Oxygen Consumption by Pediococcus halophilus

The behavior toward oxygen of several strains of Pediococcus halophilus was studied. Although these organisms are generally regarded as facultative anaerobes, this investigation showed that resting cells of P. halophilus consumed oxygen at the expense of p-giucose or L-lactate as substrate.

The oxygen consuming activities among strains of soy pediococci varied from 7.06 to 11.63 (nmol/min/mg dry cells) with glucose and 5.52 to 6.59 with L-lactate, respectively. Oxidative metabolism of glucose increased acetate production with a corresponding decrease in lactate formation. Lactate oxidation with O₂. led to the formation of acetate. The oxygen consuming activity was not inhibited by any of the respiratory inhibitors tested such as KCN or NaN₃

NADH oxidase activity was found iri cell-free extracts of P. halophilus No, 51, which is capable of lowering the redox potential of the growth medium. A direct correlation between the abilities to consume oxygen and to reduce the redox potential has not been found so far, but this enzyme is considered to be involved in the aerobic metabolism.