EVIDENCE FOR CHLORINE MIGRATION DURING OXIDATION OF 2-CHLOROBIPHENYL BY A TYPE-II METHANOTROPH

Axenic methanotrophic culture strain CSC1, which was derived from a mi xed-culture aquifer sample, oxidized 2-chlorobiphenyl to a hydroxylate d 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 migr ation during oxidation indicates that the metabolite is formed via a c oncerted oxidation mechanism involving an arene oxide, which rearrange s spontaneously to the hydroxylated intermediate via an NIH shift mech anism.