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Aitken, Carolyn M. "Identification of non-hydrocarbon metabolites of deep subsurface anaerobic petroleum hydrocarbon biodegradation." Thesis, University of Newcastle Upon Tyne, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437844.
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Toccalino, Patricia. "Optimization of hydrocarbon biodegradation in a sandy soil /." Full text open access at:, 1992. http://content.ohsu.edu/u?/etd,192.
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Ripley, Mark Brian. "Hydrocarbon bioremediation using bioactive foam." Thesis, University of York, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313765.
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Lehrer, Michael Robert. "ENHANCED HYDROCARBON BIODEGRADATION USING BIOAUGMENTATION WITH BIOWISHTM-AQUA FOG." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/763.
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This study was done to determine the effectiveness of a commercially available bioaugmentation product, BiOWiSHTM-Aqua FOG, for remediating petroleum-contaminated sandy soil. Biodegradation enhancement by BiOWiSHTM-Aqua FOG was evaluated in laboratory microcosms by directly measuring total petroleum hydrocarbon (TPH) and indirectly using respirometry. Attempts were made to enrich hydrocarbon-degrading bacteria in BiOWiSHTM-Aqua FOG, and the resulting enrichment cultures were screened using respirometry as well. Potential hydrocarbon-degrading bacteria in BiOWiSHTM-Aqua FOG were isolated. Experiments were performed at bench-scale using microcosm bottles containing sand contaminated with either motor oil or No. 2 diesel fuel. The microcosms were incubated at 25oC under aerobic conditions. TPH measurements of soil in the microcosms at 0, 25 and 56 days indicated that the addition of 500-ppm BiOWiSHTM-Aqua FOG improved biodegradation of the motor oil-contaminated soil by 45%. However, BiOWiSHTM-Aqua FOG did not have a measurable effect on biodegradation in the diesel-contaminated soil.
In the respirometry experiments, BiOWiSHTM-Aqua FOG and two hydrocarbon-enriched BiOWiSHTM-Aqua FOG cultures were evaluated indirectly by the measurement of microbial carbon dioxide production and oxygen uptake using a MicroOxymaxTM respirometer. The respirometry experiments showed that in the six-day period following motor oil-contamination of soil, the addition of BiOWiSHTM-Aqua FOG substantially improves biodegradation rates. The added organisms in the product out-performed the indigenous organisms in the 5-6 days following contamination of the soil. The CO2 production observed in the BiOWiSHTM microcosms contaminated with motor oil was much greater than CO2 production without motor oil, which confirms that the observed metabolism can be attributed to motor oil biodegradation rather than metabolism of other organic material in the soil. Enriched consortia consistently generated far less CO2 than microcosms with the 500 ppm BiOWiSHTM-Aqua FOG. Stoichiometric calculations suggested that BiOWiSHTM-Aqua FOG removed approximately 1400 ppm TPH (14%) from the soil in 6.5 days, while an enrichment culture of BiOWiSHTM-Aqua FOG only reduced TPH levels by 459 ppm (5%). This result suggests that increased biodegradation rate in bioaugmented soil is aided by biodiversity in the augmenting inoculum. A potential hydrocarbon-degrading candidate organism was isolated from the product and cultured on Bushnell-Haas agar and plate-count agar (PCA). While at least two distinct colony types were successfully grown on media with motor oil, these same colonies appeared on Bushnell-Haas agar with no apparent carbon source, and survived repeated transfers onto this same medium. Therefore, their status as hydrocarbon-degraders is inconclusive. More thorough enrichment work could be pursued, especially using soil samples collected from petroleum-contaminated sites.
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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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Molson, John W. H. "Numerical simulation of hydrocarbon fuel dissolution and biodegradation in groundwater." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0019/NQ56676.pdf.
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Aganbi, Eferhire. "Investigation of aromatic hydrocarbon biodegradation in estuarine and aquifer sediments." Thesis, University of Essex, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.446009.
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Amodu, Olusola S. "Biodegradation of polycyclic aromatic hydrocarbon contaminants in a mixed culture bioreactor." Thesis, Cape Peninsula University of Technology, 2015. http://hdl.handle.net/20.500.11838/934.
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Thesis submitted in fulfilment of the requirements for the degree of Doctor Technologiae: Chemical Engineering, Faculty of Engineering at the Cape Peninsula University of Technology - Cape Town, South AfricaPolycyclic aromatic hydrocarbons (PAHs) are one of the most common and recalcitrant environmental contaminants – known for their potential toxicity, mutagenicity, and carcinogenicity to humans. Biosurfactant application can enhance the biodegradation of PAHs. The main object of this work was to explore the novelty of biosurfactant produced by the isolated strains of Bacillus sp and Pseudomonas aeruginosa grown exclusively on Beta vulgaris, and the modification of the zeolites nanoparticles by the biosurfactant, for enhanced biodegradation of PAHs in soil. Novel biosurfactant-producing strains were isolated from hydrocarbon-contaminated environments, while several agrowaste were screened as primary carbon sources for the expression of biosurfactants, which were quantified using various standardized methods......
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Ziegler, Brady Allen. "Biogeochemical controls on arsenic cycling in a hydrocarbon plume." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/84443.
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Arsenic (As) in drinking water poses a critical threat to public health. More than 150 million people worldwide are at risk of developing diseases from unsafe concentrations of As in groundwater. Arsenic occurs naturally in rocks, soils, and sediments and generally remains associated with solid phases. However, changes in aquifer geochemistry can mobilize As into groundwater, contaminating drinking water sources.
This dissertation investigates As cycling in an aquifer contaminated by petroleum hydrocarbons near Bemidji, Minnesota, where As is mobilized into groundwater due to biodegradation of hydrocarbons coupled to reduction of ferric oxides. The first project describes how aquifer sediments act as both sources and sinks for As in groundwater, depending on the prevailing redox conditions. Results show that As is released to groundwater near the hydrocarbon source but is removed near the hydrocarbon plume's leading edge. Comparison of data from 1993 to 2016 shows that As has been redistributed in aquifer sediment as the plume has expanded over time. The second project presents a mass balance for As, which shows that despite elevated As in groundwater (up to 230 μg/L), >99.7% of As mass in the aquifer is in sediments. Calculations demonstrate that As in sediment can be 22x less than the method detection limit and still cause unsafe concentrations in groundwater, suggesting that the use of standard methods limits our ability to predict where naturally occurring As poses a threat to groundwater. In the third project, a reactive transport model simulates As cycling for 400 years. Results show that sorption of As to ferrihydrite limits As transport within 300 m of the hydrocarbon source. Modeling predicts that over the plume's lifespan, more groundwater will be contaminated by As than benzene, the primary contaminant of concern in hydrocarbon plumes.
Combined, these studies suggest that many aquifers are vulnerable to unsafe As concentrations due to mobilization of natural As if bioavailable organic carbon is introduced. Although aquifers can attenuate As, it may take centuries for As to be fully removed from groundwater, suggesting it is prudent to account for natural contaminants like As when developing remediation strategies at petroleum spill sites.Ph. D.
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Tibui, Aloysius. "Biodegradation of Aliphatic Chlorinated Hydrocarbon (PCE, TCE and DCE) in Contaminated Soil." Thesis, Linköping University, The Tema Institute, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-7908.
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Soil bottles and soil slurry experiments were conducted to investigate the effect of some additives on the aerobic and anaerobic biodegradation of chlorinated aliphatic hydrocarbons; tetrachloroethylene (PCE), trichloroethylene (TCE) and dichloroethylene (DCE) in a contaminated soil from Startvätten AB Linköping Sweden. For the aerobic degradation study the soil sample was divided into two groups, one was fertilised. The two groups of soil in the experimental bottles were treated to varying amount of methane in pairs. DCE and TCE were added to all samples while PCE was found in the contaminated soil. Both aerobic and anaerobic experiments were conducted. For aerobic study air was added to all bottles to serve as electron acceptor (oxygen). It was observed that all the samples showed a very small amount of methane consumption while the fertilised soil samples showed more oxygen consumption. For the chlorinated compounds the expected degradation could not be ascertained since the control and experimental set up were more or less the same.
For the anaerobic biodegradation study soil slurry was made with different media i.e. basic mineral medium (BM), BM and an organic compound (lactate), water and sulphide, phosphate buffer and sulphide and phosphate buffer, sulphide and ammonia. To assure anaerobic conditions, the headspace in the experimental bottles was changed to N2/CO2. As for the aerobic study all the samples were added DCE and TCE while PCE was found in the contaminated soil. The sample without the soil i.e. the control was also given PCE. It was observed that there was no clear decrease in the GC peak area of the pollutants in the different media. The decrease in GC peak area of the pollutants could not be seen, this may be so because more susceptible microorganisms are required, stringent addition of nutrients and to lower the risk of the high concentration of PCE and petroleum products in the soil from Startvätten AB.
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Ehlers, George A. C. "Integrated anaerobic/aerobic bioprocess environments and the biodegradation of complex hydrocarbon wastes." Thesis, Rhodes University, 2004. http://hdl.handle.net/10962/d1004071.
