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1

Gleisner, Florian Hans. "Bacterial degradation of polycyclic aromatic hydrocarbons." Thesis, University of York, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247752.

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2

Phillips, Pamela June. "Microbial degradation of hydrocarbons in aqueous systems." Thesis, University of Surrey, 2003. http://epubs.surrey.ac.uk/842666/.

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There is a vast worldwide consumption of petroleum hydrocarbons and accidental release in to the environment is common. For example petroleum forecourt retail outlets have 'interceptors' to prevent release of hydrocarbons into the environment. The aim of this study was to investigate options for in-situ bioremediation of the hydrocarbon substrates within these 'interceptors' in a laboratory model. The initial studies on bioremediation were undertaken with diesel as the substrate. It was shown that the addition of nitrogen and phosphorus to the system increased hydrocarbon mineralisation by a factor of 16, resulting in increased carbon dioxide evolution. There was strong evidence indicating that nitrogen and phosphorus were the limiting factor for hydrocarbon metabolism in this aqueous system. Trichoderma harzianum and a soil bacterial isolate LFC D1 FI were assessed and shown to degrade hexadecane and pristane. The positive affect of adding a cosubstrate was evident in flask studies; the rates of degradation by LFC D1 FI and T. harzianum were approximately doubled and tripled respectively in the presence of glucose compared to treatments without glucose. Previous attention has focused on the ability of Phanerochaete chrysosporium to degrade polycyclic aromatic hydrocarbons; in this study the degradation of aliphatics was investigated. Spores from P. chrysosporium induced on the hydrocarbon substrate were found to be necessary to degrade hexadecane. Pseudomonas putida was unable to grow in liquid media containing hydrocarbons, however on solid media and in an aqueous environment containing acid-washed sand, degradation of hydrocarbons was evident, hi the presence of sand P. putida degraded both hexadecane and pristane by 70% of the initial concentration added; in the absence of sand no degradation in the aqueous system was seen. This suggests surface attachment plays an important role in hydrocarbon degradation by P. putida. The attachment and use of the sessile P. putida in aliphatic hydrocarbon degradation is discussed.
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3

Pizzul, Leticia. "Degradation of polycyclic aromatic hydrocarbons by actinomycetes /." Uppsala : Department of Microbiology, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/200650.pdf.

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4

Chavez-Rivera, Rafael Alfredo. "A biofilm reactor for degradation of chlorinated hydrocarbons." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339503.

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5

Kuipers, Bianca. "Microbial degradation of polychlorinated biphenyls and alkylated polycyclic aromatic hydrocarbons." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0017/NQ48650.pdf.

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6

Johnson, Morven B. "The microbial degradation of polycyclic aromatic hydrocarbons under alkaline conditions." Thesis, Queen's University Belfast, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266761.

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7

Pawar, Rakesh Mahadev. "The effect of soil pH on degradation of polycyclic aromatic hydrocarbons." Thesis, University of Hertfordshire, 2012. http://hdl.handle.net/2299/8965.

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The environmental fate of polycyclic aromatic hydrocarbons (PAH) is a significant issue, raising interest in bioremediation. However, the physio-chemical characteristics of PAHs and the physical, chemical, and biological properties of soils can drastically influence in the degradation. Moreover, PAHs are toxic and carcinogenic for humans and their rapid degradation is of great importance. The process of degradation of pollutants can be enhanced by manipulating abiotic factors. The effect of soil pH on degradation of PAHs with a view to manipulating soil pH to enhance the bioremediation of PAH’s was studied. The degradation rate of key model PAHs (Phenanthrene, Anthracene, Fluoranthene, and Pyrene) was monitored in J Arthur Brower’s topsoil modified to a range of pH between pH 4.0 and pH 9.0 at half pH intervals. Photo-catalytic oxidation of PAHs in the presence of a catalyst (TiO2) under UV light at two different wavelengths was studied. The degradation of PAHs during photo-catalytic oxidation was carried out at varying soil pH, whilst the degradation rate of each individual PAH was monitored using HPLC. It was observed that pH 6.5 was most suitable for the photo-degradation of all the PAHs, whilst in general acidic soil had greater photo-degradation rates than alkaline soil pH. Photo-degradation of PAHs at 375 nm exhibited greater degradation rates compared to 254 nm. Phenanthrene at both the wavelengths had greater degradation rate and pyrene has lower degradation rate of the four PAHs. Pure microbial cultures were isolated from road-side soil by shaken enrichment culture and characterized for their ability to grow on PAHs. Bacterial PAH degraders, isolated via enrichment were identified biochemically and by molecular techniques using PCR amplification and sequencing of 16S rDNA. Sequences were analyzed using BLAST (NCBI) and their percentage identity to known bacterial rDNA sequences in the GeneBank database (NCBI) was compared. The 6 bacterial strains were identified as Pseudomonas putida, Achromobacter xylosoxidans, Microbacterium sp., Alpha proteobacterium, Brevundimonas sp., Bradyrhizobium sp. Similarly, fungal PAH degraders were identified microscopically and with molecular techniques using PCR amplification and sequencing of 18S rDNA and identified as Aspergillus niger and Penicillium freii. Biodegradation of four PAHs with two and four aromatic rings were studied in soil with inoculation of the six identified bacteria and two identified fungi over a range of pH. It was observed that pH 7.5 was most suitable for the degradation of all the PAHs maintained in the dark. A degradation of 50% was observed in soil pH 7.5 within first three days which was a seventh of the time taken at pH 5.0 and pH 6.5 (21 days). Greater fungal populations were found at acidic soil pH and alkaline soil pH, in comparison with neutral pH 7.0. Pencillium sp. was found to be more prevalent at acidic pH whilst Aspergillus sp. was found to be more prevalent at pH 7.5-8.0. Bacterial populations were greater at pH 7.5 which was highly correlated with soil ATP levels. It was therefore evident that the greatest rates of degradation were associated with the greatest bacterial population. Soil enzyme activities in general were also greatest at pH 7.5. The converse effect of pH was found with fastest rate of photo-catalytic degradation at the optimal conditions were observed at acidic condition in soil pH 6.5 whilst, the results obtained during biodegradation at the optimal conditions exhibits fastest rate of degradation at alkaline conditions particularly at pH 7.5. Thus, manipulation of soil pH to 7.5 has significant potential to dramatically increase the degradation rate of PAHs.
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8

Duan, Xiaoguang. "Catalytic Oxidative Degradation of Hydrocarbons Using Novel Metal-Free Nanocarbon Catalysts." Thesis, Curtin University, 2015. http://hdl.handle.net/20.500.11937/1951.

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This research presents novel nanocarbon materials as green and metal-free carbocatalysts for advanced oxidative processes toward environmental remediation. Various nanocarbons exhibit high catalytic activity in activation of sulfate oxidants for degradation of water contaminants. The tailored surface chemistry of nanocarbons and insightful mechanistic studies for catalytic activation of superoxides were revealed via deliberate materials design, advanced characterization techniques and theoretical calculations.The findings would significantly contribute to materials chemistry, environmental science, carbocatalysis and other related fields.
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9

Sharman, Ajay K. "Microbial production and utilization of epoxides." Thesis, University of Kent, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317663.

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10

Papadopoulos, Apostolos. "Linking cyclodextrin extraction and microbial degradation of polycyclic aromatic hydrocarbons in soil." Thesis, Lancaster University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.441390.

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11

PFARR, ELENA CHRISTINE. "INVESTIGATION OF TRANSPORT AND DEGRADATION PROCESSES OF POLYCYCLIC AROMATIC HYDROCARBONS IN BIOFILM." University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1092930652.

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12

Choi, Wonyong Hoffmann Michael R. "Photooxidative and photoreductive degradation of chlorinated hydrocarbons on aqueous titanium dioxide colloids /." Diss., Pasadena, Calif. : California Institute of Technology, 1996. http://resolver.caltech.edu/CaltechETD:etd-05052006-084215.

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13

Roy, Michelle-Claire. "Petrogenic Hydrocarbons in the Peace-Athabasca Delta and their Potential for Microbial Degradation." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/38749.

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Microbial biodegradation is the primary mechanism by which petrogenic hydrocarbons (PHCs) are removed from the environment. Though hydrocarbon biodegradation is widely studied in marine systems, knowledge of how it occurs in freshwater systems is still lacking. The Peace-Athabasca Delta (PAD), located in northeastern Alberta, is an ideal location to study microbial hydrocarbon degradation since it has a long history of exposure to PHCs. What’s more, these PHCs are predominately sourced from bituminous deposits and are therefore relevant to the Canadian Oil Sands Industry. This thesis investigated the genetic potential for hydrocarbon degradation of PHCs via metagenomic reconstruction of microbial communities in lakes of the Peace and Athabasca Deltas, as well as reference lakes in the nearby boreal uplands. In order to properly evaluate the microbial community and its potential for hydrocarbon degradation, a comprehensive analysis of PHCs (including n-alkanes, polycyclic aromatic compounds (PACs), and petroleum biomarkers of terpanes, hopanes, and steranes) was performed. PHC analysis showed that n-alkanes in lake sediments from all three regions were highly similar and predominately biogenic, while PAC composition was significantly different in each region. Restricted-drainage lakes of the Athabasca Delta had the highest concentrations of PACs from petrogenic sources. Closed-drainage lakes in the Peace Delta had lower concentrations of PACs that likely originated from a mixture of pyrogenic and petrogenic sources. Closed-drainage lakes in the boreal upland region had the lowest concentrations of PACs likely sourced from pyrogenic wood combustion with traces of petrogenic PACs, possibly from atmospheric deposition of dust. Petroleum biomarkers of terpanes, hopanes, and steranes were successfully used to identify the long-range fluvial, and possibly atmospheric, transport of bituminous compounds more than one hundred kilometers from their potential source. This validates the future use of these biomarkers in environmental forensics. Microbial communities in all three regions under study were highly diverse, and their composition was significantly different in both sediment and water. Targeted gene analysis identified a total of 3885 genes involved in the degradation of n-alkanes and PACs in sediment and water. The results show that organic carbon, nitrogen, and sulfur content, as well as PAC and short-chain alkane concentrations were important chemical predictors of change in degradation gene composition. Furthermore, genes for anaerobic degradation of PHCs were identified in syntrophic bacteria, methanogens, nitrate and sulfate reducers, demonstrating the potential for syntrophic hydrocarbon degradation in PAD lakes. Though this thesis confirms the genetic potential for hydrocarbon degradation in PAD and boreal upland lakes, further research is necessary to determine whether these microbial communities can actively degrade the PHCs present in these lakes.
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14

Dabai, Aliyu Ibrahim. "Metagenomic studies on the microbial communities facilitating aromatic hydrocarbons degradation in diverse environments." Thesis, Queen's University Belfast, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.707233.

