A novel green biorefinery strategy for corn stover by pretreatment with weak alkali-assisted deep eutectic solvents

Abstract

Green and efficient biorefinery strategies are essential for sustainable biomass utilization. This study reported a novel fractionation strategy using deep eutectic solvent–sodium bicarbonate (DES–SB) for full-component utilization of corn stover (CS). The results showed that the addition of SB significantly improved the delignification efficiency (90.03%) compared to that of the neat DES pretreatment (34.64%). As a result, excellent carbohydrate digestibility was achieved (glucose yield, 97.47%; xylose yield, 92.93%). Moreover, the regenerated lignin exhibited high purity (94.31%), excellent thermal stability, a low molecular weight (1593 g mol⁻¹), and good uniformity (1.76), indicating great potential for further value enhancement. NMR analysis indicated the retention of major interunit linkages (45.6% of β-O-4), and the recovered lignin presented a greater number of carboxyl groups and a lower number of p-hydroxyphenyl OH groups as the pretreatment severity increased. Finally, mass balance analysis demonstrated that 1 kg of dry CS could produce 367.03 g of glucose, 171.70 g of xylose, and 143.52 g of lignin. Overall, this study provides a green, high-efficiency, and synergistic DES–SB pretreatment strategy that has great potential for full-component biomass utilization and sustainable industrial biorefinery application.