Flow chemistry for a better fractionation of lignocellulosic biomass in products structure and yield

[Display omitted] •Flow chemistry using water supports joint valorization of lignin and carbohydrate.•Isolated lignin shows 99.8 % β-O-4 retention and 40.3 % lignin yield.•The extraction liquid contains 80.3 % xylose yield. To achieve the valorization of whole compositions of lignocellulosic biomass, flow fractionation (FF) was developed based on the flow chemistry of the major components of biomass, i.e., glucan, xylan, and lignin. Three kinds of solvent, i.e., water, formic acid, and p-toluenesulfonic acid (p-TsOH), were employed in FF treatments of poplar wood for an evaluation of performance in structure and yield of products. The advantage of FF was firstly confirmed by the nearly complete recovery of glucan in solid product, and the greatly enhanced digestibility of enzymatic hydrolysis as indicated by the glucose yield of 68.1 % at a low cellulase dosage of 10 FPU/g solid product from water treated poplar wood. The second advantage of FF was the rapid hydrolysis and very slight degradation of xylan for the three solvents explored, especially for water as indicated by the xylose yield of 80.3 % from poplar wood treated at 200 °C just for 15 min.. Last but not least, structure-preserved lignins were harvested from biomass with good yield, e.g., 40.3 % of lignin yield and 99.8 % of β-O-4 retention from poplar wood using water as solvent. Thus-obtained lignin (F72T130t30) was successfully transformed to hydrocarbons over Ru/Nb2O5 catalyst with the yield of 21 wt%. In short, these remarkable performances of FF in products structure and yield build a feasible valorization of lignocellulosic biomass for sustainable biorefinery.