Optimization of 2,3-butanediol production by Enterobacter cloacae in simultaneous saccharification and fermentation of corncob residue.

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.