Oxygen utilization by Lactobacillus plantarum

Abstract

Lactobacillus plantarum (ATCC 8014) cells, grown aerobically on glucose medium, consumed molecular oxygen when incubated with either glucose, d/l -lactate or pyruvate as substrate. Cell extracts catalyzed the oxidation of NADH, d/l -lactate or pyruvate with O_2. Per mol O_2 2mol of NADH were consumed indicating that O_2 was reduced to H_2O; reduction proceeded via H_2O_2 involving a NADH oxidase and a NADH peroxidase. Catalase activity was absent. Pyruvate oxidation with O_2 led to the formation of H_2O_2, lactate oxidation to the formation of H_2O. Thus in L. plantarum different mechanisms are available by which molecular oxygen can be used as electron acceptor for oxidation reactions.