Bacterial Degradation of Ring-Chlorinated Acetophenones

Abstract

Two strains, Alcaligenes sp. strain ACA and Pseudomonas fluorescens ACB, isolated from acetophenone and 4′-hydroxyacetophenone enrichments, respectively, cometabolize a range of chlorinated acetophenones (CAs). A biological Baeyer-Villiger reaction converts the CA to chlorophenyl acetate. This is evident only in the presence of an esterase inhibitor, since the CA is normally rapidly hydrolyzed to a chlorophenol which has the same substitution pattern as the original ketone. The oxygenase that attacks the ketone uses NADPH in the incorporation of one atom of 18 O 2 and is strongly inhibited by phenols that bear an ortho or meta chlorine or bromine, but much less by cresols or phenol itself. A feedback phenomenon may thus account for the inability of strain ACA to grow on CAs, which also fail to induce the cells for their own metabolism.