Improved 2,3-butanediol yield and productivity from lignocellulose biomass hydrolysate in metabolically engineered Enterobacter aerogenes

We previously engineered Enterobacter aerogenes for glucose and xylose co-utilization and 2,3-butanediol production. Here, strain EMY-22 was further engineered to improve the 2,3-butanediol titer, productivity, and yield by reducing the production of byproducts. To reduce succinate production, the budABC operon and galP gene were overexpressed, which increased 2,3-butanediol production. For further reduction of succinate and 2-ketogluconate production, maeA was selected and overexpressed in EMY-22. The optimally engineered strain produced 2,3-butanediol for a longer time and showed reduced byproduct formation from sugarcane bagasse hydrolysate under flask cultivation conditions. The engineered strain displayed 66.6, 13.4, and 16.8% improvements in titer, yield, productivity of 2,3-butanediol, respectively, compared to its parental strain under fed-batch fermentation conditions. The data demonstrate that the metabolic engineering to reduce byproduct formation is a promising strategy to improve 2,3-butanediol production from lignocellulosic biomass.