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Kurt, Zohre. "Biodegradation of chlorinated compounds at interfaces and biodegradation of 4-nitroaniline." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/50111.
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Most microbial activity in nature takes place at interfaces where redox discontinuities are present. Organic pollutants in groundwater encounter oxic/anoxic interfaces when they emerge to surface water bodies or volatilize above the plume. Such oxic/anoxic interfaces are key habitats for aerobic bacteria and are in turn created by the bacteria that degrade organic electron donors. In the absence of biodegradation, synthetic pollutants can migrate from the plume and impact a variety of receptors. The aims of our study were to determine whether microbes at oxic/anoxic interfaces can use synthetic chemicals as electron donors and protect the overlying vadose zone or surface water from groundwater pollutants. The approach was to design columns representing the interfaces and measure activities of the microbial communities responsible for the biodegradation of synthetic compounds.Taken together the above studies established clearly that contaminants recalcitrant under anaerobic conditions but degradable under aerobic conditions can be biodegraded at the narrow oxic/anoxic interface resulting in the protection of the overlying soil or water. The findings provide the basis for new approaches to natural attenuation that can serve to dramatically reduce the cost of bioremediation actions. Synthetic chemicals are widespread in the environment because of their extensive use in industry. These chemicals were recalcitrant until their microbial degradation pathways evolved. Currently the biodegradation pathways of many synthetic chemicals are known and serve as the basis for bioremediation strategies. The second part of the research described here involved discovery of the aerobic degradation pathway of a dye additive: 4-nitroaniline (4NA). Annotation of the whole genome sequence coupled with assays and supported with cloned enzymes revealed that the 4NA biodegradation pathway contains two monooxygenase steps prior to ring cleavage. Because nitroaniline degradation was not previously understood our work advanced the understanding of metabolic diversity in degradation of amino and nitro compounds by providing enzymes with unique activities.
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Marino, Fabien. "Biodegradation of paraffin wax." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0030/MQ50640.pdf.
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Marino, Fabien. "Biodegradation of paraffin wax." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21312.
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Nineteen bacteria were tested for growth on paraffin wax as the sole source of carbon. Paraffin wax is a solid mixture of hydrocarbons including n-alkanes ranging from C18H38 to C37H 76. Of the nineteen bacteria tested, four bacteria (Arthrobacter paraffineus ATCC 19558, Mycobacterium OFS, Pseudomonas fluorescens Texaco and Rhodococcus IS01) grew well on paraffin wax. However, only one, Rhodococcus IS01, was found to rapidly and completely degrade a mixture of paraffin wax liquefied with hexadecane using the Self-Cycling Fermentation (SCF) technology. This strain was able to degrade n-alkanes ranging from dodecane to heptatriacontane as well as highly branched hydrocarbons such as pristane and hepta-methyl-nonane.Kinetic studies performed with Rhodococcus IS01 growing on mixtures of n-alkanes showed that the hydrocarbons were degraded in ascending order of chain length: shortest to longest chain. The short lag period between the biodegradation of the different n-alkanes suggested that the growth of Rhodococcus IS01 on mixtures of n-alkanes followed some form of diauxie. Further kinetic studies were conducted growing Rhodococcus IS01 on individual and various mixtures of n-alkanes; these showed that the initial first-order oxidation constant decreased with increasing chain length. This trend is suspected to be due to an enzyme specificity constraint rather than to a mass transfer limitation. In addition, it was also observed that the maximum specific growth rate constant (mumax) increased with increasing n-alkane chain length.
Rhodococcus IS01 was also found to produce a cell-associated biosurfactant.
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McGrath, John W. "The biodegradation of organophosphonates." Thesis, Queen's University Belfast, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295419.
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Zhong, Sheng-Ping. "Biodegradation of medical polymers." Thesis, University of Liverpool, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333769.
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Arshad, Khubaib, and Muhammad Mujahid. "Biodegradation of Textile Materials." Thesis, Högskolan i Borås, Institutionen Textilhögskolan, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-20862.
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In this research work different textile materials were buried in soil and their biodegrading pattern will be studied after different specific period of times.Program: Master Programme in Textile Technology
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Malandra, Lida 1975. "Biodegradation of winery wastewater." Thesis, Stellenbosch : University of Stellenbosch, 2003. http://hdl.handle.net/10019.1/16385.
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Thesis (MSc)--University of Stellenbosch, 2003.ENGLISH ABSTRACT: Large volumes of wastewater are generated annually during the grape harvest season from various processing and cleaning operations at wineries, distilleries and other wine-related industries. South African regulatory bodies dictate that wastewater should have a pH of 5.5 to 7.5 and a chemical oxygen demand (COD) lower than 75 mg/L. However, winery wastewater has a typical pH of 4 to 5 and a COD varying between 2 000 and 12 000 mg/L. Urban wineries channel the wastewater to local sewage treatment facilities and are often heavily fined for exceeding governmental requirements. Rural wineries usually have little or no treatment operations for their wastewater and it is often irrigated onto crops, which may result in environmental pollution and contamination of underground water resources. Various criteria are important in choosing a wastewater treatment system, such as an ecofriendly process that is flexible to withstand various concentration loads and characteristics, requiring low capital and operating costs, minimal personal attention and do not require too much land. In this study, a large variation in COD, pH and chemical composition of the winery wastewater was observed that could be related to varying factors such as the harvest load, operational procedures and grape variety. Wastewater from destemming and pressing operations contained higher concentrations of glucose, fructose and malic acid, which originated from the grape berries. The fermentable sugars (glucose and fructose) contributed to almost half of the COD with a smaller contribution from ethanol and acetic acid. The low pH can be ascribed to relative high concentrations of organic acids in the wastewater. The efficacy of biological treatment systems depends strongly on the ability of microorganisms to form biofilm communities that are able to degrade the organic compounds in the wastewater. Preliminary identification of microorganisms that naturally occur in winery wastewater indicated the presence of various bacterial and yeast species that could be effective in the biological treatment of the wastewater. When evaluated as pure cultures under aerobic conditions, some of the yeast isolates effectively reduced the COD of a synthetic wastewater, whereas the bacterial isolates were ineffective. The most effective yeast isolates were identified as Pichia rhodanensis, Kloeckera apiculata, Candida krusei and Saccharomyces cerevisiae. Our search for cost-effective biological treatment systems led to the evaluation of a Rotating Biological Contactor (RBC) for the treatment of winery wastewater. The RBC was evaluated on a laboratory scale with 10% (v/v) diluted grape juice and inoculated with a mixed microbial community isolated from winery wastewater. The results showed a reduction in the COD that improved with an extended retention time. Evaluation of the RBC on-site at a local winery during the harvest season resulted on average in a 41% decrease in COD and an increase of 0,75 pH units. RFLP analysis of the biofilm communities within the RBC confirmed a population shift in both the bacterial and fungal species during the evaluation period. The most dominant yeast isolates were identified with 18S rDNA sequencing as Saccharomyces cerevisiae, Candida intermedia, Hanseniaspora uvarum and Pichia membranifaciens. All these species are naturally associated with grapes and/or water and with the exception of Hanseniaspora uvarum, they are able to form either simple or elaborate pseudohyphae.
