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Helle, Steve. "Biosurfactants & cellulose hydrolysis." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61308.
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The action of many antimicrobial agents is dependent on their ability to interact with biological membranes. A group of polypeptide antibiotics was found to have surface activite properties. One of them, gramicidinS, produced a minimum in the surface tension curve, which was attributed to instabilities in the intra-molecular hydrogen bonds. Biosurfactants were found to have a great effect on the two phase hydrolysis of cellulose by cellulase. Seven times as much sugar was produced by the hydrolysis of Sigmacell 100 when the biosurfactant sophorolipid was present. The surfactant affects the adsorption of cellulase onto cellulose, and prevents the cellulase from binding irreversibly to the cellulose and becoming inactive.
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Ballot, Francis. "Bacterial production of antimicrobial biosurfactants." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/2250.
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Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2009.Surfactants are compounds that reduce interfacial surface tension, resulting in detergency, emulsifying, foaming and dispersing properties. Surfactants produced via biochemical processes (biosurfactants) form a niche market with their low toxicity, biodegradability and high specificity attributes. Biosurfactants have recently received considerable attention owing to their potential as biomedical molecules. In this study a knowledge base was established for the development of a process which produces biosurfactants for use as antimicrobial agents. Specifically, rhamnolipid biosurfactants were produced from Pseudomonas aeruginosa and tested for antimicrobial activity against target organisms. Accurate and reproducible analyses for the quantification of rhamnolipids and antimicrobial activity were developed. The amount of rhamnolipid was determined indirectly by measuring the rhamnose concentration. A novel HPLC method as well as an orcinol colorimetric method were developed for rhamnose measurement. In order to obtain accuracy with the orcinol method it was found that samples must be extracted at least three times prior to the analysis. An examination of literature on rhamnolipid production showed that many studies used colorimetric methods without extraction. Antibacterial activity was quantified by zone clearing around wells of supernatant in soft agar containing the target organism Mycobacterium aurum. This target organism is especially important in a South African context, since it is used to indicate possible susceptibility of tuberculosis to antibiotics. This method was developed for antibacterial testing, after a standard disk diffusion method proved to be ineffective. Antifungal activity of rhamnolipids was evaluated against the fungus Botrytis cinerea, by growing a lawn of fungus on a plate and adding rhamnolipid. The factors influencing rhamnolipid production were studied by growing different Pseudomonas aeruginosa strains from the ATCC culture collection, namely ATCC 9027 and ATCC 27853 as well as a locally isolated strain under different media conditions. The initial focus was on production of biosurfactants in media containing glucose as substrate. Alkanes were subsequently investigated as an alternative substrate, since they are readily available in South Africa as byproducts from the petrochemical industry. The rhamnolipids produced from the culture collection strains were evaluated for their antibacterial activity against Mycobacterium aurum. A number of key factors were identified which were important for the development of a rhamnolipid production process. Of critical importance were the media conditions. Good production was achieved on glucose media containing a phosphate limitation, pH buffering around neutral pH and a high carbon concentration (2 % carbon). When Pseudomonas aeruginosa ATCC 9027 was cultured on this medium (a minimal salts phosphate limited medium with a Tris buffer), it produced 1.31 g/l rhamnose, equivalent to 4.0 g/l rhamnolipid. This rhamnolipid concentration is 2.7-fold higher that of 1.47 g/l reported in the literature with the same strain (cultured on a different phosphate limited medium The particular strain also proved to be a factor which influenced the yield of rhamnolipids. A rhamnose concentration of 0.43 g/l was obtained with Pseudomonas aeruginosa ATCC 27853 grown on MSM+Tris medium, compared to 1.31 g/l produced by Pseudomonas aeruginosa ATCC 9027 on the same medium. The most promising strain and medium, Pseudomonas aeruginosa ATCC 9027 and MSM+Tris medium, were evaluated under controlled conditions in an instrumented bioreactor. Nearly double the rate of growth and production were obtained in the bioreactor, indicating that production time can be shortened considerably under controlled conditions. However, when compared to shake flask studies, only a 4 % increase in growth and a 5 % increase in rhamnolipid production were achieved in the bioreactor, indicating that the yield was limited by the media components or process conditions. With media containing hexadecane as sole carbon source, negligible rhamnolipid production was achieved. Slow growth was observed and the stationary phase had not been reached even after 2 weeks of growth. It was shown that in glucose media rhamnolipid production only commenced in the stationary phase. Since the stationary phase was not reached during growth on hexadecane, rhamnolipids, which are known to increase the availability of alkanes through emulsification and solubilisation, could not be produced. A strategy was devised to accelerate growth on alkane media. A dual substrate medium containing both glucose and hexadecane was investigated. It was hypothesised that growth would be promoted by glucose leading to rhamnolipid production, which would then increase the uptake of hexadecane. Rhamnolipid was produced in the dual substrate experiments, but the hexadecane uptake was still poor. This was suggested to be due to the exposure of the cells to glucose in the inoculum or test flask, which hampered the ability of the cells to utilise hexadecane. It was reasoned that the ability to utilise hexadecane was determined by the cell hydrophobicity, which was influenced by the exposure to hydrophilic or hydrophobic substrates. Rhamnolipids from Pseudomonas aeruginosa ATCC 9027 and ATCC 27853 were shown to have antibacterial activity against Mycobacterium aurum. The largest zone of clearing of 45 mm was obtained with 4 g/l rhamnolipid from Pseudomonas aeruginosa ATCC 9027. The activity was shown to be directly related to the rhamnolipid concentration, highlighting the importance of maximising the biosurfactant yield when developing a process for the production of rhamnolipids as antimicrobial agents. Antifungal activity tests against Botrytis cinerea were inconclusive. Future studies should expand the antimicrobial application of rhamnolipids by testing their activity against a larger range of target organisms. In order to maximise the rhamnolipid yield in future studies, a fed batch process is proposed which would increase the cell density thereby increasing rhamnolipid production and prolonging the stationary phase, which was found to be the phase associated with rhamnolipid production. Different feeding strategies should be investigated, depending on the kinetics of substrate consumption. It is desirable to feed the smallest volume of substrate that is necessary with a high concentration in order to keep the dilution rate low and maximise the product concentration. A factorial design is recommended for this purpose. Further studies with alkanes as carbon source should be conducted using strains that have been maintained and cultured on media containing alkanes as sole carbon source. Alternative biosurfactant producing strains should also be investigated, which have higher natural cell hydrophobicities.
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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 0.22μm 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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Ghobadi, Fomeshi Ahmadreza. "Toward an Equation of State for Biosurfactants." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1405344829.
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Lin, Ju. "Efficiency of biosurfactants applied by means of electrokinetics." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0018/NQ47709.pdf.
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Heinemann, Gijzen Christine. "Lactobacilli biosurfactants as anti-adhesion molecules against uropathogens." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0006/MQ42154.pdf.
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Drouin, Carole M. "Partition of biosurfactants in two-phase fermentation media." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61246.
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The partition of surfactants and of a biosurfactant-producing microorganism was studied in polyethylene glycol and dextran aqueous two-phase systems. In the presence of sodium phosphate, surfactants distributed themselves according to their charge. Cationic surfactants preferred the bottom phase, while anionic surfactants were attracted to the top phase. Increasing the phosphate molarity, the pH, the polymer concentration or molecular weight all resulted in a more one-sided surfactant partitioning. Biosurfactant partition was weaker than synthetic surfactant partition due to their weaker effective charge and lack of strong specific affinity for one of the polymers.Bacillus subtilis cells partitioned very strongly to the bottom phase. Its biosurfactant, surfactin, was found in slightly larger quantities in the top phase. Batch fermentations were carried out in an aqueous two-phase system. Bacterial growth was not inhibited by the high polymer concentration. Surfactin was produced earlier and in larger quantities than in the regular mineral salts medium.
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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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McGinley, Susan. "Exploding Zoospores: Using Biosurfactants to Control Plant Pathogens." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 1998. http://hdl.handle.net/10150/622309.
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Kılıç, Eylem, Gökhan Zengin, and Arife Candaş Adıgüzel Zengin. "Use of plant-derived biosurfactants in leather industry." Thesis, КНУТД, 2016. https://er.knutd.edu.ua/handle/123456789/4750.
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Perry, Lisa J. "Development of a process for the production of a bacterial surfactant." Thesis, University of Wolverhampton, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308158.
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By using standard isolation procedures 55 microbial isolates were successfully obtained from a number of oil-contaminated sources. These microbial isolates, along with a further 17 obtained from the University culture collection were screened for their ability to degrade hexadecane. Of these, all but two strains were able to utilise hexadecane as their sole carbon and energy source. One isolate, JP1, demonstrated outstanding growth on liquid hexadecane media (final cell-density equal to 1.9 x 10 10 CFU ml -1). A number of techniques were implemented in the screening of the 70 microorganisms for the ability to produce biosurfactants. These methods were based upon the ability of a surfactant to emulsify hexadecane. However, all proved to be unsuccessful methods of detection due to limits of quantification. Surface-tension measurement of the cell-free broth of each isolate was deemed to be the most successful detection method of all those attempted. This technique was selected on the basis of its simplicity, rapidity and reproducibility. On the basis of surface-tension measurements, isolate JP1 demonstrated the greatest reduction to 30 dynes cm "1. On the basis of surface-tension measurements JP1 was deemed the best biosurfactant producer and was selected for further investigations. An absence of suitable quantitative surfactant assays led to the need for the development of such a technique. Two spectrophotometric assays were investigated, the first based upon a surfactants ability to disrupt a liposomal suspension and the second based upon the ability to induce blood haemolysis. Both assays were successfully developed using Triton X-100, a known biological surfactant. Limitations of the liposomal assay were identified when the cell-free broth of JP 1 was introduced into the system. The blood haemolysis assay was successfully implemented to determine biosurfactant production by JP I during a fourteen day fermentation period. The influence of media formulation on biosurfactant production by JP1, demonstrated that maximum production was achieved with a2% (v/v) hexadecane medium incorporating a nitrogen concentration of 0.351 g 1.1 and a phosphorus concentration of 1.218 g 1-1. These concentrations corresponded to a C: N ratio of 48: 1 and a C: P ratio of 14: 1. The biosurfactant exhibited some secondary metabolite characteristics and attained its maximum production during stationary phase. To enable a suitable downstream processing method to be selected for the harvest of the biosurfactant, the nature of the biosurfactant was elucidated. Analytical techniques identified the compound responsible for the surface-tension reducing abilities of the cell-free broth as a glycolipid (30 dynes cm "1). It was demonstrated that the lipid was not responsible for the emulsification abilities of the cell-free broth. Further analytical methods identified the bioemulsifier as a protein with a molecular weight of 14 KDa
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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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Zhao, Zhenyong. "Biosurfactants enhanced bioremediation of PAHs contamination soil under thermophilic condition." HKBU Institutional Repository, 2007. http://repository.hkbu.edu.hk/etd_ra/822.