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Metagenomic is a technique that involves the study of environmental DNA and negates the need for cultivation of microorganisms in the laboratory. The techniques have been shown to have tremendous potential for the advancement of knowledge in numerous fields such as microbial ecology, Agriculture, e.t.c. The research question this work seek to address is that ‘can we apply at least one metagenomic approach to demonstrate an improved understanding of the microbiology of a contaminated soil environment. If we can answer this question, then it is possible to develop a rapid approach to confirm whether the soil environment is contaminated, whether aerobic or anaerobic degradation is occurring in the contaminated environment and for crude oil spill characterisation in the Niger Delta. If we combine the information obtained through metagenomic approach with stable isotope probing (Metagenome-SIP), then key anaerobic benzene degrading-bacteria could be identified in the Niger Delta contaminated soil samples. Using the metagenomic-SIP information, we assess whether the same organism degrading benzene under anaerobic condition could degrade a lignin-derived phenolic compound (vanillin). The information will enable us to develop an inexpensive approach for biostimulation approach for the clean-up of the Niger Delta environment using the plant-derived waste material. The key finding of this research work include: the Niger Delta soil samples were contaminated with crude oil, aerobic and anaerobic biodegradation are important in the contaminated site, the contamination is of two class namely one set of soil are newly or freshly contaminated, and the other set is old contaminated site, microbial phyla such as Actinobacteria, Bacteroidetes and Proteobacteria were the most abundant microbial group in the contaminated soils, lllumina data uncovered the diversity of microbial community structure of the contaminated soil environment compared to the amplicon pyrosequencing data, benzene was syntrophically degraded by β-proteobacteria, δ-proteobacteria, and Clostridia while vanillin degradation was by α-Proteobacteria (order Sphingomonadales). These organisms are important in the biodegradation of the benzene and vanillin aromatic compounds, and essential hydrocarbon degradation genes detected the role of these bacteria in the utilization of such compounds. The qPCR gene ratio approach could be used as a diagnostic method for spill characterisation. The knowledge gained from the results will influence any decision towards the clean-up/monitoring of bioremediation strategy to apply on the heavily polluted Niger Delta.
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15

Steffen, Kari T. "Degradation of recalcitrant biopolymers and polyclic aromatic hydrocarbons by litter-decomposing basidiomycetous fungi." Helsinki : University of Helsinki, 2003. http://ethesis.helsinki.fi/julkaisut/maa/skemi/vk/steffen/.

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16

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.<br>Master of Science
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17

Osama, Mohammad. "Polycyclic Aromatic Hydrocarbons (PAHs): Degradation and Fungal Biomass (Ergosterol) in Sediment with added Nitrogen." Connect to resource online, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1253383776.

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18

Basu, Pradipta Ranjan. "Evaluation of biological treatment for the degradation of petroleum hydrocarbons in a wastewater treatment plant." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2418.

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Biodegradation of petroleum hydrocarbon can be an effective treatment method applied to control oil pollution in both fresh water and marine environments. Hydrocarbon degraders, both indigenous and exogenous, are responsible for utilizing petroleum hydrocarbon as their substrate for growth and energy, thereby degrading them. Biodegradation of hydrocarbons is often enhanced by bioaugmentation and biostimulation depending on the contaminated environment and the competence of the hydrocarbon degraders present. An evaluation of the performance of the biological treatment of petroleum hydrocarbon by the hydrocarbon degrading microbes at the Brayton Fire School??s 4 million gallon per day (MGD) wastewater treatment plant was the main research objective. Samples were taken for two seasons, winter (Nov 03 ?? Jan 03) and summer (Jun 04 ?? Aug 04), from each of the four treatment units: the inlet tank, equalization tank, aeration tank and the outfall tank. The population of aliphatic hydrocarbon degraders were enumerated and nutrient availability in the system were used to evaluate the effectiveness of on-going bioaugmentation and biostimulation. Monitoring of general effluent parameters was conducted to evaluate the treatment plant??s removal efficiency and to determine if effluent discharge was in compliance with the TCEQ permit. The aeration tank is an activated sludge system with no recycling. Hydrocarbon degraders are supplied at a constant rate with additional nutrient supplement. There was a significant decrease in the population of microbes that was originally fed to the system and the quantity resident in the aeration tank. Nutrient levels in the aeration tank were insufficient for the concentration of hydrocarbon degraders, even after the application of dog food as a biostimulant. The use of dog food is not recommended as a nutrient supplement. Adding dog food increases the nitrogen and phosphorus concentration in the aeration tank but the amount of carbon being added with the dog food increases the total chemical oxygen demand (COD) and biochemical oxygen demand (BOD). An increase in the concentration of total COD and BOD further increases the nitrogen and phosphorus requirement in the system. The main objective of supplying adequate nutrients to the hydrocarbon degraders would never be achieved as there would be an additional demand of nutrients to degrade the added carbon source. This research study was conducted to identify the drawbacks in the treatment plant which needs further investigation to improve efficiency.
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19

Lease, Christopher William Minto, and Lease Chris@saugov sa gov au. "Biodegradation of High Molecular Weight Polycyclic Aromatic Hydrocarbons in Soils by Defined Bacterial and Fungal Cocultures." Flinders University. Biological Sciences, 2006. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20060803.114120.

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Despite microbial degradation being the primary route of degradation of PAHs in soils, high molecular weight polycyclic aromatic hydrocarbons (such as benzo[a]pyrene) have consistently proven to e resistant to microbial attack. However, recent research has demonstrated the potential for bacterial-fungal co-cultures to achieve biodegradation of high molecular weight PAHs. The aim of this research was to determine the efficacy of co-culture bioaugmentation for the remediation of high molecular weight PAHcontaminated soils. PAH degrading bacteria were enriched on multiple PAHs and isolated on pyrene from both contaminated (soil from a former manufactured gas plant) and uncontaminated (agricultural soil, termite mound matrix and kangaroo faeces) sources. The bacterial isolates were identified using 16SrRNA analysis as Mycobacterium sp. Strain BS5, Mycobacterium sp. Strain KA5 and Mycobacterium sp. Strain KF4 or fatty acid methyl ester (FAME) analysis as Ralstonia pickettii and Stenotrophomonas maltophilia. The initial phase of assessment of PAH degradation by fungal and bacterial coculture components was undertaken using liquid media. Two fungal isolates from a previous investigation into the coculture process (Penicillium janthinellum) and the American Type Culture Collection (Phanerochaete chrysosporium) were assessed for their ability to degrade benzo[a]pyrene in minimal media and MYPD. The fungal isolates were found to be able to degrade benzo[a]pyrene cometabolically in MYPD. The bacterial isolates and two others from previous investigations were assessed for their ability to degrade single PAHs (fluorene, phenanthrene, fluoranthene, pyrene and benzo[a]pyrene) in liquid culture. This process was used as an initial screen to select the best bacterial isolates for further investigation of PAH degradation by axenic cultures and cocultures with the fungal isolates using a PAH mixture. Based on the results of these experiments four bacterial isolates (VUN 10,010, Mycobacterium 1B, Mycobacterium sp. Strain BS5 and Mycobacterium sp. Strain KA5) and the two fungal isolates were selected to investigate further using a PAH mixture composed of the previously mentioned PAHs. It was found that the use of a fungal bacterial coculture increased the degradation of the PAH mixture beyond that of axenic bacterial cultures. Based on these experiments, the coculture composed of P. janthinellum and VUN 10,010 was selected for assessment of its ability to degrade the same PAH mixture in spiked soil microcosm experiments. Natural attenuation, axenic P. janthinellum, axenic VUN 10,010 and a coculture of these two organisms were assessed for PAH degradation in soil microcosms over a 100 day period. Inoculation of microcosms with the coculture resulted in the removal of benzo[a]pyrene by 11 mg/kg (± 1.21 mg/kg) (30%) over the 100 day incubation period. Substantial PAH degradation was also observed in the microcosms assesing natural attenuation. Using an alternative sequential inoculation method, initially inoculating with P. janthinellum then 50 days later with VUN 10,010 significantly enhanced the removal of benzo[a]pyrene. After 100 days incubation, benzo[a]pyrene was degraded below detection limits in two of three microcosms, compared to a 4.95 mg/kg (± 4.64 mg/kg) (14.7 %) reduction in soil microcosms inoculated using an alternative inoculation process of VUN 10,010 followed by P. janthinellum. Attempts were made to optimise the process using sequential inoculation and soil amendments intended to enhance the performance of the fungal component using distilled water and 1% glucose. The addition of distilled water was not observed to substantially influence the ability of the coculture to degrade PAHs, whereas the addition of 1% glucose was found to inhibit PAH degradation.
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20

Wilkinson, Julian James. "The Autoxidation of Branched Hydrocarbons in the Liquid Phase as Models for Understanding Lubricant Degradation." Thesis, University of York, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485843.

