Efficient hydrolysis of cellobiose by β-glucosidase immobilized on ionic liquid-modified magnetic covalent organic frameworks

Background The efficient use of lignocellulosic biomass is key to easing energy and environmental pressures. Catalytic hydrolysis of cellobiose to glucose is the bottleneck in biomass saccharification. As a rate-limiting enzyme in cellulose degradation, β-glucosidase relieves cellobiose inhibition and improves saccharification yield. Method Here, an ionic liquid-functionalized magnetic covalent organic framework (MCOF-IL) was constructed for β-glucosidase immobilization. Magnetic covalent organic framework (MCOF) was prepared via polydopamine-mediated interfacial polymerization on Fe₃O₄, and MCOF-IL was obtained by grafting imidazolium ionic liquid. Significant findings Characterization showed that IL modification preserved COF crystallinity and mesoporous structure while introducing quaternary ammonium sites (N⁺). The immobilized enzyme's optimal temperature rose from 50 °C to 70 °C, with enhanced thermal stability (74.9% activity after 6 h at 50 °C). In cellobiose hydrolysis, the catalyst retained 76.3% activity after 10 cycles. This biocatalyst offers an efficient, recyclable platform for lignocellulose biorefinery.