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Zenginyürek, Özlem Ertürk Handan. "Effects of Biosurfactants on Remediation of Soils Contaminated with Pesticides/." [s.l.]: [s.n.], 2002. http://library.iyte.edu.tr/tezler/master/cevremuh/T000121.rar.
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CORTES, MAURICIO. "THE MORPHOLOGY OF FLOTATION FROTHS USING BIOSURFACTANTS AND ITS METABOLIC BYPRODUCTSTS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2018. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=36070@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
A agitação mecânica ou a injeção do ar geram bolhas na célula de flotação, que são estabilizadas pelo uso de espumantes. Partículas hidrofóbicas se aderem às bolhas e em movimento ascencional chegam a superfície da célula formando a espuma mineralizada que sai da célula por transbordamento e/ou remoção mecânica. Espumas na flotação são de grande importância, principalmente com respeito ao tamanho de bolhas e sua estabilidade, bem como a mobilidade; fatores estes cruciais na viabilidade cinética do processo, na recuperação global e no teor do concentrado. Os espumantes, suas ações e propriedades têm sido estudados, entretanto durante os últimos anos a tecnologia de reagentes de flotação tem sofrido inovações e evoluções consideráveis. Como outros reagentes, os espumantes também foram influenciados pela biotecnologia, levando à introdução de uma nova classe de espumantes denominada bioespumantes. As paredes celulares das bactérias produzem uma gama de proteínas e polissacarídeos, donde por procedimentos específicos se pode extrair biorreagentes que apresentam caracteristicas surfatantes similares aos reagentes sintéticos. Apesar de vários estudos sobre espumantes, ainda existe uma grande lacuna relativa aos bioespumantes. Neste trabalho foi estudado a morfologia de espumas de flotação usando os bioespumantes produzidos pelas bactérias Rhodococcus opacus e seus produtos metabólicos. Os trabalhos visaram estudos de análise de tamanho de bolhas, altura de espuma, estabilidade e persistência de espuma, tensão superficial, velocidade ascencional da bolha, utilizando diferentes técnicas e equipamentos como Bubble Sizer (Anglo Platinum), Tensiômetro K10T (Kruss), Método de Bikerman. As variáveis avaliadas foram pH, concentração de espumante, vazão de ar e tempo.
The mechanical agitation or air injection generate bubbles in the flotation cell; they are stabilized by the use of frothers. Hydrophobic particles adhere to the bubbles and by ascending movement reaches the surface of the cell forming the mineralized froth that leaves the cell by overflow and/or mechanical removal. The flotation froths are of great importance, especially with respect to the size of the bubbles and their stability, as well as mobility; these factors are crucial in the kinetics viability of the process, in the global recovery and in the grade of the concentrate. The frothers, their actions and properties have been studied, however during the last years the technology of flotation reagents has had important innovations and developments. Like other reagents, the frothers were also influences by biotechnology, leading to the introduction of a new class of frothers called biofrothers. The bacteria in their cellular walls produce a range of proteins and polysaccharides, whence by specific procedures it can be removed bioreagents which feature surfactants characteristics similar to synthetic reagents used in flotation. Despite of several investigations on frothers, there is still a large gap in regard to biofrothers. On this work was studied the morphology of flotation froths using biosurfactants produced by the bacteria Rhodococcus opacus and their metabolic byproducts and the investigations focused on studies of analysis of bubbles size, height of foam, stability and persistence of foam, surface tension, superficial velocity of gas; using different techniques and equipment such as Bubble Sizer (Anglo Platinum), Tensiometer K10T (Kruss), Bikermans Method. The evaluated variables were solution pH, frother concentration, air flowrate and time.
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Kothapalli, Chandrasekhar R. "Catalysis of gas hydrates by biosurfactants in seawater-saturated sand/clay." Thesis, Mississippi State : Mississippi State University, 2002. http://library.msstate.edu/etd/show.asp?etd=etd-07122002-150059.
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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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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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Zouari, Oumaima. "Identification, caractérisation, production et application des biosurfactants lipopeptidiques de Pseudomonas spp." Thesis, Lille 1, 2017. http://www.theses.fr/2017LIL10220.
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Des souches de Pseudomonas ont été isolées à partir d’échantillons de sol contaminés par les hydrocarbures ou par de l’huile végétale et d’effluent industriel en vue d’en sélectionner les bactéries ayant un potentielle de production des molécules biosurfactantes. Le criblage a été réalisé en s’appuyant essentiellement sur la mesure de la tension de surface et l’activité émulsifiante. Trois souches ont été choisies pour leurs intéressantes activités biosurfactantes et émulsifiantes. Une identification phénotypique et moléculaire des souches sélectionnées a été réalisée en se basant essentiellement sur le séquençage de leurs ARNr 16S et dont l’arbre phylogénétique a révélé qu’il s’agit de souches qui sont génétiquement très proches et appartiennent au groupe des Pseudomonas putida avec une grande similarité au Pseudomonas alkylphenolica KL28 (99%). L’étude de l’applicabilité des biosurfactants produits a été évaluée en testant leur stabilité à des conditions extrêmes de pH, Température et salinité. Les résultats ont révélés que ces biosurfactants ont maintenu leurs activités à un intervalle de pH compris entre 6 et 12, à une température allant jusqu’à 80°C et à une forte salinité (10%). L’étude du potentiel des souches productrices des biosurfactants dans la dégradation du diesel dans les sols contaminés a été réalisée pour une durée de 1 mois. Les résultats ont montré que les 3 souches possèdent une capacité de dégradation du diesel sur sable avec des débits d’élimination considérables. Une identification de la nature chimique des biosurfactants produits en utilisant une chromatographie sur couche mince (CCM) et la spectrométrie de masse MALDI-ToF sur des surnageants semi-purifiés par une précipitation acide a révélés que ces molécules sont de nature lipopeptidique et ayant des masses comprises dans l’intervalle de masse des syringafactines. L’identification structurale de ces molécules a été effectuée en spectrométrie de masse faite sur les biosurfactants purifiés par des techniques chromatographiques et membranaires et par l’étude bioinformatique du génome bactérien séquencé. Les résultats de cette identification ont été obtenus en combinant les révélations issus de ces 2 dernières techniques et ont montré qu’il s’agit de 2 lipopeptides ayant des structures inconnus et qui sont ~89% similaires aux Syringafactines et aux cichofactines. Une optimisation des conditions de culture a été ensuite réalisée en utilisant des plans d’expériences qualitatifs et quantitatifs. La fermentation Batch réalisée dans les conditions optimisées a montré une augmentation de la production des lipopeptides d’un facteur de 2,6Pseudomonas strains have been isolated from hydrocarbon-contaminated soil, industrial effluent and vegetable oil samples for the purpose of selecting bacteria having the potential of biosurfactant molecules production. The screening was carried out based essentially on the measurement of the surface tension and the emulsifying activity. Three strains have been chosen for their interesting biosurfactant and emulsifying activities. A phenotypic and molecular identification of the selected strains was carried out based essentially on 16S rRNA sequencing and whose phylogenetic tree revealed that the 3 selected strains are genetically very close and belong to the group Pseudomonas putida with great similarity to Pseudomonas alkylphenolia KL28 (99%). The study of the produced biosurfactants applicability, was evaluated by testing their stability under extreme conditions of pH, temperature and salinity. Results revealed that these biosurfactants maintained their activities at a pH range of 6 to 12, at a temperature of up to 80°C and high salinity (10%). The study of the biosurfactant-producing strains potential in diesel degradation in contaminated soils was carried out for duration of 1 month. Results showed that the 3 strains possess a capacity of diesel degradation on sand with considerable disposal rates. An identification of the produced biosurfactants chemical nature using thin layer chromatography (TLC) and MALDI-ToF mass spectrometry on semi purified supernatants by acid precipitation revealed that these molecules have lipopeptidic nature and having masses within syringafactins mass range. The structural identification of these molecules was carried out using purified biosurfactants on chromatographic and membrane techniques by mass spectrometry and bioinformatic studies of the bacterial genome sequenced. Identification results were obtained by combining the revelations resulting from these two techniques and showed that the produced molecules are 2 new octalipopeptides and are ~ 89% similar to Syringafactins and cichofactines. Optimization of the culture conditions of the produced lipopeptides was then carried out using qualitative and quantitative experimental designs. Batch fermentation carried out under the optimized conditions showed an increase in the production of the lipopeptides by a factor of 2.6
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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 genreThe 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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Maciel, InÃs Maria Cals Theophilo. "AvaliaÃÃo do potencial de bactÃrias para degradar derivados do petrÃleo e produzir biossurfactantes." Universidade Federal do CearÃ, 2003. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=1638.