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The Autoxidation ofPristane (C19t40), Squalane (C30H62) and partially formulated lubricant basefluids in laboratory reactors and in research engines under controlled conditions have been used as simplified models of lubricants in passenger car engines in order to increase the understanding ofthe oxidation process ofthe lubricant within automotive engines, particularly within the ring pack area of the pIston. Pristane was oxidized in stainless steel reactors in the presence ofoxygen at a range of temperatures between 90 and 250°C, using either a continuous flow ofoxygen or a single charge of oxygen in a sealed reactor. A more detailed examination ofpristane oxidation at 170°C was also undertaken where the influence ofreaction time on the formation of oxidation products was carefully studied. The main products observed were predominantly tertiary alcohols and ketones with the same chain length aslfue starting material. Significant quantities of scission products were also formed, (with ketones and alkanes being the most abundant) consistent with the formation and decomposition oftertiary alkoxyl radicals. It was also found that products arising from tertiary alkoxy radicals became more favoured compared to products from secondary alkoxy radicals as the reaction progressed..'5-memb~red lact()nes were also ~bserved in significant quantities, as well:JlS lesser amounts ofcarboxylic acids. It was found that tertiary hydrogen atoms ofthe branched alkane substrate were 15.3, 12.6, and 9.0 fold more reactive than secondary hydrogen atoms at temperatures of90, 170, 230°C respectively. i ~'I t The experiments performed in the laboratory were compl~mented.by oxidation tests performed in a res~arch engine capa~le ofpiston ring pack sampling and using a,Partia1ly formulated lubricant with detergent, or detergent and dispersant. These lubricants were then used to investigate the effect ofengine speed (1000-2000 rpm) and engine load (3375%) on the oxidation level of both sump and ring pack oil, it was found that both sump and ringpack oxidation levels increased as a function ofload. However engine speed was found to be inversely proportional oxidation level in the ringpack, and did not affect sump degradation. These results allow the calculation ofthe lubricant's flow rate through engine under different conditions to be examined. At 1500 rpm and 50 % load, the lubricant starting in the sump eventually flows through the piston and returns to the sump in 65.2:1: 7.8 hours. The viscosity of engine oils is a key consideration throughout their operating life, but the cause ofthe degradative viscosity increase during use is poorly understood. To examine this, the viscosity ofmodel mixtures were examined by basing the mixtures on the oxidation products observed during the oxidation ofpristane in the ],aboratory, in an I attempt to simulate the viscosity change observed during oxidation. It was found that polar oxidation products have little effect on viscosity at low concentrations, and viscosity increases are more likely to be caused by the formation ofhigh mass oxidation products, such as sludge precursors.
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21

Ball, Jihane Sokhn. "The effect of heavy metals on the degradation of polycyclic aromatic hydrocarbons by soil microorganisms." Thesis, University of Surrey, 2005. http://epubs.surrey.ac.uk/842888/.

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This study aimed to assess the effect of heavy metals, especially Cu, Zn and Cd, on the ability of the white rot fungus (WRF) Bjerkandera sp. BOS55 and several soil bacterial isolates to degrade a selection of polycyclic aromatic hydrocarbons (PAHs). To investigate the effect of heavy metals on PAH degradation by Bjerkandera sp. BOS55, the fungus was grown in both a rich undefined medium and a defined medium containing the PAH pyrene and different concentrations of Cu or Cd. It was found that both metals reduced fungal growth and production of ligninolytic enzymes but that toxicity was modified by the growth medium. The fungus exhibited adaptation and tolerance to both metals in the defined medium containing up to 600 ppm metal but was inhibited in the rich medium containing as little as 50 ppm metal. Whilst WRF are capable of PAH oxidation, complete mineralisation to CO2 is often unachieved resulting in the production of polar and often toxic metabolites. In soil, these metabolites can be further oxidised by bacterial populations to non-toxic products. However, bacteria often exhibit a greater sensitivity to heavy metals than WRF. This sensitivity to heavy metals could block the detoxification process of the soil environment. The three PAH-oxidising bacterial isolates that were tested for metal tolerance were found to be highly susceptible to Cu, Zn and Cd at concentrations of 200 ppm each, resulting in a reduced degradation of phenanthrene and pyrene. It was therefore concluded that the presence of heavy metals in the environment, even at fairly low levels, could potentially lead to the incomplete degradation of PAHs, and possible accumulation of toxic metabolites. Finally, co-cultures of the metal-sensitive bacterial isolates and the fungus were used to establish if a combination of WRF and a bacterial isolate could be used to accelerate the degradation of PAHs. Anthracene and anthraquinone were used as model PAHs because anthraquinone is a dead-end metabolite produced during the oxidation of anthracene by Bjerkandera sp. BOS55. It was found that some of the fungal-bacterial co-cultures tested synergistically removed anthracene, resulting in significantly faster degradation than observed for each organism individually. Moreover, one co-culture removed anthraquinone, suggesting that a combination of WRF and bacteria are essential for the rapid mineralisation of PAHs in the environment.
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22

Smith, Madelyn M. "Cometabolic Degradation of Halogenated Aliphatic Hydrocarbons by Aerobic Microorganisms Naturally Associated with Wetland Plant Roots." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1341854406.

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23

STETZENBACH, LINDA DALE ALLEN. "THE DEGRADATION AND UTILIZATION OF POLYCYCLIC AROMATIC HYDROCARBONS BY INDIGENOUS SOIL BACTERIA (NAPHTHALENE, FLUORENE, ANTHRACENE, PYRENE)." Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/183810.

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The persistance of industrially derived polycyclic aromatic hydrocarbons in the subsurface may be significantly affected by the metabolism of soil bacteria. This study was conducted to determine the ability of indigenous soil bacteria to decrease the concentration of four polycyclic aromatic hydrocarbons (naphthalene, fluorene, anthracene, and pyrene) and to utilize the compounds as a substrate for growth. Soil cores from petroleum contaminated and non-contaminated sites contained 10⁵ - 10⁷ viable microorganisms per gram dry weight of soil. Gram negative rod-shaped bacteria predominated. Decreases in the concentration of the four polycyclic aromatic hydrocarbons were observed during incubation with bacterial isolates in aqueous suspension by the use of high performance liquid chromatography. Corresponding increases in bacterial numbers indicated utilization of the compounds as a carbon source. Soil samples from the contaminated sites contained greater numbers of bacteria utilizing anthracene and pyrene than soil samples from non-contaminated sites. Degradation rates of the four polycyclic aromatic hydrocarbons were related to the compound, its concentration, and the bacterium. Biodegradation of pyrene was positively correlated with the presence of oxygen. Pyrene was biodegraded by an Acinetobacter sp. under aerobic conditions but not under anaerobic or microaerophilic conditions. Studies with radiolabeled ¹⁴C-anthracene demonstrated utilization of the labeled carbon as a source of carbon by viable bacterial cells in aqueous suspension. Incorporation of ¹⁴C into cellular biomass however was not observed during incubation of ¹⁴C-anthracene in soil.
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24

Powell, David C. "Characterization of Iron-Bearing Solids Used by Naturally-Occurring Microbes in the Anaerobic Degradation of Hydrocarbons." W&M ScholarWorks, 2000. https://scholarworks.wm.edu/etd/1539617754.

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25

Aldosary, Huda A. KH. "Polycyclic Aromatic Hydrocarbon Degradation by Anaerobic Bacteria from the Great Artesian Basin." Thesis, Griffith University, 2020. http://hdl.handle.net/10072/393639.

