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Bacterial degradation of ring-chlorinated acetophenones
1Department of Soil and Environmental Science, University of California, Riverside, California 92521.
Applied and Environmental Microbiology
|December 1, 1990
Summary
Two bacterial strains cometabolize chlorinated acetophenones (CAs) via a biological Baeyer-Villiger reaction, forming chlorophenyl acetate. This pathway is hindered by rapid hydrolysis and feedback inhibition, preventing bacterial growth on CAs.
Area of Science:
- Microbial metabolism
- Biocatalysis
- Environmental microbiology
Background:
- Chlorinated acetophenones (CAs) are environmental contaminants.
- Microbial degradation pathways for CAs are not fully understood.
- Cometabolism plays a role in the transformation of xenobiotics.
Purpose of the Study:
- To investigate the microbial metabolism of chlorinated acetophenones.
- To elucidate the biochemical pathway involved in CA transformation.
- To identify bacterial strains capable of CA cometabolism.
Main Methods:
- Isolation and characterization of bacterial strains from enrichment cultures.
- Enzymatic assays to determine metabolic pathways.
- Use of esterase inhibitors to study reaction intermediates.
- Investigating the effect of phenols on oxygenase activity.
Main Results:
- Two bacterial strains, Alcaligenes sp. strain ACA and Pseudomonas fluorescens ACB, were identified.
- These strains cometabolize various CAs via a biological Baeyer-Villiger reaction, producing chlorophenyl acetate.
- The reaction is dependent on an esterase inhibitor, as CAs are typically hydrolyzed to chlorophenols.
- The responsible oxygenase is NADPH-dependent and sensitive to chlorinated phenols, suggesting feedback inhibition.
Conclusions:
- Bacterial strains ACA and ACB can cometabolize CAs through a Baeyer-Villiger oxidation.
- Hydrolysis and feedback inhibition limit the direct growth of these bacteria on CAs.
- Understanding these pathways is crucial for bioremediation strategies.