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FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgicoO presente trabalho descreve os resultados da avaliaÃÃo de duas cepas de bactÃrias isoladas a partir de um efluente contaminado com Ãleo, para degradar derivados do petrÃleo e produzir biossurfactantes. AtravÃs de estudos de suas caracterÃsticas morfolÃgicas, culturais, bioquÃmicas e fisiolÃgicas, as bactÃrias selecionadas, nomeadas preliminarmente cepa 03 e cepa 04, foram identificadas como Acinetobacter spp. e Bacillus spp., respectivamente. A capacidade biodegradativa dessas bactÃrias foi avaliada cultivando-as em meio mineral mÃnimo, contendo, sempre, um dos hidrocarbonetos a serem testados, como Ãnica fonte de carbono e energia. As duas bactÃrias degradaram o glicerol, a gasolina, o querosene e o diesel e, produziram biossurfactantes. De maneira geral, as bactÃrias mostraram melhor desempenho na presenÃa de glicerol, como confirmado pelas medidas de densidade celular e atividade emulsificante, enquanto o diesel foi o pior substrato para ambas as bactÃrias. A produÃÃo de biossurfactante foi avaliada medindo-se a sua capacidade para emulsificar o querosene. AtravÃs dessa tÃcnica, encontrou-se um porcentual de 50% de emulsificaÃÃo para os biossurfactantes produzidos pelas duas bactÃrias a partir de glicerol. O Bacillus spp., praticamente, nÃo cresceu e nÃo produziu biossurfactante quando cultivado em meio com diesel, sobrevivendo, contudo, na forma de esporos. A suplementaÃÃo dessa cultura com extrato de levedura 0,04%, entretanto, promoveu a estimulaÃÃo do crescimento e da produÃÃo de biossurfactantes, atingindo um percentual de 95% de emulsificaÃÃo. Os resultados das anÃlises dos biossurfactantes extraÃdos a partir das culturas com glicerol, por espectroscopia infravermelha e anÃlises de carboidratos e proteÃnas, sugerem as classes dos lipossacarÃdios e polipeptÃdios, para os biossurfactantes produzidos pelas bactÃrias Acinetobacter spp. e Bacillus spp., respectivamente. As duas bactÃrias se mostraram suscetÃveis ao calor, sendo destruÃdas à temperatura de 46 ÂC, 1 ppm de hipoclorito de sÃdio e pH abaixo de 5,0. Por outro lado, resistiram a 5% de NaCl, uma caracterÃstica desejÃvel para utilizaÃÃo dessas cepas em situaÃÃes de biorremediaÃÃo de ambientes marinhos contaminados com Ãleo.
The present work describes the results of the evaluation of two bacteria strains isolated from the oil polluted effluent, to degrade petroleum derivatives and to produce biosurfactants. Morphologic, cultural, biochemical and physiologic studies showed that these bacteria, previously denominated strain 03 and strain 04, could be identified as Acinetobacter spp. and Bacillus spp., respectively. The biodegradation potential of these bacteria was evaluated by cultivating them in mineral broth, containing, glycerol, gasoline, kerosene or diesel as the only source of carbon and energy. Both bacteria degraded glycerol, gasoline, kerosene and diesel and produced biosurfactants. In general, the bacteria showed better performances at glycerol presence, as confirmed by the measures of cellular density and emulsificant activity, while the diesel was the worst substrate to both bacteria. The biosurfactant production was evaluated by measuring bacteria capacity for emulsificating kerosene. The results showed an emulsification of 50% for the biosurfactants produced from glycerol by the bacteria. Bacillus spp., practically, did not grow and did not produce biosurfactant when cultivated in medium with diesel, surviving, however, in the spore form. The supplementation of that culture with 0.04 % of yeast extract, however, stimulated the growth and biosurfactants production, reaching 95% of emulsification. The results of the analyses of the biosurfactants extracted from the cultures with glycerol, by infrared spectroscopy and carbohydrate and protein analyses, suggest the classes of the liposaccharides and polypeptides for the biosurfactants produced by the bacteria Acinetobacter spp. and Bacillus spp., respectively. These bacteria were shown to be susceptible to heat, being destroyed at the temperature of 46 ÂC, at 1,0 mg/L of sodium hypochloride and pH below 5.0. On the other hand, they resisted to 5% NaCl, a desirable characteristic for use in marine bioremediation programs.
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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
Unrestricted
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Riahi, Belkacem. "Biosurfactants : nouveaux agents de formulation de milieux microstructurés, hôtes d'une réaction enzymatique." Compiègne, 1994. http://www.theses.fr/1994COMPD748.
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De cette étude, il ressort que les sels biliaires, agents de surface biologiques, possèdent de former des solutions monophasiques ternaires ou pseudo-ternaires stables, incorporant de l'eau et des composés organiques divers (alcools et corps gras), en particulier des systèmes du type microémulsion. La détermination partielle de l'organisation interne de nombreux systèmes ternaires ou pseudo-ternaire, ainsi que, les études complémentaires de la conductivité électrique et de la viscosité des microémulsions ont montré que le pouvoir micro structurant des sels biliaires considérés est fort différent de celui du dodécylsulfate de sodium. Les milieux microstructurés contenant des sels biliaires ont été utilisés en tant que nouveaux fluides réactionnels pour des réactions enzymatiques. Des systèmes convenant ont été sélectionnés à cet égard. Les tests de l'activité enzymatique, à savoir hydrolyse d'un triglycérides ou estérification d'un acide gras par action de lipase, ont montré l'influence que divers facteurs de constitution et de composition du milieu hôte de la réaction exercent sur l'activité enzymatique. L'ensemble des résultats obtenus avec le cholates de sodium et le déoxycholate de sodium (sels biliaires non conjugués) laisse penser que ses biosurfactants peuvent remplacer les agents de surface de synthèse, dans les milieux microstructurés servant comme milieux hôtes des réactions enzymatiques. Cependant, la complexité des résultats étroitement liée au pouvoir tensioactif particulier des sels biliaires n'a pas encore permis d'aboutir à une proposition concrète d'un éventuel procédé industriel.
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Rizzi, John. "Production of emulsifier by Torulopsis petrophilum." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=64014.
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Teixeira, Liliana Patrícia dos Reis. "Production of sophorolipds with a branched hydrophobic tail." Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/15310.
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Mestrado em BiotecnologiaSophorolipids are a type of biosurfactants produced by several microorganisms, including the yeast Starmerella bombicola. They find application mainly due to their emulsifying activity and antimicrobial properties. Sophorolipids produced by Starmerella bombicola are composed by one sophorose molecule and a hydroxylated fatty acid of 16 or 18 carbon atoms. One or two acetylations can occur, one on each glucose, and a lactonization as well. Despite the interesting characteristics of classic sophorolipids produced by the referred yeast, there are indications that sophorolipids with branched a hydrophobic tail have higher activity at lower temperatures. These sophorolipids are produced by Rhodotorula bogoriensis, however the yields obtained with this yeast are low. By producing these sophorolipids in Starmerella bombicola, the yields obtained could be higher. Furthermore, the production of these novel sophorolipids will allow broadening of the biosurfactants applications. This thesis describes two approaches to produce sophorolipids with a branched hydrophobic tail: use of Guerbet alcohols as substrates for the Starmerella bombicola culture, and the introduction of genes that will take care of the in-chain hydroxylation of the sophorolipids. Guerbet alcohols are branched molecules, and are expected to be incorporated in the sophorolipids molecules. The genes to be used are from Elizabethkingia meningoseptica and Rhodococcus rhodochrous and encode for an oleate hydratase, an enzyme responsible for the conversion of oleic acid into 10-hydroxystearic acid.
Soforolípidos são um tipo de biosurfactantes produzidos por vários microorganismos, incluindo a levedura Starmerella bombicola. As suas principais aplicações devem-se à sua sua atividade emulsificante e propriedades antimicrobianas. Soforolípidos produzidos por Starmerella bombicola são compostos por uma molécula de soforose e um ácido gordo hidroxilado de 16 ou 18 átomos de carbono. Apesar das interessantes caraterísticas dos soforolípidos clássicos produzidos pela levedura referida, há indicações de que os soforolípidos com cauda hidrofóbica ramificada têm maior atividade a temperaturas mais elevadas. Estes soforolípidos são produzidos por Rhodotorula bogoriensis, no entanto o rendimento obtido por esta levedura é baixo. Ao produzir estes soforolípidos em Starmerella bombicola, o rendimento obtido poderá ser superior. A produção destes soforolípidos irá também permitir o alargamento das aplicações dos biosurfactantes. Esta tese descreve duas medidas para a produção de soforolípidos com cauda hidrofóbica ramificada: uso de álcoois de Guerbet como substrato para a cultura de Starmerella bombicola, e a introdução de genes que serão responsáveis pela hidroxilação no meio da cadeia hidrofóbica dos soforolípidos. Álcoois de Guerbet são moléculas ramificadas, sendo esperado a sua incorporação nas moléculas de soforolípidos. Os genes usados são provenientes de Elizabethkingia meningoseptica e Rhodococcus rhodochrous, e codificam para uma oleate hidratase, enzima responsável pela conversão do ácido oleico no ácido 10-hidroxistearico.
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Quinn, Christopher. "The isolation and characterisation of novel biosurfactants from frogs of the Bombina genus." Thesis, University of Ulster, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398970.
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Fallon, Agata M. "Study of Hydrocarbon Waste Biodegradation and the Role of Biosurfactants in the Process." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/36986.
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Two types of oily waste sludges generated by a railroad maintenance facility were studied to reduce the volume of hydrocarbon waste. The specific goals of this laboratory study were to evaluate rate and extent of microbial degradation, benefits of organism addition, role of biosurfactant, and dewatering properties.
The oily waste sludges differed in characteristics and contained a mixture of water, motor oil, lubricating oil, and other petroleum products. Degradation was measured using COD, suspended solids, GC measurements of extractable material, and nonextractable material concentration. Biosurfactant production was characterized using surface tension and polysaccharide measurements.
Degradation of ten percent waste oil showed that the removal in a 91 day experiment was 75 percent for COD and suspended solids, 98 percent for extractable oil, and negligible for non-extractable material. It was concluded that methylene chloride extraction could be used to estimate degradation potential of a hydrocarbon waste. Addition of organisms increased the rate and extent of degradation over 22 days, but did not provide any benefits over 91 days.
Data suggested that microorganisms degraded simple compounds first, then produced biosurfactants. It was thought that the biosurfactants remained attached to the organism membrane and increased solubility, stimulating the degradation of difficult to degrade waste oil. After oil was degraded the biosurfactants became ineffective.
The dewatering properties of 10 percent oily sludge deteriorated with the production of biosurfactant and improved after the surfactant was degraded due to changes in oil solubility.Master of Science
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Sousa, Marylane de. "BioconversÃo do glicerol para produÃÃo de biossurfactantes: aplicaÃÃo no preparo de emulsÃes." Universidade Federal do CearÃ, 2011. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=6598.
