l-Lactic acid production by Bacillus coagulans through simultaneous saccharification and fermentation of lignocellulosic corncob residue

l-Lactic acid is an important monomer of polylactic acid, a biodegradable plastic. In this study, we systematically investigated l-lactic acid fermentation by thermophilic Bacillus coagulans strains using the corncob residue (CCR), a widely available lignocellulosic material. Our results showed that 68.0 g/L l-lactic acid was obtained with a high yield of 0.85 g/g cellulose by B. coagulans strain H-1 after 36 h in batch fermentation. Strain H-1 could produce 79.1 g/L l-lactic acid with a yield of 0.76 g/g cellulose after 84 h in fed-batch fermentation. The results suggest that attractive lignocellulosic wastes such as CCR could be used in the efficient biomanufacture of l-lactic acid.