High fermentative 23-butanediol production from xylose

The effective use of xylose may significantly enhance the feasibility of using lignocellulosic hydrolysate to produce 23-butanediol (23-BD). Previous difficulties in 23-BD production include that the high-concentration xylose cannot be converted completely and the fermentation rate is slow. This study investigated the effects of yeast extract Na2EDTA and acetic acid on 23-BD production from xylose. It was found that simultaneous addition of these three components could significantly improve 23-BD production. The optimal concentrations of yeast extract Na2EDTA and acetic acid were 35.2 1.2 and 4.5 g/L respectively. The 23-BD concentration in the optimized medium reached 39.7 g/L after 48 h of shake flask fermentation. The xylose utilization ratio and the 23-BD concentration increased to 99.0% and 42.7 g/L respectively after 48 h of stirred batch fermentation. Furthermore the 23-BD yield was 0.475 g/g 95.0% of the theoretical maximum value. As the major components of lignocellulosic hydrolysate are glucose xylose and acetic acid the results of this study indicate the possibility of directly using the hydrolysate to effectively produce 23-BD.