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The Great Artesian Basin (GAB) is a vast subterranean thermal aquifer system underlying over 20% of the Australian continent. Substantial reserves of oil, gas and minerals exist within the GAB and combined with industrial activities can often contaminate the groundwaters. The current study investigated the bacterial ecology of bore waters that were in or close to oil deposits. Three sites were selected, two in the Quilpie/Eromanga region of Queensland (Naretha bore registered number 4022 and Adavale bore registered number 305), and the other in the Moomba oil field of South Australia (Moomba bore 9). A wide diversity of bacteria was detected across all of the samples collectively, including members of 32 bacterial phyla. There was greater diversity in the water samples from bores 4022 and 305 compared with Moomba 9, which was likely due to its closer association with oil. The most dominant bacterial taxa were similar in bores 4022 and 305, families Rhodobacteraceae, and Xanthomonadaceae and the order Bacillales. In contrast, the dominant taxa from Moomba 9 were the family Oxalobacteriaceae and the genus Agrococcus. Three different water samples were tested from bore 4022, from the source, 100 m and 250 m downstream in the runoff channel water. The bacterial diversity increased the further away the water flowed from the bore, due to the cooler water and contamination from the surrounding environment. A comprehensive anaerobic thermophilic enrichment program revealed that bacteria grew on a wide variety of organic substrates and a range of heavy metals as terminal electron acceptors. Isolation yielded 164 bacteria capable of using substrates from sugars and extracts through to polycyclic aromatic hydrocarbons (PAH) and reducing the metals iron(III), vanadium(V), cobalt(III) and manganese(IV). Seven pure iron(III) reducing polycyclic aromatic hydrocarbon (PAH) degrading bacteria, designated strains RN40AT, RN40BT, RN40CT, RN40DT, RN305AT, RN305BT and MBA9BT, were selected for further studies. The rates of degradation Polycyclic Aromatic Hydrocarbon Degradation by Anaerobic Bacteria from the Great Artesian Basin and PAH preference varied significantly between the isolates. Strain MBA9BT showed the highest extent (97.6%) of anthracene degradation while strain RN305BT was the lowest (9.7%). Again, strain MBA9BT also showed the highest extent (91.2%) of pyrene degradation and strain RN40DT showed the lowest (16.1%). Phenanthrene degradation was highest in strain RN40BT and the lowest in strain MBA9BT (2%). PAH degradation in all the isolates showed a direct dependence on Fe(III) reduction. A measurable decrease in the surface tension of the medium suggested the production of biosurfactants by all isolates when grown with PAHs as substrates. Genomic analysis of the isolates revealed subsystems of different pathways that are commonly found in metal acquisition, transport and utilisation as well as those for aromatic hydrocarbon degradation. Strain RN40DT had the highest number of genes involved in the metabolism of PAHs, though all of the isolates had genes for the metabolism of central aromatic intermediates, especially those related to catechol, salicylate and homogentisate degradation. The isolates had varying levels of genes involved in the metabolism and resistance to iron, copper, chromium, zinc, molybdenum, manganese and mercury. Strains RN40AT, RN305AT RN305BT, RN40BT and RN40DT contained the most genes for iron acquisition and metabolism including those for siderophores, hemin transporters and ferric ABC transport systems. The results in the current study have built upon our understanding of bacterial diversity in the GAB, particularly with insights into waters associated with oil deposits. Bacteria that degrade polycyclic aromatic hydrocarbons with the simultaneous reduction of Fe(III) under anaerobic conditions were isolated for the first time and may have significant potential in bioremediation of contaminated groundwaters.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>School of Environment and Sc<br>Science, Environment, Engineering and Technology<br>Full Text
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26

Fettig, James Drew. "A Study of the Patterns, Stoichiometry, and Kinetics of Microbial BTX Degradation Under Denitrifying Conditions by an Activated Sludge Consortium Receiving a Mixed Waste." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/45148.

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The patterns, stoichiometry, and kinetics of microbial benzene, toluene, p-xylene, m-xylene, and o-xylene degradation by a denitrifying activated sludge consortium was investigated in a sequencing batch reactor (SBR) receiving a mixed waste. After six months of acclimation, toluene and m-xylene were routinely degraded to below detection. Both toluene and m-xylene could serve as sole carbon and energy sources. The removal of o-xylene was also possible; however, its transformation was dependent upon gratuitous metabolism during toluene degradation. Benzene and p-xylene were recalcitrant throughout the study. The first order decay coefficient (b) of the denitrifying biomass was determined to be 0.016 ± 0.006 h-1 on a theoretical oxygen demand (thOD) basis. The true growth yields (Y) for the biogenic and toluene/m-xylene components of the mixed waste were determined to be 0.41 ± 0.02 and 0.35 ± 0.04 mg thOD biomass per mg thOD substrate, respectively. The Monod parameters, qmax and KS, for toluene ranged from 0.059 to 0.14 mg toluene/mg protein/h and 0.84 to 6.9 mg/L, respectively. For m-xylene, the qmax and KS parameters ranged from 0.034 to 0.041 mg m-xylene/mg protein/h and 0.28 to 3.7 mg/L, respectively. Some of the variation observed between kinetic experiments was attributed to the different accumulation levels of the denitrification intermediate nitrite (NO2-) and the inhibitory effects of its conjugate acid, nitrous acid (HNO2). Other evidence suggested that part of the variation was also due to a continuous acclimation and refinement towards higher affinity toluene- and m-xylene-degrading enzyme systems within the biomass.<br>Master of Science
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27

Heaman, Jacki B. L. "The influence of previous exposure and soil type on the degradation of polycyclic aromatic hydrocarbons in soil." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ35061.pdf.

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28

Yu, Fang. "Abiotic Degradation of Chlorinated Hydrocarbons (CHCs) with Zero-Valent Magnesium (ZVM) and Zero-Valent Palladium/Magnesium Bimetallic (Pd/Mg)-Reductant." Wright State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=wright1373881146.

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29

Ward, Collin P. "Direct and Indirect Photochemical Degradation of Two Polycyclic Musk Fragrances and Two Polycyclic Aromatic Hydrocarbons in Natural Waters." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1275577426.

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30

Filippini, Maria <1986&gt. "Geological and hydrogeological features affecting migration, multi-phase partitioning and degradation of chlorinated hydrocarbons through unconsolidated porous media." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/6812/1/Filippini_Maria_tesi.pdf.

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Chlorinated solvents are the most ubiquitous organic contaminants found in groundwater since the last five decades. They generally reach groundwater as Dense Non-Aqueous Phase Liquid (DNAPL). This phase can migrate through aquifers, and also through aquitards, in ways that aqueous contaminants cannot. The complex phase partitioning to which chlorinated solvent DNAPLs can undergo (i.e. to the dissolved, vapor or sorbed phase), as well as their transformations (e.g. degradation), depend on the physico-chemical properties of the contaminants themselves and on features of the hydrogeological system. The main goal of the thesis is to provide new knowledge for the future investigations of sites contaminated by DNAPLs in alluvial settings, proposing innovative investigative approaches and emphasizing some of the key issues and main criticalities of this kind of contaminants in such a setting. To achieve this goal, the hydrogeologic setting below the city of Ferrara (Po plain, northern Italy), which is affected by scattered contamination by chlorinated solvents, has been investigated at different scales (regional and site specific), both from an intrinsic (i.e. groundwater flow systems) and specific (i.e. chlorinated solvent DNAPL behavior) point of view. Detailed investigations were carried out in particular in one selected test-site, known as “Caretti site”, where high-resolution vertical profiling of different kind of data were collected by means of multilevel monitoring systems and other innovative sampling and analytical techniques. This allowed to achieve a deep geological and hydrogeological knowledge of the system and to reconstruct in detail the architecture of contaminants in relationship to the features of the hosting porous medium. The results achieved in this thesis are useful not only at local scale, e.g. employable to interpret the origin of contamination in other sites of the Ferrara area, but also at global scale, in order to address future remediation and protection actions of similar hydrogeologic settings.
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31

Filippini, Maria <1986&gt. "Geological and hydrogeological features affecting migration, multi-phase partitioning and degradation of chlorinated hydrocarbons through unconsolidated porous media." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/6812/.

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Chlorinated solvents are the most ubiquitous organic contaminants found in groundwater since the last five decades. They generally reach groundwater as Dense Non-Aqueous Phase Liquid (DNAPL). This phase can migrate through aquifers, and also through aquitards, in ways that aqueous contaminants cannot. The complex phase partitioning to which chlorinated solvent DNAPLs can undergo (i.e. to the dissolved, vapor or sorbed phase), as well as their transformations (e.g. degradation), depend on the physico-chemical properties of the contaminants themselves and on features of the hydrogeological system. The main goal of the thesis is to provide new knowledge for the future investigations of sites contaminated by DNAPLs in alluvial settings, proposing innovative investigative approaches and emphasizing some of the key issues and main criticalities of this kind of contaminants in such a setting. To achieve this goal, the hydrogeologic setting below the city of Ferrara (Po plain, northern Italy), which is affected by scattered contamination by chlorinated solvents, has been investigated at different scales (regional and site specific), both from an intrinsic (i.e. groundwater flow systems) and specific (i.e. chlorinated solvent DNAPL behavior) point of view. Detailed investigations were carried out in particular in one selected test-site, known as “Caretti site”, where high-resolution vertical profiling of different kind of data were collected by means of multilevel monitoring systems and other innovative sampling and analytical techniques. This allowed to achieve a deep geological and hydrogeological knowledge of the system and to reconstruct in detail the architecture of contaminants in relationship to the features of the hosting porous medium. The results achieved in this thesis are useful not only at local scale, e.g. employable to interpret the origin of contamination in other sites of the Ferrara area, but also at global scale, in order to address future remediation and protection actions of similar hydrogeologic settings.
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32

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.<br>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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33

Elie, Marc. "Use of an Activated Magnesium/cosolvent System for the Desorption and Degradation of Polycyclic Aromatic Hydrocarbons and Their Oxygenated Derivatives in Contaminated Soils." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5196.

