Hydrocarbon cooxidation in microbial systems

This review summarizes the present status of hydrocarbon cooxidation in microorganisms. Hydrocarbons, which cannot be used for growth by many soil microorganisms, can be oxidized if present as co‐substrates in systems in which another substrate is furnished for growth. Paraffinic, cycloparaffinic and aromatic hydrocarbon cooxidations have been demonstrated. Most hydrocarbon cooxidation reactions seem to involve the incorporation of molecular oxygen by mono‐ and dioxygenases. From paraffinic hydrocarbons, products accumulating in fermentation systems include acids, alcohols, aldehydes and ketones. Usually, the initial attack is at the terminal methyl group in paraffin oxidations. The only products isolated in the cycloparaffins have been ketones. Extensive studies have been carried out on cooxidation of mono‐ and dicyclic aromatic hydrocarbons. Oxidation of methyl substituents on aromatic rings usually results in the accumulation of the aromatic mono acid or alcohol. Dihydroxylation of the aromatic ring has been observed. Products of aromatic ring rupture arise via both ortho and meta cleavage pathways.