Fractionation of sugarcane trash by oxalic-acid catalyzed glycerol-based organosolv followed by mild solvent delignification

Sugarcane trash (SCT) is an under-utilized biomass with potential for conversion to fuels and chemicals. Here, we report an organosolv process involving pretreatment by aqueous glycerol followed by mild delignification with acetone for fractionation of SCT. The effects of glycerol and oxalic acid on efficiency and selectivity of the reaction were studied at different temperatures. The higher glycerol content was found to promote delignification efficiency and enhanced enzymatic digestibility of the solid. An optimal reaction using 80%v/v glycerol at 170 degrees C, with 300 mM oxalic acid followed by acetone extraction at 30 degrees C led to cellulose recovery of 71.7%, whereas 96.8% and 83.9% of the initial hemicelluloses and lignin was removed into the aqueous-glycerol and acetone fractions, respectively. The isolated lignin was recovered with 73.7% yield and 94.6% purity and showed similar chemical profiles with higher thermal stability compared to commercial organosolv lignin according to Fourier Transform Infrared Spectroscopy and Thermogravimetric analysis.