Ammonia fiber expansion-assisted deep eutectic solvent treatment for wheat straw fraction separation and bioconversion. (January 2023) - Hu, Mingyang
Graphical abstract: Highlights: Fraction separation of wheat straw with AFEX-assisted DES pretreatment. DES with reduced pH and viscosity enhances lignin removal. AFEX-assisted DES pretreatment increases cellulose accessibility in wheat straw. The enzymatic efficiency of the one-pot pretreatment of wheat straw was 97.96%. Enzyme efficiency remained greater than 85 % for three pretreatment cycles. 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.