mole fraction of TW is increased. The hypothesis about the shape change is supported by dynamic light scattering results, regular solution theory, and packing parameter theory. Polarization modulated-infrared reflection-absorption spectroscopy (PM-IRRAS) has been used to characterize the orientation of the synthetic rhamnolipid Rha-C18-C18 at the air-water interface. Although rhamnolipids exhibit pH-dependent micellization, their orientation at the air-water interface is not affected by pH. The average tilt angle of their alkyl chains is determined to be ~45° at a surface pressure π = 40 mN/m which decreases to 36° when Pb²⁺ is present in the subphase. Assisted by molecular modeling, the packing of mRLs at the air-water interface is believed to be dominated by the packing of their large hydrophilic headgroups. Finally, the adsorption isotherm of mRLs on hydrophobic polyethylene surfaces was generated by ATR-FTIR from solutions of different pH, which were then fit to a Frumkin adsorption model to yield the thermodynamic adsorption parameters, the adsorption equilibrium constant and the interaction parameter. mRLs strongly adsorb to d-PE, and the adsorption is pH dependent.

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50

Cui, Xiaohui. "Regulation of biosurfactant production by quorum sensing in Pseudomonas fluorescens 5064, the cause of broccoli head rot disease." Thesis, University of Edinburgh, 2004. http://hdl.handle.net/1842/580.

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Abstract:

Broccoli head rot is a destructive disease found in most broccoli production areas. The main pathogen is the bacterium Pseudomonas fluorescens. P. fluorescens 5064, which was first isolated from an infected broccoli head in SE Scotland, produces biosurfactants that are important for bacterial establishment on the plant surface prior to causing disease in broccoli. Preliminary experiments performed in this study showed that biosurfactant production in P. fluorescens 5064 was cell density dependent, which is a typical characteristic of the quorum sensing mechanism. Quorum sensing is a bacterial communication mechanism, which controls a number of key processes in growth, reproduction and virulence via signalling molecules (quorum sensing signal) in many gram-negative bacteria. One aim of this study was to determine if biosurfactant production in P. fluorescens 5064 is controlled via quorum sensing. To do this, 35 surfactant-minus Tn5 mutants of P. fluorescens 5064 were screened for their abilities to produce a quorum sensing signal. Six of these biosurfactant-deficient mutants showed a large reduction in quorum sensing signal production. In one mutant 6423, which contains a single Tn5 insertion, the production of the quorum sensing signal was almost eliminated. Addition of quorum sensing signal, either synthetic or extracted from wild type P. fluorescens 5064, was able to restore biosurfactant production in mutant 6423. This strongly suggests that quorum sensing regulates biosurfactant production in P. fluorescens 5064. Attempts were made to clone and sequence the Tn5 disrupted gene in mutant 6423, but the identity of the gene remains inconclusive. The quorum sensing signal in wild type P. fluorescens 5064 was identified in this study by High Pressure Liquid Chromatography and Mass Spectrometry as N-3-hydroxyoctanoyl-homoserine lactone, which has been shown by other researchers to be present in P. fluorescens strain 2-79, but not in the strains F113, 7-14 and NCIMB 10586. The discovery that biosurfactant production in P. fluorescens 5064 is regulated by quorum sensing opens up a possibility for novel control of broccoli head rot. Although only the control of biosurfactant production by quorum sensing was examined in this study, it is possible that other virulence factors, such as pectic enzyme production, are also controlled by quorum sensing as in other pathogenic bacteria. By blocking the quorum sensing system, the pathogenic P. fluorescens that use this mechanism to control virulence could potentially be rendered avirulent. In greenhouse pathogenicity tests, a quorum sensing signal-degrading bacterium, Bacillus sp. A24, was evaluated for biocontrol of head rot disease caused by P. fluorescens 5064 on broccoli. However, the Bacillus sp. A24 showed only limited control effects, despite its strong quorum sensing signal-degrading ability towards the pathogen in vitro. A subsequent test proved that Bacillus sp. A24 is a surfactant producer itself and this could explain its ineffectiveness in disease control. When screening the quorum sensing signals of the 35 biosurfactant mutants, mutant 6418 was found to produce a potent antibiotic-like compound. This was identified by thin-layer chromatography as pyrrolnitrin. Unlike wild-type P. fluorescens 5064, mutant 6418 has lost its ability to produce virulence factors and is thus non-pathogenic. It was therefore of interest to determine if mutant 6418 could be used as a biocontrol agent to control broccoli head rot disease. In greenhouse pathogenicity tests, mutant 6418 significantly reduced disease by 41 %. The practical application of this research to bacterial disease control – via the manipulation of quorum sensing to inhibit virulence gene expression – is discussed.

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