Influence of incubation temperature on the microbial reductive dechlorination of 2,3,4,6-tetrachlorobiphenyl in two freshwater sediments

Wu, Qingzhong; Bedard, Donna L.; Wiegel, Juergen

doi:10.1128/aem.62.11.4174-4179.1996

Cited by 41 publications

(42 citation statements)

References 29 publications

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“…Several investigations into the effect of temperature on degradation rates in cold and hot environments were performed (Backman & Jansson, 2005;Coulon et al, 2005;Leven & Schnurer, 2005;Polymenakou & Stephanou, 2005). Most studies concluded that degradation is preferably performed at higher temperatures, probably by stimulating the enzymes involved in the degradation process (Kohring et al, 1989;Wu et al, 1996). The metabolites of polycyclic aromatic hydrocarbon degradation under thermophilic and mesophilic conditions were shown to be different as a result of the influence of temperature on enzyme activity (Müller et al, 1998;Annweiler et al, 2000).…”

Section: Effect Of Temperature On Oil Biodegradationmentioning

confidence: 99%

Bacterial diversity of a cyanobacterial mat degrading petroleum compounds at elevated salinities and temperatures

Abed

Al‐Thukair

Beer

2006

FEMS Microbiology Ecology

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Cyanobacterial mats of the Arabian Gulf coast of Saudi Arabia experience extreme conditions of temperature and salinity. Because they are exposed to continuous oil pollution, they form ideal models for biodegradation under extreme conditions. We investigated the bacterial diversity of these mats using denaturing gradient gel electrophoresis and 16S rRNA cloning, and tested their potential to degrade petroleum compounds at various salinities (fresh water to 16%) and temperatures (5 to 50 degrees C). Cloning revealed that c. 15% of the obtained sequences were related to unknown, possibly novel bacteria. Bacteria belonging to Beta-, Gamma- and Deltaproteobacteria, Cytophaga-Flavobacterium-Bacteroides group and Spirochetes, were detected. The biodegradation of petroleum compounds at different salinities by mat microorganisms showed that pristine and n-octadecane were optimally degraded at salinities between 5 and 12% (weight per volume NaCl) whereas the optimum degradation of phenanthrene and dibenzothiophene was at 3.5% salinity. The latter compounds were also degradable at 8% salinity. The same compounds were degraded at temperatures between 15 and 40 degrees C but not at 5 and 50 degrees C. The optimum temperature of degradation was 28-40 degrees C for both aliphatics and aromatics. We conclude that the studied microbial mats from Saudi Arabia are rich in novel halotolerant and thermotolerant microorganisms with the potential to degrade petroleum compounds at elevated salinities and temperatures.

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Section: Effect Of Temperature On Oil Biodegradationmentioning

confidence: 99%

Bacterial diversity of a cyanobacterial mat degrading petroleum compounds at elevated salinities and temperatures

Abed

Al‐Thukair

Beer

2006

FEMS Microbiology Ecology

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“…In the laboratory, dechlorination activity of PCBs in uncontaminated sediments was also detected after PCBs were added to the sediments (Table 1). Presumably due to environmental selections, microbial communities in PCB-contaminated sites are better adapted for the PCB dechlorination than those from environments containing no or only traces of PCBs [42,49]. For example, a higher dechlorination rate (46 versus 16 Wmol l 31 day 31 ) and a higher extent of dechlorination (1.6+0.1 versus 2.1 total chlorines per biphenyl remaining after 1 year of incubation) were observed for the dechlorination of the supplemented tetrachlorobiphenyl 2,3,4,6-CB to trichlorobiphenyls in microcosms from a contaminated Woods Pond (MA, USA) grab sample versus from a non-contaminated site (a small pond in a wooded area of the Sandy Creek Nature Park, Athens, GA, USA) [42].…”

Section: Anaerobic Dechlorination Of Pcbsmentioning

confidence: 99%

“…Presumably due to environmental selections, microbial communities in PCB-contaminated sites are better adapted for the PCB dechlorination than those from environments containing no or only traces of PCBs [42,49]. For example, a higher dechlorination rate (46 versus 16 Wmol l 31 day 31 ) and a higher extent of dechlorination (1.6+0.1 versus 2.1 total chlorines per biphenyl remaining after 1 year of incubation) were observed for the dechlorination of the supplemented tetrachlorobiphenyl 2,3,4,6-CB to trichlorobiphenyls in microcosms from a contaminated Woods Pond (MA, USA) grab sample versus from a non-contaminated site (a small pond in a wooded area of the Sandy Creek Nature Park, Athens, GA, USA) [42]. PCB-dechlorinating organisms are apparently only present in low numbers in PCB-non-contami-nated sites, as is also suggested by the observed longer lag times before dechlorination was observed [42,49].…”

