Chemomechanical pretreatment for efficient delignification and saccharification of corn stover biomass

Abstract

The development of multifunctional pretreatments for effective and economical fractionation of lignocellulosic biomass (LCB), while targeting entirely lignocellulose-oriented valorization can pave the cutting-edge innovation in biorefinery. Herein, a promising high-solid chemomechanical pretreatment (CMP) based on ball milling (BM) coupled with ethylenediamine (EDA) pretreatment was designed to maximize the output of corn stover (CS) biomass under the mild temperature (≤120 °C) and active stabilization. The synergistic effects of EDA/BM configuration brought about desirable characteristics that eventually intensify delignification and saccharification at the expense of less solvent load and energy consumption up to 3.0 MJ kg−1 compare with EDA pretreatment (7.3 MJ kg−1). Importantly, CMP generated aminated and uncondensed lignin up to 85 % at 400 rpm for 1 h, with a high content of β-O-4 linkages (44.7/100Ar), which render it competently suitable for valorization into nitrogen-containing aromatic chemicals and lignin-based fluorescent materials. CMP led to 97 % conversion of glucan, and 94 % of xylan in 72 h at enzymatic loading of 1 and 0.5 %w. w-1 of Cellic CTec3 and xylanase, respectively. This lignin-first and entirely lignocellulose-oriented pretreatment could overcome the hampering of solid-state conversion and contribute to the sustainable LCB-based economy.