Two-step liquefication process of lignocellulose in acetone/H 2 O medium for non-enzymatic sugar production

The use of lignocellulosic biomass to produce biofuels and biobased products requires effective fractionation and valorization of the three main lignocellulose constituents. A novel two-step process was developed using acetone/H 2 O as solvent to fractionate lignocellulose into cellulose, hemicellulose derivatives, and lignin, followed by non-enzymatic hydrolysis of recovered cellulose into soluble sugars by ultra-low concentration acid. In the first step, about 87.6% of the hemicelluloses and 88.7% of the lignin were successfully removed and recovered in different streams, under the reaction condition of 140 °C for 1 h with 0.6 wt% H 2 SO 4 in acetone/H 2 O medium. Then the recovered cellulose residues were hydrolyzed into monomers and soluble oligomers catalyzed by 0.25 wt% H 2 SO 4 at the temperature of 180 °C for 15 min in the solvent mixture. This two-step method avoided the mutual interference of different components during the degradation process and successfully hydrolyzed and recovered 77.2% of the total carbohydrates from the raw corn stover without using expensive cellulase enzymes. This method has potential application in the effective utilization of lignocellulose and could serve as an alternative to current lignocellulosic derived sugar platform scheme. Graphical abstract