Initial reactions in the bacterial degradation of aromatic hydrocarbons.

Bacteria incorporate two atoms of molecular oxygen into aromatic hydrocarbons with the formation of cis dihydrodiols. The production of cis dihydrodiols has been demonstrated for substrates that range in size from benzene to benzo[a]pyrene. These results are in direct contrast to the mechanisms utilized by mammals, and possibly all eucaryotic organisms, for the oxidation of aromatic hydrocarbons. Thus, mammals incorporate one atom of molecular oxygen into these substrates to form arene oxides. Hydration of the latter compounds produces dihydrodiols that have a trans stereochemistry.