A Comprehensive Study of Cellulignin Production from Sugarcane Bagasse, Sugarcane Straw, and Energy Cane for Advanced Biofuels: Liquor Composition and Cellulignin Characterizations

This work aims to comprehensively study the optimal conditions for hydrothermal pretreatment, which selectively solubilizes hemicellulose without using chemicals for sugarcane bagasse (SCB), sugarcane straw (SCS), and energy cane (EC). Raw SCB, SCS, and EC were submitted to hydrothermal pretreatments at temperatures and time ranging from 180 to 300 ^oC and 0 to 180 min. Glucose, xylose, arabinose, furfural, hydroxymethyl furfural, and acids were analyzed in collected liquor. The solid materials, i.e., biomass and cellulignin, were characterized using X-ray diffraction, mid-infrared, thermogravimetric analysis, and scanning electron microscopy. The characterizations were helpful in identifying changes in solid materials in the different pretreatments. Best pentose and furfural yields were obtained from SCB pretreatment, reaching respectively 98.8 g kg^− 1 and 30.6 g kg^− 1 at 90 min and 180 ºC. SCS reached at 170 ºC and 165 min, 60.7 g kg^− 1 and 24.7 g kg^− 1 of pentoses and furfural, respectively. EC provided 50.6 and 28.5 g kg^− 1 of pentose and furfural, respectively, at 180 ºC and 90 min. However, it was not possible to achieve higher pentose yields in shorter times, which requires further study with the addition of catalysts to improve pentoses’ conversion rate to furfural.