Enhancing biomass enzymatic hydrolysis performance by modified DES lignin

Abstract

The enzymatic hydrolysis of lignocellulose continues to be encumbered by elevated production costs and diminished cellulase efficiency. In this work, modified DES recovered lignin was obtained by grafting acrylamide and acryloyl chloride to enhance glucose release. At a cellulase dosage of 5 FPU/g-cellulose and pH of 5.5, modified lignin promoted glucose yield of dilute-acid-pretreated wheat straw by 158 % compared with control. The mechanism by which modified lignin promotes enzymatic hydrolysis was further explored. The binding constant was reduced from (3.3510 ± 0.8361)* 10⁴ to (2.7600 ± 0.6027)* 10³ L•mol⁻¹ after modification. Modified lignin could make α-helix content enhancement so that cellulase had a compact and stable spatial structure. Lignin binds within the catalytic tunnel of cellulase and that the modified lignin interacts with cellulase with increased hydrogen bonding, resulting in a more compact cellulase structure. The modified lignin might reduce the unproductive adsorption of cellulase, and increase stability and cellulose accessibility to reduce cellulase cost.