L-lactic acid production by Bacillus subtilis MUR1.

Bacillus subtilis MUR1 is a novel lactic acid (LA) producing strain that has the potential for industrial production of LA due to its high productivity of LA, high yield of substrate conversion, and high final concentration of LA produced. B. subtilis MUR1 can produce 99.3 and 183.2g/l of L-LA in 12 and 52 h respectively with a 98.5% substrate conversion yield and a maximum L-LA production rate of 16.1g/l/h. Compared with batch culture, and several fed-batch cultures with different initial glucose concentrations, the fed-batch culture with initial 30 g/l glucose produced the highest final concentration and productivity of L-LA. Corn steep liquor can be used to partly replace yeast extract in the production medium for the production of L-LA by B. subtilis MUR1.