Screening of a highly inhibitor-tolerant bacterial strain for 2,3-BDO and organic acid production from non-detoxified corncob acid hydrolysate

Fermentation of chemicals from lignocellulose hydrolysate is an effective way to alleviate environmental and energy problems. However, fermentation inhibitors in hydrolysate and weak inhibitor tolerance of microorganisms limit its development. In this study, atmospheric and room temperature plasma mutation technology was utilized to generate mutant strains of Enterobacter cloacae and screen for mutants with high inhibitor tolerance to acid hydrolysate of corncobs. A highly inhibitor-tolerant strain, Enterobacter cloacae M22, was obtained after fermentation with non-detoxified hydrolysate, and this strain produced 24.32 g/L 2,3-butanediol and 14.93 g/L organic acids. Compared with that of the wild-type strain, inhibitor tolerance was enhanced twofold with M22, resulting in improvement of 2,3-butanediol and organic acid production by 114% and 90%, respectively. This work presents an efficient method to screen for highly inhibitor-tolerant strains and evidence of a novel strain that can produce 2,3-butanediol and organic acids using non-detoxified acid hydrolysate of corncobs.