Engineering of Klebsiella oxytoca for production of 2,3-butanediol using mixed sugars derived from lignocellulosic hydrolysates

Abstract

2,3-Butanediol (2,3-BDO) is a promising bulk chemical owing to its high potential in industrial applications. Here, we engineered Klebsiella oxytoca for the economic production of 2,3-BDO using mixed sugars from renewable biomass. First, to improve xylose consumption, the xylose transporter gene (xylE) was integrated into the methylglyoxal synthase A (mgsA)-coding gene loci, and the engineered CHA004 strain showed much faster consumption of xylose than wild-type (WT) strain with 1.4-fold increase of overall sugar consumption rate. To further improve sugar utilization, we performed adaptive laboratory evolution for 90 days. The evolved strain (CHA006) was evaluated by cultivating it in the media containing single- or mixed-sugars, and it was clearly observed that CHA006 has improved sugar consumption and 2,3-BDO production than those of the parental strain. Finally, we demonstrated the superiority of CHA006 by culturing in two lignocellulosic hydrolysates derived from sunflower or pine tree. Particularly, in the pine tree hydrolysate containing xylose, glucose, galactose, and mannose, the CHA006 strain showed much improved consumption rates for all sugars, and 2,3-BDO productivity (0.73 g L-1 hr(-1)) increased by 3.2-fold compared to WT strain. We believe that the engineered CHA006 strain can be a potential host in the development of economic bioprocess for 2,3-BDO through efficient utilization of mixed sugars derived from lignocellulosic biomass.