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The contamination of soils, with polycyclic aromatic hydrocarbons (PAHs), remains a widespread environmental concern. In the past two decades, many physical, chemical and biological methods have been developed and evaluated for the degradation of PAHs. However, due to their low aqueous solubility, high sorption affinity, hydrophobicity and recalcitrance, the environmental remediation of PAHs in soil continues to be economically challenging. In addition to PAH contamination, the presence of oxygenated derivatives of PAHs (OPAHs), in soils, has increasingly become a concern due to their greater toxic properties compared to parent PAH compounds. To date, no investigations on OPAH-remediation methods have been presented in the literature. The use of zero-valent metals (ZVMs) has been reported for several halogenated contaminants in solution systems, but the effectiveness of ZVM to degrade sorbed PAHs and OPAHs has been rarely addressed. This present research focuses on the development of a combined technique for the feasible desorption and degradation of PAHs and OPAHs in soils. PAH and OPAH degradation efficiency, using activated magnesium (Mg) metal combined with an ethanol-ethyl lactate cosolvent (1:1 ratio), was initially examined in soil-free systems. This metal/cosolvent system demonstrated adequate degradation (above 80%) for high-molecular-weight (HMW) PAHs, which were subsequently converted into hydroaromatic compounds; while OPAHs were degraded and converted into hydroxylated or hydrogenated derivatives. Further soil-free studies revealed that the degradation rate was affected by the surface or reactive sites of the metal and that optimum degradation efficiency were obtained with Mg ball milled with graphite (Mg/C). In a bench-scale feasibility test, the efficacy of this system was assessed on a soil spiked with a mixture of three HMW PAHs compounds and three OPAHs compounds with amounts ranging from 0.033 mmol to 0.060 mmol. The experimental results show that 2 mL of an ethanol-ethyl lactate solvent mixture resulted in 58% to 85% extraction efficiency for the selected contaminants in 1 g of spiked soil, followed by 64 - 87% degradation efficiency of the extracted contaminants with 4.11 mmol of the activated metal. This activated-Mg/cosolvent system can be considered as a promising alternative method for ex situ remediation of PAH and OPAH-contaminated soils.<br>Ph.D.<br>Doctorate<br>Chemistry<br>Sciences<br>Chemistry
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34

Dörr, Fabiane. "Consórcios degradadores de BTEX: isolamento, caracterização e avaliação do potencial de degradação." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/87/87131/tde-11042012-152743/.

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Amostras de água subterrânea provenientes de uma área industrial contaminada por hidrocarbonetos monoaromáticos foram utilizadas para a obtenção de bactérias degradadoras de BTEX (benzeno, tolueno, etilbenzeno e isômeros de xileno), com o intuito de realizar sua identificação, caracterização e avaliação do potencial de degradação. Foram estudados os perfis de crescimento dos consórcios de bactérias enriquecidos em BTEX, isoladamente e com diferentes substratos. Apenas parte das cepas isoladas apresentaram capacidade de crescimento quando expostas individualmente aos compostos em que foram previamente adaptadas. Foram identificadas, por análises de ácidos graxos e seqüenciamento do DNAr 16S, as espécies Stenotrophomonas maltophilia, Serratia marcescens, Burkholderia cepacia, Enterobacter sp., Bacillus cereus e Bacillus tropicalis.<br>Groundwater samples from an industrial area contaminated with monoaromatic hydrocarbons were used to obtain BTEX (benzene, toluene, ethylbenzene and xylene isomers) degrading bacteria, for the purpose of do their identification, characterization and evaluate their degradation potential. The growth rate of bacterial consortia enriched on BTEX was studied, individually and with different substrates. Just some of the strains isolated showed growth capacity when individually exposed to the compounds in which they were previously adapted. Were identified, by fatty acid analysis and 16S rDNA sequencing, the species Stenotrophomonas maltophilia, Serratia marcescens, Burkholderia cepacia, Enterobacter sp., Bacillus cereus and Bacillus tropicalis.
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35

Khorasanizadeh, Zohreh. "The effect of biotic and abiotic factors on degradation of polycyclic aromatic hydrocarbons (PAHs) by bacteria in the soil." Thesis, University of Hertfordshire, 2014. http://hdl.handle.net/2299/13893.

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Polycyclic aromatic hydrocarbons (PAHs) are a group of ubiquitous environmental contaminants with two or more aromatic rings and originating from different emission sources. They are extremely toxic, carcinogenic and mutagenic to human, animals and plants. Consequently, the need to expand economical and practical remediation technologies for PAH contaminated sites is evident. In this study, the effect of biotic and abiotic factors on degradation of PAH was studied. The degradation was studied on the key model PAH (phenanthrene, anthracene, fluoranthene and pyrene) in J. Arthur Bower’s top soil. The hypothesis for this study was that roadside soil would contain PAH degrading bacteria; pH would influence the microbial degradation of PAH, chemical oxidation of PAH would be as efficient as microbial breakdown of PAH and mobilising agents, would move PAH throughout soil, potentially making the PAH more available for biodegradation. The greatest degradations were found for the lowest molecular weight PAH, phenanthrene and anthracene; whilst lowest degradation was observed for higher molecular weight PAH, fluoranthene and pyrene. Twelve bacteria genera were isolated and identified by biochemical and molecular techniques from the roadside soil with the four PAHs as the sole carbon source. However, potentially new PAH biodegrader bacteria species and a novel were found in this study, which was not reported in the literature. The effect of pH between 5.0 and 8.0 at half pH intervals on biodegradation of the four PAHs and on bacterial populations in the soil over 32 days was monitored. The greatest population of bacteria and greatest biodegradation for the four PAHs was found at pH of 7.5. It is likely that the general increase in population was also linked with greater metabolic activities of bacteria at basic pHs which assists pollutant biodegradation. Although there is high pollutant mobility at low pHs, the biodegradation was limited due to reduced microbial activity. High pHs resulted in greater PAH biodegradation suggesting that pH manipulation by liming may be an effective way of stimulating biodegradation of PAH. The effect of potassium permanganate on oxidation of the four PAHs in the soil was examined. Studies in this thesis, indicated that potassium permanganate had a significant (p<0.05) effect on oxidation of the four PAHs at pH 7.5 over 35 days. However in comparison to biodegradation, chemical oxidation has significantly (p<0.05) less effect. Finally, the effect of Tween 20 only on translocation and biodegradation of the four PAHs at pH 7.5 over 35 days was examined. Studies indicated that Tween 20 had significantly (p<0.05) enhanced translocation of the four PAHs in the sterile soil. Moreover, the greatest biodegradation was found in the soil inoculated with only the roadside soil microorganisms but without Tween 20. This suggested that Tween 20 had a significant (p<0.05) inhibitory effect on the roadside soil microorganisms and therefore less microorganism were grown in the soil containing Tween 20. This indicated that Tween 20 was translocated PAH, but inhibited breakdown. This study indicated microbial biodegradation was the most effective technique for removing of the PAH from contaminated soil, which was cost effective and easier to perform in comparison to the other two techniques. Microbial biodegradation could be improved by adjusting pH through liming if soil was acid.
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36

ANDREOLLI, Marco. "Molecular, phylogenetic and functional characterization of Burkholderia sp. DBT1, a bacterial strain involved in polycyclic aromatic hydrocarbons (PAHs) degradation." Doctoral thesis, Università degli Studi di Verona, 2010. http://hdl.handle.net/11562/342874.

