L-Lactic Acid Production from Starch in a Mixed Culture of Bacillus amyloliquefaciens and Lactococcus lactis

Abstract

L-lacticacid (L-LA) production from starch was investigated Bacillus amyloliquefaciens IFO 14141 was selected for its higher amylase productivity in 6 stock cultures of Bacillus strains . Most of the hydrolysates from the starch yielded the amylase were maltose and maltooligosaccharides . Lactococcus lactis NRIC 1074 was selected in view of the higher productivity of L-LA from maltose from among 137 stock cultures of lactic acid bacteria. When the mixed culture of the two strains was carried out for 96 hrs with and without aeration to the culture broth containing starch, the L-LA productivity was low. However, 0.5 V. V. M. of aeration for 18 hrs to the culture stimulated the growth and amylase production of B. amyloliquefaciens, and the L-LA production by Lc. lactis increased sufficiently when accompanied by the cessation of aeration after 18 hrs. As a result of the conditions of culture , 15 g of L-LA per liter of 3% starch medium was obtained and the yield of L-LA to the starch consumed was about 85%.