AFRIKAANSE OPSOMMING: Groot hoeveelhede afloopwater word jaarliks gedurende die druiwe-oestyd deur verskeie prosessering- en skoonmaakoperasies deur wynkelders, distilleer- en ander wynverwante industrieë gegenereer. Suid-Afrikaanse beheerliggame vereis dat afloopwater ‘n pH van 5.5 tot 7.5 en ‘n chemiese suurstofbehoefte (COD) van minder as 75 mg/l moet hê. Kelderafloopwater het egter gewoonlik ‘n pH van 4 tot 5 en ‘n COD van 2 000 tot 12 000 mg/L. Stedelike wynkelders voer die afloopwater na ń plaaslike rioolsuiweringsaanleg wat dikwels tot swaar boetes vir oortreding van die wetlike vereistes lei. Plattelandse wynkelders het gewoonlik min of geen behandelingsprosesse vir hul afloopwater nie en gebruik die water dikwels vir gewasbesproeiing, wat tot omgewingsbesoedeling en kontaminasie van ondergrondse waterbronne kan lei. Verskeie kriteria is belangrik in die keuse van ‘n waterbehandelingstelsel, byvoorbeeld ‘n omgewingsvriendelike proses wat verskillende konsentrasieladings en samestellings kan hanteer, ‘n lae kapitaal- en bedryfskoste en minimale persoonlike aandag vereis en min ruimte benodig. Hierdie studie het getoon dat kelderafloopwater ‘n groot variasie in COD, pH en chemiese samestelling het wat met wisselende faktore soos die oeslading, operasionele prosesse en selfs die druifkultivar verband kan hou. Afloopwater van ontstingeling- en parsoperasies het hoër konsentrasies glukose, fruktose en appelsuur wat van die druiwekorrels afkomstig is. Die fermenteerbare suikers (glukose en fruktose) dra tot amper 50% van die COD by, met ‘n kleiner bydrae deur etanol en asynsuur. Die lae pH kan grootliks aan organiese sure in die afloopwater toegeskryf word. Die effektiwiteit van biologiese behandelingstelsels steun sterk op die vermoë van mikroorganismes om biofilmgemeenskappe te vorm wat die organiese verbindings in die afloopwater kan afbreek. Voorlopige identifikasie van mikro-organismes wat natuurlik in wynafloopwater voorkom, het die teenwoordigheid van verskeie bakteriese en gisspesies aangedui. Evaluering van hierdie isolate onder aërobiese toestande het getoon dat sommige van die gis-isolate die COD van ‘n sintetiese afloopwater effektief kon verlaag, terwyl die bakteriese isolate oneffektief was. Die mees effektiewe gis-isolate is as Pichia rhodanensis, Kloeckera apiculata, Candida krusei en Saccharomyces cerevisiae geïdentifiseer. Ons soektog na ‘n koste-effektiewe biologiese behandelingsisteem het tot die evaluering van ‘n ‘Rotating Biological Contactor’ (RBC) vir die behandeling van afloopwater gelei. Die RBC is op laboratoriumskaal met 10% (v/v) verdunde druiwesap geëvalueer en met ‘n gemengde mikrobiese gemeenskap wat uit afloopwater geïsoleer is, innokuleer. Die resultate het ‘n verlaging in die COD getoon wat met ‘n langer retensietyd verbeter het. Evaluering van die RBC by ‘n plaaslike wynkelder gedurende die oesseisoen het gemiddeld ‘n verlaging van 41% in die COD en ‘n verhoging van 0,75 pH eenhede getoon. RPLP analise van die biofilmgemeenskappe in die RBC het ‘n bevolkingsverskuiwing in beide die bakteriese en swamspesies aangetoon. Die mees dominante gisspesies is met 18S rDNA volgordebepaling as Saccharomyces cerevisiae, Candida intermedia, Hanseniaspora uvarum en Pichia membranifaciens geïdentifiseer. Al hierdie spesies word gewoonlik met druiwe en/of water geassosieer en is, met die uitsondering van Hanseniaspora uvarum, in staat om òf eenvoudige òf komplekse pseudohife te vorm.
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Tikoo, Vidya. "Microalgal biodegradation of pentachlorophenol." Thesis, University of the West of England, Bristol, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319256.
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Pentachlorophenol (PCP) is a chlorophenol with a pronounced biocidal activity that has led to its use in a number of applications. It was introduced in the 1930s as a preservative for timber and lumber and since then has found wide use as a biocide in agricultural and industrial applications. Many different physical, chemical and biological methods have been tried for the removal of PCP from wastewater. However, using microalgae for the removal of PCP and other organochlorine compounds from water may prove to be a cheaper alternative and give complete degradation of the compounds. The aim of this project was to study the efficiency of microalgae to degrade PCP. An algal strain named VT -1 and a bacterial strain named AT -14 were isolated from PCP containing conditions in the laboratory. The growth of VT -1 in the presence of PCP was compared with Chlorella emersonii and Chlorella vulgaris in two different autotrophic media. It was observed that VT-1 had the highest IC50 value of 25-26mg }-l PCP and EC50 value of 11.3mg }-1 PCP in S&K medium. With glucose as an additional carbon source the IC50 value for VT-1 in S&K medium was 29-30mg t 1 PCP. Bacterium AT-14 could grow in the presence of PCP, only with glucose as a carbon source. Mineralization of PCP by VT -1 and the two Chlorella strains was compared by using 14C_PCp. With all the three algae exposed to 14C_PCp, only VT-1 showed release of 14C02, which was evidence of mineralization of PCP by VT-1 which occurred only in the presence of light. Bacterium AT-14 did not produce 14C02. However, the consortium of VT-1 and AT-14 showed enhanced 14C02 evolution in the presence of glucose. The release of chloride ions from PCP can also indicate PCP dehalogenation and degradation. The evolution of 14C02 lagged behind chloride release (90 %) indicating that dechlorination of PCP could be the first step in its biodegradation. Breakdown of PCP was also followed by its extraction from the cells and medium. Normally dichloromethane (DCM) was used to extract PCP. The changes in the label extracted in DCM and iso-butanol were studied under different light condjtions, which showed that the 14C counts in DCM reduced and those in iso-butanol extract increased with time. The 14C counts in the iso-butanol extract could be a metabolite of PCP which is more hydrophilic. VT-1 appeared not to degrade PCP completely, since only 15% of 14C was recovered as 14C02. It appears that intermediates are formed which are distributed in the growth medium and in the biomass. It can thus be concluded that VT -1 is tolerant of PCP, appears to dechlorinate PCP and then releases some part of it as CO2.
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Shearer, Brad David. "Enhanced Biodegradation in Landfills." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/33215.
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The objective of this paper is to evaluate the effectiveness of leachate recirculation and bioreactor landfills at enhancing biodegradation, and to optimize the operation of a bioreactor. Waste Management has been examining leachate recirculation landfills for several years. Samples of Municipal Solid Waste (MSW) from existing leachate recirculation (LR) landfills were collected and analyzed for several physical and biochemical properties. These parameters of interest were moisture content, pH, density, temperature, volatile solids, cellulose/lignin ratios, and biological methane potential (BMP). Leachate recirculation increased the dry density 55% faster and decreased the BMP 125% more rapidly. Moisture content was the biggest factor influencing overall degradation. Therefore, leachate reciculation effectively increases biodegradation of MSW in landfills.
Waste Management built a pilot-scale bioreactor in Franklin, WI, which was sampled for one year. It contained a bioreactor side and a control side. The volatile solids, cellulose, and BMP degradation rates for the bioreactor were increased by 56%, 87%, and 271% versus the control, respectively. Moisture content was the biggest factor influencing overall degradation.
The column study is designed to optimize three parameters under the control of an operator: moisture content, initial aeration period, and biosolids addition. The optimum moisture content is above 45%, but it is not safe to operate heavy equipment on refuse with greater than 45% moisture. Initial aeration did not speed up the overall degradation, but it did shorten the acidogenic phase. Finally, biosolids did not have a significant effect on degradation rates. The columns maintained an average temperature of 70oF.Master of Science
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PAULUS, SYLVIE. "Biodegradation de steranes petroliers." Université Louis Pasteur (Strasbourg) (1971-2008), 1993. http://www.theses.fr/1993STR13041.
