Abstract:

To further enhance the production and yield of converting xylose to L-lactic acid, an atmospheric- and room
temperature-plasma (ARTP) mutation system was employed to induce the mutation of Bacillus coagulans NL01, a wild-type
strain for production of L-lactic acid from xylose. A positive mutant, named as NL-CC-17, was obtained through enrichment and
screening. Compared with that of previously reported strains, NL-CC-17 had an improved tolerance to xylose. This strain was
capable of converting 100 g/L xylose into 82.30 g/L L-lactic acid after being cultured at 50 ℃ for 72 h with a yield of 92.37%. The
concentration of L-lactic acid was increased by 21.51% and the yield by 16.00%. After preliminary optimization of fermentation
conditions, the optimal fermentation temperature was determined as 50 ℃ and the optimal pH as 5.5.

Key words: atmospheric and room temperature plasma (ARTP), Bacillus coagulans, mutation, L-lactic acid, xylose