Anaerobic degradation of toluene and o-xylene by a methanogenic consortium
- 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), Vol. 60:1; ISSN 0099-2240
- Country of Publication:
- United States
- Language:
- English
Similar Records
Transformation of non-oxygenated, homocyclic aromatic compounds by aquifer microorganisms under methanogenic and sulfate-reducing conditions
Anaerobic microbial transformation of aromatic hydrocarbons and mixtures of aromatic hydrocarbons and halogenated solvents. Final report, 30 September 1988-31 March 1992
Related Subjects
METHANOGENIC BACTERIA
ANAEROBIC CONDITIONS
TOLUENE
BIODEGRADATION
ALKYLATED AROMATICS
AROMATICS
BACTERIA
CHEMICAL REACTIONS
DECOMPOSITION
HYDROCARBONS
MICROORGANISMS
ORGANIC COMPOUNDS
560300* - Chemicals Metabolism & Toxicology