Anaerobic degradation of toluene and o-xylene by a methanogenic consortium

Journal Article · Sat Jan 01 04:00:00 EST 1994 · Applied and Environmental Microbiology; (United States)

OSTI ID:7104428

Edwards, E A; Grbic-Galic, D ^[1]

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1. Stanford Univ., CA (United States)

Toluene and o-xylene were completely mineralized to stoichiometric amounts of carbon dioxide, methane, and biomass by aquifer-derived microorganisms under strictly anaerobic conditions. The source of the inoculum was creosote-contaminated sediment from Pensacola, Fla. The adaptation periods before the onset of degradation were long (100 to 120 days for toluene degradation and 200 to 255 days for o-xylene). Successive transfers of the toluene- and o-xylene-degrading cultures remained active. Cell density in the cultures progressively increased over 2 to 3 years to stabilize at approximately 10[sup 9] cells per ml. Degradation of toluene and o-xylene in stable mixed methanogenic cultures followed Monod kinetics, with inhibition noted at substrate concentrations above about 700 [mu]M for o-xylene, and 1,800 [mu]M for toluene. The cultures degraded toluene or o-xylene but did not degrade m-xylene, p-xylene, benzene, ethylbenzene, or naphthalene. The degradative activity was retained after pasteurization or after starvation for 1 year. Degradation of toluene and o-xylene was inhibited by the alternate electron acceptors oxygen, nitrate, and sulfate. Degradation was also inhibited by the addition of preferred substrates such as acetate, H[sub 2] propionate, methanol, acetone, glucose, amino acids, fatty acids, peptone, and yeast extract. These data suggest that the presence of natural organic substrates or cocontaminants may inhibit anaerobic degradation of pollutants such as toluene and o-xylene at contaminated sites.

• OSTI ID: 7104428
• Journal Information: Applied and Environmental Microbiology; (United States), Journal Name: Applied and Environmental Microbiology; (United States) Vol. 60:1; ISSN AEMIDF; ISSN 0099-2240
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKYLATED AROMATICS
ANAEROBIC CONDITIONS
AROMATICS
BACTERIA
BIODEGRADATION
CHEMICAL REACTIONS
DECOMPOSITION
HYDROCARBONS
METHANOGENIC BACTERIA
MICROORGANISMS
ORGANIC COMPOUNDS
TOLUENE