Oxygen utilization by Lactobacillus plantarum. I. Oxygen consuming reactions.

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 of pyruvate with O2. Per mol O2 2mol of NADH were consumed indicating that O2 was reduced to H2O; reduction proceeded via H2O2 involving a NADH oxidase and a NADH peroxidase. Catalase activity was absent. Pyruvate oxidation with O2 led to the formation of H2O2, lactate oxidation to the formation of H2O. Thus in L. plantarum different mechanisms are available by which molecular oxygen can be used as electron acceptor for oxidation reactions.