Bioconversion of dinitrile to mononitrile, a tranexamic acid intermediate, by Corynebacterium sp.

Abstract

An isolated bacterial strain, Corynebacterium sp. C5, could produce fra/is-4-cyanocyclohexane-l- carboxylic acid (t-MCC), an intermediate in the chemical synthesis of tranexamic acid, from trans- 1, 4-dicyanocyclohexane (t-DCC), through catalysis by two enzymes, nitrile hydratase and amidase. The two enzymes were constitutively formed in cells. The activity of nitrile hydratase increased with the addition of FeS04 and isobutyronitrile to the culture medium. The activity of amidase increased with the addition of isobutyronitrile. Peptone, as the nitrogen source, was effective for production of the two enzymes without a decrease in their activities in the stationary growth phase. The cells could produce 92.1 mg/ml f-MCC from 100 mg/ml t-DCC on 20-hr incubation in a resting cell system.