Utilization of a combined fractionation process involving steam explosion and the recycling of self-produced acetone-butanol-ethanol to promote biomass valorisation

A two-stage fractionation strategy integrating steam explosion (SE) with cyclical organosolv (CO) was developed to valorize corn stover (CS) for enhanced acetone-butanol-ethanol (ABE) production. Under the optimized condition (180 °C for ABE pulping), the glucan-enriched pulp afforded a high glucose yield (86.99 %) with a low dosage of cellulase (7 FPU/g) in the subsequent saccharification process. Moreover, alcohol compounds present in the crude ABE pulping liquor could effectively alkylate the α-carbon atom via etherification and promote the demethoxylation of lignin. After mixing the washing water from the SE stage with the CS pulp from the CO stage, the obtained liquid could be directly used as a substrate for ABE fermentation. Mass balance showed that 117.3 g of technical lignin and 128.2 g ABE were co-generated from 1 kg of dry CS using this novel fractionation process. Overall, this study enables the high-value utilization of all lignocellulosic components and provides a foundation for further intensification of biorefinery processes toward cost-effective biobutanol production, while also demonstrating the recyclability potential of ABE within integrated biorefinery systems.