Fabrication of ternary deep eutectic solvent choline chloride:p-toluene sulfonic acid:Glycerol for pretreating wheat straw to augment cellulose accessibility, xylan removal, and lignin removal.

In this research, a novel ternary deep eutectic solvent (TDES) ChCl:p-TsOH:Gly (1:1:1), composed of choline chloride (ChCl), p-toluene sulfonic acid (p-TsOH), and glycerol (Gly), was successfully fabricated and adopted to pretreat wheat straw under relatively mild conditions (80 °C, 45 min) for removing xylan (99.9 %), eliminating lignin (88.5 %) and elevating subsequent enzymatic saccharification efficiency (98.1 %). The combined hydrolysis factor and combined delignification factor quantitatively predicted the dissolution kinetics of residual xylan and residual lignin, respectively, with high accuracy. Following ChCl:p-TsOH:Gly treatment, the accessibility of cellulose in wheat straw elevated considerably to 691.5 mg dye/g cellulose, while surface lignin area diminished to 134.6 m/g and lignin hydrophobicity was weakened to 2.6 L/g. These structural and surface property modifications contributed to the enhancement of enzymolysis. Molecular dynamics simulations and quantum chemical calculations were adopted to reveal van der Waals interactions between ChCl:p-TsOH:Gly and lignin, as well as dispersion interactions between ChCl and lignin, consequently elucidating the molecular-level interaction mechanism between lignocellulose and ChCl:p-TsOH:Gly. In summary, this study achieved effectual pretreatment of wheat straw using the TDES ChCl:p-TsOH:Gly but also considerably promoted the depolymerization of lignocellulosic biomass in biorefining processes, offering new insights into the value-added utilization of biomass resources.