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Title: Evidence for para dechlorination of polychlorobiphenyls by methanogenic bacteria

Abstract

When microorganisms eluted from upper Hudson River sediment were cultured without any substrate except polychlorobiphenyl (PCB)-free Hudson River sediment, methane formation was the terminal step of the anaerobic food chain. In sediments containing Aroclor 1242, addition of eubacterium-inhibiting antibiotics, which should have directly inhibited fermentative bacteria and thereby should have indirectly inhibited methanogens, resulted in no dechlorination activity or methane production. However, when substrates for methanogenic bacteria were provided along with the antibiotics (to free the methanogens from dependence on eubacteria), concomitant methane production and dechlorination of PCBs were observed. The dechlorination of Aroclor 1242 was from the para positions, a pattern distinctly different from, and more limited than, the pattern observed with untreated or pasteurized inocula. Both methane production and dechlorination in cultures amended with antibiotics plus methanogenic substrates were inhibited by 2-bromoethanesulfonic acid. These results suggest that the methanogenic bacteria are among the physiological groups capable of anaerobic dechlorination of PCBs, but that the dechlorination observed with methanogenic bacteria is less extensive than the dechlorination observed with more complex anaerobic consortia. 27 refs., 5 figs., 1 tab.

Authors:
; ;  [1]
  1. Michigan State Univ., East Lansing, MI (United States) [and others
Publication Date:
OSTI Identifier:
98638
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied and Environmental Microbiology; Journal Volume: 61; Journal Issue: 6; Other Information: PBD: Jun 1995
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 55 BIOLOGY AND MEDICINE, BASIC STUDIES; METHANOGENIC BACTERIA; BIOLOGICAL PATHWAYS; POLYCHLORINATED BIPHENYLS; DECHLORINATION

