Effects of sodium acetate on the production of stereoisomers of lactic acid by Lactobacillus sakei and other lactic acid bacteria

Abstract

Lactobacillus sakei and other lactic acid bacteria were studied on the change of the type of stereoisomers (the ratio of L-form to D-form) of lactic acid produced in the presence of sodium acetate and under other cultural conditions. Of 49 strains tested, only L. sakei NRIC 1071T and L. coryniformis subsp. coryniformis NRIC 1638T changed the type in the presence of 50 mM sodium acetate compared with the absence of sodium acetate. The type produced by L. sakei NRIC 1071T was shifted 30% or more from the DL-type to the L-type in the presence of 50 mM sodium acetate. L. sakei NRIC 1071T produced not only twice or more the amount of L-lactic acid but decreased the amount of D-lactic acid compared with the absence of sodium acetate. The shift of the DL-type to the L-type by L. sakei is due to the high production of L-lactic acid and the low production of D-lactic acid. The type of stereoisomers produced by 11 L. sakei strains was also shifted from the DL-type to the L-type in the presence of 50 mM sodium acetate. The shift of stereoisomers by the majority of L. sakei strains seems interesting from the viewpoint of the delineation of this species.