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An investigation of the biodegradation of complex hydrocarbon wastes, with emphasis on chlorinated aromatic compounds, in an anaerobic/aerobic bioprocess environment was made. A reactor configuration was developed consisting of linked anaerobic and aerobic reactors which served as the model for a proposed bioremediation strategy targeting subterranean soil/sediment/aquifer chlorinated phenol-contaminated environments. Here oxygen is frequently limited and sulphate is readily available, as occurs especially in marine sediment and intertidal habitats. In the anaerobic system the successful transformation and mobilization of the model contaminant, 2,4,6-trichlorophenol, was shown to rely on reductive dechlorination by a sulphate-reducing dependent dechlororespiring co-culture. This was followed in the aerobic system by degradation of the pollutant and its metabolites, 2,4-dichlorophenol, 4-chlorophenol and phenol, by immobilized white-rot fungi.The strategy was initially investigated separately in laboratory bench- and intermediate scale reactors whereafter reactors were linked to simulate the integrated biodegradation strategy. The application of the fungal reactor to treat an actual waste stream by degrading complex mixtures of hydrocarbons in a waste oil recycling effluent was also investigated. The mineralization of phenol and 2,4,6-TCP by immobilized fungal cultures was studied in pinewood chip and foam glass bead-packed trickling reactors. The reactors were operated in sequencing batch format. Removal efficiency increased over time and elevated influent phenol and TCP (800 and 85 mg.L⁻¹) concentrations were degraded by > 98 % in 24 – 30 h batch cycles. Comparable performance between the packing materials was shown. Uptake by the packing was negligible and stripping of compounds induced by aeration had a minimal effect on biodegradation efficiency. Reactor performances are discussed in relation to sequencing batch operation and nutrient requirements necessary to sustain fungal activity in inert vs. organic material packed systems. It was shown that a co-culture consisting of sulphate-reducing and dechlororespiring bacteria established in fed-batch and soil flasks, as well as pine chip-packed fluidized bed reactors. Results showed reductive dechlorination of 2,4,6-TCP to be in strict dependence on the activity of the sulphate-reducing population, sulphate and lactate concentrations. Transformation to 2,4-DCP, 4-CP and phenol was enhanced in sulphate deficient conditions. Dechlororespiring activity was found to be dependent on the fermentative activity of sulphate-reducing bacteria, and the culture was also shown to mobilize and dechlorinate TCP in soils contaminated with the pollutant. Linking the systems achieved degradation of the compound by > 99 % through fungal mineralization of metabolites produced in the dechlororespiring stage of the system. pH correction to the anaerobic reactor was found to be necessary since acidic effluent from the fungal reactor inhibited sulphate reduction and dechlorination. The fungal reactor system was evaluated at intermediate-scale using a complex waste oil recycling effluent. Substantial COD reduction (> 96 % in 48 h batch cycles) and removal of specific effluent hydrocarbon components was shown in diluted, undiluted (COD > 37 g.L⁻¹) and 2,4,6-TCP-spiked effluents. Industrial application of the fungal reactor was evaluated in a 14 m³ pilot plant operated on-site at a waste oil processing plant.
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Baruah, Mihika. "Laboratory evaluation of polycyclic aromatic hydrocarbon biodegradation at a former tar plant site." Connect to this title online, 2008. http://etd.lib.clemson.edu/documents/1220474373/.
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Zoeckler, Jeff Radcliffe. "Aerobic Biodegradation of MTBE in Uncontaminated and Gasoline-Contaminated Aquifer Sediments." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/43865.
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In this study, the biodegradation potential of MTBE in uncontaminated and previously contaminated aquifer sediments under aerobic conditions was investigated. Laboratory microcosms were constructed using aquifer samples collected from three different areas of a shallow gasoline-contaminated aquifer in eastern Fairfax Co., Va in the Atlantic Coastal Plain province. Uncontaminated aquifer samples were collected upgradient of the plume, and contaminated aquifer samples were collected in the source area and in an area downgradient of the source. Biodegradation of MTBE was observed in microcosms that contained previously contaminated aquifer sediments. More complete degradation was observed in aquifer sediments containing a low level of petroleum contamination than in heavily contaminated aquifer sediments. Biodegradation of MTBE appeared to be limited by a lack of oxygen in heavily contaminated soils. When degradation was discernible it appeared to follow a first order pattern with a rate constant (l) of between 0.037 and 0.066 d-1, following a lag period of 20 to 40 days. In microcosms containing lightly contaminated aquifer material, MTBE was respiked during active metabolism, and degradation occurred with no lag or acclimation period. Results indicated that little or no degradation occurred in the microcosms containing uncontaminated soil. The results of this research suggest that the availability and level of petroleum hydrocarbon compounds influence indigenous microorganisms capable of degrading MTBE.Master of Science
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Feng, Yuchi. "Effect of Salt on Biodegradation of Model Alkanes and Crude Oil Saturates by Hydrocarbon-degrading Bacteria." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32580.
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Crude oil leakages often give rise to in situ contamination with both oil and salt. In this study, the biodegradation of model alkanes and of saturated hydrocarbons in whole crude oil by hydrocarbon-degrading bacteria was investigated at different salt (NaCl, KCl, Na2SO4) concentrations. Changes in cell surface hydrophobicity at different NaCl concentrations were also investigated.
The results show that with increasing NaCl concentration, the lag phase for strain growth on hydrocarbons was prolonged; however, the total degradation efficiency was not influenced greatly. The formation of different sizes of cell aggregates at different salt concentrations indicated that salt could indirectly influence mass transfer of hydrocarbons from the medium to the interior of the cells. The results also showed that KCl had a less inhibitory effect on biodegradation than NaCl, and changes of Na2SO4 concentration did not greatly affect biodegradation. In addition, cell surface hydrophobicity increased with increasing NaCl concentration when the cultures were grown on hydrocarbons.
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Vogdt, Joachim. "Bioremediation of petroleum hydrocarbon contaminated soil." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-02132009-172348/.
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Wu, Tong. "Application of computational fluid dynamics to the biopile treatment of hydrocarbon contaminated soil." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/5713.
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Biopiles are a common treatment for the ex-situ remediation of contaminated soil. Much research has been carried out on understanding and modelling of bioremediation techniques related to biopiles, but hitherto no study has attempted to model the effect on a biopile by its ambient surroundings. A hydraulics-based approach to simulating a biopile in the context of its ambient surroundings is presented in this study, taking into account physical, chemical and biological processes within the pile, external conditions of wind and temperature, the location of aeration pipes and venting pressure, and considering the spatial distribution of treatment as well as contaminant within the pile. The simulation approach was based upon a fluid flow model which couples Eulerian multiphase flow model and Darcy’s Law for immiscible fluid flow through porous media, a species transport model integrating advection, diffusion/dispersion and biodegradation, and a heat transfer model considering the interphase temperature equilibrium. A Computational Fluid Dynamics (CFD) system has been developed to solve this set of mathematical models by applying the commercial CFD package FLUENT, and various trial simulations have been carried out to examine the potential of the hydraulics approach for practical applications. The simulation produces reasonable results: the biodegradation process relates to the temperature within the pile, and the temperature in turn relates to wind speed and aeration details; due to the various fluid flow patterns, the contribution of each remediation mechanism (contaminant loss to atmosphere via pile surface, contaminant loss to aeration pipe and biodegradation) varies according to the aeration method; contaminant interphase transfer between different pairs of phases have greatly different impacts on contaminant removal. A number of counter-intuitive results are presented, indicating that simulations of this type will give valuable insight into the practical design of biopiling systems. The simulation system also allows the total environmental footprint of biopiling to be considered, examining not just degradation of contaminant but also its removal via volatilization and the energy used in heating air for venting. Further, the application of the approach formulated in this study is not limited to biopiles, but can also be expanded to related in situ bioremediation techniques.
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Vivian, Rafael Bitencourt. "ANÁLISE DE CONTAMINAÇÃO EM SOLO E ÁGUA SUBTERRÂNEA POR HIDROCARBONETOS DERIVADOS DE PETRÓLEO." Universidade Federal de Santa Maria, 2015. http://repositorio.ufsm.br/handle/1/7649.
