TY - JOUR
T1 - Deep eutectic solvent-driven mild lignocellulose pretreatment
T2 - unlocking lignin valorization and carbohydrate digestibility
AU - Wang, Yang
AU - Liu, Qiaoling
AU - Yan, Chuanyu
AU - Song, Guoyong
AU - Price, William S.
AU - Zheng, Gang
AU - Torres, Allan M.
AU - Xue, Zhimin
PY - 2025
Y1 - 2025
N2 - High-value utilization of lignocellulose and its components is generally constrained by the pretreatment efficiency and the structural robustness of fractionated components. Harsh pretreatment conditions can promote pretreatment efficiency but also cause serious condensation of lignin structure, thus inhibiting the depolymerization of lignin into valuable chemicals. Herein, we designed a novel deep eutectic solvent (DES) composed of pyridine hydrochloride, ethylene glycol, and AlCl3 for the pretreatment of lignocellulose. In the developed DES, the lignocellulose could be efficiently fractionated into the natural lignin derivatives with satisfactory hydrogenolysis reactivity and the carbohydrate fraction with high enzymatic digestibility owing to the synthesized DES having adjustable hydrogen-bond acidity, high affinity for lignin, and good protection role on lignin structure. After being pretreated under a mild fractionation condition (70°C, 6 h), a promising delignification ratio of 70.4 % was obtained for poplar, and the extracted lignin exhibited native substructure with well-preserved β-O-4 linkages (42.1 per 100 aromatic units), abundant hydroxyl groups content (4.97 mmol/g), and high molecular weight (5643 g/mol). These structural features contributed to the conversion of the obtained lignin into aromatic monomers with a high yield (27.4 %). Besides, the pretreated residue could be efficiently converted into glucose with a yield of 88.2 % due to the abundant hydroxyl groups of lignin in the cellulose-rich residues. Remarkably, comprehensive studies of lignin structural evolution during pretreatment revealed that the structure-controllable lignin could be effectively isolated by modulating the hydrogen-bond acidity of DESs. This work proposed a mild and efficient lignin-first biorefinery approach that was conducive to the integrated valorization of lignocellulose.
AB - High-value utilization of lignocellulose and its components is generally constrained by the pretreatment efficiency and the structural robustness of fractionated components. Harsh pretreatment conditions can promote pretreatment efficiency but also cause serious condensation of lignin structure, thus inhibiting the depolymerization of lignin into valuable chemicals. Herein, we designed a novel deep eutectic solvent (DES) composed of pyridine hydrochloride, ethylene glycol, and AlCl3 for the pretreatment of lignocellulose. In the developed DES, the lignocellulose could be efficiently fractionated into the natural lignin derivatives with satisfactory hydrogenolysis reactivity and the carbohydrate fraction with high enzymatic digestibility owing to the synthesized DES having adjustable hydrogen-bond acidity, high affinity for lignin, and good protection role on lignin structure. After being pretreated under a mild fractionation condition (70°C, 6 h), a promising delignification ratio of 70.4 % was obtained for poplar, and the extracted lignin exhibited native substructure with well-preserved β-O-4 linkages (42.1 per 100 aromatic units), abundant hydroxyl groups content (4.97 mmol/g), and high molecular weight (5643 g/mol). These structural features contributed to the conversion of the obtained lignin into aromatic monomers with a high yield (27.4 %). Besides, the pretreated residue could be efficiently converted into glucose with a yield of 88.2 % due to the abundant hydroxyl groups of lignin in the cellulose-rich residues. Remarkably, comprehensive studies of lignin structural evolution during pretreatment revealed that the structure-controllable lignin could be effectively isolated by modulating the hydrogen-bond acidity of DESs. This work proposed a mild and efficient lignin-first biorefinery approach that was conducive to the integrated valorization of lignocellulose.
KW - Deep eutectic solvent
KW - Lignin extraction
KW - Lignocellulose valorization
KW - Native structure
UR - http://www.scopus.com/inward/record.url?scp=85212945532&partnerID=8YFLogxK
UR - https://ezproxy.uws.edu.au/login?url=https://doi.org/10.1016/j.cej.2024.158825
U2 - 10.1016/j.cej.2024.158825
DO - 10.1016/j.cej.2024.158825
M3 - Article
AN - SCOPUS:85212945532
SN - 1385-8947
VL - 504
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
M1 - 158825
ER -