Lewis base enhanced neutral deep eutectic solvent pretreatment for enzymatic hydrolysis of corn straw and lignin characterization

In order to improve the pretreatment behavior of neutral deep eutectic solvent (DES), a novel method was proposed by using three types of Lewis base (sodium carbonate, sodium sulfite and sodium acetate as catalysts to pretreat corn straw at 120 °C for 3 h. As compared to DES, DES with Na 2 SO 3 , DES with NaAC and DES with Na 2 CO 3 , all can remove most of hemicellulose and lignin in pretreated corn straw. Meanwhile, the 94.5% of glucose yield was obtained treated by DES with Na 2 CO 3 and was approximately five-fold higher than that of the untreated substrate at an enzyme loading of 15 FPU/g material. The regenerated lignin displayed well-preserved structures, and possessed a high purity (more than 84%), narrow molecular weight distribution (PDI <2.4), excellent thermal stability. Overall, this work provided detailed analysis for efficient deconstruction of corn straw for future industrialized application. • Lewis base enhanced neutral DES pretreatment was proposed. • DES with Lewis base approvingly retained most of cellulose in pretreated corn straw. • 88.1% of lignin was removed by Na2CO3 catalyzed ChCl/EG treatment. • Sugar yield was significantly increased from 17.9% to 94.5% in the saccharification process. • A high-quality lignin stream was obtained.