Comprehensive study of xylobiose and cellobiose separation from corn stover enzymatic hydrolysate by adsorption

The enzymatic hydrolysis of pretreated lignocellulose to produce value-added oligosaccharides presents the advantages of a simplified procedural approach with reduced environmental impact. The subsequent purification is necessary to improve the purity of oligosaccharides for further application. In this work, a high-yield xylooligosaccharides-rich hydrolysate was obtained by ball-mill-assisted alkaline peroxide (BAP) pretreatment and enzymatic hydrolysis, and the sequential separation of xylobiose and cellobiose was performed by activated carbon adsorption. Adsorption kinetics and isotherm models of saccharides on activated carbon were systematically investigated to understand the adsorption behavior. Results indicate that separation achieves a purity exceeding 70 %, with 38.21 % of xylobiose and 84.22 % of cellobiose being adsorbed. Density functional theory (DFT) calculations reveal the involvement of oxygen-containing groups on the activated carbon surface in sugar adsorption from the molecular level. The findings of this study establish a theoretical foundation for separating xylobiose and cellobiose from oligosaccharides hydrolysate through activated carbon adsorption.