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This research aimed to delineate the contamination plume, coming from a leak in the fuel station dealer, penetrating crystalline aquifer in the Rio Grande do Sul state southern Brazil. Determined with the use of a steam THERMO GASTECH Analyzer, model Innova SV, were measured in situ concentrations of volatile organic compounds (VOC) in soils. For the identification of hydrocarbons in free phase (portion of supernatant contaminants in groundwater). Was employed a digital level meter model HSIFD-30, which allowed the detection of fluids (contaminants) in free phase using probe that measures the water and oily fluid interface. The heterotrophic bacteria count and identification of the groundwater, to verify the existence of autochthonous microbiota with ability to degrade hydrocarbons derived from oil. As a result, were mapped and determined the concentrations of TPH plume contamination in form of VOCs every 0.5 m deep, reaching up to 3.5 m in deep. The largest concentrations of VOCs, occurred in the depths of 2.5; 3.0 and 3.5 m, where concentrations were above 10.000 ppm, even to register 100% LEL, limit of detection equipment. As the free phase, mapped a plume of contamination supernatant in groundwater with thicknesses ranging from 2 to 5 mm. Both vapour and free phase plumes, already surpassed the physical limits of the enterprise reaching existing residential and commercial areas to the North direction. The existence of microorganisms were identified species-degrading Pseudomonas aeruginosa, Bacillus sp., Burkholderia glandioli, Pseudomonas sp. and Acinetobacter sp. both species considered by several authors such as hydrocarbon degrading. The identification of the contaminated area and the study of the interactions of these compounds with the medium are of the utmost importance to the development of strategies and technologies aimed at their recovery.Esta pesquisa teve como finalidade delimitar uma pluma de contaminação, oriunda de um vazamento em posto revendedor de combustível, penetrando aquífero cristalino no Estado do Rio Grande do Sul. Determinaram-se com o emprego de um analisador de vapor THERMO GASTECH, modelo Innova SV, as concentrações in situ de Compostos Orgânicos Voláteis (COV) existentes no solo. Para a identificação de hidrocarbonetos em fase livre, (porção de contaminantes sobrenadante na água subterrânea), empregou-se um medidor de nível digital modelo HSIFD-30, que permitiu a detecção de fluidos (contaminantes) em fase livre usando-se sonda, que mede a interface água e fluidos oleosos. Realizou-se a contagem e identificação de bactérias heterotróficas na água subterrânea, isso para verificar a existência ou não de microbiota autóctone com capacidade para degradar hidrocarbonetos derivados de petróleo. Como resultado, conseguiu-se mapear e determinar as concentrações das plumas de TPH em forma de COV a cada 0,5 m de profundidade, atingindo-se até 3,5 m. As maiores concentrações de COV, ocorreram nas profundidades de 2,5; 3,0 e 3,5 m, onde se registraram concentrações acima de 10.000 ppm, chegando inclusive a se registrar 100% LEL, limite máximo de detecção do equipamento. Quanto à fase livre, mapeou-se uma pluma de contaminação sobrenadante na água subterrânea com espessuras que variaram de 2 a 5 mm. Ambas as plumas, fase vapor e fase livre, já ultrapassaram os limites físicos do empreendimento atingindo áreas residenciais e comerciais existentes ao norte. Quanto à existência de microrganismos degradadores, foram identificadas as espécies Pseudomonas aeruginosa, Bacillus sp., Burkholderia glandioli, Pseudomonas sp. e Acinetobacter sp. ambas espécies consideradas por vários autores como degradadoras de hidrocarbonetos. A identificação da área contaminada e o estudo das interações destes compostos com o meio é de extrema importância para a definição de estratégias e tecnologias visando sua recuperação.
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Caivano, Antonio. "The impact of nutrients on microbial Hydrocarbon degradation at deep-sea Temperature and Hydrostatic Pressure." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
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Currently available physical and chemical remediation technologies are not effective in the deep sea, where ultimate fate of oil is strongly dependent on degradation by microorganisms. In order to setup an efficient bioremediation strategy, the effect of the environmental constraints on oil degrading communities’ metabolism needs to be assessed.
In this work, natural surface seawater communities were incubated under different T, P and in different dilutions of the medium ONR7a. Then, after 1 day, 1 week and 3 weeks, cell number, SO4, NH4 and DIC concentration were assessed.
When only one environmental stress (low T or high HP) is applied, a positive effect of nutrients’ concentration is highlighted, with increased growth rates and DIC production; at 23 °C and 20 MPa, a lower cell growth is observed with respect to atmospheric pressure samples, but a relatively high value of oil degradation is mostly sustained by respiration to DIC: this result evidence the possibility to setup an effective biostimulation strategy in deep seas characterized by milder temperatures (Sulu, Mediterranean, Red Sea). High Ammonium concentrations are needed to sustain large production of proteins for cell maintenance process required for adaptation to HP. Moreover, at 23 °C and 20 MPa, significant Sulphate uptake occurs, whose role in HP adaptation needs to be clarified. Also at low T and atmospheric pressure oil biodegradation mostly relies on respiration to DIC, however biodegradation rates seems to be more affected by T reduction than HP increase.
When both low T and high HP are applied, cellular metabolism is still active but any growth is observed, drastically reducing the oil biodegradation, that relies only on respiration to DIC. Surface communities subject to combination of 2 stresses may need more than 3 weeks to adapt to the deep sea environment and start a growth phase.
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Sun, Xiaoxu. "Biodegradation of Macondo oil by aerobic hydrocarbon-degrading bacteria in the water column and deepsea sediments of the northern Gulf of Mexico." Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53102.
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Previous studies have come to contrasting conclusions regarding nutrient limitation of hydrocarbon biodegradation in the Gulf of Mexico, and rate measurements are needed to support oil plume modeling. Thus, this study investigates the rates and controls of biodegradation in seawater and sediments, largely in the deepsea. Sediment and seawater samples were collected on research cruises in the northern Gulf from 2012 to 2014, where the seafloor was impacted by the Deepwater Horizon (DWH) oil spill. Biodegradation was clearly limited by both nitrogen and phosphorus availability in surface waters with significant rates of CO₂ production (100 μmol CO₂ l⁻¹ d⁻¹) only observed in treatments amended with ammonium and phosphate. In deepsea sediments, nutrient amendments resulted in an average of 6 fold higher degradation rates (0.49 μmol CO₂ g sed⁻¹ d⁻¹) compared to unamended controls. Microbial communities responded to oil contamination rapidly in a series of enrichment cultures, and selection was observed for populations of native hydrocarbon-degrading bacteria. Temperature was shown to be a major factor in controlling microbial community composition in the enrichments. At room temperature, community diversity in the enrichments was significantly reduced in the presence of oil, while under 4 °C, the community diversity and evenness remained relatively high upon oil amendment. From the same deepsea sediments, 30 strains of known oil-degrading bacteria (Rhodococcus and Halomonas) were enriched and isolated with hexadecane, phenanthrene, and Macondo oil as the sole carbon and energy source. Detection of these strains in sequence libraries indicates that they may have contributed to the degradation of oil deposited onto the sediments. Rhodococccus strain PC20 degraded approximately one-third of total petroleum hydrocarbons amended into cultures within 7 days. This work elucidates the controls of biodegradation and we provide model pure cultures to further elucidate the ecophysiology of hydrocarbon degradation, focusing on deepsea sediments of the northern Gulf of Mexico.
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Baranger, Claire. "Polycyclic aromatic hydrocarbon biodegradation for soil bioremediation : potential of microfluidics to understand benzo[a]pyrene uptake by the filamentous fungus Talaromyces helicus." Thesis, Compiègne, 2020. http://www.theses.fr/2020COMP2559.
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Ce travail de thèse examine différents aspects de la bioremédiation fongique des hydrocarbures aromatiques polycycliques, selon trois grands axes : mobilisation, incorporation, biodégradation. L’étude se concentre sur les interactions entre le polluant, le champignon, et l’environnement à travers l’exemple de la mobilisation du benzo[a]pyrène, un composé cancérogène, mutagène et reprotoxique bien étudié comme modèle de polluant hydrophobe, par Talaromyces helicus, un champignon du sol récemment identifié comme présentant un intérêt pour la dépollution de contaminations multiples. La prédictibilité des résultats en fonction des caractéristiques du site à traiter est un verrou en matière de bioremédiation des sols, ainsi il est important de disposer d’outils expérimentaux adaptés pour identifier des stratégies de biostimulation pertinentes au cas par cas. Plusieurs modèles expérimentaux sont utilisés à cette fin. Dans un premier temps, des tests en cultures liquides ont été réalisés afin de quantifier la biodégradation dans des conditions contrôlées. Les microcosmes de sol sont aussi une approche classique pour l’étude de la bioremédiation de pollutions, utilisés ici pour évaluer les capacités de la souche dans un milieu plus proche d’un site réel, et tester plusieurs paramètres de biostimulation. Enfin, un environnement modèle compartimenté a été mis en place sous la forme d’une puce microfluidique, dans le but de développer un milieu poreux modèle transparent et adaptable pour étudier à une micro-échelle la mobilisation et l’incorporation de polluants par un organisme non motileThe present work examines several aspects of the fungal bioremediation of polycyclic aromatic hydrocarbons, following three main axes: mobilization, uptake and biodegradation. This study focuses on the interactions between the pollutant, fungus and the environment through the example of benzo[a]pyrene (BaP) mobilization by Talaromyces helicus. BaP is a carcinogenic, mutagenic and reprotoxic compound well-studied as a model hydrophobic pollutant, while T. helicus in a soil fungus recently identified as holding potential for the remediation of multiple contaminations. Result predictability depending on each site’s characteristics is a limitation in the field of bioremediation, and having adapted experimental tools is important to identify relevant biostimulation strategies on a case-by-case basis. Therefore, several experimental set-ups were used. As a first step, tests in liquid cultures were carried out to quantify BaP degradation in controlled conditions. Soil microcosms are also a classical approach for the study of pollution remediation, used here to evaluate the strain’s performance in conditions closer to a real site, and to test several biostimulation parameters. Finally, a compartmentalized model environment was set up in the form of a microfluidic chip, the goal being to develop a transparent, adaptable model of porous medium to study pollutant mobilization and uptake by a non-motile organism at the microscale
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Andong, Omores Raissa. "Spatio-temporal distribution of polycyclic aromatic hydrocarbons (PAHs) in soils in the vicinity of a petrochemical plant in Cape Town." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2432.
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Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2016.Polycyclic aromatic hydrocarbons (PAHs) are an alarming group of organic substances for humans and environmental organisms due to their ubiquitous presence, toxicity, and carcinogenicity. They are semi-volatile substances which result from the fusion of carbon and hydrogen atoms and constitute a large group of compounds containing two to several aromatic rings in their molecule. Natural processes and several anthropogenic activities involving complete or incomplete combustion of organic substances such as coal, fossil fuel, tobacco and other thermal processes, generally result in the release of the PAHs into the environment. However, the fate of the PAHs is of great environmental concern due to their tendency to accumulate and their persistence in different environmental matrices and their toxicity. Animal studies have revealed that an excessive exposure to PAHs can be harmful. Evidence of their carcinogenic, mutagenic, and immune-suppressive effects has been reported in the literature. In the soil environment, they have the tendency to be absorbed by plants grown on soil being contaminated by the PAHs. It is, therefore, important to evaluate their occurrence levels in different environmental matrices such as soil concentrations.
