Generation of lignin and enzymatically digestible cellulose from ethanol-based organosolv pretreatment of sugarcane bagasse

This work proposes a new methodology for sugarcane bagasse pretreatment with ethanol, allowing production of lignin and enzymatically digestible cellulose in a one-step fractionation process. After ethanol-based organosolv pretreatment, the enzymatic digestibility of pretreated sugarcane bagasse was greatly enhanced: based on 100 g raw material, 39.96 g glucose could be obtained during enzymatic hydrolysis, representing 91.39 % of the glucose in the raw material. Furthermore, characterization of raw material and solids pretreated at various temperatures by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR) spectroscopy, and thermogravimetric (TG) analysis was carried out to better understand how delignification and hemicellulose removal affected subsequent enzymatic hydrolysis. Pyrolysis–gas chromatography/mass spectroscopy (Py–GC/MS) analysis of lignins recovered after ethanol-based pretreatment and enzymatic residues indicated that the two lignin fractions generated different pyrolysis products, but they were both enriched in p-hydroxyphenyl (H) units.