Alteration of cellulose accessibility, surface lignin area, and lignin hydrophobicity of Poplar Detritus through p-toluenesulfonic acid-assisting hydrothermal pretreatment.

In this work, altering cellulose accessibility, surface lignin area, and lignin hydrophobicity of Poplar Detritus (PD) was implemented through organic acid-assisting hydrothermal pretreatment, co-producing reducing sugars, xylo-oligosaccharides, furfural, and organic acids. After being treated under the optimal conditions [160 °C, 90 min, 1:10 solid-liquid ratio and 1 % p-toluenesulfonic acid (p-TsOH) concentration], the yield of reducing sugar increased by 8-folds, and the elimination of lignin and xylan were 63.7 % and 87.7 % respectively. Co-manufacturing of furfural, xylo-oligosaccharides, formic acid and reducing sugars was realized. The increased cellulose accessibility, decreased lignin surface area, and weakened hydrophobicity results indicated that the p-TsOH-assisted hydrothermal treatment considerably destroyed the surface structure of PD, made its pores larger, and remarkably improved the enzymatic hydrolysis ability. It also further verified the value of p-TsOH-assisted hydrothermal treatment in biomass resource utilization. Based on molecular dynamics simulations, DFT calculations elucidated the interaction mechanism between p-TsOH and lignocellulose. Computational simulations reveal that the improvement of electrostatic and van der Waals repulsive forces may facilitate the removal of lignin and hemicellulose. Through comprehensive characterization analyses, it was observed that the accessibility of PD was markedly enhanced, while hydrophobicity and lignin content were reduced, accompanied by significant alterations in the surface structure. These changes provide a clear explanation for the improved sugar recovery rate achieved through p-TsOH-assisted hydrothermal treatment. In general, hydrothermal treatment assisted by p-TsOH was a simple, green and environmentally friendly PD sustainable pretreatment method.