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Al, Mallah Maha. "Biodegradation des hydrocarbures dans les milieux sursales." Aix-Marseille 2, 1988. http://www.theses.fr/1988AIX22040.
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Surridge, Angela Karen Joanna. "Denaturing gradient gel electrophoresis characterisation of microbial communities in polycyclic aromatic hydrocarbon and polychlorinated biphenyl contaminated soil." Thesis, Pretoria : [s.n.], 2007. http://hdl.handle.net/2263/25070.
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Fossil fuels are currently the primary industrial energy source on Earth. They are principally composed of complex hydrocarbons in either long-chain or cyclic conformation. Industrial use of petroleum, diesel, oil, tar and other coal-derived products inevitably leads to pollution of the environment. The most serious pollution is caused by polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) that are not easily removed from soil after a spill. Long-chain and cyclic conformation makes fossil fuel hydrocarbons difficult to break down. However, certain free-living soil microorganisms have adapted to utilising these PAHs/PCBs as a source of energy. In many cases, their efficacy is greatly enhanced by the presence of plants. By inhabiting the rhizosphere, microbes form a mutualistic relationship with the plant, receiving nutrients from it and in return providing a less polluted environment in which the plant can grow. The purpose of this study was to elucidate some of the microbial population diversity in PAH/PCB-polluted soils in South Africa through the use of denaturing gradient gel electrophoresis (DGGE). In an initial study, DGGE was employed to separate soil communities in polluted and unpolluted soils into a genetic fingerprint, the main bands of which were sequenced and subjected to a BLAST analysis through a database for possible identification of species present. Phylogenetic and distance studies indicated that unpolluted soils have a far greater species diversity. It thus was evident that PAH/PCB pollution of soil leads to a decrease in microbial diversity by selecting for microorganisms with the ability to activate metabolic pathways allowing them to utilise the pollutants as an alternative source of carbon. Population diversity of pro- and eukaryotes found within polluted and non-polluted soils was compared. DGGE was employed to determine the genetic fingerprint of each population. Following this, dendogram analyses based on Shannon indices were done to determine PAH breakdown potential of prokaryotic vs. eukaryotic communities. A higher diversity and better adaptation potential were evident within prokaryotic than eukaryotic communities in pollution-stressed environments, indicating that the prokaryotic component of these samples had the greatest PAH-metabolism potential. To determine the capacity for PAH/PCB metabolism by the organisms within the soil samples being studied, the presence of xylE and ndoB genes, responsible for toluene/xylene and naphthalene biodegradation, respectively, was determined. DGGE was performed to analyse genetic diversity between these two genes, based on community fingerprints. Polluted soil communities tended to have comparable community diversity within their functional genes, depending on their physical situation, plant species proximity and soil conditions. In general, soil contained indigenous microbes with a high natural potential for biodegradation of PAHs/PCBs. A portion of the 16S gene of eight bacterial isolates representing the most dominant culturable taxa in the polluted soils was sequenced and analysed for identification purposes. These identifications were conducted in conjunction with the use of the catabolic gene probes xylE and ndoB to establish the hydrocarbon degrading capacity of the isolates. Pseudomonas, from the rhizosphere of Cyperus esculentus, was the most common PAH-degrading genus found in this study. Considering the well-established rhizosphere competence and PAH-degrading capacity of Pseudomonas, this genus seems to be the best suited for bioaugmentation purposes in South Africa. The presence of the nifH gene, the general marker gene of nitrogen-fixing bacteria in communities from unpolluted and polluted soils, was determined. It was hypothesised that bioremediation could be enhanced by nitrogen addition to polluted environments. Nested-PCR of the nifH gene was conducted on a diagnostic basis and was followed by DGGE of the product to determine the functional gene diversity within pollution-dwelling, nitrogen-fixing bacterial communities. Nitrogen-fixing microorganisms were present in all the soils sampled but, in only 80% of the pure cultures isolated from polluted and unpolluted soils and rhizospheres. Although different rhizospheres and pollutants were examined, it was found that of the polluted soils studied, most nifH gene diversity of polluted soils existed within machinery oil polluted, wood chip mulched, non-rhizosphere soil. Thus, it would appear that the more polluted the soil the higher the free microbe nitrogen fixation diversity possibly due to environmental stress.Thesis (PhD (Microbiology))--University of Pretoria, 2007.
Microbiology and Plant Pathology
unrestricted
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Haddad, Aziza. "Dégradation d'hydrocarbures aromatiques par une souche d'Arthrobacter sp. : régulation des voies de biodégradation." Vandoeuvre-les-Nancy, INPL, 1997. http://www.theses.fr/1997INPL072N.
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Au cours de ce travail, une bactérie gram-positif identifiée comme étant Arthrobacter sp. MI-97 a été isolée à partir d'un sol pollué par de nombreux hydrocarbures aromatiques. Nous avons étudié par la suite son potentiel dégradatif, l'effet de la nature, de la concentration en substrats et de mélanges de xénobiotiques et identifiés les voies cataboliques. La régulation de l'expression des voies ortho et méta a été abordée en présence de différents substrats et dans différentes conditions de culture (batch et continu). L’assimilation du benzoate inhibe/réprime l'acetyl-CoA synthetase. Dans certains cas, les deux voies cataboliques sont induites pour éviter l'accumulation d'un substrat suicide. L’analyse génétique montre que les gènes responsables de la dégradation de ces composés aromatiques sont tous chromosomiques. Le gène codant pour la métadioxygenase a été cloné et séquencé. Il est classé dans la famille des métadioxygenases responsables de la dégradation des composés mono-aromatiques. Une tentative de purification de cette protéine a été entreprise à partir de la souche recombinante et sauvage et une caractérisation biochimique a été réalisée.
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Melo, Abinadabe Jackson de. "Metagen?mica: busca de novos genes envolvidos com a biodegrada??o de hidrocarbonetos e s?ntese de biossurfactantes." Universidade Federal do Rio Grande do Norte, 2012. http://repositorio.ufrn.br:8080/jspui/handle/123456789/13080.
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Previous issue date: 2012-07-19Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
Industrial activities, oil spills and its derivatives, as well as the incomplete combustion of fossil fuels have caused a great accumulation of hydrocarbons in the environment. The number of microorganisms on the planet is estimated at 1030 and prokaryotes the most abundant. They colonized diverse environments for thousands of years, including those considered extreme and represent an untapped source of metabolic and genetic diversity with a large biotechnological potential. It is also known that certain microorganisms have the enzymatic capacity to degrade petroleum hydrocarbons and, in many ecosystems, there is an indigenous community capable of performing this function. The metagenomic has revolutionized the microbiology allowing access uncultured microbial communities, being a powerful tool for elucidation of their ecological functions and metabolic profiles, as well as for identification of new biomolecules. Thus, this study applied metagenomic approaches not only for functional selection of genes involved in biodegradation and emulsification processes of the petroleum-derived hydrocarbons, but also to describe the taxonomic and metabolic composition of two metagenomes from aquatic microbiome. We analyzed 123.116 (365 ? 118 bp) and 127.563 sequences (352 ? 120 bp) of marine and estuarine metagenomes, respectively. Eight clones were found, four involved in the petroleum biodegradation and four were able to emulsify kerosene indicating their abilities in biosurfactants synthesis. Therefore, the metagenomic analyses performed were efficient not only in the search of bioproducts of biotechnological interest and in the analysis of the functional and taxonomic profile of the metagenomes studied as well
Atividades industriais, derramamentos de petr?leo e seus derivados, bem como a combust?o incompleta de combust?veis f?sseis t?m causado um grande ac?mulo de hidrocarbonetos no meio ambiente. O n?mero de microrganismos no planeta ? estimado em 1030, sendo os procariotos os mais abundantes. Eles colonizaram diversos ambientes durante milhares de anos, incluindo aqueles considerados extremos e representam uma fonte inexplorada de diversidade gen?tica e metab?lica com um grande potencial biotecnol?gico. Sabe-se que muitos microrganismos possuem vias metab?licas complexas atuando na biodegrada??o de hidrocarbonetos derivados de petr?leo e, em muitos ecossistemas, existe uma comunidade aut?ctone capaz de realizar essa fun??o. A metagen?mica tem revolucionado a Microbiologia permitindo o acesso ?s comunidades microbianas n?o cultiv?veis, sendo uma potente ferramenta para elucida??o de suas fun??es ecol?gicas, dos perfis metab?licos, bem como para identifica??o de novas biomol?culas. Assim, o presente estudo aplicou abordagens metagen?micas n?o apenas para sele??o funcional de genes envolvidos nos processos de biodegrada??o e biossurfacta??o de hidrocarbonetos derivados do petr?leo, mas tamb?m para descri??o da composi??o taxon?mica e metab?lica de dois metagenomas de microbiota aqu?tica. Foram analisadas 123.116 (365 ? 118 pb) e 127.563 sequ?ncias (352 ? 120 pb) dos metagenomas marinho e estuarino, respectivamente. Oito clones foram encontrados, sendo quatro envolvidos na biodegrada??o de petr?leo e quatro capazes de emulsificar querosene, indicando a habilidade de sintetizar biossurfactantes. Portanto, as an?lises metagen?micas realizadas foram eficientes n?o apenas na busca de bioprodutos de interesse biotecnol?gico como tamb?m na an?lise do perfil funcional e taxon?mico dos metagenomas estudados
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Safinowski, Michael. "Anaerobic biodegradation of polycyclic aromatic hydrocarbons." kostenfrei, 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=97648627X.