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La biodegradation in vitro du 5-alpha-cholestane, par une souche de bacteries du sol du genre nocardia, a permis d'identifier plusieurs intermediaires de degradation par comparaison avec des standards. Ils resultent d'une part, de la degradation de la chaine laterale par un processus analogue a la beta-oxydation des acides gras, et d'autre part, d'une 4-alpha-hydroxylation. Les intermediaires caracterises precedemment ont ete recherches dans des echantillons biodegrades de sol pollue par du petrole. Differents isomeres du 20-carboxy-5-alpha-pregnane ont ete identifies. Si les acides carboxyliques proviennent bien de la degradation des steranes en c27 correspondants, alors les microorganismes ne sont pas particulierement selectifs au niveau de la stereochimie des steranes en c27 dans notre cas, et suivent tous le meme processus de biodegradation qui est celui mis en evidence dans l'etude precedente. Enfin, nous avons tente d'elucider la structure de molecules inconnues, des secosteranes, presentes dans un sediment italien. Si aucun des secosteranes synthetises ne correspond aux composes sedimentaires, les spectres de masse des 1,10-secosteranes comportent cependant de nombreuses analogies avec les composes sedimentaires
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Zibdeh, I. R., G. R. Lanza, and Phillip R. Scheuerman. "Biodegradation of Cresol Isomers." Digital Commons @ East Tennessee State University, 1995. https://dc.etsu.edu/etsu-works/2901.
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Princivalle, Jessica. "How important is soil microbial diversity for pesticide biodegradation function and robust biodegradation kinetics?" Thesis, University of Reading, 2017. http://centaur.reading.ac.uk/73803/.
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Soil microbial communities are highly diverse and implicated in delivering many ecosystem services including the degradation of pesticides. The aim of this thesis was to study the relationship between microbial species richness and pesticide biodegradation kinetics in order to contribute to the understanding of the causes of variability in pesticide degradation kinetics between test systems used as a component part of the discovery process for new crop protection active ingredients. This thesis was in collaboration with Syngenta who were keen to gain an understanding of the importance of soil microbial diversity for pesticide biodegradation function in order to underpin the design of improved test systems for screening pesticides at an early stage of their development. A series of soils encompassing a microbial diversity gradient using a dilution to extinction approach were created, in which the soil was y-irradiated/lautoclaved and then re-inoculated with a suspension of serial dilutions of fresh soil (la', 10', 106, 10', 101"). Illumina MiSeq sequencing demonstrated gradual decrease of bacterial OTUs of 45, 54, 66, 83 and 88 % in the dilutions compare to the control fresh soil while the y-irradiated control soils showed a reduction of 97% after a soil equilibration period of 20 weeks to allow microbial re-colonisation of the soil. These manipulated soils were used to conduct pesticide degradation studies following the OEC0307 guideline using radio labelled compounds: 2,4-Dichlorophenoxyaceticacid (2,4-0), Terbuthylazine (TBA), Azoxystrobin (AZ) and Bicyclopyrone (BIR). The degradation of 2,4-0 was robust up to 106 dilution, but was disrupted beyond 10'. Conversely, AZ half-life was much prolonged (>388 days) in all diluted soils compared to the 'fresh control' DT50 of 77 days, indicating a high dependency on microbial diversity. TBA was degraded similarly in all soils (DT50 range 75-166 days) suggesting a possible reliance on microbial community structure. BIR degradation was slower than the other compounds with half-life exceeding the duration of the study, however, a reduction in the extrapolated half-life in diluted soils compare to the fresh control was recorded. Analysis of compound degradation kinetics therefore revealed pesticide-specific sensitivity to microbial diversity erosion. The findings of this project contribute to the understanding of the causes of variability in pesticide biodegradation behaviour between the test systems component to the pesticide discovery pipeline. The dilution to extinction system that was evaluated in this thesis could potentially provide a valuable tool to agrochemical R&D through providing a means to identify (and discard) compounds not displaying robust biodegradation kinetics at an early stage in the discovery process.
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Smith, Maree J. "Biodegradation of the cyanotoxin cylindrospermopsin /." [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18474.pdf.
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Gilardi, Gianfranco. "Spectroscopic studies of lignin biodegradation." Thesis, Imperial College London, 1991. http://hdl.handle.net/10044/1/46785.
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Müller, Stefan. "Biodegradation of polyethylene thermolysis residue." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0005/MQ44028.pdf.
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Müller, Stefan 1971. "Biodegradation of polyethylene thermolysis residue." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20509.
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The ability of several microorganisms to degrade polyethylene thermolysis residue was investigated. This residue is mainly comprised of n-alkanes and n-1-alkenes ranging in chain length of 15 to 45 carbon units and therefore resembles crude oil. The microorganisms investigated were: Y. lipolytica ATCC 8662, Y. lipolytica ATCC 20460, A. paraffineus ATCC 19558, P. aeruginosa PAO1, P. putida ATCC 12633, R. rhodochrous ATCC 21766 and Rhodococcus sp. ATCC 29671. It was found that all seven microorganisms tested were able to degrade the polyethylene thermolysis residue. Results suggest that R. rhodochrous produced a biosurfactant when growing on the polyethylene thermolysis residue.It was also found that the acclimation of the microorganism to the substrate was an important factor in the degradation of the residue. Using two different acclimation times, two different strains of R. rhodochrous were selected for in the acclimation step. The two different strains showed very different degradation patterns of the polyethylene thermolysis residue. Strain A showed almost no effect of chain length on the degradation rate of the hydrocarbons while the degradation rate of the hydrocarbons for strain B decreased with increasing chain length. This difference in the degradation pattern was attributed to the varying amounts of enzymes present in each strain. Another factor found to affect the degradation pattern was the liquidity of the polyethylene thermolysis residue.
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Gauthier, Herve. "Biodegradation of pharmaceuticals by microorganisms." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32347.
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The presence of pharmaceutical residues in water poses a serious treat to human health. The fate of many of these pharmaceuticals in the environment has not been thoroughly investigated. Sulfamethoxazole, sulfamethizole, trimethoprim and carbamazepine are among these pharmaceuticals with significant bioactivity that are considered to be persistent pollutants. The biodegradation of these compounds has been studied in this project in order to assess the fate of these pharmaceuticals in the environment. An easily degradable carbon source was added in these biodegradation experiments to optimize co-metabolism as a removal mechanism. Five microorganisms were used to determine if the selected drugs were biodegradable and, also, to identify the metabolites arising from their biodegradation. It was demonstrated that biodegradation occurred for sulfamethoxazole, sulfamethizole and carbamazepine. Trimethoprim showed a high resistance to biodegradation. It appeared that the microorganism Rhodococcus rhodochrous showed a particular ability to degrade the pharmaceuticals. The presence of metabolites was confirmed by HPLC and mass spectra analyses.La présence de résidus de produits pharmaceutiques dans l'eau représente une sérieuse menace pour l'environnement et la santé humaine. Le devenir de ces produits pharmaceutiques dans l'environnement n'a pas été adéquatement étudié. Le sulfaméthoxazole, le sulfaméthizole, le triméthoprime ainsi que le carbamazepine sont parmi ces composés pharmaceutiques qui ont une importante bioactivité et sont considérés comme polluants persistants. Dans ce projet, la biodégradation des ces produits à été étudiée afin d'évaluer le devenir de ceux-ci dans l'environnement. Une source de carbone facilement biodégradable a été utilisé lors des expériences afin de stimuler le mécanisme d`élimination par co-métabolisme. Cinq microorganismes ont été utilisés afin d'évaluer la biodégradabilité des produits pharmaceutiques sélectionnés et aussi identifier les métabolites résultant de leur biodégradation. Il a été démontré que la biodégradation est survenue pour le sulfaméthoxazole, le sulfaméthizole ainsi que le carbamazépine. Le triméthoprime à quant lui démontré une forte résistance à la biodégradation. Le microorganisme Rhodococcus rhodochrous a démontré une habileté particulière à dégrader les produits pharmaceutiques. La présence de métabolites a également été confirmée par analyse HPLC et spectrometrie de masse.
