Facile Fractionation of Bamboo Wood Toward Biomass Valorization by p-TsOH-Based Methanolysis Pretreatment

Abstract

A mild methanolysis pretreatment strategy was developed with a recyclable acid, p-TsOH, as the catalyst for the fractionation of lignocellulosic biomass toward its main components. Bamboo fiber was fractionated in one step with dissolution of more than 88% lignin and 90% xylan with most of the cellulose (86.8%) retained in pretreated bamboo at mild conditions (110 °C, 30 min, and 10% p-TsOH). Enzymatic hydrolysis of the cellulose-rich fraction was enhanced to 89.2% at an enzyme loading of 15 FPU g–1 substrate, nearly 4-fold higher than the untreated bamboo. Most of the xylan (hemicellulose) and lignin in the biomass were extracted and dissolved into the spent liquor. The extracted lignin had higher purity (>94%) and a moderate and homogeneous molecular weight, which could be adapted to add value to lignin. p-TsOH can be effectively recovered by recrystallization technology after concentrating the spent liquor. Hemicellulose (xylan) was transformed into methyl xyloside and furfural during the pretreatment. Overall, the described process showed practical significance for the effective fractionation and comprehensive utilization of lignocellulosic biomass components.