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Corncob residue, a waste in xylose or xylitol production, was utilized to produce 2,3-butanediol (2,3-BD) via simultaneous saccharification and fermentation (SSF). This study developed the optimal conditions for production of 2,3-BD by using a heat-resistant strain, Enterobacter cloacae UV4, to perform SSF of the corncob residue. Urea, lactic acid, sodium citrate, and MgSO4 , selected by the Plackett-Burman experiment, were determined to be significant independent variables to conduct the response surface experiment. With the optimized medium, a total production of 28.923 g/L for 2,3-BD and acetoin (BA) was obtained at 60 H. Furthermore, 43.162 g/L of BA production and 0.553 g/L/H of productivity were obtained by fed-batch SSF, which was 0.424 g diol/g consumed corncob residue. The results suggest that the waste corncob residue could be used as an available substrate for the production of 2,3-BD by E. cloacae UV4, as well as a potential resource to improve the economics of microbial compound production.

Chinese liquor is one of the 6 well-known distilled spirits in the world. High-temperature Daqu acts as an important source of nutrients and of microorganisms in the solid-state fermentation of Chinese Moutai-flavor liquor, which has a critical impact on the final flavor of the liquor. The study identifies a novel DGGE marker and provides an efficient way to identify bacterial diversity in Daqu from different fermentation stages. Importantly, the study defines dynamic changes of the physicochemical parameters and the infrared spectra analysis of Daqu during the fermentation process. These studies will help to (1) establish a standard operation procedure for Daqu production; (2) stabilize manufacturing process for Daqu fermentation and even for liquor brewing.