The effect of sodium acetate on the growth yield, the production of smallL/small- and smallD/small-lactic acid, and the activity of some enzymes of the glycolytic pathway of Lactobacillus sakei NRIC 1071T and Lactobacillus plantarum NRIC 1067T

摘要

The effect of sodium acetate was studied on the change of the growth yield, the production of L- and D-lactic acid, and the activity of lactate dehydrogenases (LDHs; L-lactate dehydrogenase [EC 1.1.1.27, L-LDH] plus D-lactate dehydrogenase [EC 1.1.1.28, D-LDH]), fructose-1, 6-bisphosphate aldolase [EC 4.1.2.13, FBP-aldolase], and phosphofructokinase [EC 2.7.1.11, PFK] of Lactobacillus sakei NRIC 1071T and Lactobacillus plantarum NRIC 1067T. The growth yield of L. sakei NRIC 1071T was increased 1.6 times in the presence of sodium acetate compared with its absence. The activity of LDHs in L. sakei NRIC 1071T and L. plantarum NRIC 1067T was retained longer under the addition of sodium acetate in the reaction mixture. As a result, these strains produced much more lactic acid in the presence of sodium acetate compared with its absence. Furthermore, the activity of L-LDH in L. sakei NRIC 1071T cultivated in the presence of sodium acetate increased three times or more compared with the activity of the cells cultivated in its absence. Consequently, the type of stereoisomers of lactic acid produced by L. sakei shifted from the DL-type to the L-type because the ratio of L-lactic acid to D-lactic acid produced became larger with the addition of sodium acetate to culture media. This phenomenon was not observed in L. plantarum NRIC 1067T. Further, the participation of lactate racemase is discussed from the viewpoint of the production of D-lactic acid by L. sakei.