A Novel Choline Alkali–Thiourea Pretreatment for Enhanced Enzymatic Hydrolysis of Reed Straw

A new alkaline deep eutectic solvent (ChOH-TH) was developed using choline hydroxide and thiourea to pretreat reed straw for enhanced enzymatic hydrolysis. The study systematically examined the impact of ChOH-TH pretreatment on reed straw’s composition, microstructure, crystalline structure, and enzymatic saccharification efficiency to determine optimal conditions. Results showed that adding 70% deionized water to ChOH-TH and pretreating at 70 °C for 3 h effectively removed 70.73% of lignin from reed straw. This condition led to a 93.52% increase in reducing sugar output from the pretreated cellulose-enriched substrate, a 12.04-fold rise compared to untreated straw. Structural analysis revealed enhanced cellulose crystallinity to 51.38% in the residual biomass, along with surface modifications and changes in functional groups and components, contributing to improved enzymatic hydrolysis efficiency. Moreover, ChOH-TH maintained a 60.41% reducing sugar yield after five reuse cycles in the enzymatic hydrolysis of pretreated reed straw, highlighting its reusability and sustainability. It showed effective pretreatment performance on various lignocellulosic biomass types, indicating universality. The optimized ChOH-TH solvent is efficient, stable, and versatile for biomass pretreatment, improving enzymatic hydrolysis efficiency with economic and environmental benefits. This presents a green pathway for utilizing lignocellulosic waste with significant academic and industrial potential.