Citation Formats

Ye, D., Quensen, J.F., and Tiedje, J.M.. Evidence for para dechlorination of polychlorobiphenyls by methanogenic bacteria. United States: N. p., 1995. Web.
Ye, D., Quensen, J.F., & Tiedje, J.M.. Evidence for para dechlorination of polychlorobiphenyls by methanogenic bacteria. United States.
Ye, D., Quensen, J.F., and Tiedje, J.M.. 1995. "Evidence for para dechlorination of polychlorobiphenyls by methanogenic bacteria". United States. doi:.
@article{osti_98638,
title = {Evidence for para dechlorination of polychlorobiphenyls by methanogenic bacteria},
author = {Ye, D. and Quensen, J.F. and Tiedje, J.M.},
abstractNote = {When microorganisms eluted from upper Hudson River sediment were cultured without any substrate except polychlorobiphenyl (PCB)-free Hudson River sediment, methane formation was the terminal step of the anaerobic food chain. In sediments containing Aroclor 1242, addition of eubacterium-inhibiting antibiotics, which should have directly inhibited fermentative bacteria and thereby should have indirectly inhibited methanogens, resulted in no dechlorination activity or methane production. However, when substrates for methanogenic bacteria were provided along with the antibiotics (to free the methanogens from dependence on eubacteria), concomitant methane production and dechlorination of PCBs were observed. The dechlorination of Aroclor 1242 was from the para positions, a pattern distinctly different from, and more limited than, the pattern observed with untreated or pasteurized inocula. Both methane production and dechlorination in cultures amended with antibiotics plus methanogenic substrates were inhibited by 2-bromoethanesulfonic acid. These results suggest that the methanogenic bacteria are among the physiological groups capable of anaerobic dechlorination of PCBs, but that the dechlorination observed with methanogenic bacteria is less extensive than the dechlorination observed with more complex anaerobic consortia. 27 refs., 5 figs., 1 tab.},
doi = {},
journal = {Applied and Environmental Microbiology},
number = 6,
volume = 61,
place = {United States},
year = 1995,
month = 6
}
  • Tetrachloroethylene (perchloroethylene, PCE) is widely used in many industries and particularly as a degreasing and dry-cleaning solvent. It is commonly found as a groundwater contaminant and because of its carcinogenic properties is considered a pollutant, which must be eliminated by proper treatment. This research examines the role of a mixed culture in PCE dechlorination at high concentration from an ecological point of view. The respective role of sulfate-reducing and methaogenic bacteria in tetrachloroethylene cechlorination is studied. 19 refs., 5 figs., 2 tabs.
  • Although abundant geochemical data indicate that anaerobic methane oxidation occurs in marine sediments, the linkage to specific microorganisms remains unclear. In order to examine processes of methane consumption and oxidation, sediment samples from mud volcanoes at two distinct sites on the Mediterranean consumption and oxidation, sediment samples from mud volcanoes at two distinct sites on the Mediterranean Ridge were collected via the submersible Nautile. Geochemical data strongly indicate that methane is oxidized under aerobic conditions, and compound-specific carbon isotope analyses indicate that methane is oxidized under anaerobic conditions, and compound-specific carbon isotope analyses indicate that this reaction is facilitated bymore » a consortium of archaea and bacteria. Specifically, these methane-rich sediments contain high abundances of methanogen-specific biomarkers that are significantly depleted in {sup 13}C ({delta}{sup 13}C values are as low as {minus}95%). Biomarkers inferred to derive from sulfate-reducing bacteria and other heterotrophic bacteria are similarly depleted. Consistent with previous work, such depletion can be explained by consumption of {sup 13}C-depleted methane by methanogens operating in reverse and as part a consortium of organisms in which sulfate serves as the terminal electron acceptor. Moreover, their results indicate that this process is widespread in Mediterranean mud volcanoes and in some localized settings in the predominant microbiological process.« less
  • Photodechlorination of Aroclor 1254 (1000 mg/L) in an alkaline 2-propanol solution at [lambda] = 254 nm proceeded with a high quantum yield ([Phi] = 35.0) as determined by Cl[sup [minus]] release. The Aroclor was completely dechlorinated in 30 min and gave predominantly biphenyl (BP). After 20 h of solar irradiation, only partial dechlorination (25%) was observed, and no BP was formed. In the presence of phenothiazine (PT) sensitizer (5 mM) Aroclor was completely dechlorinated to BP in 1 h at 350 nm ([Phi] = 2.33) and in 4 h by exposure to sunlight. Under the same conditions, Aroclor 1254 extractsmore » of contaminated soil (730 mg/L) were dechlorinated in 2 h at 350 nm ([Phi] = 0.28) and in 20 h on exposure to sunlight. The photoreaction was completely quenched by oxygen and nitrobenzene (0.1 M). Moreover, Aroclor was thermally (ca. 80 [degrees]C) dechlorinated to BP using di-tert-butyl peroxide. A free-radical chain reaction was suggested in which the aryl radical anion, Ar[sup [sm bullet][minus]]-Cl, was a key intermediate in the dechlorination process. 30 refs., 2 figs., 2 tabs.« less
  • A polychlorobiphenyl (PCB)-dechlorinating inoculum eluted from upper Hudson River sediments was treated with either heat or ethanol or both. The treated cultures retained the ability to dechlorinate PCBs (Aroclor 1242) under strictly anaerobic conditions. The dechlorination activity was maintained in serial cultures inoculated with transfers of 1% inoculum when the transferred inoculum was treated each time in the same manner. No methane production was detected in any treated culture, although dechlorination of PCBs in the untreated cultures was always accompanied by methane production. All treated cultures preferentially removed meta chlorines, yielding a dechlorination pattern characterized by accumulation of certain ortho-more » and para-substituted congeners such as 2-4-chlorobiphenyl (2-4-CB), 2,4-2-CB, and 2,4-4-CB. In contrast, the untreated cultures showed more extensive dechlorination activities, which almost completely removed both meta and para chlorines from Aroclor 1242. These results suggest that microorganisms responsible for the dechlorination of PCBs in the upper Hudson River sediments can be grouped into two populations according to their responses to the heat and ethanol treatments. Microorganisms surviving the heat and ethanol treatments preferentially remove meta chlorines, while microorganisms lost from the enrichment mainly contribute to the para dechlorination activity. These results indicate that anaerobic sporeformers are at least one of the physiological groups responsible for the reductive dechlorination of PCBs.« less
  • Dechlorination of (PCB Aroclor 1242) by pasteurized microorganisms was inhibited by 2-bromoethanesulfonate (BES), sulfate, molybdate, and ethanesulfonate. Consumption of these anions and production of sulfide from BES were detected. The inhibition could not be relieved by hydrogen. Taken together these results suggest that pattern M dechlorination is mediated by spore-forming sulfidogenic bacteria. These results also suggest that BES may inhibit anaerobic dechlorination by nonmethanogens by more than one mechanism.