Hydrothermal pretreatment optimization and deep eutectic solvent pretreatment of lignocellulosic biomass: An integrated approach

Abstract

The combined effect of hydrothermal (HT) and deep eutectic solvent (DES) pretreatment on hemicellulose and lignin removal was studied to enhance cellulose digestibility during saccharification. The operating conditions (water loading and time) for HT pretreatment of sugarcane bagasse (SB) were optimized using response surface methodology (RSM). The SB optimum conditions were applied to other biomass with similar lignin and hemicellulose composition (rice straw (RS) and napier grass (NG)). The HT solids were further subjected to DES pretreatment using ChCl/LA (1:2). The pretreatment efficiency was compared between untreated, HT, ChCl/LA, and HT-ChCl/LA treated solids based on the glucose yield during saccharification. The hemicellulose recovery and delignification were higher in HT-ChCl/LA solids compared to HT and ChCl/LA solids. During saccharification (72 h) of HT- ChCl/LA solids, the glucose yield increased 3.1, 3.4, and 2.9-times for SB, RS, and NG, respectively. Hemicellulose and lignin obtained at different pretreatment stages could benefit the biorefineries. © 2022 Elsevier Ltd