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Baessa, Marcus Paulus Martins. "Assinaturas geoelétricas em área contaminada por hidrocarboneto no pólo industrial de Cubatão - SP /." Rio Claro : [s.n.], 2007. http://hdl.handle.net/11449/92836.
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Orientador: Chang Hung KiangBanca: Walter Malagutti Filho
Banca: Vagner Roberto Elis
Resumo: Visando caracterizar assinaturas geoelétricas em áreas contaminadas por hidrocarbonetos de petróleo, foram realizados levantamentos geofísicos utilizando-se os métodos da eletrorresistividade e análises hidroquímicas em área localizada no Pólo Industrial de Cubatão - SP. Foram realizadas 19 sondagens elétricas verticais (SEVs), 4 imageamentos elétricos 2D e 3 imageamentos elétricos 3D, tendo sido identificadas, por meio destas técnicas, 12, 21 e 9 anomalias, respectivamente. Constatou-se que a presença de anomalias condutivas na zona não saturada coincide com a ocorrência de fase livre nos poços de monitoramento. A identificação de NH4 +, subjacente à ocorrência de fase livre, confirmou a atuação de processo de denitrificação. As baixas concentrações dos íons sulfato (SO4 2-) e ferroso (Fe2+) indicam que os mesmos foram reduzidos biologicamente para sulfeto (S2-) e precipitado como sulfeto de ferro (FeS), respectivamente. Esses resultados permitem concluir que as anomalias condutivas estão diretamente associadas à presença de fase residual de hidrocarbonetos, em processo de biodegradação, na zona não saturada. Desta forma, os métodos de investigação geofísica utilizados permitiram identificar áreas sob influência de hidrocarbonetos de petróleo.
Abstract: Geophysical surveys using electroresistivity methods and hydrochemical analyses were applied aiming the characterization of geoelectrical signatures in hydrocarbon contaminated sites located in the Polo Industrial de Cubatão - SP. There have been accomplished nineteen vertical electric soundings (VESs), four 2D and three 3D electrical imaging, which identified 12, 21 and 9 geophysical anomalies respectively. It was verified that the presence of conductive anomalies within the non-saturated zone coincided with the occurrence of free phase on the monitoring wells. Ammonium (NH4 +) identification, underlying the free phase occurrence, reinforced the activity of denitrifying process. Additionally, low concentration values of sulfate (SO4 2-) and ferrous (Fe2+) ions indicated that they were, respectively, biologically reduced to sulfide (S2-) and precipitated as iron sulfide (FeS). Based on those results, it was concluded that the conductive anomalies detected inside the non-saturated zone were directly associated with the presence of hydrocarbon residual phase, with was undergoing a biodegradation process. Therefore, the geophysical methods applied in this study allowed the identification of sites under petroleum hydrocarbons influence.
Mestre
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Verde, Leandro Costa Lima 1979. "Avaliação da diversidade filogenética e funcional da microbiota envolvida na biodegradação de hidrocarbonetos em amostras de petróleo de reservatórios brasileiros = Evaluation of the phylogenetic and functional diversity of the microbiota involved in hydrocarbon biodegradation in petroleum samples from Brazilian reservoirs." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/317327.
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Orientador: Valéria Maia MerzelTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: O processo de biodegradação do petróleo em reservatórios pode resultar em mudanças na composição e propriedades físico-químicas de óleos brutos e gases naturais, as quais levam à diminuição do teor de hidrocarbonetos saturados, produzindo óleos mais pesados e com baixo valor econômico. O uso combinado de técnicas dependentes e independentes de cultivo pode nos permitir um melhor entendimento acerca da comunidade de micro-organismos que habita os reservatórios de petróleo, incluindo aqueles responsáveis por esta biodegradação. O conhecimento sobre a composição microbiana, suas funções e interações com outros micro-organismos e com o ambiente pode levar à definição de estratégias de monitoramento e/ou controle da biodegradação em reservatórios. Este estudo teve como finalidade avaliar a diversidade de micro-organismos e genes envolvidos na degradação de hidrocarbonetos presentes em amostras de petróleo provenientes de dois poços terrestres da Bacia Potiguar (RN), identificados como GMR75 (poço biodegradado) e PTS1 (poço não-biodegradado), através da construção de bibliotecas de genes catabólicos (alcano monooxigenases - alk, dioxigenases que hidroxilam anéis aromáticos ¿ ARHDs e 6-oxocyclohex-1-ene-1-carbonyl-CoA hidroxilase - bamA) e sequenciamento em larga escala de metagenoma e metatranscriptoma de enriquecimentos microbianos aeróbios. Os resultados obervados mostraram uma distribuição diferencial dos genes catabólicos entre os reservatórios, sendo o óleo biodegradado mais diverso para os genes alk e bamA. As sequências foram semelhantes aos genes alkB dos gêneros Geobacillus, Acinetobacter e Streptomyces, aos genes ARHD dos gêneros Pseudomonas e Burkholderia, e aos genes bamA do gênero Syntrophus. A análise quantitativa dos genes catabólicos de degradação de hidrocarbonetos presentes e expressos nos enriquecimentos microbianos em diferentes etapas da biodegradação do óleo, através de PCR Tempo Real, demonstrou maior atividade do gene que codifica a enzima dioxigenase nas comunidades microbianas enriquecidas, e os resultados obtidos pela técnica de microarray sugeriram a existência de novas sequências dos genes alk e ARHD provindas do reservatório de petróleo. As análises das sequências obtidas a partir do metagenoma e metatranscriptoma mostraram que a comunidade bacteriana recuperada no enriquecimento aeróbio é bastante diversa, com predominância do Filo Actinobacteria, seguido de Proteobacteria. As sequências com maior abundância e níveis de expressão foram relacionadas aos genes que codificam as proteínas ligase CoA de ácido graxo de cadeia longa, envolvida na degradação de compostos aromáticos; descarboxilase, envolvida com o ciclo do glioxilato, e o fator sigma da RNA polimerase, envolvida com a regulação da resposta ao estresse oxidativo, sugerindo uma adaptação da comunidade microbiana às condições do enriquecimento e um processo inicial de biodegradação dos hidrocarbonetos. Os resultados obtidos neste trabalho fornecem dados inéditos sobre a diversidade de genes catabólicos e de membros da comunidade microbiana potencialmente envolvidos com a degradação do óleo em reservatórios de petróleo
Abstract: The process of oil biodegradation in reservoirs may result in changes in the composition and physico-chemical properties of crude oils and natural gases, which lead to the decrease of the content of saturated hydrocarbons, producing heavy oils and with low economic value. The combined use of both dependent and independet cultivation techniques may allow us to better understand the microbial community inhabiting oil reservoirs, including those microorganisms responsible for oil degradation. The knowledge about the microorganisms, ther functions and interactions with other microorganisms and the environment may lead to the definition of monitoring and/or control strategies of biodegradation in oil reservoirs. This study aimed at evaluating the diversity of microorganisms and genes involved in the degradation of hydrocarbons present in oil samples from two onshore reservoirs at Potiguar Basin (RN), identified as GMR75 (biodegraded) and PTS1 (non- biodegraded), through the construction of catabolic gene libraries (alkane monooxygenases - alk, aromatic ring hydroxylating dioxygenases ¿ ARHD and 6-oxocyclohex-1-ene-1-carbonyl-CoA hydroxylase - bamA) and highthroughput sequencing of metagenome and metatranscriptome from aerobic microbial enrichments. Results observed showed a differential distribution of catabolic genes between the reservoirs, being the biodegraded oil more diverse for the alk and bamA genes. The sequences were similar to alkB genes from Geobacillus, Acinetobacter and Streptomyces genera, to the ARHD genes from Pseudomonas and Burkholderia genera, and to the bamA genes from Syntrophus genus. Quantitative analysis of the hydrocarbon degradation genes present and expressed in the microbial enrichments during the different phases of oil biodegradation by Real-Time PCR showed that there was a higher activity of dioxygenase enzymes in the enriched microbial communities and results from microarray assays suggested the existence of new alk and ARHD gene sequences originated from the oil reservoir. Metagenomic and metatranscriptomic analyses showed a highly diverse bacterial community, dominated by the Phylum Actinobacteria, followed by Proteobacteria. The most abundant and active sequences were affiliated to the Long-chain-fatty-acid-CoA ligase protein, involved in the degradation of aromatic compounds; decarboxylase, which is involved with the glyoxylate cycle, and RNA polymerase sigma factor, which is involved in regulating the oxidative stress response, suggesting an adaptation of the microbial community to the enrichment conditions and an initial process of biodegradation of hydrocarbon compounds. The results obtained in this work bring innovative data on the diversity of catabolic genes and microbial community members potentially involved with oil degradation in petroleum reservoirs
Doutorado
Genetica de Microorganismos
Doutor em Genetica e Biologia Molecular
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Amin, Ali Oulfat. "Physiologie des procaryotes sulfato-réducteurs : dégradation d'hydrocarbures et oxydo-réduction d'éléments métalliques." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4796.
