The metabolism of 3-cyclohexenecarboxylic acid by Alcaligenes faecalis

Abstract

Alcaligenes faecalis, grown on 3-cyclohexenecarboxylic acid supplemented with gluconate, was induced to metabolize cyclohexanecarboxylic acid, 3-cyclohexenecarboxylic acid, 1, 4-cyclohexadienecarboxylic acid, benzoic acid, and catechol. During growth, 1, 4-cyclohexadienecarboxylic acid, 3-heptene-1, 7-dioic acid, and benzoic acid were shown to be present in the culture supernatants. The results suggest that 3-cyclohexenecarboxylic acid may be metabolized by two pathways having 1, 4-cyclohexadienecarboxylic acid as a common intermediate. One pathway involved β-oxidation of coenzyme A intermediates; the other pathway involved benzoic acid as an intermediate. Studies on the consumption of oxygen per mole of substrate by cell suspensions indicated that the major portion of 3-cyclohexenecarboxylic acid was metabolized by the pathway involving benzoic acid. When grown on 3-cyclohexenecarboxylic acid as sole carbon and energy source, the organism was additionally induced to metabolize salicylic acid and gentisic acid, and growth medium contained salicylic acid. Thus, under the latter growth conditions a pathway involving salicylic acid as an intermediate was also induced.