(477b) Application of Three-Component Dihyroxybenzoic Acid-Based Deep Eutectic Solvent in a Sustainable Biorefinery Process

In this study, 3,4-dihydroxybenzoic acid (DHBA)-based three-component deep eutectic solvents (DESs) were used to pretreat transgenic sorghum bagasse with lignin rich in DHBA. DESs were formed with choline chloride (ChCl), DHBA, and a third component (water, ethanol, ethylene glycol, respectively). Without the addition of the third component, ChCl and DHBA formed DESs at molar ratios of 2:1 and 3:2. DESs formed with both molar ratios were evaluated for delignification and xylan removal of sorghum bagasse, and ChCl-DHBA formed at 3:2 resulted in better pretreatment performance. Recently, an increasing number of studies have reported the utilization of three-component DESs in biomass pretreatment. However, studies on three-component lignin-derived phenolic compound-based DESs are limited. To further increase the pretreatment performance, three-component DESs were synthesized based on ChCl-DHBA 3:2 DES and applied to pretreat both wild-type and transgenic sorghum bagasse. Chemical compositions, cellulose properties, and enzymatic digestibility of various sorghum bagasse samples before and after pretreatment were characterized. Cellulolytic enzyme lignin and fractionated lignin were isolated and structurally characterized to provide a comprehensive investigation of three-component DHBA-based DES. The results of this study will aid in the development of a sustainable biorefinery process using lignin-based DESs.