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Les procaryotes sulfato-réducteurs (PSRs)jouent un rôle majeur dans les cycles biogéochimiques de la matière et interviennentnotamment dans la dégradation de la matière organique récalcitrante (e.g. hydrocarbures) mais également dans les processus d’oxydo-réduction de métaux et/ou métalloïdes.L’objet de ce travail a consisté à approfondir certain de ces aspects de la physiologie des PSRs. La dégradation d’hydrocarbures a été étudiée en mésophilie, avec la caractérisation d’une souche bactérienne issue d’un site pollué. Cette souche décrite comme une nouvelle espèce,Desulfatiferulaberrensis BE2801, est capable de dégrader les n-alcènes. La dégradation d’hydrocarbures a également été étudiée à très haute température chez une archée,Archaeoglobus fulgidus. Cette souche oxyde les n-alcanes, l’oxydation étant vraisemblablement catalysée par la protéine PflD.L’ensemble des travaux réalisés montre que PflDserait une alkylsuccinate synthase qui permettrait l’activation de l’hydrocarbure par addition au fumarate. Outre ses capacités hydrocarbonoclastes à haute température, A. fulgidusest également capable de corroder le fer, de manière indirecte par la production de sulfures, et directement, en oxydant le fer de manière originale avec la formation de « micro-cheminées ». Outre l’oxydation de matière organique et de métaux, les PSRs sont également capables de réduire un grand nombre d’éléments, notamment les métaux et métalloïdes. C’est le cas de Desulfotomaculum hydrothermale, connue pour réduire à haute température l’arsenic, métalloïde hautement toxique. L’analyse de la séquence du génome de cette souche a confirmé ses capacités de détoxicationSulfate-reducing prokaryotes (SRPs) play a significant role in the biogeochemical cycles of matter, in particular in the degradation of recalcitrant organic compounds (e.g. hydrocarbons) but also in oxido-reduction of metals and/or metalloids. The aim of this work was to deepen some of these aspects of SRPs physiology. Hydrocarbon degradation was studied with a mesophilic bacterial strain isolated from a polluted site.This strain, described as a new species, Desulfatiferula berrensis BE2801, is able to degrade n-alkenes. Degradation of hydrocarbons has also been studied at high temperatures with an archaeon, Archaeoglobus fulgidus. This archaeon oxidize n-alkanes with most likely involvement of the PflD protein. All our experiments showed that PflD would be an alkylsuccinate synthase allowing hydrocarbon activation by addition to fumarate. Moreover, A. fulgidus was shown to corrode iron at high temperature, through the production of sulfide and also by directly oxidizing iron with formation of unusual "micro-chimneys". In addition to organic matter oxidation, SRPs are known to reduce a large number of elements, including metals and metalloids. This is the case for Desulfotomaculum hydrothermale reported to reduce arsenic at high temperature. Analyses of the genome sequence of this bacterium confirmed its ability to detoxify this mineral
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Eriksson, Mikael. "Biodegradation of hydrocarbons in soil and water /." Stockholm : Tekniska högsk, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3072.
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Al-Bashir, Bilal. "Biodegradation of polycyclic aromatic hydrocarbons in soilwater systems." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59963.
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This study is concerned with the biodegradation of polycyclic aromatic hydrocarbons (PAHs), particularly the utilization of biological processes in the bioremediation of PAH-contaminated soils. In this regard, the effects of the contaminant bioavailability and the redox environment on the biodegradation process have been investigated.First, the mineralization of naphthalene in soil/water systems under denitrifying conditions has been studied. Results showed that naphthalene mineralization is influenced by its availability to the microbial population, which in turn is a function of the compound initial concentration, the sorption/desorption characteristics of the soil/contaminant complex and the organic content of the soil.
Second, the biodegradation of four PAH compounds, acenaphthene, acenaphthylene, fluorene and anthracene, in a soil/water system under four redox environments has been studied. Both aerobic and denitrifying environments supported appreciable PAH biodegradation rates. The denitrifying environment was chosen for a further experiment to investigate the performance of a bioreactor system in treating PAH-contaminated soils. Results showed that by enlarging the scale of the reactor by approximately eight times and simultaneously reducing the mixing intensity of the soil slurry, the biodegradation rates of the PAH compounds remained virtually unchanged.
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Diegor, Elizabeth Justa M. "Biodegradation of aromatic hydrocarbons : microbial and isotopic studies /." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0016/MQ55501.pdf.
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Agbeotu, Emibra E. "Plant enhanced biodegradation of petroleum hydrocarbons in soil." Thesis, University of Aberdeen, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=59440.
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Hydrocarbons in soil may assert acute or chronic impacts to plants, animals and microbial processes if contacted. These have raised political and scientific concerns. Consequential research efforts corroborated that constitutive microorganisms contact the compounds for their metabolic activities. This may result in mineralisation, transformation and/or detoxification (biodegradation) of the compounds. Hydrocarbon biodegradation is relatively cost-effective and ecological, but often marred with limited availability to plant or animal cells (bioavailability) for metabolism. Several authors reported that growth of some plants or administration of requisite rootexudates into soil with hydrocarbons often increases hydrocarbon bioavailability for enhanced biodegradation. However, development of knowledge about this respite from plants is often founded on impacts of plants on single dose or selected mixture of hydrocarbons in soils or culture solutions. These do not; and cannot represent the heterogeneous complex mixture of numerous organic and inorganic compounds in soils where plants grow naturally. In this study, synthetic root-exudates, seedlings of lupin and ryegrass were applied separately into respective soils that were contaminated with aged and/or fresh petroleum hydrocarbons. Individual impacts of the treatments on bulk hydrocarbon concentrations, rate of microbial respiration and total numbers of culturable bacterial colonies in the soils were investigated. Results suggested that application of lupin, ryegrass or synthetic root-exudates into the soils significantly (p ≤ 0.05) induced reduction or upsurge of hydrocarbon biodegradation end-points relative to the type and concentration of hydrocarbons in soil. Thus, it is inferred that growth of plants or administration of root-exudates into hydrocarbon contaminated soils could result in enhanced biodegradation of hydrocarbons in soil.
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McCormick, Amy J. "The effects of pH on the biodegradation of benzene, toluene, ethylbenzene, m-Xylene in soils." Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-10222009-124953/.
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Baessa, Marcus Paulus Martins [UNESP]. "Assinaturas geoelétricas em área contaminada por hidrocarboneto no pólo industrial de Cubatão - SP." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/92836.
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baessa_mpm_me_rcla.pdf: 2451214 bytes, checksum: 3876fa480ca0e2bb77803a47b1630c54 (MD5)Visando caracterizar assinaturas geoelétricas em áreas contaminadas por hidrocarbonetos de petróleo, foram realizados levantamentos geofísicos utilizando-se os métodos da eletrorresistividade e análises hidroquímicas em área localizada no Pólo Industrial de Cubatão – SP. Foram realizadas 19 sondagens elétricas verticais (SEVs), 4 imageamentos elétricos 2D e 3 imageamentos elétricos 3D, tendo sido identificadas, por meio destas técnicas, 12, 21 e 9 anomalias, respectivamente. Constatou-se que a presença de anomalias condutivas na zona não saturada coincide com a ocorrência de fase livre nos poços de monitoramento. A identificação de NH4 +, subjacente à ocorrência de fase livre, confirmou a atuação de processo de denitrificação. As baixas concentrações dos íons sulfato (SO4 2-) e ferroso (Fe2+) indicam que os mesmos foram reduzidos biologicamente para sulfeto (S2-) e precipitado como sulfeto de ferro (FeS), respectivamente. Esses resultados permitem concluir que as anomalias condutivas estão diretamente associadas à presença de fase residual de hidrocarbonetos, em processo de biodegradação, na zona não saturada. Desta forma, os métodos de investigação geofísica utilizados permitiram identificar áreas sob influência de hidrocarbonetos de petróleo.
Geophysical surveys using electroresistivity methods and hydrochemical analyses were applied aiming the characterization of geoelectrical signatures in hydrocarbon contaminated sites located in the Polo Industrial de Cubatão – SP. There have been accomplished nineteen vertical electric soundings (VESs), four 2D and three 3D electrical imaging, which identified 12, 21 and 9 geophysical anomalies respectively. It was verified that the presence of conductive anomalies within the non-saturated zone coincided with the occurrence of free phase on the monitoring wells. Ammonium (NH4 +) identification, underlying the free phase occurrence, reinforced the activity of denitrifying process. Additionally, low concentration values of sulfate (SO4 2-) and ferrous (Fe2+) ions indicated that they were, respectively, biologically reduced to sulfide (S2-) and precipitated as iron sulfide (FeS). Based on those results, it was concluded that the conductive anomalies detected inside the non-saturated zone were directly associated with the presence of hydrocarbon residual phase, with was undergoing a biodegradation process. Therefore, the geophysical methods applied in this study allowed the identification of sites under petroleum hydrocarbons influence.
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Stoecker, Matthew A. "Biodegradation of aromatic and aliphatic hydrocarbons by Rhodococcus spp. /." Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/11495.
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Ugochukwu, Uzochukwu Cornelius. "Biodegradation of crude oil hydrocarbons supported on clay minerals." Thesis, University of Newcastle Upon Tyne, 2011. http://hdl.handle.net/10443/1329.