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Con il termine bonifica biologica si definiscono un insieme di metodiche in grado di usufruire delle capacità metaboliche di microrganismi e/o piante, al fine di recuperare siti contaminati da sostanze pericolose. In caso di forti contaminazioni, tuttavia, la sola stimolazione dei microrganismi autoctoni – mediante aggiunta d’ammendanti e/o tramite aerazione del suolo - risulterebbe troppo lenta. L’aggiunta di un inocula batterico direttamente in suolo o, alternativamente, in piante selezionate al fine di aumentare il potenziale biodegradativo in planta, può aumentare l’efficienza nel recupero del sito contaminato. D’altra parte, la selezione di microrganismi opportuni a tal fine, riveste una fase critica per buon esito di un protocollo. In particolar modo, l’efficienza di degradazione verso i composti interessati, e la non pericolosità per uomo e/o animali, sono due aspetti da tenere in forte considerazione a monte di un loro eventuale sversamento in situ. A questo scopo, un’attenta caratterizzazione di ceppi microbici potenzialmente utilizzabili in protocolli di bonifica biologica appare di fondamentale importanza. Nel nostro laboratorio è stato isolato da una matrice inquinata da IPA un ceppo batterico appartenente al genere Burkholderia, denominato Burkholderia sp. DBT1. Questo ceppo batterico è in grado di trasformare in maniera molto efficiente il dibenzotiofene a HFBT tramite la “via di Kodama”. Lo scopo, quindi, è la caratterizzazione molecolare, filogenetica e funzionale del ceppo B. sp. DBT1 al fine di valutare il suo utilizzo in protocolli di bonifica biologica per il recupero di suoli contaminati da IPA. Gli obiettivi generali della sperimentazione sono stati: - Identificare e sequenziare la regione a valle del frammento genico p51, al fine di valutare la presenza delle sequenze geniche mancanti nella via di degradazione di Kodama. - Condurre uno studio filogenetico del ceppo, al fine di collocare il ceppo DBT1 all’interno di una delle specie di Burkholderia ad oggi conosciute, o se, invece, esso andrà a costituire una nuova specie a se stante. Sarà inoltre fondamentale valutare se esso appartiene ad una specie potenzialmente patogena (e.g. Bcc). - Valutare il potenziale metabolico del ceppo DBT1 verso i composti IPA non solo di natura tiofenica, maggiormente rappresentati nei suoli contaminati da idrocarburi. - Condurre uno studio finalizzato ad una valutazione tossicologica del ceppo DBT1 verso cellule animali e umane. - Caratterizzare, mediante tecniche molecolari e biochimiche, ceppi endofiti isolati da pioppo ibrido - in relazione con il ceppo DBT1 -, potenzialmente utilizzabili in protocolli di bonifica biologica di suoli contaminati da IPA. L’analisi condotta al fine d’identificare la regione a valle del frammento genico p51 ha permesso l’identificazione di due sequenze geniche. Le indagini d’omologia in banche dati hanno permesso di rilevare la funzione dei relativi enzimi. La prima sequenza genica, denominata dbtAa, codifica per la componente ferrodossina reduttasi dell’enzima ISP; mentre la seconda, denominata dbtE, codifica per l’enzima idratasi-aldolasi. Dai risultati ottenuti si può quindi affermare di aver identificato il completo set genico, e quindi enzimatico, coinvolto nella degradazione del DBT mediante il pathway di Kodama all’interno degli operoni p51 e pH1A nel ceppo DBT1. Il soggetto del presente studio, B. sp. DBT1, ha mostrato un’interessante capacità metabolica nei confronti di molecole IPA – dibenzotiofene, fenantrene, naftalene e fluorene - sia se forniti come unica fonte di carbonio ed energia, sia in condizione di cometabolismo. In quest’ultimo processo un composto è degradato da un enzima prodotto da organismi impegnati in altre reazioni e la degradazione del composto inquinante è considerato un evento fortuito, da cui i microrganismi non traggono energia. Di conseguenza, non dovendo supportare la crescita microbica, possono essere degradate anche concentrazioni molto basse d’inquinante. Stabilite le potenzialità metaboliche del ceppo DBT1, è stato importante assicurare la sua non tossicità e pericolosità di un suo eventuale utilizzo. Gli studi tassonomici hanno dimostrato che il ceppo DBT1 appartiene alla specie fungorum, una specie in cui sono presenti alcuni membri che sono stati isolati da uomini e animali affetti da alcuni tipi di patologie. In quanto il ruolo di questi ceppi nel decorso della malattia, a parte per un singolo caso, non è stato ancora determinato, è stato ritenuto importante effettuare uno studio più approfondito al fine di valutare le capacità di produrre tossine da parte del ceppo DBT1 verso sistemi animali e umani. I risultati hanno chiaramente evidenziato che il ceppo DBT1 non è in grado di danneggiare né il potenziale di membrana cellulare, né il gradiente protonico mitocondriale. Da recenti studi, un protocollo di bonifica biologica che ha dimostrato una buon’efficienza nel recupero di siti contaminati è risultato essere l’utilizzo di un sistema in grado di sfruttare la capacità della pianta di assorbire i composti tossici, associata alle capacità degradative dei microrganismi presenti in essa. La caratterizzazione effettuata sui ceppi endofiti isolati da pioppo ha evidenziato la presenza di ceppi IPA degradatori. Tra questi ceppi, dieci appartengono alla specie fungorum uno alla specie sordidicola e l’ultimo identificato con il nome di Burkholderia sp. R-701, un ceppo appartenente alla specie sartisoli. Mentre l’identificazione di specie quali fungorum o sordidicola all’interno d’organismi superiori quali piante e/o funghi sono stati già documentati, per la prima volta si è isolato un ceppo della specie sartisoli in tessuti vegetali. Le successive analisi di PCR hanno sorprendentemente evidenziato la presenza degli operoni pH1A e p51 nei dieci ceppi endofiti di fungorum e nel ceppo R-701. Analisi PCR-DGGE e analisi di restrizione non hanno mostrato variazioni nella sequenza di questi operoni tra i ceppi endofiti, rilevando, tuttavia, una notevole differenza con la sequenza di p51 e pH1A del ceppo DBT1. Le differenze riscontrate tra i ceppi di fungorum isolati dal pioppo ed il ceppo DBT1 non si sono rilevate essere solo a livello genico. Infatti, successive analisi biochimiche e microbiologiche hanno evidenziato che il ceppo DBT1 risulta essere più efficiente nella degradazione del fenantrene e del DBT rispetto ai ceppi endofiti fungorum sopra descritti. Ovviamente, con i dati ad oggi ricavati non si può correlare i diversi genotipi degli operoni p51 e pH1A con le diverse efficienze degradative degli IPA. Questi risultati incoraggiano un possibile utilizzo di DBT1 come ceppo endofita del pioppo, essendo anch’esso appartenente alla specie fungorum. Concludendo, i risultati ottenuti da questo lavoro di tesi incentivano l’utilizzo del ceppo Burkholderia fungorum DBT1 in protocolli di bonifica biologica per il recupero di siti contaminati da composti IPA; e suggerisce una reale fattività di DBT1 come ceppo endofita in pioppo al fine di migliorare la biodegradazione in planta.<br>Polycyclic aromatic hydrocarbons (PAHs) are a class of organic compounds that have accumulated in the natural environment mainly as a result of anthropogenic activities. These compounds are largely suspected to act as potential mutagens, teratogens as well as carcinogens. Moreover, their low aqueous solubility and, consequently, their low bioavailability are a great obstacle to microbial degradation. The word “bioremediation” has been used to describe the process of using microorganisms to degrade or remove hazardous compounds and wastes such as PAHs from the environment. Nevertheless, before developing an efficient protocol for bioremediation is necessary to perform an upstream study, in order to isolate, identify and characterize organisms suitable to this purpose. Burkholderia sp. DBT1 is a bacterial strain identified in an oil refinery wastewater which can degrade DBT nearly completely through the Kodama pathway within three days. Aimed to clarify the effective potential and actual utilization of such strain in bioremediation protocol, different aspects of B. sp. DBT1 have been investigated. - Identification of DNA sequences flanking p51 operon: Molecular characterization of strain DBT1 has showed that six of eight genes required for DBT degradation by Kodama pathway are present in two operons – p51 and pH1A. p51 genetic fragment harbor dbtC,Ab,ORF6,ORF7 replicative unit. The sequence of p51 genetic fragment stopped at the end of ORF 7 and the transcription terminator was not yet detected. Therefore, identification of DNA sequence flanking p51 operon was carried out in order to detect possible gene sequence downstream ORF 7. - Taxonomic analysis: Taxonomic status of Burkholderia sp. DBT1 has never been resolved. It is important to remark that several species of Burkholderia can cause food poisoning or can behave as plant and animal pathogens. Furthermore, different strains belonging to the Burkholderia cepacia complex (Bcc) are involved in life-threatening infections of humans such as cystic fibrosis. - Study of PAHs degrading activity: Since normally several organic pollutants contribute together to the contamination at different sites, isolation and characterization of microbes able to use a wide range of PAHs compounds as sole source of carbon and energy are of great interest in order to select useful candidates for applications in bioremediation. - Toxicology and pathogenic analysis: Several Burkholderia species are common soil inhabitants, nevertheless some species of this genus are known as toxin producer. Therefore, some tests will be carried out to even investigate the eco-toxicological safety of strain DBT1 for environmental use. - Study of endophytes bacterial strains: Once it is been clarified the metabolic, taxonomic aspect of strain DBT1, it results very important to set up an efficient protocol for a future application in open field (in situ). A new promise strategy is to use endophitic bacterial equipped with appropriate degradation pathway in order to improve in planta PAHs degradation. Thus, selection and study of bacterial strains able both to degrade PAHs and to colonize host plants (e.g. Aspen) in order to verify the bioremediation potential of plant-endophytic bacteria systems, using both molecular and physiologic analysis. The work here presented has demonstrated that the hydratase-aldolase and ferredoxin reductase sequences, the two genes missing, are collocated downstream the putative sequence ORF 7 within p51 operon. Thus, the missing enzymes have been recovered, demonstrating that the whole set of enzyme involved in Kodama pathway degradation is harbored in p51 and pH1A operons. Moreover, the results so far achieved suggest that the strain DBT1 presents a versatile metabolism towards PAHs, and this is an important trait for the possible use of this strain in environmental clean up. This strain is able to use fluorene, naphtalene, DBT and phenanthrene for growing, although growth on the first two compounds needs a pre-induction. Therefore, it can be suggested that phenanthrene is metabolized through 2-carboxycinnamic acid, phthalic acid and further metabilized in protocatechol. The PAHs degradation can occur even by a co-metabolism process. The application of bacterial strains in environmental clean up is severely subject to another crucial pre-requisites: the ecotoxicological safety of the selected strain and its probative exclusion from pathogenic species such as Burkholderia cepacia complex. The data presented in this study indicate that strain DBT1 can be considered a member of the species fungorum, for which the name Burkholderia fungorum strain DBT1 is here proposed. Since the original report, B. fungorum was identified in a wide range of environment such as soil, plant-associated samples, in infections of the central nervous system of a pig and a deer, and in the respiratory secretions of people with cystic fibrosis. Therefore, the investigation about possible toxic effects by strain DBT1 has been considered of prominent significance in the present study; and bioassay to detect mitochondrial toxicity in mammalian cells by JC-1 and PI staining of human cell lines would be useful to investigate toxic microbial metabolites. Results so far achieved show that B. DBT1 and B. fungorum type strain was unable to damage mitochondrial and human cells membranes. However, it is important to underline that this strategy does not rule out the possibility that the strain investigated might be pathogenic under specific circumstances or on different targets not yet ascertained, such as to substances affecting the synthesis of proteins or nucleic acids or their regulation. Besides, as cited before, the second strategy for a better use the bioremediation potential of plant-endophytic bacteria systems is focused on isolating, identifying and characterizing the bacteria that already exist as bacterial endophytes in plants and which are applyable to phytoremediation protocols. Poplar trees (Populus spp.) are commonly used as phytoremediation tools because they are perennial, hardy, tolerant to high concentration of organic compounds, highly tolerant to flooding, fast growing, easily propagated and have a wide range adaptation. Thus, a careful screening and characterization of endophytes from poplar plants growth on PAHs contaminated soils were carried out. The results obtained confirm that natural bacteria degrading recalcitrant compounds are largely present among endophytic populations of plants growth in contaminated sites, this could mean that endophytes have a role in metabolizing these substances. Moreover, Burkholderia is resulted be the genera mainly involved in PAHs degradation, and fungorum the species more representative. Interestingly, the majorities of these bacteria are involved in phenanthrene and DBT degradation, and harbor p51 and pH1A, the operons formerly identify in DBT1 strain. However, the subsequent DGGE and restriction analysis on these DNA fragments, showed the presence of a single genotype among the endophytic bacteria, but different from DBT1. The difference between strains isolated in Finland and DBT1 is not only at genetic level. In fact, B. sp. DBT1 resulted to be more efficient in the degradation towards PAHs tested, especially in the metabolism of DBT. Moreover, the results suggest the application of B. sp. DBT1 as poplar endophyte. Eventually, the results obtained from this thesis work incentives the use of the strain Burkholderia fungorum DBT1 for a possible exploitation in bioremediation protocols of PHA-contaminated sites; moreover it suggest an actual use of such strain as endophytes in poplar plant in order to improve in planta degradation.
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37

Wang, Bo. "Degradation of Halogenated Hydrocarbons by Zero-Valent Magnesium andCopper/Magnesium Bimetallic Reductant, & Characterization of Poly- andPerfluoroalkyl Substances in Treated Wastewater Reclaimed for Direct Potable Reuse." Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1568048522860247.

