Quantum Mechanical Insights into Lignocellulosic Biomass Fractionation through an NaOH-Catalyzed Triton-X 100 System: <i>In Vitro</i> and <i>In Silico</i> Approaches

Despite the notable efficacy of the NaOH-catalyzed Triton-X 100 system in fractionating lignocellulosic biomass (LCB), a significant gap remains in understanding the mechanistic pathways that drive this process. This study uses a dual-faceted approach, combining laboratory experiments with computational simulations to elucidate the mechanisms of delignification and lignin-carbohydrate complex (LCC) disruption. Under optimized conditions, both cellulose and hemicellulose recoveries reached around 88.5%, with delignification attaining an impressive 92.3%. Substantial changes in the physicochemical properties of the pretreated substrates were observed, including the removal of lignin and LCC-associated linkages, an enhanced crystallinity index (1.2–1.9 times), and an increase in surface area (1.2–1.4 times) compared to controls. This pretreatment system also facilitated frequent lignin depolymerization, leading to pronounced dissolution of syringyl and ferulate units. Furthermore, mechanical analyses demonstrated that this system promoted the highest interaction energy formations during LCB fractionation compared to individual NaOH or Triton-X 100 treatments alone. Self-consistent field analysis indicated that the combined system achieved core energy densities of −247.4 a.u. with veratrylglycerol-β-guaiacyl ether (VG, as a lignin model) and −209.9 a.u. with phenolic glycoside (PG, as an LCC model), both more energy-dense than individual methods. The combined system also exhibited the highest interaction energy formation due to robust hydrogen bonding, with total energies of −49.41 kcal/mol for VG and −44.59 kcal/mol for PG, underscoring the critical role of these interactions in achieving effective delignification and LCC disruption.