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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoOs biossurfactantes formam molÃculas anfipÃticas, que possuem em sua estrutura quÃmica segmentos hidrofÃbicos e hidrofÃlicos, espacialmente separados que auxiliam a formaÃÃo de emulsÃes e disponibilizam compostos à cÃlula microbiana. Em funÃÃo dessas caracterÃsticas, os emulsificantes reduzem a tensÃo superficial na interface das fases imiscÃveis, permitindo, portanto, que elas se misturem, formando a emulsÃo. Com isso, este trabalho foi dividido em seis etapas: a primeira tendo como objetivo avaliar a produÃÃo de biossurfactante a partir da glicerina, proveniente da produÃÃo do biodiesel de soja, pela cepa comercial de Bacillus subtilis ATCC 6633, possÃvel produtora de biossurfactante que foi selecionada devido a sua habilidade em sintetizar biossurfactantes a partir de diferentes fontes de carbono; a segunda, resolveu-se avaliar o potencial de produÃÃo de surfactina por cepas de Bacillus sp. nÃo patogÃnicas isoladas da EstaÃÃo de Tratamento de Efluentes da Universidade Federal do CearÃ, com propÃsito de avaliar o maior potencial de produÃÃo do biossurfactante; a terceira, avaliar e otimizar experimentalmente a produÃÃo de biossurfactante em mesa agitadora, utilizando a cepa selecionada durante o screening; a quarta, produÃÃo do biossurfactante utilizando biorreator de 4 L; a quinta, caracterizar o biossurfactante produzido, determinando os grupos funcionais, os estudos de conformaÃÃo e estrutura dos compostos; a sexta, estudar o poder de emulsificaÃÃo do biossurfactante atravÃs da construÃÃo de diagramas de fases para uma posterior aplicaÃÃo do emulsificante. Inicialmente, foi analisada uma cepa produtora de biossurfactante de Bacillus subtilis (ATCC 6633), cultivada em meio de cultura contendo glicerina, um resÃduo da indÃstria do biodiesel, como fonte de carbono e energia, a fim de avaliar a viabilidade desta matÃria-prima na sÃntese de biossurfactante. Uma concentraÃÃo mÃxima de surfactina de 158,14 mg.L-1 foi obtida. Posteriormente, um screening com sete cepas isoladas de Bacillus sp. foi realizado quanto ao crescimento e produÃÃo de biossurfactante a partir da glicerina. Apenas duas cepas (LAMI005 e LAMI009) foram selecionadas atravÃs de dois mÃtodos indiretos, quanto a reduÃÃo da tensÃo superficial e a capacidade de emulsionar trÃs fontes hidrofÃbicas (querosene, Ãleo de soja e n-hexadecano). Foi avaliada a cinÃtica de crescimento e a produÃÃo de biossurfactante para as cepas selecionadas e o melhor resultado em frascos de Erlenmeyer foi realizado com Bacillus subtilis LAMI005, com concentraÃÃo de surfactina de 441,06 mg.L-1 e tensÃo superficial que manteve-se numa faixa estÃvel de 28,8  0,05 mN.m-1 com uma concentraÃÃo micelar crÃtica (CMC) de 19,8 mg.L-1. Posteriormente, ensaios foram realizados em biorreator de 4L, porÃm nÃo se atingiu a concentraÃÃo de surfactina produzida em mesa agitadora, devido, provavelmente, a condiÃÃes de aeraÃÃo, que nÃo foi monitorada quando os ensaios foram realizados em frascos agitados. A surfactina produzida em biorreator foi submetida a anÃlises de espectroscopia vibracional no infravermelho com transformada de Fourier (FTIR), atravÃs destes espectros foi confirmado que o biossurfactante produzido tinha caracterÃsticas similares a surfactina padrÃo da Sigma. O comportamento dos diagramas de fases demonstrou o potencial de emulsificaÃÃo do biossurfactante produzido nestes experimentos, que à bastante positivo em relaÃÃo à possibilidade de aplicaÃÃes do biossurfactante analisado em diversos setores industriais.
Biosurfactants are amphipathic molecules, which possess in their chemical structure hydrophobic and hydrophilic segments, separated spatially, that favor the formation of emulsions and improve the availability of compounds to microbial cell. Given these characteristics, emulsifiers reduce surface tension at the interface of immiscible phases, thereby allowing them to blend in, forming an emulsion. Thus, this study was divided into six stages: the first stage aimed at studying the biosurfactant producers using glycerol, a co-product of biodiesel production from soybean oil, the commercial strain of Bacillus subtilis ATCC 6633, a known biosurfactant-producing was selected due their ability to synthesize biosurfactants from different carbon sources; the second stage aimed at studying the potential of Bacillus sp. strains, isolated from the tank of chlorination, at the Wastewater Treatment Plant on the âCampus do Piciâ (WWTP-PICI), at the Federal University of CearÃ, in producing biosurfactants; the third step was to experimentally evaluate and optimize the production of biosurfactant in shaker, using the strains selected during the screening; the fourth step was the process by using a 4 L batch bioreactor; the fifth step was to characterize the biosurfactant produced by determining the functional groups through studies of conformation and structure of compounds; and the sixth, to study the emulsifying power of the biosurfactant produced by the construction of phase diagrams for a subsequent application of the surfactant. Initially, a biosurfactant-producing strain of Bacillus subtilis (ATCC 6633) was cultived in a culture medium containing glycerin, a residue of the biodiesel industry, as carbon and energy source, in order to evaluate the viability of this raw material in the synthesis of biosurfactants. A maximum concentration of surfactin of 158.14 mg. L-1 was achieved. Next, a screening with seven strains of Bacillus sp. was performed aiming to study growth and biosurfactant production from glycerin. Only two strains (LAMI005 and LAMI009) were selected through two indirect methods, surface tension reduction and the ability to emulsify three hydrophobic sources (kerosene, soybean oil and n-hexadecane). Kinetics of growth and biosurfactant production was evaluated for the selected strains and best results in Erlenmeyer flasks was achieved with Bacillus subtilis LAMI005, 441.06 mg.L-1 of surfactin concentration and the surface tension remained stable in the range of 28.8 Â 0.05 mN.m-1 with a critical micelle concentration (CMC) of 19.8 mg.L-1. Later, tests were conducted in 4L bioreactor, but the concentration of surfactin obtained during grothw in shaker flasks were not achieved probably due to different aeration condition. The surfactin produced in bioreactor was subjected to analysis of the vibrational spectroscopy of Fourier transform infrared (FTIR), the spectra confirmed that the biosurfactant produced had similar characteristics to a standard of surfactin from Sigma. The behavior of phase diagrams showed the potential of the biosurfactant produced for emulsification, which is very encouraging regarding the possibility of biosurfactant applications in many industrial sectors.
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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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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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Kandasamy, Ramananthan Shreekanth. "Enhancement of hydrocarbon degradation using biosurfactants from Rhodococcus species in a membrane reactor system." Thesis, Heriot-Watt University, 2014. http://hdl.handle.net/10399/2837.
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Bacterial degradation of hydrocarbons has achieved greater prominence after the discovery of organisms that have been reported to degrade a host of recalcitrant compounds. The ability of bacteria to degrade hydrocarbons is a viable alternative to other energy intensive clean up options. One of these degradative pathways is through the production of biosurfactants, which have exhibited greater advantages than their chemical counterparts. In this work, two strains of the robust Rhodococcus genus namely Rhodococcus opacus and Rhodococcus ruber have been tested for their ability to degrade n-hexadecane. In order to elicit the maximum production of surfactants, the optimisation of the growth medium with respect to nitrogen source, temperature and rotation speed was carried out. The Phenol-Sulphuric acid assay was employed to quantify the amount of surfactant produced. Biosurfactant efficacy was then determined by measuring the emulsification activity, adhesion to hydrocarbons and reduction in surface tension. Two different mixed-culture reactors were utilized whereby one involved use of a conventional 3L automated batch reactor and another where a specially designed membrane reactor, in which by the use of membrane partitions, enables the two strains of bacteria to be physically separated. From the experiments carried out there is clear indication that using a membrane reactor would be better suited for mixed culture reactor systems. Mixed culture membrane reactors are promising in the field of bioremediation.
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Neta, Nair do Amaral Sampaio. "Estudo da reaÃÃo de produÃÃo de Ãsteres de Ãcidos graxos por via enzimÃtica objetivando aplicaÃÃes alimentÃcias." Universidade Federal do CearÃ, 2008. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=1502.
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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorDiversos experimentos foram realizados com o objetivo de estudar a reaÃÃo de esterificaÃÃo enzimÃtica do Ãcido olÃico com a frutose em meio etanÃlico, visando a sÃntese de biosurfactantes biodegradÃveis. Para tanto, foi utizada a enzima CÃndida Antartica B na temperatura de 55 ÂC e em tempos de reaÃÃo variando entre 48, 72, 96 e 120 horas. De acordo com os resultados obtidos, constatou-se que a citada enzima catalisou preferencialmente o etanol presente no meio reacional para a formaÃÃo do Ãster oleato de etila. Este fato foi confirmado atravÃs do espectro de ressonÃncia magnÃtica nuclear (1H e 13C), bem como do espectro de infravermelho pela presenÃa de um pico de absorÃÃo em 1738,4 cm-1, caracterÃstico deste Ãster. Os resultados da reaÃÃo de formaÃÃo do oleato de etila indicam que o maior rendimento da reaÃÃo foi observado no tempo de 96 horas e que o tempo de 120 horas o rendimento foi inferior. Os experimentos realizados com o objetivo de se obter Ãsteres de frutose a partir do Ãcido olÃico em meio etanÃlico nÃo lograram Ãxito, apesar da literatura indicar a possibilidade de se realizar esta reaÃÃo em outros meios que utilizam solventes nÃo recomendados para o uso alimentÃcio. O oleato de etila apresenta carÃter lipofÃlico e na indÃstria de alimentos encontra aplicaÃÃo na desidrataÃÃo osmÃtica de tomates e pimentas do tipo âdedo de moÃaâ, facilitando a perda de Ãgua, ganho de aÃÃcar e cor mais luminosa. O uso do oleato de etila no processo de desidrataÃÃo diminui o tempo de secagem, aumenta sua eficiÃncia sem deixar nenhum tipo de resÃduo quÃmico.
