A high-solid DES pretreatment using never-dried biomass as the starting material: towards high-quality lignin fractionation

This study investigated a high-solid diol deep eutectic solvent (DES) pretreatment using a wet substrate as the starting material. This pretreatment led to a remarkable glucan saccharification of 94.8% with efficient lignin and xylan removal (as high as 63.1% and 73.0%, respectively). The chemical structures of the substrates were analyzed comprehensively to reveal the impact of the pretreatment. In addition, over 90% of the removed lignin was recovered from the pretreated liquid, which exhibited a well-preserved beta-O-4 structure (46-56/100Ar). The protection mechanism of our DES was investigated by 2D HSQC NMR, GPC, and P-31 NMR analysis. This study emphasized that diol-based DES pretreatment of undried lignocellulosic biomass at a high-solid loading can significantly utilize both carbohydrates and lignin fractions with high saccharification yields and high-quality lignin as a co-product.

Automated summary

This study explored the pretreatment of high-solid diol deep eutectic solvent (DES) using wet substrate, resulting in a glucan saccharification rate of 94.8% and efficient removal of lignin and xylan (63.1% and 73.0%, respectively). Comprehensive analysis of the substrate's chemical structures revealed the impact of the pretreatment. Moreover, more than 90% of the removed lignin was recovered from the pretreated liquid, showing a well-preserved beta-O-4 structure (46-56/100Ar). The protective mechanism of the DES was investigated using 2D HSQC NMR, GPC, and P-31 NMR analysis. This study emphasized the significant utilization of carbohydrates and lignin fractions with high saccharification yields and high-quality lignin as a co-product through diol-based DES pretreatment of undried lignocellulosic biomass at a high-solid loading.