Efficient Fast Fractionation of Biomass Using a Diol‐Based Deep Eutectic Solvent for Facilitating Enzymatic Hydrolysis and Obtaining High‐Quality Lignin

Abstract Current DES pretreatment is often performed under relatively severe conditions with high temperature, long time, and high DES usage. This work studied a short‐time diol DES (deep eutectic solvent) pretreatment under mild conditions to fractionate the bamboo, facilitate enzymatic hydrolysis, and obtain high‐quality lignin. At an optimized condition of 130 °C for only 10 min, lignin and xylan removal reached 61.34 % and 84.15 %, with residual glucan showing a ~90 % enzymatic hydrolysis yield. Equally important, the dissolved lignin could be readily recovered with 97.51 % yield, exhibiting 96.65 % β‐O‐4 preservation. The fractionation and lignin protection mechanisms were unveiled by XRD, FTIR, cellulose‐DP, 2D HSQC NMR, 31 P NMR and GPC analysis. This study highlighted that short‐time fractionation of bamboo can be achieved by a diol‐based DES which is an ideal strategy to upgrade the lignocellulose biomass for high enzymatic hydrolysis yields and high‐quality lignin stream.