Simultaneous production of lignin oil and digestible cellulose from moso bamboo fibers and parenchyma cells via deep eutectic solvent pretreatment.

Enhancing the high-value utilization potential of lignocellulosic biomass through pretreatment fractionation has become a widely accepted strategy. In this study, a green and environmentally friendly deep eutectic solvent (DES) system was developed using Ru/C as a catalyst to enable the efficient fractionation and depolymerization of lignin, as well as to improve the saccharification efficiency of cellulose. Moso bamboo fibers and parenchyma cells, which possess distinct lignin structures and levels of biomass recalcitrance, were selected as feedstocks. The study focused on the influence of pretreatment temperature on lignin fractionation and depolymerization, as well as enzymatic saccharification of cellulose. The results revealed tissue-specific fractionation behaviors, with parenchyma cells exhibiting higher delignification ratio compared to fibers. Notably, the yield of lignin-derived monophenols from parenchyma cells reached up to 25.29%. Multidisciplinary characterization demonstrated significant structural differences in lignin fractions obtained from fibers and parenchyma cells, confirming the intrinsically lower recalcitrance of parenchyma cell walls. Subsequent enzymatic saccharification of the pretreated residues yielded glucose with a conversion efficiency as high as 93.19%. These findings suggest that this strategy holds great promise for advancing the practical application of lignocellulosic fractionation technologies and offers new insights into the valorization of structurally heterogeneous biomass resources.