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38

Smit, Martin Francis. "Effect of trifluoroacetate, a persistent degradation product of halogenated hydrocarbons, on photosynthesis of C₃ and C₄ crop plants / Martin Francis Smit." Thesis, North-West University, 2006. http://hdl.handle.net/10394/1377.

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39

Gacura, Matthew David. "Effect of Pleurotus ostreatus on Bioremediation of PAH Contaminated River Sediment." Youngstown State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1254341459.

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40

Smith, Kiara L. "Anaerobic Degradation of Polycyclic Aromatic Hydrocarbons at a Creosote-Contaminated Superfund Site and the Significance of Increased Methane Production in an Organophilic Clay Sediment Cap." PDXScholar, 2010. https://pdxscholar.library.pdx.edu/open_access_etds/101.

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The overall goal of this work was to investigate microbial activity leading to the anaerobic degradation of polycyclic aromatic hydrocarbons and an organophilic clay sediment cap used at a creosote-contaminated Superfund site. To determine whether or not PAHs were being degraded under anaerobic conditions in situ, groundwater and sediment porewater samples were analyzed for metabolic biomarkers, or metabolites, formed in the anaerobic degradation of naphthalene (a low-molecular weight PAH). In addition, a groundwater push-pull method was developed to evaluate whether the transformation of deuterated naphthalene to a deuterated metabolite could be monitored in situ and if conservative rates of transformation can be defined using this method. Metabolites of anaerobic naphthalene degradation were detected in all samples that also contained significant levels of naphthalene. Anaerobic degradation of naphthalene appears to be widespread in the upland contaminated aquifer, as well as within the adjacent river sediments. A zero-order rate of transformation of naphthalene-D₈ to naphthoic acid-D₇was calculated as 31 nM·d-¹. This study is the first reported use of deuterated naphthalene to provide both conclusive evidence of the in situ production of breakdown metabolites and an in situ rate of transformation. Methane ebullition was observed in areas of the sediment cap footprint associated with organophilic clay that was used a reactive capping material to sequester mobile non-aqueous phase liquid (NAPL) at the site. Anaerobic slurry incubations were constructed using sediment core samples to quantify the contribution of the native sediment and the different layers of capping material (sand and organophilic clay) to the overall methane production. Substrate addition experiments using fresh, unused organophilic clay, as well as measured changes in total carbon in organophilic clay over time supported the hypothesis that microbes can use organophilic clay as a carbon source. Quantitative PCR (qPCR) directed at the mcrA gene enumerated methanogens in field samples and incubations of native sediment and capping materials. Denaturing gradient gel electrophoresis (DGGE) was also performed on DNA extracted from these samples to identify some of the predominant microorganisms within the sediment cap footprint. The organophilic clay incubations produced up to 1500 times more methane than the native sediment and sand cap incubations. The organophilic clay field sample contained the greatest number of methanogens and the native sediment contained the least. However, the native sediment incubations had greater numbers of methanogens compared to their respective field sample and comparable numbers to the organophilic clay incubation. An increase in methane production was observed with the addition of fresh, unused organophilic clay to the already active organophilic clay incubations indicating that organophilic clay stimulates methanogenesis. In addition, organophilic clay retrieved from the field lost about 10% of its total carbon over a 300-day incubation period suggesting that some component of organophilic clay may be converted to methane. DGGE results revealed that some of the predominant groups within the native sediment and sediment cap were Bacteriodetes, Firmicutes, Chloroflexi, and Deltaproteobacteria. An organism 98% similar to Syntrophus sp. was identified in the organophilic clay suggesting this organism may be working in concert with methanogens to convert the organic component of organophilic clay ultimately to methane. The capacity of organophilic clay to sequester organic contaminants will likely change over time as the organic component is removed from the clay. This, in turn, affects the use of this material as a long-term remedial strategy in reduced, contaminated environments.
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41

Zhang, Chun. "Study of Genes Relating To Degradation of Aromatic Compounds and Carbon Metabolism in Mycobacterium Sp. Strain KMS." DigitalCommons@USU, 2013. http://digitalcommons.usu.edu/etd/1532.

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Polycyclic aromatic hydrocarbons, produced by anthropological and natural activities, are hazardous through formation of oxidative radicals and DNA adducts. Growth of Mycobacterium sp. strain KMS, isolated from a contaminated soil, on the model hydrocarbon pyrene induced specific proteins. My work extends the study of isolate KMS to the gene level to understand the pathways and regulation of pyrene utilization. Genes encoding pyrene-induced proteins were clustered on a 72 kb section on the KMS chromosome but some also were duplicated on plasmids. Skewed GC content and presence of integrase and transposase genes suggested horizontal transfer of pyrene-degrading gene islands that also were found with high conservation in five other pyrene-degrading Mycobacterium isolates. Transcript analysis found both plasmid and chromosomal genes were induced by pyrene. These processes may enhance the survival of KMS in hydrocarbon-contaminated soils when other carbon sources are limited. KMS also grew on benzoate, confirming the functionality of an operon containing genes distinct from those in other benzoate-degrading bacteria. Growth on benzoate but not on pyrene induced a gene, benA, encoding a benzoate dioxygenase α-subunit, but not the pyrene-induced nidA encoding a pyrene dioxygenase α-subunit; the differential induction correlated with differences in promoter sequences. Diauxic growth occurred when pyrene cultures were amended with benzoate or acetate, succinate, or fructose, and paralleled delayed expression of nidA. Single phase growth and normal expression of benA was observed for benzoate single and mixed cultures. The nidA promoters had potential cAMP-CRP binding sites, suggesting that cAMP could be involved in carbon repression of pyrene metabolism. Growth on benzoate and pyrene requires gluconeogenesis. Intermediary metabolism in isolate KMS involves expression from genes encoding a novel malate:quinone oxidoreductase and glyoxylate shunt enzymes. Generation of C3 structures involves transcription of genes encoding malic enzyme, phosphoenolpyruvate carboxykinase, and phosphoenolpyruvate synthase. Carbon source modified the transcription patterns for these genes. My findings are the first to show duplication of pyrene-degrading genes on the chromosome and plasmids in Mycobacterium isolates and expression from a unique benzoate-degrading operon. I clarified the routes for intermediary metabolism leading to gluconeogenesis and established a potential role for cAMP-mediated catabolite repression of pyrene utilization.
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42

Therrien, Annamarie F. "Degradation of Chlorinated Hydrocarbons in Groundwater Passing Through the Treatment Wetland at Wright-Patterson Air Force Base: Analysis of Results Collected During 2001-'06." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1363477561.

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43

Laso, Pérez Rafael [Verfasser], Antje [Akademischer Betreuer] Boetius, Antje [Gutachter] Boetius, and Ida Helene [Gutachter] Steen. "A novel mechanism for the anaerobic degradation of non-methane hydrocarbons in archaea / Rafael Laso Pérez ; Gutachter: Antje Boetius, Ida Helene Steen ; Betreuer: Antje Boetius." Bremen : Staats- und Universitätsbibliothek Bremen, 2018. http://d-nb.info/1186248777/34.

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Laso, Pérez Rafael Verfasser], Antje [Akademischer Betreuer] [Boetius, Antje [Gutachter] Boetius, and Ida Helene [Gutachter] Steen. "A novel mechanism for the anaerobic degradation of non-methane hydrocarbons in archaea / Rafael Laso Pérez ; Gutachter: Antje Boetius, Ida Helene Steen ; Betreuer: Antje Boetius." Bremen : Staats- und Universitätsbibliothek Bremen, 2018. http://d-nb.info/1186248777/34.

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45

Santos, Ligia Gibini dos. "Utilização de consórcio bacteriano para biodegradação de hidrocarbonetos aromáticos policíclicos em solo." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254773.

