Abstract
The metabolism of sorbic acid (trans-2, trans-4-hexadienoic acid) and its related compounds by Mucor sp. A-73 was investigated. Sorbic acid was reduced by this fungus to trans-4-hexenol (more than 90% yield). In a series of hexamonoenoic acids, carboxyl groups and α, β-double bond were reduced, but β, γ and γ, δ double bonds were hardly reduced. The reduction of cis-2-hexenoic acid was slower than that of the corresponding trans isomer. Sorbic alcohol, one of α, β-unsaturated alcohols, was converted well to trans-4-hexenol by the fungus. These results showed that this fungus could carry out two independent reductions: (i) carboxyl group-alcohol, (ii) α, β-unsaturated alcohol→α, β-saturated one. Furthermore, α, β-unsaturated alcohols were temporarily detected in the course of fungal reductions of some α, β-unsaturated acids. The fact suggested that the reduction of α, β-unsaturated acids to α, β-saturated alcohols was initiated by the reaction (i) and followed by (ii). The biological hydrogenation of α, β-unsaturated alcohols is a new reaction.