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Clay minerals are the most abundant minerals near the earth’s surface and play very important roles in biogeochemical processes. They have been found very useful in various industrial applications. The surface properties of clay minerals such as high specific surface area (SSA) and cation exchange capacity (CEC) make them able to act as catalysts, supports and sorbents of toxic and radioactive chemicals. However, their role during the biodegradation of crude oil hydrocarbons is not well understood. The main aim of this research project was to investigate the capabilities of the various forms and types of clay minerals in supporting the microbial degradation of crude oil hydrocarbons so as to gain better understanding of their potential role in the bioremediation of oil polluted sites. The role of clays in hydrocarbon removal was investigated in aqueous clay/oil microcosm experiments with a hydrocarbon degrading microorganism community. The clays used for this study were bentonite, palygorskite, saponite and kaolinite. Clays were treated to produce acid activated clays and organoclays; homoionic interlayer bentonites were also used in this study. The study identified volatilization and adsorption as processes that will take place alongside biodegradation and therefore needed to be accounted for in the assessment of the effects of the clays. The study indicated that acid activated clays, organoclays, untreated kaolinite, K-bentonite, Zn-bentonite and Cr-bentonite were inhibitory to biodegradation of the hydrocarbons, via different mechanisms, whereas Ca-bentonite and Fe-bentonite were stimulatory to biodegradation with about 80% removal of the total petroleum hydrocarbons (TPH) due to biodegradation. The ‘local bridging effect’ and polarization of the interlayer water were identified as two opposing influences arising from the interlayer cations of clay minerals that probably determine the extent of biodegradation of the hydrocarbons. Adsorption of hydrocarbons was significant during biodegradation especially with unmodified palygorskite, Zn-bentonite and K-bentonite as each of them caused more than 40% removal of TPH by adsorption in the experimental microcosm containing 5:1 ratio (w/w) of clay to oil. The process of adsorption of aromatic compounds in the crude oil was believed to take place via cation-π interactions. The correlation between extent of biodegradation and surface area is more robust than that between extent of biodegradation and CEC. The same trend applies with adsorption indicating that both biodegradation and adsorption are more surface area dependent than CEC.
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Robson, John Nicholas. "Synthetic and biodegradation studies of some sedimentary isoprenoid hydrocarbons." Thesis, University of Plymouth, 1987. http://hdl.handle.net/10026.1/1111.
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Ives, Sian E. "The biodegradation of polycyclic aromatic hydrocarbons (PAHs) in groundwater." Thesis, University of Huddersfield, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368319.
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Ibrahim, Ashraf Samir Abdel-Aziz. "Biodegradation of crude oil and individual hydrocarbons by microorganisms." Thesis, Loughborough University, 1991. https://dspace.lboro.ac.uk/2134/27943.
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Samples collected from Kuwait were screened for microorganisms capable of oil degradation. A wide range of bacteria and fungi were able to degrade oil. The bacterial and fungal isolates differed in their ability to degrade crude oil. Rhodococcus isolates were more active than fungi in n-alkane biodegradation. Fungi also utilised one or more of the aromatic hydrocarbons studied while bacteria failed to do so.
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Fisher, Steven J. "The use of advanced analytical techniques for studying the biodegradation of aromatic hydrocarbons." Curtin University of Technology, School of Applied Chemistry, 2002. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=13440.
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Two case studies are described where partially biodegraded petroleum residues were collected from the marine environment and analysed to investigate the changes in aromatic hydrocarbons with increasing biodegradation.The first of these studies, involved following the weathering of sea-floor residues from drilling discharges from an offshore petroleum exploration and production platform situated off the coast of North Western Australia. During operations, formation cuttings with adhering oil-based drilling muds were discharged into the ocean via a chute into approximately 125n1 of water, forming a substantial mound at the base of the platform. A suite of seabed sediments was collected from 16 sampling sites at various distances from the platform immediately following the cessation of drilling operations. The distribution of hydrocarbons in the sediment directly under tile cuttings chute was consistent with that found in drilling fluids formulated from a kerosene-like fluid. The samples from more remote sites exhibited the successive enhancement of an unresolved complex mixture relative to the n-alkanes, associated with tile presence of residues from petroleum biodegradation processes. In a subsequent sampling some three years later, a 10 cm core was retrieved from the cuttings pile and divided into 1 cm depth intervals. Samples within 6 cm of the surface of the cuttings pile contained biodegraded residues of the drilling mud, where the extent of biodegradation increased with decreasing proximity to the surface, most likely indicative of aerobic biodegradation. Biodegradation was less evident in the underlying sediments, where anaerobic conditions prevailed.Analysis of the aromatic hydrocarbons in both sets of sediment extracts by using gas chromatography-mass spectrometry (GC-MS) revealed the successive depletion of alkylnaphthalenes, and due to the subtlety of changes in the extent of biodegradation, provided an excellent opportunity to examine the susceptibility of biodegradation towards the individual alkylnaphthalenes in the marine environment. Conventional GC-MS analysis of these mixtures is performed under chromatographic conditions where complete resolution of the mixture is not achieved and several isomers co-elute. The mass spectra of these co-eluting isomers may be so similar that one is unable to differentiate between them, and their abundance may therefore not be determined. Since each isomer has a unique infrared spectrum, however, the abundance of each individual isomer was determined by comparing the infrared spectrum of the co-eluting compounds with the spectrum of each of the isomers. To this end, techniques were developed for the application of direct-deposition gas chromatography - Fourier transform infrared spectroscopy (GCFTIR) to the analysis of the complex mixture of alkylnaphthalenes present in the petroleum. This technique was also extended to discriminate between individual alkylphenanthrene isomers, and to clarify the sorption behaviour of the dimethylphenanthrenes by mordenite molecular sieves. The identification of other compounds of geochemical significance in petroleum is also described.
Analyses of' the aromatic hydrocarbons in the contaminated sea-floor sediments using GC-FTIR enabled the unambiguous identification and quantification of each of the dimethylnaphthalene, trimethylnaphthalene and tetramethylnaphthalene isomers present in the samples, from which the relative extents of depletion of each with increasing extent of biodegradation were determined. It was apparent from the considerable differences in the observed susceptibility to biodegradation that a strong relationship exists between the compound structure and its susceptibility to biodegradation, with 1,6-disubstituted polymethylnaphthalenes being preferentially depleted relative to other isomers that lack this feature. The second case study involved tracking the fate (weathering) of hydrocarbons from an accidental release of condensate from a buried pipeline into intertidal coastal (mangrove) sediments in North Western Australia. Sediment samples were collected on nine occasions over a three-year period. Chemical analysis of the saturated and aromatic hydrocarbon components of the petroleum extracts revealed that both hydrocarbon fractions exhibited an increasingly biodegraded profile with increased residence time in the sediments. In a similar manner to the first case study, detailed analysis of the aromatic hydrocarbons using GC-FTIR techniques was performed to determine the depletion of individual alkylnaphthalene isomers with increasing extent of biodegradation. It was apparent that a relationship similar to that observed for the sea-floor sediments exists between the alkylnaphthalene structure and its susceptibility to biodegradation.
Changes in the distribution of methylphenanthrene and dimethylphenanthrene isomer mixtures were also studied and the susceptibility to biodegradation amongst these determined in a similar manner. These relative susceptibilities to biodegradation of the aromatic hydrocarbons were then related to the established hierarchy of susceptibilities of the saturated hydrocarbons, in effect providing a second parallel system for the assessment of the extent of biodegradation. Finally, a system of ratios calculated from the relative abundances of selected aromatic hydrocarbons was developed and used as indicators to differentiate between several crude oils that have been biodegraded to varying extents. These parameters also offer promise as indicators of multiple accumulation events in oil reservoirs where petroleum fluids biodegraded to differing extents are mixed.
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Orlu, Rosemary Nmavulem. "Geochemical controls during the biodegradation of petroleum hydrocarbons in soils." Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/19846/.
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The microbial transformation of Fe (III) to Fe (II) can be coupled to the oxidation and reduction of organic contaminants in sub-oxic to anoxic environments. A multidisciplinary approach was adopted in this study to investigate the biogeochemical influences on the degradation of toluene (a representative of the class of aromatic hydrocarbons collectively known as BTEX) using experimental analogues of subsurface soil environments under predominantly iron-reducing conditions. The removal of toluene over the period of incubation indicated the soil-water mixture supported the degradation of toluene under predominantly iron-reducing conditions. Chemical sequential extractions showed the removal of toluene in the active mesocosms induced an increase in carbonate-bound iron fractions from 196.1 ± 11.4 mg/kg to 5,252.1 ± 291.8 mg/kg and a decrease in the reducible iron fraction from 2,504.4 ± 1,445.9 mg/kg to 375.6 ± 20.8 mg/kg. Analysis of the soil-water mixture showed slight shifts in the pH of the control and active mesocosms at the start of the experiments however these shifts occurred to a lesser degree over the remainder of the incubation period. Further experiments analysed the degree of influence of differing soil matrices and extraneous sources of iron (hematite, goethite, magnetite, ferrihydrite and lepidocrocite) on toluene removal. With the exception of the lepidocrocite-amended mesocosms, all of the iron-amended mesocosms were shown to have supported toluene removal. The presence of hematite, goethite and magnetite did not produce a significant change in the pH or total iron concentrations of the soil-water mixture. However the presence of ferrihydrite in the ferrihydrite-amended mesocosms induced a decrease in pH to slightly acid values ranging between pH 6.5 at the start of the experiments and 5.2 at the end of the experiments. The lepidocrocite-amended mesocosms induced a change to slightly alkaline values ranging between pH 8.4 and 8.8 during the period of incubation. All of the soil-amended mesocosms supported the removal of toluene in the soil-water mixture. The mesocosms containing soils with a greater percentage clay fraction removed higher amounts of toluene, possibly an indication that the bulk of this removal was sorption-induced and not microbially-mediated. An experimental approach based on the standard stable carbon isotope analytical method made it possible to determine the source of carbon in the incubated mesocosm material. The application of the mixed effects model approach to analyse the repeatedly measured experimental data demonstrated the possibility of producing predictive models for toluene removal in soil.