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Dooley, S. "Biodegradation of machine cutting oil." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.598601.
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The aim of this dissertation was to improve the biodegradation performance of a machine cutting oil employed in the processing of uranium at AWE. The machine cutting oil is chemically complex containing mineral oil, surfactants to improve emulsification and a phenolic biocide. Biodegradation was performed by a mixed culture of bacteria isolated from used cutting oil. Continuous, semi-batch and fed-batch systems were examined and stirred tanks and well-mixed biosupport reactors (immobilised cell systems) were compared. A continuous flow system was shown to provide a high rate of productivity with respect to COD removal. The extent of biodegradation would be important for a radioactive application and this ranged from 61-77% for hydraulic residence times of 10-53 hours, however it was noted that the extent of biodegradation was greater in the batch start-up period. The application of a Tween 80 emulsified feed to increase the bioavailability of the oil phase inhibited rather than improved the biodegradation performance. The use of a biosupport reactor improved biodegradation at shorter residence times. Development of these observations led to the operation of semi-batch (SBR) and fed-batch reactor systems (FBR). Following acclimatisation of the culture, the semi-batch systems consistently yielded higher extents of biodegradation in the range of 86-94% removal of COD for a bioprocess cycle of 5 days. The addition of n-hexadecane, as a readily metabolised co-substrate, to two semi-batch experiments did not noticeably increase biodegradation. A fed-batch configuration did not improve on the performance of the semi-batch configuration. GC-MS analysis of the extracted organics produced an unresolved complex mixture (UCM). Oxidation using chromium trioxide (CrO3) of the UCM suggested that the remaining components were undegraded molecules from the base oil rather than excreted biodegradation intermediates. Phenotypic and genotypic assessment of the bacterial community showed that the overall diversity of the mixed culture was low. The bacterial population shifted throughout the batch period and diversity was further reduced as the cutting oil was degraded. Maximum diversity was observed at the start of the batch period and at steady state for the continuous system.
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Chongcharoen, Rotsaman. "Biodegradation of formaldehyde by methylotrophs." Thesis, University of Warwick, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269080.
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Starkey, Michelle. "Biodegradation of lubricants in soil." Thesis, University of Reading, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413409.
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Ali, Saiqa Mubeen. "Thermophilic biodegradation of phenolic compounds." Thesis, University College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339092.
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Lubben, Anneke Twaambo. "Biodegradation of liquid scintillant cocktails." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395992.
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Kuippers, Gina. "The biodegradation of isosaccharinic acid." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/the-biodegradation-of-isosaccharinic-acid(6a3cd692-8997-4cbc-bd33-2bee7c9741b4).html.
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The nuclear waste inventory of the UK comprises large quantities of intermediate level wastes (ILW), which will be immobilised by encapsulation within a cementitious grout in stainless steel containers, followed by disposal in a deep engineered geological disposal facility (GDF) within a suitable geological formation. These wastes contain, in addition to radioactive elements, a heterogeneous mix of organic materials, including plastics, cellulose and rubber. Cellulosic items, such as cloth, tissue, filters, paper and wood, are considered particularly problematic, because they are known to be susceptible to degradation under alkaline conditions, forming small chain organic acids with the ability to complex metals and radionuclides. It is predicted that under alkaline conditions isosaccharinic acid (ISA) will form particularly strong complexes with Ni(II), Am(III), Eu(III), Np(IV), Th(IV), and U(IV). As a result, the presence of ISA could affect the migration behaviour of these elements, by increasing their solubility and reducing sorption, thus enhancing their mobility into the near and far field surrounding a GDF. During site operation and then after closure of a GDF, microbial communities have the potential to colonise the steep biogeochemical gradients, running from highly alkaline in the GDF ânear fieldâ to circumneutral pH conditions in the surrounding geosphere. Within these steep pH gradients microbial processes can control the fate of organic compounds, such as ISA, and have therefore been considered as an effective self-attenuating mechanism to remove ISA from the groundwater. This thesis aims to deliver a greater understanding of the microbial processes that can potentially use ISA as a carbon source and electron donor, removing it from solution, and thus having a positive impact on radionuclide mobility under GDF-relevant conditions. A microbial enrichment approach was chosen that approaches GDF-relevant conditions to explore the biodegradation of ISA. Cross-disciplinary analyses of water chemistry (pH, Eh, photospectroscopy, IC, ICP), mineralogy (ESEM, XRD, TEM, XAS) and microbiology (light microscopy, next generation sequencing) have demonstrated the ability of bacteria to degrade ISA over a wide range of biogeochemical conditions. Furthermore, key radionuclides (and their non-active analogues), including Ni(II) and U(VI), were precipitated from the groundwater system during ISA biodegradation. Moreover, in the case of uranium, microbial metabolism led to the reduction of U(VI) to U(IV), which is also less soluble. This study highlights the potential for microbial activity to help remove chelating agents from groundwaters surrounding an ILW GDF, and suggests that safety cases that do not include microbial processes may be overly conservative, over-estimating the impact of ISA on radionuclide transport.
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Yagoub, Sally. "Biodegradation of leather solid waste." Thesis, University of Northampton, 2006. http://nectar.northampton.ac.uk/2675/.
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Waste management in the leather industry worldwide is an issue of major importance for both solid and liquid wastes. It has been recognised that there are major environmental impacts from the poorly managed disposal of such wastes and these have a clear health impact upon human society. Within Europe, under EU driven legislation, the costs of wastes management are increasing rapidly and there is a clear need to research improved methods to cost effectively deal with leather industry wastes. Biodegradation (anaerobic), as a management option, of solid wastes from the leather industry is an area that is attracting increased interest in recent years as being a technique that has wide public acceptability as well as process efficiency. However, tanning agents that prolong the lifetime of leather goods have a negative impact on biodegradation and this needs to be addressed before efficient treatment can occur. To drive the agenda this research has the aims of • Highlighting the effects of tanning agent on anaerobic digestion. • Understanding the mechanism(s) by which different leather tannages can biodegraded. • Developing a process to reverse the action of tannage. Leather solid wastes were anaerobically digested using Serum Bottle Assays (SBA). The effect of a range of vegetable, mineral and aldehyde tanning agents of leather on the rate of anaerobic digestion was assessed. Common tanning agents used included; myrica, valonea, glutaraldehyde and chrome. To further identify key factors for cost effective anaerobic digestion, tanned hide powders and tanned leathers were also pre-treated using autoclaving, liming, enzymes etc, in an attempt to determine whether tannage may be reversed. Major techniques used in the research include: anaerobic digestion, Biochemical Methane Potential (BMP), Total Solids contents (TS), Gas Chromatography (GC) and Gas Chromatography Mass Spectrometry (GC-MS). Hydrolysable tannins are less resistant to anaerobic digestion than condensed tannins. However, enzymatic pre-treatment reduces the resistance and this offers a new effective pre-treatment route. Thermal pre-treatment also decreased resistance to anaerobic digression especially for chrome, glutaraldehyde, myrica and tannic acid tanned leathers. Chemical pre-treatment also generally lowered the resistance to anaerobic digestion. Selective pre-treatment offers a means of improving the cost effectiveness of anaerobic digestion of leather and therefore enabling a new waste management method to be adopted by the industry. A relationship emerges, in some cases, between chemical structure of tanning agent and inhibition of anaerobic digestion. This offers the possibility of producing new, designed organic tanning agents with, suitable properties, to be adopted by the industiy, The research agenda within the leather industry is still ongoing and recommendations for future research are addressed
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Romakkaniemi, I. (Idamaria). "Biodegradation of synthetic textile fibres." Bachelor's thesis, University of Oulu, 2018. http://urn.fi/URN:NBN:fi:oulu-201808232664.