Several experiments were done aiming at the study on the enzymatic esterification of the oleic acid with fructose in ethanolic medium, focusing the synthesis of biodegradable biosurfactants. For that purpose, it was utilized the enzyme, Candida antartica B., at temperature of 55 ÂC, in reacting time of 48, 72, 96 e 120 hours. Accordingly to the obtained results it was verified that the related enzyme catalyzed primarily the ethanol present in the reactional medium to form the ester: ethyl oleate. This fact was confirmed through magnetic nuclear resonance spectra (1H and 13C) as well as, through infrared spectrum, by the presence of absorption peak at 1738, 4 cm- 1, characteristic of that ester. The results of the reaction of ethyl oleate production indicate that the highest yield was observed in about 96 hours time, and for the 120 hours time it was observed also an inferior yield. The experiments accomplished for the obtention of fructose esters from oleic acids in ethanolic medium were not successful like in other solvents not recommended for food use. The ethyl oleate shows a lipophilic character and in the food industry it finds application in the osmotic dehydration of tomatoes and peppers âdedo de moÃaâ, improving water release, sugar yield and solar brightness. The use of ethyl oleate in the dehydration process decreases the drying time increases its efficiency without leaving any traces pf chemical residues
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Sampaio, Neta Nair do Amaral. "Estudo da reação de produção de ésteres de ácidos graxos por via enzimática objetivando aplicações alimentícias." reponame:Repositório Institucional da UFC, 2007. http://www.repositorio.ufc.br/handle/riufc/18154.
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SAMPAIO NETA, Nair do Amaral. Estudo da reação de produção de ésteres de ácidos graxos por via enzimática objetivando aplicações alimentícias. 2007. 99 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Tecnologia de Alimentos, Fortaleza-CE, 2007Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-07-05T15:42:42Z No. of bitstreams: 1 2007_dis_nasampaioneta.pdf: 429587 bytes, checksum: e95171ae3ed4bc0f19b43d878deb4444 (MD5)
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Several experiments were done aiming at the study on the enzymatic esterification of the oleic acid with fructose in ethanolic medium, focusing the synthesis of biodegradable biosurfactants. For that purpose, it was utilized the enzyme, Candida antartica B., at temperature of 55 ºC, in reacting time of 48, 72, 96 e 120 hours. Accordingly to the obtained results it was verified that the related enzyme catalyzed primarily the ethanol present in the reactional medium to form the ester: ethyl oleate. This fact was confirmed through magnetic nuclear resonance spectra (1H and 13C) as well as, through infrared spectrum, by the presence of absorption peak at 1738, 4 cm- 1, characteristic of that ester. The results of the reaction of ethyl oleate production indicate that the highest yield was observed in about 96 hours time, and for the 120 hours time it was observed also an inferior yield. The experiments accomplished for the obtention of fructose esters from oleic acids in ethanolic medium were not successful like in other solvents not recommended for food use. The ethyl oleate shows a lipophilic character and in the food industry it finds application in the osmotic dehydration of tomatoes and peppers “dedo de moça”, improving water release, sugar yield and solar brightness. The use of ethyl oleate in the dehydration process decreases the drying time increases its efficiency without leaving any traces pf chemical residues
Diversos experimentos foram realizados com o objetivo de estudar a reação de esterificação enzimática do ácido oléico com a frutose em meio etanólico, visando a síntese de biosurfactantes biodegradáveis. Para tanto, foi utizada a enzima Cândida Antartica B na temperatura de 55 °C e em tempos de reação variando entre 48, 72, 96 e 120 horas. De acordo com os resultados obtidos, constatou-se que a citada enzima catalisou preferencialmente o etanol presente no meio reacional para a formação do éster oleato de etila. Este fato foi confirmado através do espectro de ressonância magnética nuclear (1H e 13C), bem como do espectro de infravermelho pela presença de um pico de absorção em 1738,4 cm-1, característico deste éster. Os resultados da reação de formação do oleato de etila indicam que o maior rendimento da reação foi observado no tempo de 96 horas e que o tempo de 120 horas o rendimento foi inferior. Os experimentos realizados com o objetivo de se obter ésteres de frutose a partir do ácido oléico em meio etanólico não lograram êxito, apesar da literatura indicar a possibilidade de se realizar esta reação em outros meios que utilizam solventes não recomendados para o uso alimentício. O oleato de etila apresenta caráter lipofílico e na indústria de alimentos encontra aplicação na desidratação osmótica de tomates e pimentas do tipo “dedo de moça”, facilitando a perda de água, ganho de açúcar e cor mais luminosa. O uso do oleato de etila no processo de desidratação diminui o tempo de secagem, aumenta sua eficiência sem deixar nenhum tipo de resíduo químico.
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Mulligan, Catherine N. "On the capability of biosurfactants for the removal of heavy metals from soil and sediments." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0017/NQ44526.pdf.
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Mulligan, Catherine. "On the capability of biosurfactants for the removal of heavy metals from soil and sediments." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=35023.
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Batch soil washing experiments were used to evaluate the feasibility of using biosurfactants for the removal of heavy metals from a contaminated soil and sediments. Surfactin from Bacillus subtilis, rhamnolipids from Pseudomonas aeruginosa and sophorolipid from Torulopsis bombicola were evaluated using a soil contaminated with hydrocarbon and metals (890 mg/kg zinc, 420 mg/kg copper, 12.6% oil and grease) and metal contaminated sediments (110 mg/kg copper, 3300 mg/kg zinc).Although water alone removed insignificant levels of metals, results showed that the biosurfactants could remove 5% of the zinc (with 12% rhamnolipid) and 19.5% of the zinc (with 4% sophorolipid with 0.7% HCl). Copper could also be removed and was most efficiently extracted (greater than 25%) with 12% rhamnolipid or with 2% rhamnolipid with 1% NaOH. 1% NaOH alone removed only 5% of the copper and 2% zinc. After a series of five batch washes, 90% of the copper could be removed by 0.1% surfactin with 1% NaOH while 4% sophorolipid with 0.7% HCl was able to remove 100% of the zinc. From the sediment, a single washing with 0.5% rhamnolipid removed 65% of the copper and 18% of the zinc whereas 4% sophorolipid removed 25% of the copper and 60% of the zinc.
Sequential extraction procedures were used on the soil and sediments. For both matrices, the carbonate and the oxide fractions accounted for over 90% of the zinc present in the soil. The organic fraction constituted over 70% of the copper in the soil and sediments. Sequential extraction of the soil and sediments after washing with the various surfactants indicated that the biosurfactants, rhamnolipid or surfactin with NaOH, could remove the organically-bound copper and that the sophorolipid with acid could remove the carbonate and oxide bound zinc and cadmium.
Concerning the mechanism for metal removal by the surfactants, the techniques of octanol-water partitioning, ultrafiltration and zeta potential measurements indicated that the surfactants removed the metals first by sorption at the soil interphase, followed by desorption of the metal through interfacial tension lowering and fluid forces and then solubilization of the metal within the micelle.
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Davila, Anne-Marie. "Production par fermentation et structures chimiques d'une famille de biosurfactants : les sophorolipides de "Candida bombicola"." Aix-Marseille 1, 1993. http://www.theses.fr/1993AIX11014.
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L'etude d'une fermentation produisant un biosurfactant glycolipidique, les sophorolipides de candida bombicola a ete effectuee. Dans des conditions optimisees mettant en uvre une alimentation controlee en glucose et en un substrat lipidique, les esters ethyliques de l'huile de colza, des concentrations de sophorolipides superieures a 300 g. L##1 ont ete obtenues. On decrit dans une premiere partie, la cinetique et le bilan detailles de cette fermentation ou le produit, apparaissant en limitation azotee apres la croissance de la levure, se separe du milieu aqueux. Une deuxieme partie concerne la mise au point d'une technique permettant la determination qualitative et quantitative des sophorolipides individuels (20 a 30 composes) produits. La chromatographie liquide haute performance avec elution par un gradient eau/acetonitrile associee a un detecteur evaporatif a diffusion de lumiere a permis d'obtenir ce resultat. L'identification des composes a mis en uvre un ensemble de techniques variees comme diverses conversions chimiques des composes, chromatographie en phase gazeuse, spectrometrie de masse et resonance magnetique nucleaire. Dans une troisieme partie, l'outil analytique developpe a ete utilise pour le suivi de la composition en sophorolipides de fermentations effectuees dans differentes conditions. Deux points ont ete etudies: l'influence du mode de conduite de la fermentation (conditions physico-chimiques, mode d'apport des sources de carbone); effet de la nature du substrat lipidique (n-alcanes, huiles vegetales, esters d'acides gras). Des conclusions relatives au mode de biosynthese des sophorolipides en sont tirees
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CERESA, CHIARA. "Activity of bacterial biosurfactants against Candida albicans adhesion and biofilm formation on medical-grade silicone." Doctoral thesis, Università del Piemonte Orientale, 2015. http://hdl.handle.net/11579/115553.
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Barros, Francisco Fabio Cavalcante. "Estudo das variaveis de processo e ampliação de escala na produção de biossurfactante por Bacillus subtilis em manipueira." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256706.
