Metabolism of Cinnamic Acid and Hydroxy-Cinnamic Acids by Lactobacillus pastorianus var. quinicus

Abstract

PREVIOUS work has shown that caffeic acid, 3 : 4 dihydroxy-cinnamic acid is metabolized by Lactobacillus pastorianus var. quinicus 1,2 with the formation of dihydrocaffeic acid and ethyl catechol3. A pure culture of this organism was inoculated into a basal medium1 with the addition of 0.025 per cent cinnamic acid and 0.25 per cent fructose. After seven days' incubation at 25° C. under conditions of reduced oxygen tension, the cinnamic acid was completely metabolized. The end-product, an acid, was obtained as prismatic crystals, m.p. 47–48° C. in 85 per cent yield. A mixed melting-point with an authentic specimen of dihydrocinnamic acid showed no depression. Elementary analysis (Drs. Weiler and Strauss) gave C 71.85 per cent, H 6.84 per cent; C9H10O2 require requires C 72.0 per cent, H 6.7 per cent. The yield indicated that the organism had reduced cinnamic acid to dihydrocinnamic acid with little or no subsequent decarboxylation.