Oxidation of the Carcinogens Benzo[a]pyrene and Benzo[a]anthracene to Dihydrodiols by a Bacterium

A mutant strain of Beijerinckia, after growth with succinate plus diphenyl, contains an enzyme system that oxidizes benzo[a]pyrene and benzo[a]anthracene to mixtures of vicinal dihydrodiols. The major dihydrodiol formed from benzo[a]pyrene was identified as cis-9,10-dihydroxy-9,10-dihydrobenzo[a]pyrene by comparison with a synthetic sample. Benzo[a]anthracene was metabolized to four dihydrodiols, the major isomer being cis-1,2-dihydroxy-1,2-dihydrobenzo[a]anthracene.