Diacetyl Production and Utilization by Lactobacillus Species

Abstract

Single-strain cultures of Lactobacillus casei and L. plantarum accumulated detectable amounts of diacetyl when grown in milk culture at broth 8 and 30 C, but strains of L. lactis and L. brevis did not. Lactobacillus casei strains produced relatively large amounts of diacetyl under these incubation conditions, whereas L. plantarum accumulated this compound in levels of less than 1 ppm. Significant differences in the production of diacetyl were noted between strains of a species. Diacetyl reductase activity was demonstrated in single-strain cultures of L. casei, L. lactis, and L. brevis. Diacetyl reductase could be induced in L. plantarum by growth in the presence of citrate. Growth in a milk medium supplemented with citrate resulted in a stimulation of diacetyl reductase activity with L. casei.