The microbial degradation of cyclohexanecarboxylic acid by a β-oxidation pathway with simultaneous induction to the utilization of benzoate

Abstract

The metabolism of cyclohexanecarboxylic acid by a bacterium, designated PRL W19, follows a pathway involving β-oxidation of coenzyme A intermediates analogous to the classical oxidation of fatty acids. The organism appears to have the property for the constitutive metabolism of caproic acid, and cell extracts contain high levels of the enzymes required for the functioning of the fatty acid cycle. However, the metabolism of cyclohexanecarboxylic acid requires induction by growth or incubation with an appropriate substrate. Extracts of induced cells contain several enzyme activities which are synthesized in response to the induction process. These enzymes include cyclohexanecarboxyl-CoA synthetase, cyclohexanecarboxyl-CoA dehydrogenase, 1-cyclohexenecarboxyl-CoA hydratase, and trans-2-hydroxycyclohexanecarboxyl-CoA dehydrogenase. A characteristic feature of this organism is that it becomes induced for the metabolism of benzoate and catechol during growth on cyclohexanecarboxylic acid, but benzoate does not appear to be an obligatory intermediate in the metabolism of cyclohexanecarboxylic acid.