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Orientador: Glaucia Maria PastoreDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: A bactéria Bacillus subtilis tem a capacidade de produzir biossurfactantes do grupo dos lipopeptídeos, dentre os quais, o que mais se destaca é a surfactina, um dos que possui maior atividade superficial. Esse composto é capaz de reduzir a tensão superficial da água a 20°C de 72 para 27 mN/m em concentrações menores que 20 _M. A aplicação de resíduos industriais como substrato para produção de biossurfactante de Bacillus subtilis tem sido estudada como forma de reduzir custos associados à produção destes. A manipueira, que é o resíduo líquido da produção de farinha e fécula, tem sido apontada como potencial meio de cultura para processos biotecnológicos, incluindo produção de biossurfactantes. Esse uso tem significativa relevância quando se consideram os resultados de redução de tensão superficial e de produtividade obtidos. Este trabalho estudou o processo produtivo, as propriedades e a estabilidade de biossurfactante produzido pela linhagem LB5a de Bacillus subtilis em escala piloto utilizando manipueira como substrato. O composto produzido foi capaz de reduzir a tensão superficial da água de 72 para 27 mN/m além de apresentar concentração micelar crítica de 12 mg/l. Manteve estabilidade frente à temperatura de 100°C por 140 minutos e 121°C por 60 minutos. Também foi estável na faixa de pH de 6 a 10 e suportou concentrações salinas testadas (de até 20%). A eficiência da extração primária realizada através da coleta de espuma mostrou bons resultados, sendo perfeitamente aplicável ao processo. Além disso, os parâmetros envolvidos no preparo da manipueira foram otimizados visando um melhor aproveitamento do substrato. Os resultados apontam temperatura de aquecimento ótima de 95°C (máxima temperatura testada), tempo de aquecimento de 1 minuto, a aceleração centrífuga de 17,85 G x 103 e o tempo de centrifugação de 14,86 minutos. Os resultados apresentados são bastante animadores em relação à possibilidade de aplicações do biossurfactante produzido em diversos setores. Além de permitir um melhor aproveitamento da manipueira
Abstract: The bacteria Bacillus subtilis is well known by their capacity of production surfactants lipopeptides. Among these, the most studied is surfactin, a powerfull surfactant that reduces the superficial tension of the water from 72 to 27 mN/m in concentrations less than 20_M. The application of industrial wastewaters as substrate for production of biosurfactant by Bacillus has been studied in order to reduce manufacturing costs. Manipueira is the residue from cassava industrialization process to the production of flour and starch. It has been pointed as potential culture medium for biotechnological processes, including production of biosurfactants. This work studied the productive process, the properties and the stability of biosurfactant produced by Bacillus subtilis strain LB5a in pilot scale using manipueira as substrate. The produced compounds were capable of reducing the superficial tension of the water from 72 to 27 mN/m beyond presenting critical micelar concentration of 12 mg/l. It remaing stable on temperature of 100°C during 140 minutes and 121°C during 60 minutes. It was also stabile in the range of pH from 6 to 10 and in saline concentrations (until 20%). The efficiency of the primary extration by foam collection showed good results, being perfectly applicable to the process. Moreover, the involved parameters in the preparation of the manipueira has been optimized with the objective of better using of the substrate. The results presented the optimal points of heating temperature was 95°C (maximum tested temperature), warm up time of 1 minute, the acceleration centrifugal of 17,85 G x 103 and the centrifugalization time of 14,86 minutes. The results showed that the biosurfactant produced have potential applications in several industrial sectors, beyond allowing one better exploitation of the manipueira
Mestrado
Mestre em Ciência de Alimentos
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Bazire, Alexis. "Influence de l'environnement et des communications inter-bactériennes sur la production de biosurfactants par Pseudomonas Aeruginosa." Lorient, 2005. http://www.theses.fr/2005LORIS058.
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La bioremèdiation, qui utilise la capacité naturelle des micro-organismes à disperser et dégrader les hydrocarbures, est l'une des perspectives des plus attractives pour la décontamination des zones souillées par les marées noires. Pseudomonas aeruginosa produit des biosurfactants (dispersants) de type glycolipides nommés rhamnolipides, dont la régulation dépend d'un système relatif à la densité cellulaire, le quorum sensing (QS). Lors de cette étude, la hiérarchie du QS fut pour la première fois mise en évidence par des cinétiques de production des deux molécules signal : la N-(3-oxododecanoyl)-L-homoserine lactone (3OC12-HSL) et la N-butyryl-L-homoserine lactone (C4-HSL) (HSL), les rhamnolipides étant produits ultérieurement. Nous avons montré que le facteur sigma RpoN était impliqué dans l'arrêt de synthèse des 3OC12-HSL et qu'il n'avait aucune influence sur la production des C4-HSL, alors qu'il inhibait la synthèse des rhamnolipides. En revanche, RpoS activait indirectement la production des rhamnolipides, via les HSL. Nous avons observé qu'une concentration en sel proche de celle de l'eau de mer inhibait la production des rhamnolipides, en diminuant l'expression des gènes impliqués dans la synthèse des biosurfactants (rhlAB et rhlC). L'expression de rhlI et la synthèse des HSL qui en dépend, étaient également diminuées. Le stress hyperosmotique agissait sur d'autres facteurs associés au QS comme la pyocyanine et la formation du biofilm. Un apport en osmoprotecteur (glycine bétaïne) a permis une restauration partielle des expressions génétiques et des phénotypes, démontrant l'intérêt de son utilisation pour la bioremèdiation maritime. Les facteurs environnementaux agissent également sur la production des rhamnolipides indépendamment du QS, puisqu'une carence en phosphate favorisait la production des biosurfactants alors qu'elle diminuait la concentration en HSL. Contrairement aux autres gènes impliqués dans la production des rhamnolipides, rhlG était induit par le stress salin. Nos résultats indiquent que RhlR (régulateur de transcription fixant C4-HSL) est le principal inhibiteur de rhlG et que l'inhibition est augmentée par une concentration élevée en C4-HSL. Les facteurs sigma RpoN et σ70 paraissent impliqués à parts égales dans la transcription de rhlG, et le complexe C4-HSL/RhlR inhiberait la transcription dépendante de RpoN. Nous n'avons en revanche pas pu confirmer que rhlG soit indispensable à la production des rhamnolipides. RhlG et rcsF qui sont organisés en opéron, seraient toutefois impliqués dans la croissance de P. Aeruginosa en milieu limité en oxygèneThe ability of micro-organisms to disperse and degrade hydrocarbons is used in bioremediation, which is one of the most attractive methods for the removal of crude oil in marine areas. Pseudomonas aeruginosa produces glycolipidic biosurfactants named rhamnolipids, the synthesis of which is regulated by a system depending of bacterial density: the quorum sensing (QS). In this study, the QS hierarchy was for the first time clearly shown by a time-course analysis of production of the two cell-to-cell signal molecules: N-(3-oxododecanoyl)-L-homoserine lactone (3OC12-HSL) and N-butyryl-L-homoserine lactone (C4-HSL), the rhamnolipids being subsequently produced. We showed here that the sigma factor RpoN stopped the production of 3OC12-HSL but had no effect on the C4-HSL one, despite its inhibitory effect on rhamnolipid production. RpoS was able to induce rhamnolipid production, probably by activating HSL production. We observed that a sea-water saline concentration inhibited rhamnolipid production, by reducing the expression level of the rhlAB, C and I genes, which are responsible for C4-HSL and rhamnolipid syntheses. Hyperosmotic stress also altered other QS-depending phenotypes such as pyocyanin production and biofilm formation. The osmoprotectant glycine betaine was able to partially restore genetic and phenotypic expressions, suggesting that its use is of interest for bioremediation procedures. Environmental factor could act on rhamnolipid production independently from the QS, since phosphate starvation increased the biosurfactant production although it decreased HSL concentration. Contrary to the other genes involved in rhamnolipid production, rhlG was induced by hyperosmotic stress. Our results indicate that RhlR (the transcription regulator which binds C4-HSL) is the main inhibitor of rhlG expression and that the inhibition is increased by high C4-HSL concentrations. RpoN and σ70 sigma factors could be equally involved in rhlG transcription, and the C4-HSL/RhlR complex could inhibit the RpoN-dependent transcription. Surprisingly, the requirement of rhlG for rhamnolipid production was not confirmed in our conditions. The co-transcribed rhlG and rcsF genes seemed to be involved in P. Aeruginosa growth in a poorly oxygenated medium
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Rosato, Antonella <1987>. "Bioremediation Enhancement of Marine Sediments Contaminated by Crude Oil with Biogenic Pollutants Mobilizing Agents and Biosurfactants." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amsdottorato.unibo.it/8143/1/Rosato_Antonella_tesi.pdf.
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One of the main limitations to the bioremediation of oil-contaminated marine sediments is the low hydrocarbons bioavailability. Aim of this PhD research project is to identify an environmental friendly approach to increase hydrocarbons bioavailability and biodegradation in oil-contaminated marine sediments.
Several surfactants/pollutant mobilizing agents have been selected and applied to slurry microcosms: two microbial surfactants (sophorolipids and rhamnolipids), two types of cyclodextrins (hydroxypropyl- and randomly methylated- β-cyclodextrins; HPB-CD and RAMEB-CD), two commercial soy lecithin products (de-oiled and raw) and bile acids.
Sophorolipids, cyclodextrins and to less extent, soy lecithins stimulated n-alkanes anaerobic degradation of actual oil-contaminated marine sediment from Gela (Sicily). Molecular analysis of 16S rRNA gene suggested that an Acidobacteria was probably responsible for the anaerobic biodegradation. Under aerobic condition, the same surfactants had inhibitor effects on n-alkanes degradation in Gela sediment, while HPB-CD and de-oiled soy lecithin were able to increase the degradation in crude oil-contaminated sediment from Ravenna.
Increase of n-alkane bioavailability in oil-contaminated Gela sediment occurred in the presence of the two cyclodextrins and raw soy lecithin, both immediately after oil contamination as well as after the complete adsorption of hydrocarbons to sediment.
Investigations of surfactant releasing formulations for the deployment of these agents to the sediments showed that HPB-CD could be efficiently encapsulated in agar hydrogels, while sophorolipids in polybutylene succinate (PBS) microspheres. The release rate of encapsulated HPB-CD was higher than encapsulated sophorolipids when formulations were incubated in marine water and similar in oil-contaminated sand slurries.
Both encapsulated surfactants remarkably reduced adsorption of freshly spiked hydrocarbons to sand; conversely, only agar-encapsulated HPB-CD were able to desorb n-alkanes in weathered contaminated sand and increase their bioavailability and biodegradation similarly to free cyclodextrins.
Therefore, encapsulation of HPB-CD in agar capsules might be the most promising solution for the enhancement of the bioremediation in marine sediment.
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Šimšová, Veronika. "Biotechnologická produkce sophorolipidů." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2019. http://www.nusl.cz/ntk/nusl-401874.
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This diploma thesis deals with the microbial production of sophorolipids by the Starmerella genus yeasts. The theoretical part of the thesis includes general characteristics of biosurfactants with the focus on sophorolipids. There are described the options of biotechnological production of sophorolipids and fields of their possible applications. Furthermore, the theoretical part deals with the describtion of Starmerella bombicola yeast, which is often used for biotechnological production of sophorolipids. Six strains of the Starmerella genus were cultured in the basic medium suitable for sophorolipid produsction. The amount of produced sophorolipids was tested by the emulsification capacity assay, solubilization of crystalline anthracene assay, measuring the surface tension by the Du-Noüy-Ring method and determination of the sophorolipid concentration by extraction with ethyl acetate. The purity of the extracted sophorolipids was inspected by the Fourier Transform infrared spectrosopy (FT-IR) Based on the results, the Starmerella bombicola CBS 6009 and the Starmerella anomalae CBS 14178 strains were studied in greater detail. They were cultured in several production media of different composition and the effect of the individual components on the ability of the sophorolipid production was monitored. Based on the results, it was evaluated that the composition of the medium has a great influence on the production ability of the strains. The highest production rate of sophorolipids was achieved in the basic production medium and so was in the medium containing molasses and Indian waste oil. The cultivation mode has great effect on the sophotolipid production rate. It has been found that when cultured in a bioreactor, the strains produced sophorolipids in a larger amount and of a different quality than in the shaker flasks.