Section: Anaerobic Dechlorination Of Pcbsmentioning

confidence: 99%

Microbial reductive dehalogenation of polychlorinated biphenyls

Wiegel¹,

Wu²

2000

FEMS Microbiology Ecology

293

139

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Under anaerobic conditions, microbial reductive dechlorination of polychlorinated biphenyls (PCBs) occurs in soils and aquatic sediments. In contrast to dechlorination of supplemented single congeners for which frequently ortho dechlorination has been observed, reductive dechlorination mainly attacks meta and/or para chlorines of PCB mixtures in contaminated sediments, although in a few instances ortho dechlorination of PCBs has been observed. Different microorganisms appear to be responsible for different dechlorination activities and the occurrence of various dehalogenation routes. No axenic cultures of an anaerobic microorganism have been obtained so far. Most probable number determinations indicate that the addition of PCB congeners, as potential electron acceptors, stimulates the growth of PCB-dechlorinating microorganisms. A few PCB-dechlorinating enrichment cultures have been obtained and partially characterized. Temperature, pH, availability of naturally occurring or of supplemented carbon sources, and the presence or absence of H(2) or other electron donors and competing electron acceptors influence the dechlorination rate, extent and route of PCB dechlorination. We conclude from the sum of the experimental data that these factors influence apparently the composition of the active microbial community and thus the routes, the rates and the extent of the dehalogenation. The observed effects are due to the specificity of the dehalogenating bacteria which become active as well as changing interactions between the dehalogenating and non-dehalogenating bacteria. Important interactions include the induced changes in the formation and utilization of H(2) by non-dechlorinating and dechlorinating bacteria, competition for substrates and other electron donors and acceptors, and changes in the formation of acidic fermentation products by heterotrophic and autotrophic acidogenic bacteria leading to changes in the pH of the sediments.

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“…First, Lake Hartwell is considerably warmer than other freshwater environments in which in situ dechlorination has been evaluated, having an annual water temperature ranging from 14 to 30°C. Laboratory studies with contaminated and spiked sediments have shown that temperature can exert an impact on the nature and extent of PCB dechlorination [10–13]. Second, PCBs are the only major contaminant in Lake Hartwell sediment [14] in contrast to other sites where PCBs are present with other contaminants, such as oils or polynuclear aromatic hydrocarbons [1,15–17].…”

Section: Introductionmentioning

confidence: 99%

Reductive dechlorination of polychlorinated biphenyls in sediment from the Twelve Mile Creek arm of Lake Hartwell, South Carolina, USA

Pakdeesusuk

Freedman

Lee

et al. 2003

Environmental Toxicology and Chemistry

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Lake Hartwell is a U.S. Army Corps of Engineers reservoir system located on the state line between South Carolina and Georgia, USA. The lake was contaminated with an estimated 200 metric tons of polychlorinated biphenyls ([PCBs]; mainly Aroclor 1016 and 1254), and the entire Twelve Mile Creek watershed and the Seneca River arm of Lake Hartwell were placed on the National Priorities List. Monitored natural attenuation was chosen as a remedy for the contaminated sediment. The relatively warm temperature of Lake Hartwell and lack of significant cocontaminants along with the PCBs distinguish this site from others that have been studied for microbially mediated reductive dechlorination. Microcosm studies were conducted with sediment from two locations in the Twelve Mile Creek arm and confirmed the presence of indigenous microorganisms capable of reductively dechlorinating Aroclor 1254, which contains predominantly tetra-, penta-, and hexachlorobiphenyl. The average number of total chlorines per biphenyl decreased from 4.8 to 4.9 to 2.9 to 3.0, following 250 to 260 d of incubation. The maximum observed dechlorination rates were 0.29 to 0.87 microg-atoms Cl- per gram sediment dry weight per week. The onset of dechlorination activity correlated strongly with maximum methanogenesis, which occurred without a lag in samples from the site that showed signs of in situ fermentation activity. Dechlorination occurred primarily at the meta and para positions (58-63% removal), with no apparent decrease in ortho chlorines. This most closely resembles pattern M, characterized by preferential removal of unflanked and flanked meta chlorines. The microcosm results are consistent with sediment cores analyzed from the same locations, which indicate accumulation with depth of the same ortho- and para-substituted congeners. It therefore appears that the success of monitored natural attenuation for Lake Hartwell will hinge on covering the recalcitrant PCBs with a sufficient amount of uncontaminated sediment to isolate them from the food chain.

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Influence of incubation temperature on the microbial reductive dechlorination of 2,3,4,6-tetrachlorobiphenyl in two freshwater sediments

Cited by 41 publications

References 29 publications

Bacterial diversity of a cyanobacterial mat degrading petroleum compounds at elevated salinities and temperatures

Bacterial diversity of a cyanobacterial mat degrading petroleum compounds at elevated salinities and temperatures

Microbial reductive dehalogenation of polychlorinated biphenyls

Reductive dechlorination of polychlorinated biphenyls in sediment from the Twelve Mile Creek arm of Lake Hartwell, South Carolina, USA

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