Insights into acidic deep eutectic solvent-mediated softwood pretreatment for high fermentable sugar yield and efficient lignin recovery
Chenjie Ji, Rou Weng, Chang Yu, Yuyang Fan, Jia Ouyang
Abstract
This study addresses the critical challenges of softwood pretreatment, focusing on Chinese fir as a model substrate to tackle its high lignin content and recalcitrant structure. To enhance the fractionation efficiency of softwood components and improve enzymatic glucose yield, four deep eutectic solvent (DES) systems—ChCl/LA, ChCl/FA, TEBAC/LA, and TEBAC/FA—were systematically evaluated. Using density functional theory (DFT) calculations and molecular dynamics (MD) simulations, TEBAC/LA (1:4) was identified as the optimal DES system, exhibiting exceptional binding energy (-162.37 kcal/mol) and strong hydrogen bonding interactions that effectively disrupted lignin’s hydrogen bond network. Furthermore, Pearson correlation analysis between the physicochemical properties of DES (e.g., density, viscosity, surface tension, and Kamlet-Taft parameters) and enzymatic hydrolysis yield revealed that low surface tension, high Kamlet-Taft α, and high π parameters significantly enhance pretreatment efficiency. Guided by these computational insights, experimental validation revealed that TEBAC/LA achieved outstanding lignin removal (97.41 %) and glucose yield (97.09 %) under optimized conditions (150 °C, 90 min). This work not only advances the understanding of DES-biomass interactions but also demonstrates the power of integrating molecular simulations with experimental validation to design efficient biomass pretreatment systems. This study provides a scalable and sustainable approach for optimizing solvent systems, advancing renewable energy and material production. • A new and efficient pretreatment method was established for Chinese fir wood. • MS and DTF calculations revealed the H-bond interactions in TEBAC/LA and lignin. • Higher values of Kamlet Taft α and π indicated superior pretreatment. • 97.09 % enzymatic hydrolysis yield and 97.41 % lignin removal were obtained.