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Synthetic fibres are a raw-materials, that have rapidly become more commonly used in the textile industry. They are used in many everyday products as such or as blends with other fibres like cotton. Synthetic fibres are utilized to achieve the wanted special abilities in textiles. Synthetic textile fibres are composed of polymers and mainly do not decompose in nature as such. Accumulation of these fibres is a growing environmental problem across the globe. If digested, synthetic fibres can be dangerous to organisms. To solve this problem, research has been done to find biological ways of degrading synthetic fibres. Different kinds of micro-organisms have been examined to find organisms that can utilize synthetic fibres in their metabolism. In this bachelor’s thesis the aim was to gather as much information as possible on researches done on synthetic fibre biodegradation to date. Different kinds of fibres and their components were identified and the production processes were examined. Biodegradation of each fibre and their components by microbes and enzymes was investigated. The majority of results were found on polyurethane fibres while less results related to aromatic polyamide fibres. As a result of this data collection it could be stated, that the topic needs more scientific research to find effective ways to biodegrade synthetic fibres. The goal of this literary research is to give an extensive overview on the pollution problem caused by synthetic textile fibres and the biological methods of degrading them as well as to emphasize that the gathered information should be utilized to solve the problemSynteettiset kuidut ovat nopeasti yleistynyt materiaali tekstiiliteollisuudessa. Niitä käytetään monissa arkipäiväisissäkin tuotteissa sellaisenaan tai sekoitettuna muiden kuitujen kuten puuvillan kanssa. Niillä pyritään saavuttamaan tekstiilille halutut erityisominaisuudet. Synteettiset tekstiilikuidut koostuvat polymeereistä ja eivät pääsääntöisesti hajoa luonnossa sellaisenaan. Niiden kerääntyminen luontoon ja meriin on kasvava ympäristöongelma ympäri maailmaa. Synteettiset polymeerit voivat olla vaarallisia eliöille joutuessaan niiden ruuansulatukseen. Tämän ongelman ratkaisemiseksi on pyritty löytämään biologisia menetelmiä hajottaa synteettisiä kuituja. Erilaisia mikro-organismeja on tutkittu, jotta löydettäisiin organismeja, jotka pystyisivät hyödyntämään synteettisiä kuituja metaboliassaan. Tässä kandidaatin työssä pyrittiin keräämään mahdollisimman kattavasti tietoa tähän päivään mennessä tehdyistä tutkimuksista synteettisten kuitujen biohajoamisesta. Erilaiset kuitulajit ja niiden komponentit määriteltiin ja selvitettiin, millaisella prosessilla niitä valmistetaan. Jokaisen kuidun ja niiden komponenttien biohajoamista selvitettiin mikrobien ja entsyymien avulla. Eniten tutkimustuloksia löytyi polyuretaanikuiduista ja vähiten aromaattisista polyamidikuiduista. Tiedonhankinnan tuloksena voisi todeta, että aihe vaatii yhä tieteellistä lisätutkimusta, jotta löydetään tehokas biologinen keino hajottaa synteettisiä kuituja. Tämä kirjallisuustutkielman tavoite on antaa laaja yleiskuva synteettisten tekstiilikuitujen aiheuttamasta saasteongelmasta ja niiden biologisesta hajottamisesta sekä pyrkiä korostamaan, että kerättyjä taustatietoja tulisi hyödyntää ongelman ratkaisemisessa
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Wu, Shuyun. "Anaerobic Biodegradation Patterns for Biodiesel." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1417784154.
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Phale, Prashant S. "Biodegradation Of 1-Naphthoic Acid." Thesis, Indian Institute of Science, 1994. https://etd.iisc.ac.in/handle/2005/91.
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Polycyclic aromatic hydrocarbons (PAHs) are compounds containing carbon and hydrogen atoms of fused benzene rings in linear, angular or cluster arrangements. These compounds have a large (negative) resonance energy, resulting in a thermodynamically stable structures. PAHs may also contain alkyl- and nitro-substituent groups. The complexity in these molecules can be generated by substituting the aromatic carbon atom with nitrogen, oxygen or sulfur, giving rise to heterocyclic PAHs.
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Phale, Prashant S. "Biodegradation Of 1-Naphthoic Acid." Thesis, Indian Institute of Science, 1994. http://hdl.handle.net/2005/91.
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Polycyclic aromatic hydrocarbons (PAHs) are compounds containing carbon and hydrogen atoms of fused benzene rings in linear, angular or cluster arrangements. These compounds have a large (negative) resonance energy, resulting in a thermodynamically stable structures. PAHs may also contain alkyl- and nitro-substituent groups. The complexity in these molecules can be generated by substituting the aromatic carbon atom with nitrogen, oxygen or sulfur, giving rise to heterocyclic PAHs.
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Cruz, Morató Carles. "Biodegradation of pharmaceuticals by Trametes versicolor." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/283222.
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Els fàrmacs (PhACs) són un important grup de contaminants emergents que degut a la seva presència en el medi ambient i la seva difícil degradació han aixecat un gran interès en la comunitat científica. Alguns d’aquests PhACs són àmpliament utilitzats sense recepta i després de la seva ingestió son excretats per la orina i els fems, ja sigui en forma de compost actiu o com a metabòlit. Aquests productes entren a les estacions depuradores d’aigües residuals, on alguns d’aquests compostos no són eliminats eficaçment, sent capaços d’arribar a les aigües superficials, subterrànies i, posteriorment, a l’aigua potable.
El present treball avalua la viabilitat de la bioremeïació dels PhACs per fongs de podridura blanca. Aquests fongs tenen el potencial de degradar una àmplia gamma de contaminants xenobiòtics i recalcitrants degut al seu sistema enzimàtic inespecífic, capaç d’actuar sobre diversos substrats a través de l’acció d’enzims intracel·lulars (com el citocrom P450) i extracel·lulars (com la lacasa i peroxidasas). De tots els fongs, s’ha escollit Trametes versicolor per dur a terme l’estudi sobre la degradació d’analgèsics i anti-inflamatoris (ketoprofen i diclofenac), antiepilèptics (carbamazepina), reguladors de lípids (àcid clofibric), antibiotics (ofloxacina) i un agent de contrast per rajos X (iopromida).
El primer pas en la investigació va consistir en el estudi de la degradació de PhACs de forma individual per T. versicolor a escala Erlenmeyer i en condicions estèrils. Per tal d’obtenir més coneixements en el mecanisme de degradació dels PhACs pel fong, es va estudiar en detall la transformació dels fàrmacs anteriorment esmentats i en alguns casos es va proposar la via de degradació. Paral·lelament es va estudiar els enzims implicats en la degradació dels PhACs. També es va avaluar la toxicitat del brou de cultiu, on els productes de degradació estaven presents i d’aquesta manera poder observar si els compostos produïts son més tòxics que el propi fàrmac.
Posteriorment, amb l’objectiu d’escalar el procés de la degradació de PhACs, es va utilitzar un bioreactor de llit fluïditzat per la eliminació de la carbamazepina i de l’àcid clofibric, operat tant en continu com discontinu. En els resultats també es va incloure la identificació dels productes de transformació, junt amb l’avaluació de la toxicitat dels efluents.
