Direct conversion of starch to L(+) lactic acid by amylase producing Lactobacillus amylophilus GV6

Abstract

 Lactobacillus amylophilus strain GV6, isolated from corn starch processing industrial wastes, was amylolytic and produced 0.96 g L(+) lactic acid per gram of soluble starch. The optimum temperature and pH for growth and L(+) lactic acid production were 37 °C and 6.5, respectively. At low substrate concentrations, the lactic acid production on corn starch was almost similar to soluble starch. The strain is fermenting various naturally available starches directly to lactic acid. The total amylase activity of the strain is 0.59 U/ml/min. The strain produced 49 and 76.2 g/l L(+) lactic acid from 60 g/l corn starch and 90 g/l soluble starch, respectively. This is the highest L(+) lactic acid among the wild strains of L. amylophilus reported so far.