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, an organic solvent and acid aqueous biphasic pretreatment was employed to fractionation of corn stover. The 2-phenoxyethanol and silicotungstic acid (EPH/STA) biphasic system had remarkable fractionation efficiency. 85.60% of cellulose was retained, and 90.23% of xylan and 88.54% of lignin were removed 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 biphasic EPH/STA pretreament, respectively. In the further process, the 94.27% of saccharification was achieved by enzymatic hydrolysis of cellulose-rich solid residues, 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 film with good mechanical properties. Notably, acid solvents in biphasic system had an important role in fractionation efficiency of corn stover. The heteropoly acid (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.

Keywords: Biphasic pretreatment, 2-phenoxyethanol, Silicotungstic acid, Enzymatic hydrolysis, Biomass valorization