Evidence for novel mechanisms of polychlorinated biphenyl metabolism in Alcaligenes eutrophus H850
Previous studies indicated that Alcaligenes eutrophus H850 attacks a different spectrum of polychlorinated biphenyl (PCB) congeners than do most PCB-degrading bacteria and that novel mechanisms of PCB degradation might be involved. To delineate this, the authors have investigated the differences in congener selectivity and metabolite production between H850 and Corynebacterium sp. strain MB1, an organism that apparently degrades PCBs via a 2,3-dioxygenase. H850 exhibited a superior ability to degrade congeners via attack on 2-, 2,4-, 2,5-, or 2,4,5-chlorophenyl rings in PCBs but an inferior ability to degrade congeners via attack on a 4-chlorophenyl ring. Reactivity preferences were also reflected in the products formed from unsymmetrical PCBs; thus, MB1 attacked the 2,3-chlorophenyl ring of 2,3,2',5'-tetrachlorobiphenyl to yield 2,5-dichlorobenzoic acid, while H850 attacked the 2,5-chlorophenyl ring to yield 2,3-dichlorobenzoic acid and a novel metabolite, 2',3'-dichloroacetophenone. Furthermore, H850 oxidized 2,4,5,2',4',5'-hexachlorobiphenyl, a congener with no adjacent unsubstituted carbons, to 2',4',5'-trichloroacetophenone. The atypical congener selectivity pattern and novel metabolites produced suggest that A. eutrophus H850 may degrade certain PCB congeners by a new route beginning with attack by some enzyme other than the usual 2,3-dioxygenase.
- Research Organization:
- GE Research and Development Center, Schenectady, NY
- OSTI ID:
- 6351118
- Journal Information:
- Appl. Environ. Microbiol.; (United States), Vol. 53:5
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BACTERIA
GROWTH
CHLORINATED AROMATIC HYDROCARBONS
METABOLISM
BIOLOGICAL PATHWAYS
BIOLOGICAL VARIABILITY
COMPARATIVE EVALUATIONS
METABOLITES
OXYGENASES
AROMATICS
ENZYMES
HALOGENATED AROMATIC HYDROCARBONS
MICROORGANISMS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXIDOREDUCTASES
560300* - Chemicals Metabolism & Toxicology