Hydrocarbon cooxidation in microbial systems

Abstract

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.

Microbial conversion of ethylbenzene to 1-phenethanol and acetophenone by Nocardia tartaricans ATCC 31190

“…The biologically catalyzed production of industrial chemicals from petroleum-based raw materials provides a promising concept currently under study. Typifying the results of this research are the variety of oxidation products formed during metabolism of alkylbenzenes by bacteria and fungi (3,6,9). For example, Davis, Raymond, and co-workers (3,6) reported the production of phenylacetic acid from ethyland butylbenzene by species of Norcardia growing on aliphatic hydrocarbons.…”

Polycyclic Aromatic Hydrocarbons and Azaaromatic Compounds

“…It accumulates in shrimp, clams, and other marine species. Dimethyl derivatives with 2-position occupancy were oxidized to the acid by Nocardia species (86). The oral toxicity in the rat appeared lower for the 1,6-dimethyl derivative than for the monomethyls (14).…”

“…The toxicity and the bioaccumulation increase with molecular weight. Nocardia cultures, isolated from soil, preferentially oxidized alkylnaphthalenes when methylated in the two positions (86). Methylnaphthalene can occur as the 1-or 2-, the alpha or the beta isomer.…”

“…Of the methyl derivatives, Nocardia cultures oxidized only the 2-methyl isomer (86). The major metabolite of 1-and 2-methylnaphthalene by Cunninghamella elegans is 1-and 2-hydroxymethylnaphthalene (95).…”

Citrate production from hydrocarbons by use of a nonsterile, semicontinuous cell recycle system

“…Kitai et a1. * and Raymond et al 9 reported the incorporation of ion-exchange resin into culture media to "trap" toxic fermentation products in their hydrocarbon fermentations. Removal of the product in these cases permitted its continued synthesis.…”