D’altra banda, a causa del gran nombre de publicacions sobre la degradació de PhACs individuals per fongs publicats durant el transcurs d’aquesta tesis, es va realitzar una revisió bibliogràfica sobre aquest camp de recerca.
Per últim, en un intent d’escalar el procés a nivells més reals i per tant proporcionar una millor estimació del possible impacte ambiental de l’aplicació d’aquest procés, es va tractar una aigua residual urbana i d’hospital en un bioreactor operat en discontinu. El tractament de l’aigua residual es va fer en condicions no estèrils, on altres microorganismes estan presents, i a les concentracions preexistents dels contaminants, és a dir, sense afegir cap contaminant. En un experiment preliminar amb l’aigua residual urbana, es va observar la necessitat d’afegir una font addicional de carboni i nitrogen per mantenir l’activitat del fong. Per altra banda, els resultats obtinguts van ser positius ja que es va observar l’eliminació de gairebé tots els PhACs detectats en les aigües urbanes i d’hospital, juntament amb una notable reducció de la toxicitat global després del tractament, el que fa concloure que pot ser un tractament adequat i cal seguir investigant en altres aspectes per desenvolupar i optimitzar el procés abans de implementar-lo a escala real.Pharmaceutical active compounds (PhACs) are an important group of emerging contaminants that have raised an increasing interest in the scientific community due to their ubiquitous presence in the environment and their difficult degradation. Some of these drugs are extensively used as non-prescription drugs and after their intake, are excreted with urine and faeces either as active substances or metabolites. These substances come into wastewater treatment plants where some compounds are not efficiently removed, being able to reach surface, groundwater and subsequently, drinking water. The present work assesses the feasibility of PhACs bioremediation by white-rot fungi (WRF). WRF have the potential to degrade a wide range of xenobiotic and recalcitrant contaminants due to their unspecific enzymatic system, able to act on diverse substrates through the action of intracellular (i.e. cytrochrome P450 system) and extracellular (i.e laccases and peroxidases) enzymes. The fungus Trametes versicolor has been chosen to carry out the degradation study of some analgesics and anti-inflammatory (ketoprofen and diclofenac), anti-epileptics (carbamazepine), lipid regulators (clofibric acid), antibiotics (ofloxacin) and a X-ray contrast agent (iopramide). The first step in the research deals with the preliminary assessment of the individual PhACs degradation by T. versicolor at Erlenmeyer scale and sterile conditions. To obtain further insights in the mechanism of PhACs degradation by the fungus, the transformation products were identified as well as the enzyme responsible for the degradation of the parent compound with the aim of proposing a degradation pathway. In addition, an assessment of the toxicity of the broth, where transformation products were present, was included. Furthermore, with the aim of scale up the PhACs degradation process, a fluidized bed bioreactor was employed for the degradation of carbamazepine and clofibric acid, operated in both continuous and batch mode. Results also include the identification of transformation products and the toxicity assessment.On the other hand, due to the great number of publications about the degradation of pharmaceuticals by white-rot fungi that appeared over the course of this thesis, it was decided to include a literature review to evaluate the current state of the art in this topic. Finally, in an attempt to scale up the process to real approaches and thus provide a better estimation of the potential environmental impact of the application of such process, T. versicolor was used in a non-sterile batch bioreactor treatment for the removal of pre-existent PhACs from urban and hospital wastewater, where many contaminants and other microorganism are present. In preliminary experiments with urban wastewater, it was found the necessity of an extra source of carbon and nitrogen to maintain the activity of the fungus in the wastewater. Moreover, an important removal was observed for almost all drugs detected in both urban and hospital wastewater, together with a remarkable reduction of the overall toxicity.
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Shin, Kwanghee. "Biodegradation of diphenylamine and cis-dichloroethene." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33974.
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Past operational practices at chemical manufacturing facilities and widespread use of synthetic chemicals in agriculture, industry, and military operations have introduced many anthropogenic compounds to the biosphere. Some of them are readily biodegradable as a likely consequence of bacterial evolution of efficient degradation pathways, whereas others are partially degraded or persistent in the environment. Insight about biodegradation mechanisms and distribution of bacteria responsible provide the basis to predict the fate of synthetic chemicals in the environment and to enable bioremediation.
The main focus of the research described here encompasses basic science to discover pathways and evolutionary implications of aerobic biodegradation of two specific synthetic chemicals, cis-dichloroethene (cDCE) and diphenylamine (DPA). cDCE is a suspected carcinogen that frequently accumulates due to transformation of perchloroethene and trichloroethene at many contaminated sites. Polaromonas sp. strain JS666 is the only isolate able to use cDCE as the growth substrate, but the degradation mechanism was unknown. In this study, the degradation pathway of cDCE by strain JS666 and the genes involved were determined by using heterologous gene expression, inhibition studies, enzyme assays, and analysis of intermediates. The requirement of oxygen for cDCE degradation and inhibition of cDCE degradation by cytochrome P450 specific inhibitors suggested that cytochrome P450 monooxygenase catalyzes the initial steps of cDCE degradation. The finding was supported by the observation that an E. coli recombinant expressing cytochrome P450 monooxygenase catalyzes the transformation of cDCE to dichloroacetaldehyde and small amounts of the epoxide. Both the transient accumulation of dichloroacetaldehyde in cDCE degrading cultures and dichloroacetaldehyde dehydrogenase activities in cell extracts of JS666 further support a pathway involving the degradation of cDCE through dichloroacetaldehyde. Molecular phylogeny of the cytochrome P450 gene and organization of neighboring genes suggest that the cDCE degradation pathway evolved in a progenitor capable of degrading dichloroacetaldehyde by the recruitment of the cytochrome P450 monooxygenase gene from alkane assimilating bacteria. The discovery provides insight about the evolution of the aerobic cDCE biodegradation pathway and sets the stage for field applications.
DPA has been widely used as a precursor of dyes, pesticides, pharmaceuticals, and photographic chemicals and as a stabilizer for explosives, but little was known about the biodegradation of the compound. Therefore, bacteria able to use DPA as the growth substrate were isolated by selective enrichment from DPA-contaminated sediment and the degradation pathway and the genes that encode the enzymes were elucidated. Transposon mutagenesis, the sequence similarity of putative open reading frames to those of well characterized dioxygenases, and 18O2 experiments support the conclusion that the initial reaction in DPA degradation is catalyzed by a multi-component ring-hydroxylating dioxygenase. Aniline and catechol produced from the initial reaction of DPA degradation are then completely degraded via the common aniline degradation pathway. Molecular phylogeny and organization of the genes involved were investigated to provide insight about the evolution of DPA biodegradation.
The fate and transport of toxic chemicals are of a great concern at several historically contaminated sites where anoxic contaminant plumes emerge into water bodies. The release of toxic chemicals to overlying water poses a potential source of environmental exposure. Bench scale studies were conducted to evaluate the impact of biodegradation on the transport of toxic chemicals across the sediment/water interface. These studies demonstrated that substantial populations of bacteria associated with organic detritus at the interface rapidly biodegrade toxic chemicals as they migrate from contaminated sediment to overlying water, suggesting that the natural attenuation processes serve as a remedial strategy for contaminated sediments and protect the overlying water.
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Al-Lagtah, Nasir Mohammed A'mro. "Nutrient biodegradation in sequential batch reactor." Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491979.
