Fractionation of corncob powder via an amine-based ternary deep eutectic solvent pretreatment for biomass valorization

Developing an efficient and feasible pretreatment is vital for biomass refining. Herein, three kinds of deep eutectic solvents (DESs) were synthesized and evaluated for corncob powder (CCP) pretreatment. Results indicated that lignin removal and feedstock surface disruption were key factors influencing pretreated solids enzymatic digestion. Maximum glucose and xylose yields of this work were 86.4 % and 73.6 %, respectively, which obtained after choline chloride-urea-ethanolamine (ChCl-U-EOA) = 1:1.4:0.6 pretreatment. The characterizations of various recovered lignin revealed that the ester bonds on lignin side chain were broken and corresponding amides were generated, the lignin molecular weight recovered from ChCl-U-EOA was much smaller compared with other two DESs system, and more tricin and methoxyl groups were retained after pretreatment, thus the recovered lignin has better anti-oxidation and anti-ultraviolet potential. The developed ternary DESs pretreatment could not only effectively separate and convert the hemicellulose and cellulose in CCP into xylose and glucose, respectively, the lignin recovered from pretreated liquid also displayed a good potential application in lignin-based sunscreen preparation, which provided a good reference for biomass integrated valorization.