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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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Maciel, Inês Maria Cals Theophilo. "Avaliação do potencial de bactérias para degradar derivados do petróleo e produzir biossurfactantes." http://www.teses.ufc.br/, 2003. http://www.repositorio.ufc.br/handle/riufc/1229.
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MACIEL, Inês Maria Cals Theophilo. Avaliação do potencial de bactérias para degradar derivados do petróleo e produzir biossurfactantes. 2003. 40 p. Dissertação (Mestrado em Ciências Marinhas Tropicais) - Universidade Federal do Ceará, Instituto de Ciências do Mar, Fortaleza, 2009.Submitted by Debora Oliveira (deby_borboletinha@hotmail.com) on 2011-11-22T14:03:20Z No. of bitstreams: 1 2003_dis_imctmaciel.pdf: 490927 bytes, checksum: c86bd045b67c0d15f211c99957f58bdf (MD5)
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The present work describes the results of the evaluation of two bacteria strains isolated from the oil polluted effluent, to degrade petroleum derivatives and to produce biosurfactants. Morphologic, cultural, biochemical and physiologic studies showed that these bacteria, previously denominated strain 03 and strain 04, could be identified as Acinetobacter spp. and Bacillus spp., respectively. The biodegradation potential of these bacteria was evaluated by cultivating them in mineral broth, containing, glycerol, gasoline, kerosene or diesel as the only source of carbon and energy. Both bacteria degraded glycerol, gasoline, kerosene and diesel and produced biosurfactants. In general, the bacteria showed better performances at glycerol presence, as confirmed by the measures of cellular density and emulsificant activity, while the diesel was the worst substrate to both bacteria. The biosurfactant production was evaluated by measuring bacteria capacity for emulsificating kerosene. The results showed an emulsification of 50% for the biosurfactants produced from glycerol by the bacteria. Bacillus spp., practically, did not grow and did not produce biosurfactant when cultivated in medium with diesel, surviving, however, in the spore form. The supplementation of that culture with 0.04 % of yeast extract, however, stimulated the growth and biosurfactants production, reaching 95% of emulsification. The results of the analyses of the biosurfactants extracted from the cultures with glycerol, by infrared spectroscopy and carbohydrate and protein analyses, suggest the classes of the liposaccharides and polypeptides for the biosurfactants produced by the bacteria Acinetobacter spp. and Bacillus spp., respectively. These bacteria were shown to be susceptible to heat, being destroyed at the temperature of 46 ºC, at 1,0 mg/L of sodium hypochloride and pH below 5.0. On the other hand, they resisted to 5% NaCl, a desirable characteristic for use in marine bioremediation programs.
O presente trabalho descreve os resultados da avaliação de duas cepas de bactérias isoladas a partir de um efluente contaminado com óleo, para degradar derivados do petróleo e produzir biossurfactantes. Através de estudos de suas características morfológicas, culturais, bioquímicas e fisiológicas, as bactérias selecionadas, nomeadas preliminarmente cepa 03 e cepa 04, foram identificadas como Acinetobacter spp. e Bacillus spp., respectivamente. A capacidade biodegradativa dessas bactérias foi avaliada cultivando-as em meio mineral mínimo, contendo, sempre, um dos hidrocarbonetos a serem testados, como única fonte de carbono e energia. As duas bactérias degradaram o glicerol, a gasolina, o querosene e o diesel e, produziram biossurfactantes. De maneira geral, as bactérias mostraram melhor desempenho na presença de glicerol, como confirmado pelas medidas de densidade celular e atividade emulsificante, enquanto o diesel foi o pior substrato para ambas as bactérias. A produção de biossurfactante foi avaliada medindo-se a sua capacidade para emulsificar o querosene. Através dessa técnica, encontrou-se um porcentual de 50% de emulsificação para os biossurfactantes produzidos pelas duas bactérias a partir de glicerol. O Bacillus spp., praticamente, não cresceu e não produziu biossurfactante quando cultivado em meio com diesel, sobrevivendo, contudo, na forma de esporos. A suplementação dessa cultura com extrato de levedura 0,04%, entretanto, promoveu a estimulação do crescimento e da produção de biossurfactantes, atingindo um percentual de 95% de emulsificação. Os resultados das análises dos biossurfactantes extraídos a partir das culturas com glicerol, por espectroscopia infravermelha e análises de carboidratos e proteínas, sugerem as classes dos lipossacarídios e polipeptídios, para os biossurfactantes produzidos pelas bactérias Acinetobacter spp. e Bacillus spp., respectivamente. As duas bactérias se mostraram suscetíveis ao calor, sendo destruídas à temperatura de 46 ºC, 1 ppm de hipoclorito de sódio e pH abaixo de 5,0. Por outro lado, resistiram a 5% de NaCl, uma característica desejável para utilização dessas cepas em situações de biorremediação de ambientes marinhos contaminados com óleo.
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Liley, Jessica R. "Optimising the blending of biosurfactants with conventional home and personal care components : a surface and solution study." Thesis, University of Oxford, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.711697.
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Chaprão, Marcos José. "Aplicação de biossurfactantes na remediação de areia contaminada com hidrocarbonetos." Universidade Católica de Pernambuco, 2015. http://www.unicap.br/tede//tde_busca/arquivo.php?codArquivo=1075.
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Os biossurfactantes, compostos tensoativos produzidos por microorganismos, vem sendo utilizados com sucesso na remediação de solos em função da eficiência dessas biomoléculas no aumento da dispersão e da biodegradação de hidrocarbonetos e de suas propriedades como biodegradabilidade e toxicidade reduzida. Nesse sentido, esse trabalho teve como objetivo investigar a aplicação de dois biossurfactantes, sendo um obtido da levedura Candida sphaerica e outro da bactéria Bacillus sp., produzidos a partir de resíduos industriais, na remediação de hidrocarbonetos de óleo lubrificante de motor em solo arenoso contaminado em laboratório. Os
biossurfactantes foram testados na remoção do óleo em ensaios cinéticos e estáticos. Estudos comparativos com os surfactantes sintéticos Tween 80 e Triton X-100 também foram conduzidos. Em seguida, os biossurfactantes foram aplicados na biorremediação do solo arenoso contaminado a fim de avaliar a capacidade dessas biomoléculas em facilitar a biodegradação microbiana do contaminante. Ambos os biossurfactantes brutos e isolados mostraram
eficiência na remoção do óleo de motor da areia contaminada em condições cinéticas (70-90 %), enquanto que os surfactantes sintéticos removeram entre 55 e 80 % do óleo sob as mesmas condições. O aumento na concentração dos biossurfactantes e dos surfactantes sintéticos não aumentou o percentual de remoção do óleo, enquanto que um tempo de contato de 5-10 min, sob agitação, foi suficiente para a remoção do óleo por todos os agentes tensoativos testados. O biossurfactante bruto e isolado de C. sphaerica foi capaz de remover cerca de 90 % de óleo de motor nas colunas empacotadas quando comparado com o biotensoativo de B. sp., o qual removeu cerca de 40
% do óleo. Para os experimentos de degradação conduzidos na areia
contaminada com o óleo de motor e enriquecida com melaço de cana de açúcar; no entanto, a degradação do óleo atingiu aproximadamente 100 % após 90 dias na presença das células do isolado de B. sp., enquanto que o percentual de degradação do óleo não ultrapassou os 50 % na presença da C. sphaerica. A presença dos biossurfactantes aumentou a taxa de degradação do óleo em 10-20 %, especialmente durante os primeiros 45 dias de experimento, indicando que os biossurfactantes aceleraram a taxa de degradação dos hidrocarbonetos. Os resultados obtidos demonstraram que os
biossurfactantes testados são promissores como agentes de remediação, podendo agir não só na remoção de óleos como também no aumento da capacidade de biodegradação de poluentes hidrofóbicos em solos.The biosurfactants, tension active compounds produced by microorganisms, have been successfully used in bioremediation processes and soil washing since the efficiency of these biomolecules in increasing the dispersion and the biodegradation of hydrocarbons. Their properties such as low toxicity and biodegradability are also very attractive for environmental applications. Thus, this study investigated potential application of two biosurfactants for enhanced removal capability and biodegradation of motor oil contaminated sand under laboratory conditions. The biosurfactants were produced by the yeast Candida sphaerica and by the bacterium Bacillus sp. cultivated in low-cost substrates. The ability of removing motor oil from soil by the two biosurfactants was identified and compared with that of the synthetic surfactants Tween 80 and Triton X-100. Both crude and isolated biosurfactants showed excellent effectiveness on motor oil removal from contaminated sand under kinetic conditions (70-90%), while the synthetic surfactants removed between 55 and 80% of the oil under the same conditions. The increase in biosurfactants and synthetic surfactants concentration did not enhance the removal of oil. A contact time of 5-10 min under agitation seemed to be enough for oil removal with the biosurfactants and synthetic surfactants tested. The crude and the isolated biosurfactant produced by C. sphaerica were able to remove high percentages of motor oil from packeded comumns (around 90%) when compared to the biosurfactant from Bacillus sp. (40%). For the degradation experiments conducted in motor oil contaminated sand enriched with sugar cane molasses, however, oil degradation was approximately 100% after 90 days in the presence of B. sp. cells, while the percentage of oil degradation did not exceed 50 % in the presence of C. sphaerica. The presence of the biosurfactants increased the degradation rate in 10-20%, especially during the first 45 days of the experiments, indicating that biosurfactants acted as efficient enhancers for hydrocarbon biodegradation. The results indicated the biosurfactants enhancing capability on both removal and rate of motor oil biodegradation in soil systems.
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Invally, Krutika Ravi. "Process optimization for rhamnolipids production and their environmental impacts." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1541755267451868.
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Meylheuc, Thierry. "Influence de biosurfactants sur l'adhesion de listeria monocytogenes a des surfaces inertes : consequences sur la desinfection (doctorat : microbiologie)." Paris 11, 2000. http://www.theses.fr/2000PA114835.
