초록
The use of lignocellulosic feedstock for lactic acid production with a difficulty is that the release of inhibitory compounds during the pretreatment process which inhibit the growth of microorganism. Thus we report a novel lactic acid bacterium, Lactobacillus paracasei 7BL, that has a high tolerance to inhibitors and produced optically pure l-lactic acid after the interruption of ldhD gene. The strain 7BL fermented glucose efficiently and showed high titer of l-lactic acid (215g/l) by fed-batch strategy. In addition, 99g/l of l-lactic acid with high yield (0.96g/g) and productivity (2.25-3.23g/l/h) was obtained by using non-detoxified wood hydrolysate. Rice straw hydrolysate without detoxification was also tested and yielded a productivity rate as high as 5.27g/l/h. Therefore, L. paracasei 7BL represents a potential method of l-lactic acid production from lignocellulosic biomass and has attractive application for industries.