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Orientador: Lucia Regina Durrant, Matthew James Grossman<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos<br>Made available in DSpace on 2018-08-22T02:43:16Z (GMT). No. of bitstreams: 1 Santos_LigiaGibinidos_M.pdf: 3848321 bytes, checksum: 46f91a01a783f6fd7d5153ba73c6e8a0 (MD5) Previous issue date: 2013<br>Resumo: Dentre os contaminantes ambientais mais abundantes, destacam-se os Hidrocarbonetos aromáticos policíclicos (HAPs), que apresentam elevado potencial tóxico, sendo imprescindível sua remoção do ambiente. O objetivo deste trabalho foi analisar, em microcosmos, a biodegradação de HAPs por um consórcio bacteriano e identificar fatores que influenciam nesta degradação e na análise dos dados. A degradação dos HAPs no solo sem histórico de contaminação foi muito semelhante em todos os microcosmos, apresentando uma porcentagem de aproximadamente 85%. Para analisar a toxicidade do solo antes e depois da biorremediação, realizou-se um testes de germinação de sementes de Lactuca sativa (alface). O teste mostrou baixa toxicidade do solo após 80 dias da contaminação, com ou sem a adição do consórcio. Durante estudos de remediação biológica, é necessário utilizar um marcador interno para minimizar a dispersão e extração irregulares dos contaminantes. Neste estudo foi utilizado o hexaclorobenzeno, que mostrou excelente, uma vez que não sofreu nenhum tipo de degradação. Análises moleculares mostram que a adição de HAPs alterou significativamente a comunidade microbiana, favorecendo os membros degradadores de tais poluentes. O consórcio adicionado inibiu o crescimento de alguns micro-organismos autóctones. Além disso, não houveram evidências de que os micro-organismos degradadores de HAPs adicionados persistiram, sugerindo que eles podem não competir eficientemente com a população microbiana autóctone. Não houve efeito claramente identificado do hexaclorobenzeno sobre o crescimento de micro-organismos, com exceção de um aumento no número de organismos pertencentes da classe Alphaproteobacteria<br>Abstract: Polycyclic aromatic hydrocarbons (PAHs) stand out as among the most abundant and toxic of environmental contaminants, and their removal from contaminated sites is indispensable for a healthy environment. The objective of this study was to analyze, in soil microcosms, the biodegradation of PAHs by a bacterial PAH degrading consortium and identify factors that influence this degradation and data analysis. Degradation of PAHs in soil with no history of contamination was very similar in microcosms with or without bioaugmentation, with the extent of PAH removal of about 85% in all cases. The germination of Lactuca sativa (lettuce) in soils taken from the microcosms was used to examine the toxicity of the soil before and after bioremediation. The test showed a low toxicity of the soil 80 days after PAH contamination, with or without the addition of the consortium. During studies of biological remediation it is necessary to use an internal non-biodegradable marker to minimize the effect of uneven dispersion and irregular extraction of pollutants. This study used hexachlorobenzene as the nonbiodegradable marker and it proved to be an excellent marker as it did not suffer any significant degradation in the soil microcosms. Molecular analyzes showed that the addition of PAHs significantly altered the microbial community by encouraging the growth of PAH degraders. In addition, the added microbial consortium was found to inhibit the growth of some of the indigenous microorganisms. Furthermore, there was no evidence that the added PAH degraders persisted, suggesting that they might not compete effectively with the native microbial population. There was little effect of hexachlorobenzene on the microbial community or on the removal of the PAH contaminants, with the exception of an increase in the number of organisms belonging to the class Alphaproteobacteria<br>Mestrado<br>Ciência de Alimentos<br>Mestra em Ciência de Alimentos
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46

Sajja, Sarala Kumari. "Microbial Community Structure by Fatty Acid Analysis during Polycyclic Aromatic Hydrocarbon Degradation in River Sediment Augmented with Pleurotus ostreatus." Connect to resource online, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1211992408.

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47

Pandey, Dhurba Raj. "Degradation of Select Chlorinated Hydrocarbons by (i) Sulfide-Treated Hydrous Ferric Oxide (HFO) and (ii) Hydroxyl Radicals Produced in the Dark by Oxygenation of Sodium Dithionite-Reduced HFO." Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright1535462165887662.

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48

Araujo, Juliana Eschholz de. "Caracterização genômica e metabólica de Planctomycetes isolados de solos de manguezais brasileiros." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/11/11138/tde-10102018-171413/.

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Os Planctomycetes são bactérias que possuem características peculiares, ainda pouco conhecidas. São bactérias de difícil cultivo, sendo descritas em diversos ambientes, mas frequentemente isoladas de ambientes marinhos, principalmente em associações com algas. Aqui apresentamos um amplo estudo deste grupo em solos de manguezais, e reportamos de maneira inovadora o isolamento dessas bactérias. A comparação das comunidades de Planctomycetes em manguezais com diferentes históricos de contaminação permitiu fazer inferências sobre a resposta da comunidade ao ambiente. A análise de sequências pertencentes a este filo, obtidas a partir de amostras dos manguezais - tanto sequências do gene 16S DNAr ou sequências metagenômicas - permitiu inferir sobre a diversidade e as funções destes grupos nos solos dos manguezais estudados. Destacam-se dentre estas o aumento da biodiversidade deste grupo em áreas contaminadas, e as evidências de sua participação na degradação de xenobióticos (demonstrada por predição metagenômica baseada em biblioteca de 16S rDNA, e análise de sequencias metagenômicas). Com estes resultados, foram encontrados em dados metagenômicos, a ocorrência de genes envolvidos na biodegradação de compostos intermediários centrais das vias de degradação. Adicionalmente, mesmo com a dificuldade no cultivo de membros desse grupo, foram obtidos 43 isolados afiliados filogeneticamente principalmente às espécies Blastopirellula marina, Rhodopirellula baltica e Planctomycetes sp. e Pirellula. Foram selecionados dois isolados (Rhodopirellula sp. MGV e Rhodopirellula baltica BR-MGV) para estudos genômicos e metabólicos (via análise de consumo de diferentes fontes de carbono-Biolog). Além disso, foi realizado teste de degradação de hidrocarbonetos com os 43 isolados aferindo as respostas ao contato com contaminantes como hexadecano, naftaleno, fenantreno e fenol. Cinco isolados mostraram a capacidade em degradar três diferentes hidrocarbonetos exceto fenantreno. Estes isolados (Blastopirellula cremea Hex-1 MGV, Blastopirellula marina Nap-Phe MGV, Blastopirellula cremea Hex-2 MGV, Blastopirellula cremea Hex PRIS-MGV e Blastopirellula marina Nap PRIS-MGV) foram enviados a uma análise genômica e suas anotações indicaram a presença de genes envolvidos em vias de degradação de hidrocarbonetos corroborando com o teste realizado em laboratório de degradação dos hidrocarbonetos. Além disso, foi observada através das anotações dos genomas desses microrganismos a ocorrência de síntese de metabólitos secundários, sendo os principais terpenos, bacteriocinas e resorcinol.<br>Planctomycetes are bacteria with peculiar characteristics and still little known. They are bacteria of difficult cultivation, being described in diverse environments, but often isolated from marine environments, mainly in associations with algae. Here we present an extensive study of this group in mangrove soils and report in an innovative way the isolation of these bacteria. The comparison of the communities of Planctomycetes in mangroves with different contamination histories allowed to make inferences about the response of the community to the environment. The analysis of sequences from this phylum, obtained from samples of the mangroves - both sequences of the 16S DNAr gene or metagenomic sequences - allowed to infer about the diversity and the functions of these groups in the mangrove soils studied. The highlights are the increase of this group\'s biodiversity in contaminated areas, and evidence of its participation in the degradation of xenobiotics (demonstrated by 16S rDNA library-based metagenomic prediction and metagenomic sequence analysis). With these results, the occurrence of genes involved in the biodegradation of central intermediates of the degradation pathways was found in metagenomic data. In addition, even with the difficulty in the cultivation of members of this group, 43 isolates belonging to this phylum were obtained phylogenetically, mainly the species Blastopirellula marina, Rhodopirellula baltica and Planctomycetes sp. and Pirellula. Two isolates (Rhodopirellula sp. MGV and Rhodopirellula baltica BR-MGV) were selected for genomic and metabolic studies (via consumption analysis of different sources of carbon-Biolog). Furthermore, a hydrocarbon degradation test was performed with this library of 43 isolates, assessing the responses to contact with contaminants such as hexadecane, naphthalene, phenanthrene and phenol. Five isolates showed the ability to degrade three different hydrocarbons except phenanthrene. These isolates (Blastopirellula cremea Hex-1 MGV, Blastopirellula marina Nap-Phe MGV, Blastopirellula cremea Hex-2 MGV, Blastopirellula cremea Hex PRIS-MGV and Blastopirellula marina Nap PRISMGV) were sent to a genomic analysis and their notes indicated the presence of genes involved in hydrocarbon degradation pathways, corroborating with the laboratory test for hydrocarbon degradation. In addition, the synthesis of secondary metabolites was evaluated through the annotations of the genomes of these microorganisms, being the main terpenes, bacteriocins and resorcinol.
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49

Hussein, Emad Ibraheim. "Investigation into the mechanism(s) which permit the high-rate, degradation of PAHS and related petroleum hydrocarbons in sequencing batch reactors by attached cells in a controlled mixed bacterial community." unrestricted, 2006. http://etd.gsu.edu/theses/available/etd-12012006-073228/.

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Thesis (Ph. D.)--Georgia State University, 2006.<br>Title from title screen. George E. Pierce,committee chair; Eric S. Gilbert, Sidney A. Crow, committee members. Electronic text (135 p. : ill. (some col.)) : digital, PDF file. Description based on contents viewed Aug. 20, 2007. Includes bibliographical references (p. 120-124).
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50

Stallwood, Bethan. "Hydrocarbon-degradation by bacteria from Antarctica." Thesis, Bangor University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275134.

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