l(+)-Lactic acid producer Bacillus coagulans SIM-7 DSM 14043 and its comparison with Lactobacillus delbrueckii ssp. lactis DSM 20073

Bacillus coagulans SIM-7 DSM 14043 is a novel lactic acid (LA) producing strain that is suitable for industrial production of LA according to its physiological characteristics, production rate of lactic acid and high final concentration of produced LA. We compare productivity parameters between LA producers Lactobacillus delbrueckii ssp. lactis DSM 20073 and B. coagulans SIM-7. Fermentation media were optimized for both strains to complete batch fermentations in 24 h. It was shown that SIM-7 is able to grow in the media containing less complex source of nitrogen (yeast autolysate) than DSM 20073 and produce a high final concentration of LA. The final concentrations of LA were remarkably high reaching 91.5 g/L and 91.6 g/L produced by SIM-7 in batch and fed-batch cultivations in 23 and 21 h, respectively. Yield of LA registered already in 10 h was 56 g/L by SIM-7 whereas comparable result 52 g/L was achieved only in 24 h by DSM 20073. The maximal production rates of strains SIM-7 and DSM 20073 were 9.9 and 5.6 g/L h, respectively.