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Smith, Michael John. "Bioremediation of polycyclic aromatic hydrocarbons in soil." Thesis, University of Kent, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242929.
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Zhang, Yimin. "Role of Pseudomonas rhamnolipid surfactants in biodegradation of slightly soluble hydrocarbons." Diss., The University of Arizona, 1995. http://hdl.handle.net/10150/187280.
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Biodegradation of hydrocarbons is often limited by the low water solubility. Surfactants can increase hydrocarbon solubility, however, the effects of surfactants on hydrocarbon biodegradation are not well known. Therefore, the purpose of this research is to investigate the fundamental interactions between surfactants, hydrocarbons and microorganisms. This three-way interaction was studied in the defined experimental system consisting of Pseudomonas rhamnolipid surfactants, hydrocarbons and Pseudomonas hydrocarbon degraders. A variety of system factors affecting biodegradation were examined. These factors included surfactant structure, surfactant concentration, hydrocarbon structure and cell hydrophobicity of microorganisms. Pseudomonas sp. are able to produce several rhamnolipid types. Among three rhamnolipid types tested in this study, dirhamnolipid methyl ester had the greatest effect on alkane solubilization and biodegradation. Monorhamnolipid acid exhibited higher solubilization of alkanes than dirhamnolipid acid. Monorhamnolipid acid at high concentrations ( > 0.1 mM) enhanced alkane biodegradation more effectively than dirhamnolipid acid. In contrast, dirhamnolipid acid enhanced degradation more effectively at low concentrations ( < 0.1 mM). The biodegradation of alkanes was affected by microbial cell surface hydrophobicity. Results showed that inherently slow alkane degraders had low cell hydrophobicity while the inherently fast alkane degraders had high cell hydrophobicity. Rhamnolipids enhanced cell hydrophobicity of the slow degraders but had no effect on the cell hydrophobicity of the fast degraders. The rate at which the cells became hydrophobic depended on the rhamnolipid concentration and was directly related lo the rate of alkane biodegradation. Rhamnolipid mixtures had a different effect from single rhamnolipids on solubilization and biodegradation of alkanes. The effect can be synergistic or additive depending on the surfactant mixture. For instance, the mixture of dirhamnolipid acid and methyl ester had a synergistic effect on solubilization and additive effect on biodegradation. The effect of rhamnolipids on the hydrocarbon biodegradation varied with hydrocarbon structure. For instance, enhanced biodegradation of model alkanes was determined by both rhamnolipid structure and concentration. In contrast, enhanced phenanthrene biodegradation seemed to depend only on rhamnolipid concentration. The results of this research suggest that rhamnolipids have potential use for remediation of petroleum-contaminated sites. Further research is recommended to investigate the effect of rhamnolipids on hydrocarbon biodegradation in soil systems.
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Lü, Xiaoying, and 吕晓莹. "Biodegradation of polycyclic aromatic hydrocarbons in marine sediment under anoxic conditions." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B45961062.
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Obuekwe, Ifeyinwa S. "Biodegradation of polycyclic aromatic hydrocarbons in soils co-contaminated with metals." Thesis, Lancaster University, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.656325.
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Mixtures of polycyclic aromatic hydrocarbons (PARs) and heavy metals are of major concern in contaminated soil. The aim of this project was to investigate the impact of heavy metals and PAHs on microbial activity, concentrating on the mineralisation of PAHs and partitioning of phenanthrene in the presence of metals. Naphthalene and phenanthrene were used as model PAHs and Zn, Cu, Al and Fe were used as model heavy metals. 14C_ Naphthlene and 14C-phenanthrene mineralisation were followed in soil with varying concentrations of Zn, Cu, Al and Fe; a sequential aqueous\solvent extraction scheme was also used to assess the partitioning of phenanthrene in the presence of these metals. Zn and Cu (50 and 100 mg/kg) stimulated (p < 0.05) 14C-naphthalene mineralisation, but had no impact on 14C-phenanthrene mineralisation. Zn (500 and 1000 mg/kg) had no impact on 14C-phenanthrene mineralisation (p > 0.05), but Cu (500 and 1000 mg/kg) significantly reduced (p < 0.05) phenanthrene catabolism, particularly in aged Cu. Zn and Cu mixtures (500 and 1000 mg/kg) inhibited 14C-phenanthrene catabolism. 14C-Glucose mineralisation (maximum rates) and incorporation into the microbial biomass were significantly reduced at higher Zn and Cu concentrations (500 and 1000 mg/kg). Al and Fe (50 and 100 mg/kg) stimulated (p < 0.05) both 14C-naphthalene and phenanthrene mineralisation, however, Al (500 mg/kg) significantly reduced (p < 0.05) mineralisation of both PAHs. Fe (500 mg/kg) stimulated both 14C-naphthalene and phenanthrene mineralisation. Cu and Al (500 mg/kg) significantly increased (p < 0.05) 14C-phenanthrene extractable CaCh and HPCD fractions, this could be because of their great affinity for the organic and mineral soil components. The impact of metals on the biodegradation of PAHs depends on the type and concentrations of the metals, as well as the incubation time. Studies on metal-P AH impact in soil facilitates the assessment of risk, hazard and bioremediation potential at sites contaminated with both contaminants.
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Spence, Keith Harvey. "The biodegradation of MTBE and fuel hydrocarbons in the chalk aquifer." Thesis, University of Leeds, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426844.
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Rodriguez-Lattuada, Sylian J. "Characterization of Soil Biofilms for the Biodegradation of Polycyclic Aromatic Hydrocarbons." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1129320613.
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Mejeha, Obioma Kelechi. "Biodegradation of petroleum hydrocarbons in soils co-contaminated with petroleum hydrocarbons and heavy metals derived from petroleum." Thesis, University of Newcastle upon Tyne, 2016. http://hdl.handle.net/10443/3391.
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The biodegradation of sites co-contaminated by organic pollutants and Heavy Metals is often a challenge due to the inhibition of microbial activities. Microbes play important role in the mineralization of petroleum hydrocarbons to CO2 by utilizing petroleum hydrocarbons as a carbon/ energy source. Heavy metals are often constituents of petroleum. Petroleum spills may result to the release associated metals (e.g. Ni, Cd, Pb, As) into the environment. Subsequent spills may cause an increase in metal concentrations in soils that may build to concentrations above intervention values. This may result to the inhibition of important biological activities such as the biodegradation of organic contaminants. This research investigates the effects of Ni, Cd and Pb contamination on biodegradation of petroleum hydrocarbons in complex soil system using a microbiological approach combined with geochemical approach. Such an approach will provide a more detailed understanding of the patterns of oil degradation under different and increasing metal stresses and how microbial communities change in such environments. Results indicated that Ni has stimulatory or no effects on biodegradation of petroleum hydrocarbons in soils depending on the chemical form of added Ni. The stimulatory effect was observed in Ni-Porphyrin contaminated soils and declined with increasing Ni concentration. In NiO soils, no effects occurred at low concentrations and increased concentration of Ni resulted to increased inhibition of biodegradation. This is unlike NiCl2 amended soils where Ni effects on biodegradation were neutral irrespective of Ni concentration. The microbial diversity study of the microbial soil community indicated that there was a selective enrichment of species in the soil communities. Phylogenetic study indicated that the dominant microorganism in the community is a strain of Rhodococcus (100%), which was closely related to most Rhodococcus strains isolated from hydrocarbon-contaminated environments, metal contaminated environments and extreme environments. Results indicated that Cd inhibited biodegradation of crude oil in soils, irrespective of Cd form or concentrations. The inhibitory effect increased with increasing concentrations. Also, the microbial diversity study of the microbial soil community indicated that there was a selective enrichment of species in the soil communities. Similar to Ni, Phylogenetic study indicated that the dominant microorganism in the community is a strain of Rhodococcus. Also biodegradation of petroleum was significantly reduced in crude oil degrading short-term Pb contaminated soils, irrespective of Pb form or concentration. However, in long-term Pb contaminated soils, while maximal rate of petroleum degradation reduced at high- Pb concentration, no effect was observed at low lead concentration. Also, the microbial diversity study of the microbial soil community indicated that there was a selective enrichment of species in the soil communities. Two dominating specie were identified in Pb-soils depending on soil. Both are closely related to a strain belonging to Bacillales that were originally isolated Rock, Scopulibacillus darangshiensis strain (98%) and oil contaminated soil Bacillus circulans (99%). While the former dominated in Pb -short-term contaminated soils as well as Pb-long term contaminated soil at high concentration, the later dominated long-term-Pb contaminated soil at low concentration.
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Aemprapa, Sirinun. "Toluene/xylene catabolic pathway of Pseudomonas putida strain Oâ†2Câ†2." Thesis, Bangor University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321526.
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