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Many proposed and implemented packet classification algorithms trade off JT1emory against lookup-time. Matching algorithms implemented in software cannot keep up with ever-increasing data rates. On the other hand, devices implemented in hardware such as Content Addressable Memory (CAM) have deterministic high lookup rates, but they are expensive in terms of silicon cost and power dissipation. Therefore, a trade-off between hardware and software solutions Le. algorithmic-architectural solutions take advantage of the emerging technologies to provide the required high speed classification without sacrificing the deterministic performance of CAMs. I~ chapter 3 an algorithmic-architectural solution is provided that exploits the geometrical distribution of rules, Hypercuts packet classification algorithm, and CAMs. It works by multi-level cutting ofthe classification space into sub-spaces. It prOVides the deterministic performance of CAMs, support for dynamic updates, and fleXibility for the system designer to trade off the components of the architecture. In chapter 4 Adaptive Rules Cutting (ARC), a heuristic algorithm for packet classification, is proposed. This heuristic algorithm works by selecting the bit positions that divide the classification space into sub-spaces at l-Ievel in a way that reduces the redundancy of rules in cuts and maximizes the equal distribution of rules in cuts. An architecture for packet classification by l-Ievel cutting of the classification space is presented. In chapter 5, architecture for hardware acceleration of session-based IP packet classification is provided and implemented in FPGA. The architecture works by dividing the classification space into sub-spaces at l-Ievel using CRC16. Overall, the thesis provides three new solutions for packet classification based on cutting the classification space into smaller spaces. Supplied by The British Library - 'The world's knowledge'
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Elsayed, Omniea. "Biodegradation of chloroacetanilide herbicides in wetlands." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAJ003/document.
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Les chloroacétanilides sont une famille d'herbicides largement utilisée en agriculture, et contribuent de ce fait à la pollution environnementale. Leur devenir, y compris dans les écosystèmes rédox-dynamiques récepteurs comme les zones humides, est encore mal compris. Dans ce travail, la dégradation microbienne de chloroacétanilides (métolachlore, acétochlore et l'alachlore) a été étudiée par des approches innovantes de chimie analytique et de biologie moléculaire, à l'échelle du laboratoire en utilisant des microcosmes en colonnes, et in situ dans des zones humides construites à ciel ouvert et conçues pour traiter les intrants chimiques issus de l'agriculture.Une nouvelle méthode d’analyse isotopique composés-spécifiques a été développée. Les résultats indiquent la biodégradation des chloroacétanilides dans les zones humides, également suggérée par la détection des produits de dégradation correspondants (acides éthane sulfonique et oxanilique). Dans les expériences en microcosme de laboratoire, les chloroacétanilides ont principalement été dégradés dans les zones anoxiques de la rhizosphère, suggèrant un rôle prépondérant des processus anaérobies. L'analyse par chromatographie chirale du métolachlore a en outre révélé la dégradation préférentielle de l'énantiomère S du métolachlore, confirmant l'importance des processus biologiques dans la dissipation des chloroacétanilides. Les corrélations qui ont pu être observées entre les changements de variables hydrochimiques et de conditions hydrauliques et des différences de composition bactérienne détectées par génotypage par polymorphisme de longueur des fragments de restriction (T-RFLP) et par pyroséquençage du gène ARNr 16S confirme le potentiel de bio-indicateurs basés sur l'ADN pour suivre le fonctionnement des écosystèmes.Sur la base de ce travail, la détection et l'identification des micro-organismes et des voies biochimiques responsables de la dégradation de chloroacétanilides dans les zones humides, ainsi que l'élaboration d'indicateurs génétiques bactériens pour le suivi de la dégradation de chloroacétanilides en zones humides, émergent comme autant d’objectifs de recherche à court-termeChloroacetanilide herbicides are widely used in agriculture, and thereby contribute to environmental pollution. Their fate, including in redox-dynamic receptor ecosystems such as wetlands, remains poorly understood. In this work, microbial degradation of chloroacetanilides (metolachlor, acetochlor and alachlor) was investigated by emerging chemical and molecular biological approaches, at the lab-scale using microcosm columns, and in situ, in outdoor constructed wetlands designed for the treatment of chemical pollutants originating from agriculture.A novel compound-specific isotope analysis (CSIA) method was developed, and the results indicated biodegradation of chloroacetanilides in wetlands, which was also suggested by detection of ethane sulfonic acid and oxanilic acid degradation products. In lab-scale wetland microcosms, chloroacetanilides were mainly degraded in anoxic rhizosphere zones, suggesting a predominant role of anaerobic processes. Chiral chromatographic analysis of metolachlor revealed preferential degradation of the (S) enantiomer of metolachlor, and further confirmed the role of biological processes in chloroacetanilide dissipation. Changes in hydrochemical variables and hydraulic conditions correlated with differences in wetland bacterial composition detected by terminal restriction fragment length polymorphism (T-RFLP) and pyrosequencing analyses of the bacterial 16S rRNA gene, confirming the potential of DNA-based bioindicators for follow-up of ecosystem functioning.On the basis of this work, detecting and identifying the microorganisms and biochemical pathways responsible for chloroacetanilide degradation in wetlands, as well as developing bacterial gene-based indicators of wetland functioning, emerge as research objectives for the near future
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Launen, Loren A. "Pyrene biodegradation by Penicillium janthinellum SFU403." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0022/NQ51887.pdf.
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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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Herwijnen, René van. "Metabolic and cometabolic biodegradation of PAHs." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2003. http://dare.uva.nl/document/87041.
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Razal, Ramon A. "Studies on lignin biosynthesis and biodegradation." Diss., This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-07282008-135150/.
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Painter, Susan Elizabeth. "Anaerobic biodegradation of phthalic acid esters." Thesis, Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/25185.
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Bourne, Thomas Franklin. "Biodegradation of keratins and phenolic compounds." Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/25403.
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O'Grady, Devin. "Biodegradation of 17alpha-ethinylestradiol in wastewater." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=18488.
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Pharmaceutical substances such as 17a-ethinylestradiol (EE2), the active component of contraceptive pill, are often not eliminated during wastewater treatment and are not biodegraded in the environment. In this Master's project, analytical techniques for analyzing the low concentration of EE2 during biodegradation were developed and the biodegradability of 17a-ethinylestradiol was studied using five bacteria. A preliminary identification of the produced metabolites was also completed. A low cost solid phase extraction (SPE) procedure was developed and optimized to obtain reproducible analyte recoveries in order to pre-concentrate the EE2 samples prior to HPLC analysis. The limit of analysis (LOA) was significantly lowered from 1.73 ppm to 0.173 ppm upon implementation of the combined SPE/HPLC method. R. erythropolis degraded EE2 up to 47% of its initial concentration in 13 h, while after 65 h, R. equi degraded EE2 up to 39% of its initial concentration. No significant EE2 degradation was observed using Rhodococcus rhodochrous and Rhodococcus zopfii. Preliminary analysis of EE2 degradation products confirmed the presence of phenol among other possible metabolites of high molecular weight.Plusieurs composés pharmaceutiques tel que le 17a-ethinylestradiol (EE2), l'ingrédient actif des contraceptifs oraux, ne sont pas efficacement éliminés lors du traitement des eaux usées et se biodégradent peu dans l'environnement. Au cours de ce projet de maîtrise, des techniques analytiques ont été développées afin de mesurer de faibles concentrations d'EE2 et la biodégradabilité d'EE2 a été étudiée en utilisant cinq types de bactéries. Une identification préliminaire des produits de dégradation a également été effectuée. Une méthode d'extraction en phase solide a été développée afin de préconcentrer les échantillons avant l'analyse par HPLC. L'optimisation de la méthode a permis d'obtenir une méthode reproductible offrant un haut pourcentage de récupération de l'analyte et ce, à faible coût. La préconcentration de l'échantillon a aussi permis de réduire la limite d'analyse par HPLC de 1.73 ppm à 0.173 ppm. R. erythropolis a dégradé jusqu'à 47% de la concentration initiale d'EE2 en 13 h, tandis qu'après 65 h, R. equi a engendré une dégradation atteignant 39% de la concentration initiale d'EE2. Aucune dégradation significative a été observée en utilisant R. rhodochrous et R. zopfii. Finalement, l'analyse préliminaire des produits de dégradation confirme la présence de phénol parmi d'autres produits de dégradation de poids moléculaires élevés.
