AEROBIC GROWTH OF SOME LACTIC-ACID BACTERIA ENABLED BY THE EXTERNAL ADDITION OF PEROXIDASE (HORSERADISH) TO THE CULTURE-MEDIUM

The growth of Lactobacillus fermentum H3, L. fermentum Y6, and L. delb rueckii subsp. delbrueckii NRIC 1053(T), which do not grow well and ac cumulate hydrogen peroxide in the culture medium under ordinarily aero bic conditions, was gradually enhanced by increasing the concentration of peroxidase up to 100 U. In addition, the concentration of hydrogen peroxide accumulated was decreased by adding 100 U of peroxidase to t he culture medium. These findings indicate that peroxidase efficiently catalyzes the decomposition of hydrogen peroxide accumulated during a erobic growth of the strains tested. A physiological role for peroxida se, for example NADH peroxidase, in the aerobic growth of lactic acid bacteria is discussed.