초록
In this study, efficient polymer-grade l-lactic acid production was achieved with the strain Bacillus sp. P38 by using cellulosic hydrolysate as the sole carbon source. In fed-batch fermentation, 180gL<SUP>-1</SUP>l-lactic acid was obtained with a volumetric productivity of 2.4gL<SUP>-1</SUP>h<SUP>-1</SUP> and a yield of 0.96gg<SUP>-1</SUP> total reducing sugars. No d-isomer of lactic acid was detected in the broth. Strain P38 tolerated up to 10gL<SUP>-1</SUP> 2-furfural, and lactate production was sharply inhibited only when the 2-furfural concentration was higher than 6gL<SUP>-1</SUP>. Moreover, strain P38 also tolerated high concentrations (>6gL<SUP>-1</SUP>) of other fermentation inhibitors in cellulosic hydrolysate, such as vanillin and acetic acid, although it was slightly sensitive to formic acid. The efficient l-lactic acid production, combined with high inhibitor tolerance and efficient pentose utilization, indicate that Bacillus sp. P38 is a promising producer of polymer-grade l-lactic acid from cellulosic biomass.