Evidence for Chlorine Migration during Oxidation of 2-Chlorobiphenyl by a Type II Methanotroph

Axenic methanotrophic culture strain CSC1, which was derived from a mixed-culture aquifer sample, oxidized 2-chlorobiphenyl to a hydroxylated chlorobiphenyl intermediate identified as 2-hydroxy-3-chlorobiphenyl. Minor amounts of another hydroxylated chlorobiphenyl isomer, assumed to be the nonmigrated product 3-hydroxy-2-chlorobiphenyl, were found in axenic culture incubation extracts. The occurrence of chlorine migration during oxidation indicates that the metabolite is formed via a concerted oxidation mechanism involving an arene oxide, which rearranges spontaneously to the hydroxylated intermediate via an NIH shift mechanism.