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Gartshore, James. "Biodegradation of plasticizers by rhodotorula rubra." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33968.
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The degradation of plasticizers by the yeast Rhodotorula rubra J-96-1 (ATCC 9449) was studied in the presence of a water-soluble substrate (glucose). The plasticizers studied included bis 2-ethylhexyl adipate (B(EH)A), dioctyl phthalate (DOP) and terephthalate (DOTP), which are in widespread use. In addition, the degradation of two less common plasticizers, di-propylene glycol dibenzoate (D(PG)DB) and di-ethylene glycol dibenzoate (D(EG)DB), were studied. It has been proposed that the latter plasticizers be used as alternatives to the commonly used plasticizers, which have been associated with negative environmental impacts.The degradation of D(PG)DB or D(EG)DB led to a significant increase in solution toxicity. This increase in toxicity was associated with the production of metabolites resulting from the incomplete breakdown of the original plasticizers. The metabolites responsible for the acute toxicity in the D(PG)DB system were identified as isomers of di-propylene glycol monobenzoate. A mechanism for the formation of this metabolite was proposed. Although the metabolite observed when D(EG)DB was being degraded was not isolated, it was tentatively identified as di-ethylene glycol monobenzoate by analogy to the D(PG)DB system. This same metabolite was observed when D(EG)DB was degraded by the fungus, Aspergillus niger ATCC 9642-U.
In contrast, there were no observable metabolites nor increases in toxicity in the media during the degradation of B(EH)A, DOP, or DOTP by R. rubra. These observations also differ from those of earlier work in which it was reported that the degradation of all three of these plasticizers by bacteria resulted in the production of toxic metabolites.
Collectively, these results do not support the use of D(PG)DB and D(EG)DB as environmentally safe alternatives to B(EH)A, DOP or DOTP.
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Ternan, Nigel G. "Biodegradation of aminoalkylphosphonates by environmental bacteria." Thesis, Queen's University Belfast, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361307.
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McClure, P. J. "The biodegradation of pharmaceutical effluent constituents." Thesis, Bucks New University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233071.
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Miller, N. D. "On the biodegradation of implantable polymers." Thesis, University of Liverpool, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378650.
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Wright, Michael Alan. "Biodegradation of synthetic ester-based lubricants." Thesis, Cranfield University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283863.
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Dhillon, Hardial Singh. "Microbial biodegradation in soil and groundwater." Thesis, Loughborough University, 1988. https://dspace.lboro.ac.uk/2134/33040.
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All cores supplied by the British Geological Survey were heavily polluted with wide variety of organic compounds. The total organic carbon (TOC/ppm) values increased over tenfold between 5m and 10m levels. Each core of borehole VF 1020 was characterised by soil lithology, microbial numbers and metabolic activity at l0°C and 30°C, using air as the gas phase. The metabolic activity at 10°C was approximately 40% of that found at 30°C in the two core samples examined. The fluctuation in bacterial numbers and their metabolic activity show some correlation with the type of soil present, being higher with smaller the particle size and vice versa. No correlation was observed between depth, pH, moisture content, redox values, temperature or TOC values.
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Vilo, Muñoz Claudia Andrea. "Understanding Microbial Biodegradation of Environmental Contaminants." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc801956/.
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The accumulation of industrial contaminants in the natural environments have rapidly become a serious threat for human and animal life. Fortunately, there are microorganisms capable of degrading or transforming environmental contaminants. The present dissertation work aimed to understand the genomic basis of microbial degradation and resistance. The focus was the genomic study of the following bacteria: a) Pseudomonas fluorescens NCIMB 11764, a unique bacterium with specific enzymes that allow cyanide adaptation features. Potential cyanide degradation mechanisms found in this strain included nit1C cluster, and CNO complex. Potential cyanide tolerance genes found included cyanide insensitive oxidases, nitric oxide producing gene, and iron metabolism genes. b) Cupriavidus sp. strain SK-3 and strain SK-4. The genome of both bacteria presented the bph operon for polychlorinated biphenyl (PCB) degradation, but we found differences in the sequences of the genes. Those differences might indicate their preferences for different PCB substrates. c) Arsenic resistant bacterial communities observed in the Atacama Desert. Specific bacteria were found to thrive depending on the arsenic concentration. Examples were Bacteroidetes and Spirochaetes phyla whose proportions increased in the river with high arsenic concentrations. Also, DNA repair and replication metabolic functions seem to be necessary for resistance to arsenic contaminated environments. Our research give us insights on how bacteria communities, not just individually, can adapt and become resistant to the contaminants. The present dissertation work showed specific genes and mechanisms for degradation and resistance of contaminants that could contribute to develop new bioremediation strategies.
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Bertin, Marcus A. "Biodegradation and Environmental Fate of Nonylphenol." University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1092067810.
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Zafar, Urooj. "Biodegradation of polyurethane under composting conditions." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/biodegradation-of-polyurethane-under-composting-conditions(0157c580-bffe-4b2f-a019-a7510fa3ac4e).html.
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Plastic are a highly durable, lightweight and low cost family of polymeric materials that form an essential and integral component of today’s world. Their continued world-wide large scale manufacture has led them to be a major component of man-made waste. A large proportion of plastic waste is directed to the landfill sites, however their low degradation rates, scarcity of landfill sites and growing water and land pollution problems require alternatives to be developed. Composting is a natural process involving aerobic decomposition of organic wastes by a mixed microbial consortium that involves thermophilic microbes during the process due to the heat generated during decomposition. In this study we investigated the biodegradation of polyurethane under composting conditions. Polyurethanes are heteropolymers with a wide range of applications in the medical, automotive, construction and domestic field and in Europe account for 7% of all plastic manufacture and have been shown to be susceptible to biodegradation, particularly by fungi. In this thesis, it was found that loss in tensile strength of >70% occurs at both mesophilic (25°C) and thermophilic (45° and 50°C) temperatures under laboratory conditions and so is susceptible to degradation at all stages of the composting process. Moreover, polyester PU buried in compost piles at a commercial composting site during the maturation phase of an in silo composting process also underwent substantial degradation. Non-culture based analysis by TRFLP, DGGE and 454 pyrosequencing revealed that the fungal communities colonising the surface of PU was substantially different from the surrounding compost indicating selection of fungi on the PU surface. Pyrosequencing revealed that under laboratory conditions, at 25°C Fusarium solani, and 45°C and 50°C, Candida ethanolica was the dominant organism recovered from the PU surface, whereas at the commercial composting site an unidentified fungal clone and Arthrographis kalrae were the dominant organisms recovered. When the microparticulate polyester PU dispersion impranil was added to compost, a substantial shift in the indigenous fungal population was observed along with an increase in fungal viable numbers, however, addition of larger solid PU had no lasting effect on the surrounding compost community. This study demonstrates that polyester PU is highly susceptible to degradation in during composting and indicates a future potential for directing PU wastes to existing commercial composting processes.
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McCloskey, Colleen B. "Biodegradation of benzene in soil systems." Thesis, This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-01312009-063028/.
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Pruden, Amy. "Biodegradation of methyl tert-butyl ether." Cincinnati, Ohio : University of Cincinnati, 2002. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=ucin1027943573.
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