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Ngoya, Sandra. "Caractérisation physiologique et physico-chimique des Pseudomonas Fluorescens productrices ou non de biosurfactants. Première approche du comportement bioadhésif." Rouen, 2007. http://www.theses.fr/2007ROUES054.
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Pseudomonas fluorescens est une bactérie psychrotrophe ubiquitaire retrouvée dans tout type d’environnement, incluant les sols, les eaux (marines et douces), l’air, mais également associée à des hôtes eucaryotes (végétaux, animaux, voire humain). Les biosurfactants sont une classe de molécules tensioactives, structuralement variées et synthétisées par de nombreux microorganismes. De nombreux travaux ont révélé que les biosurfactants avaient un effet limitant sur l’adhésion des bactéries aux surfaces. La surface membranaire étant la première barrière entre les cellules et l’environnement, ce travail se propose d’étudier les effets des surfactants sur la surface membranaire. Nous avons recherché les biosurfactants produits par une collection de souches de P. Fluorescens provenant d’environnements très différents tels que hôpitaux, végétaux et rhizosphère en fonction de la température de culture des bactéries. Les principaux biosurfactants identifiés chez ces bactéries sont des cyclolipopeptides (CLP). Ces CLP sont surtout connus pour leurs propriétés antifongiques ou antibiotiques au niveau de la rhizosphère. Nos études ont révélé de fortes potentialités de production de CLP à 17°C, dont certains n’avaient pas encore été identifiés, voire découverts. Cette présence exclusive de CLP est indépendante de l’origine d’isolement des souches et peut varier suivant la température. La caractérisation morphologique, physico-chimique et hémolytique de souches bactériennes productrices ou non de CLP a montré que les biosurfactants, suivant leur polarité, pouvaient induire de nombreuses modifications des paramètres liés à la surface bactérienne. Des tests permettant d’évaluer le comportement bactérien au cours des premières étapes de l’adhésion aux surfaces ont démontré que ces variations intra-espèces sont liées à la composition de la surface bactérienne ainsi qu’au micro-environnementPseudomonas fluorescens is a psychrotrophic ubiquitous bacterium which is found in several environments, including grounds and marine or fresh water and air, but also associated to eukaryote hosts (plants, animals and human). Biosurfactants are a tensioactive class of molecules, structurally varied and synthesised by many micro-organisms. Many studies revealed that biosurfactants have a limiting effect to the bacterial adhesion on surface. Because of the outer membrane constituting the first barrier between the cell and the environment, we studied the effects of biosurfactants on surface membrane physicochemical properties. Surface actives compounds were searched for many Pseudomonas fluorescens strains from various environments such as hospitals, plants and rhizosphere according to the temperature of culture of the bacteria. Several biosurfactants identified in these bacteria are cyclic lipopeptides (CLP). These CLP are mostly known for their antifungal or antibiotic properties on rhizosphere. Our studies revealed many possibilities of CLP production at 17°C, including some unidentified or even discovered yet. This exclusive presence of CLP is independent of the origin of isolation of strains and varies depending on temperature. For bacteria strains producer or not of CLP, morphologic, physiochemical and haemolytic characterization show that biosurfactants, depending on their polarities, might induced many modifications linked to bacteria surfaces parameters. Some studies allowing the bacteria evaluation behaviour during the first stage of adhesion on surfaces, have demonstrated that these intra species changes are associated to the surface composition and also to micro-environment
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Shakeri, Fard Parvin. "Production and purification of biosurfactants and study of their influence on surface properties of stainless steel and Teflon." Thesis, Lille 1, 2010. http://www.theses.fr/2010LIL10006/document.
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Dans cette étude, un ensemble de molécules biosurfactantes a été choisi en fonction de leur diversité structurale et leur aptitude à être produites dans des procédés industriels. Cet ensemble contient des membres des trois familles de composés lipopeptidiques produits par des souches de Bacillus subtilis comprenant la surfactine S1, l’iturine A et la mycosubtiline (deux membres de la famille des iturines) et la fengycine, ainsi que des rhamnolipides produits par Pseudomonas aeruginosa PTCC 1637. Après purification et/ou caractérisation par plusieurs méthodes analytiques, ces composés ont été étudiés pour leur aptitude à modifier l’hydrophobicité de surface de deux substrats, l’acier inoxydable et le Téflon. Ces modifications ont été évaluées par des mesures d’angle de contact de l’eau. Les effets dépendent de la biomolécule, de sa concentration et du substrat. Le traitement de l’acier inoxydable avec différentes concentrations, entre 1 et 100 mg l-1, de surfactine S1 et de rhamnolipides a montré une augmentation de l’hydrophobicité. Sur le même substrat, la fengycine augmente l’hydrophobicité jusqu’à sa concentration micellaire critique (6,25 mg l-1). Avec des concentrations plus élevées en fengycine, une réduction de l’hydrophobicité est observée. La surfactine, la mycosubtiline et l’iturine diminuent l’hydrophobicité sur le Téflon. Des analyses par XPS de surfaces traitées par les lipopeptides ont confirmé la présence des différentes biomolécules. Les relations entre structure, CMC et les propriétés de modifications de surface sont discutées. L’adhésion de spores de Bacillus cereus 98/4, à des surfaces conditionnées par ces biosurfactants, a ensuite été étudiée. Il y a une bonne correlation entre les modifications de l’hydrophobicité et l’adhésion des spores de B. cereus 98/4 à ces surfaces. L’augmentation de l’hydrophobicité des surfaces augmente l’adhésion des spores et vice versaIn this study, a set of biosurfactant molecules was chosen in function of their structural diversity and their ability to be easily produced in industrial processes. This set contains members of three families of lipopeptidic compounds produced by Bacillus subtilis strains including surfactin S1, iturin A and mycosubtilin (two members of the iturin family) and fengycin, as well as rhamnolipids produced by Pseudomonas aeruginosa PTCC 1637. After purification and/or characterization by several analytical methods, these compounds were examined for their ability to modify the surface hydrophobicity of the two substrata stainless steel and Teflon.These modifications were evaluated by water contact angle measurements. The effects depend on the biomolecule, the concentration, and the substratum. Treatment of stainless steel with different concentrations between 1 and 100 mg l-1 of surfactin S1 and rhamnolipids showed an increase in the hydrophobicity. On the same substratum, fengycin increased hydrophobicity up to its critical micelle concentration (6.25 mg l-1). With higher concentrations of fengycin, a decrease in hydrophobicity was observed. Surfactin, mycosubtilin and iturin A decreased hydrophobicity on Teflon. XPS analyses of surfaces treated by lipopeptides confirmed the presence of the different biomolecules. Relationships between structure, CMC, and modifications of surface properties are discussed.Then, the attachment of Bacillus cereus 98/4 spores to conditioned surfaces by these biosurfactants was studied. There are promising correlations between hydrophobicity modifications of surfaces and the attachment of B. cereus 98/4 spores to these surfaces. Enhancement in hydrophobicity of surfaces increases the number of adhering spores to them and vice versa. Finally, a strategy was developed to overproduce a less studied lipopeptide from Bacillus licheniformis, lichenysin which was structurally slightly different from surfactin
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Corre, Marie-Hélène. "Identification et caractérisation de composés produits par des bactéries environnementales pour la lutte biologique contre Legionella pneumophila." Thesis, Poitiers, 2018. http://www.theses.fr/2018POIT2309/document.
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Les circuits et réseaux d’eau subissent épisodiquement des problèmes de contamination par des microorganismes tels que Legionella pneumophila, conduisant à la dégradation de la qualité microbiologique de l’eau circulante. De nouveaux moyens de traitements doivent être mis en place de façon notamment à limiter l’usage de biocides chimiques. Ce travail de thèse s’inscrit dans cette problématique et a pour objectif d’identifier de nouveaux composés actifs contre L. pneumophila en tenant compte de son comportement et de ses interactions au sein de son microenvironnement. De manière à obtenir des composés produits par des souches bactériennes appartenant à la même niche écologique que L. pneumophila, une campagne de prélèvement d’eau a été réalisée. Un total de 273 isolats environnementaux ont été isolés et testés contre L. pneumophila. Les résultats obtenus indiquent que 178 de ces isolats (65%) présentent une activité anti-Legionella. Quatre souches ont ensuite été sélectionnées (Aeromonas bestiarum SW257, Rahnella aquatilis SW265, Flavobacterium spp. PW52 et Pseudomonas spp PW329) et les composés actifs produits ont été caractérisés. A. bestiarum SW257 produit un peptide anti-Legionella. Flavobacterium sp. PW52 produit un mélange de composés anti-Legionella ayant des propriétés tensioactives, les flavolipides. Pseudomonas sp. PW329 produit des composés organiques volatiles, identifiés par SPME-GC-MS, actifs contre L. pneumophila. Enfin, R. aquatilis SW265 produit un sidérophore à activité anti-LegionellaWater is essential to sustain life and water sources used for human consumption must be biologically safe, to avoid any risk for health. Indeed, the most common and widespread health risk associated with drinking water are infectious diseases caused by pathogenic microorganisms such as Legionella pneumophila. However, more efforts are needed to control disinfection by-products and minimize people exposure to potentially hazardous chemicals while maintaining adequate disinfection to ensure good water quality. Thus, this work aimed to find natural antibacterial compounds to control L. pneumophila growth using bacteria from freshwater environments. Environmental aquatic bacteria were sampled from five freshwater sources to get a large culturable bacterial collection. A total of 273 bacterial isolates were recovered and screened for their ability to produce anti-Legionella compounds. Among those, 178 (65%) were shown to be active against L. pneumophila. Four strains (Aeromonas bestiarum SW257, Rahnella aquatilis SW265, Flavobacterium spp. PW52, and Pseudomonas spp PW329) were next selected for the characterization of their active compounds. A. bestiarum SW257 produces an anti-Legionella peptide, and Flavobacterium spp PW52 produces a mixture of anti-Legionella compounds with surface active properties, named flavolipids. Finally Pseudomonas sp. PW329 delivers many volatile organic compounds, and R. aquatilis SW26 produces a anti-Legionella siderophore
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Gueissaz-Teufel, Muriel. "Production sous conditions non stériles de biosurfactants synthétisés à partir de rejets industriels pour le lavage de sol contaminé." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0018/MQ46651.pdf.
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