High-efficient cellulosic butanol production from deep eutectic solvent pretreated corn stover without detoxification

Abstract Biobutanol is one of the most promising renewable biofuels, which can be produced from lignocellulosic biomass by Clostridium. However, due to the dense structure of lignin, biomass is difficult to be hydrolyzed into fermentable sugars. This study has developed a short time (90 min) and low energy consumption (120 °C) pretreatment process using deep eutectic solvent (DES). Importantly, the cellulose recovery of treated corn stover (CS) after DES pretreatment at 120 °C was 99.24 %, while the removal of xylan and lignin reached 57.58 % and 61.40 %, respectively. The total sugars released from treated CS at 120 °C reached 37.94 g L−1 (glucose: 30.59 g L−1; xylose: 7.35 g L−1) at a low enzyme loading of 7.5 filter paper unit (FPU) g−1 pretreated CS. Furthermore, the DES treated CS hydrolysate was successfully used to produce butanol by Clostridium beijerinckii P260 without any detoxification and sterilization, thus producing 13.65 g L-1 total acetone-butanol-ethanol (ABE) with a high productivity (0.68 g L-1 h−1) and yield (0.38 g g−1). Overall, the present work provides a new insight into the efficient application of DES systems in lignocellulose biomass biorefinery.