Biodegradation of polychlorinated methanes in methanogenic systems. Annual report, 1 Dec 88-1 Mar 89
This research investigated biodegradation of several halogenated methanes under methanogenic conditions. Biodegradation of dichloromethane to C02 and acetic acid (both environmentally acceptable products) was demonstrated in a fixed-film reactor, operated at 20 deg C, a residence time as low as 0.25 day, and an influent concentration of 91 micro M. The biodegradability of chloroform was examined in a dichloromethane-degrading enrichment culture. Sustained consumption of chloroform (approximately 8.5 micron M) was achieved only when vitamin B 12 was also added. Initially, equimolar amounts of chloroform and B 12 were added; when the amount of B 12 added was gradually decreased to zero, chloroform degradation continued at the same rapid rate. Biodegradation of 14C chloroform yielded approximately 77% C02, 10% carbon monoxide, 7% soluble compounds (about 15% of which consisted of acetate), and 2% nonsoluble compounds; no 14CH4 was formed. Brominated methanes (dibromomethane, bromochloromethane, and bromomethane) degraded much more slowly' if at all, than dichloromethane, they inhibited methanogenesis and dichloromethane degradation. Sustained degradation of chloromethane was demonstrated for an extended period without the need for an electron donor. Preliminary results suggest chloromethane serves as an electron donor under methanogenic conditions, just as dichloromethane does. Biotransformation of carbon tetrachloride was also demonstrated in the dichloromethane-degrading enrichment culture.
- Research Organization:
- Illinois Univ., Urbana, IL (United States). Dept. of Civil and Environmental Engineering
- OSTI ID:
- 7004551
- Report Number(s):
- AD-A-254605/9/XAB; CNN: AFOSR-89-0189
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CHLORINATED ALIPHATIC HYDROCARBONS
BIODEGRADATION
ACETATES
BIOREACTORS
CARBON 14 COMPOUNDS
CARBON MONOXIDE
TRACER TECHNIQUES
VITAMIN B-12
CARBON COMPOUNDS
CARBON OXIDES
CARBOXYLIC ACID SALTS
CHALCOGENIDES
CHEMICAL REACTIONS
DECOMPOSITION
DRUGS
HALOGENATED ALIPHATIC HYDROCARBONS
HEMATINICS
HEMATOLOGIC AGENTS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
VITAMIN B GROUP
VITAMINS
560300* - Chemicals Metabolism & Toxicology