Ammonia fiber expansion-assisted deep eutectic solvent treatment for wheat straw fraction separation and bioconversion

Abstract

In this study, an ammonia fiber expansion (AFEX)-assisted deep eutectic solvent (DES) pretreatment method was developed for the rapid separation of wheat straw fractions, which reduced the pretreatment time for DES and improved the pretreatment efficiency. This study describes the feasibility of the AFEX-assisted DES pretreatment in terms of both progressive and parallel relationships and analyzes the subsequent enzymatic effect in generating glucose from cellulose. Ammonia fiber expansion-assisted DES one-pot pretreatment at 120 °C, for 1.5 h resulted in an enzymatic efficiency of 98.0 ± 3.1 %. Moreover, the enzyme efficiency remained greater than 85 % after three recovery cycle experiments. The comparison between regenerated-lignin (d-lignin) and alkaline-lignin showed that regenerated lignin has a lower molecular weight and belongs to para-hydroxy-phenyl-guaiacyl-syringyl (H-G-S) type lignin. This study developed is a green and efficient pretreatment process with great potential in the separation and utilization of biomass fractions.