An efficient and mild fractionation of corn stover via 2-phenoxyethanol and silicotungstic acid biphasic pretreatment for biomass valorization

Abstract

Developing an efficient and facile pretreatment is of great importance to comprehensive utilization of lignocellulosic biomass. Herein, a biphasic system of 2-phenoxylethanol (EPH) and silicotungstic acid (STA) was employed for fractionation of corn stover. The EPH/STA biphasic system demonstrated remarkable fractionation efficiency to remove 90.23 % of xylan and 88.54 % of lignin, while retaining 85.60 % of cellulose under the mild pretreatment conditions of 130 °C for 90 min with 7/3 of EPH/STA and 40 mM of STA. The xylose of 52.93 % and lignin of 88.01 % were recovered in aqueous phase and organic phase by EPH/STA biphasic pretreatment, respectively. In the further process, 94.27 % of saccharification was achieved by enzymatic hydrolysis of cellulose-rich solid residue, and 106.17 mg/g of xylonic acid was obtained by oxidation of xylose in aqueous phase. Additionally, the recovered lignin in organic phase could be fabricated to lignin-based films with good mechanical properties. Notably, acid solvent in biphasic system had an important role in fractionation efficiency of corn stover. The STA had the best effect among the different acid solvents. This work provided a promising route to full components utilization of corn stover for biomass valorization.