Development of an immobilized cellulase system based on metal-organic frameworks for improving ionic liquid-tolerance and in situ saccharification of bagasse

To achieve high ionic liquid (IL)-tolerance and promote in situ enzymatic hydrolysis of biomass, four metal-organic framework (MOF) carriers, including ZIF-8, UIO-66-NH2, MIL-100-Fe, and PCN-250 were used for cellulase immobilization through simple physical adsorption. The results showed that ZIF-8 had the largest enzyme adsorption capacity at 176.16 mg/g support. In addition, the immobilized cellulases activity was evaluate in the presence of 1-ethyl-3-methylimidazolium diethylphosphate ([Emim]DEP) by using caryboxymethyl cellulose (CMC), and filter paper (FP) as substrates, respectively. When IL concentration increased from 0-50% (v/v), the immobilized cellulase displayed superior IL-tolerance compared with free cellulase. In particular, ZIF-8 immobilized cellulase exhibited a remarkable IL-tolerance, in which the activity of caryboxymethyl cellulase (CMCase) and filter paper cellulase (FPase) were increased by 112.59% and 59.86% in 50% (v/v) [Emim]DEP, respectively. The analysis of kinetic parameters f...