An enhanced ionic liquid-tolerant immobilized cellulase system via hydrogel microsphere for improving in situ saccharification of biomass.

A novel immobilized cellulase based on hydrogel microsphere was established to accommodate ionic liquid (IL)-involved in situ biomass saccharification. For immobilization, poly(N-isopropylacrylamide) (PNIPAM) was employed to immobilize cellulase, with immobilization yielded up to 95.6%. Besides, 1-ethyl-3-methyllimidazolium acetate ([EMIM]OAc) was found as an appropriate IL for in situ saccharification due to its relative enzymatic activity, which was as high as 167.5%. With utilization of immobilized cellulase in IL-pretreated in situ bagasse (BC) saccharification, relative enzymatic activity was 40.9%, which was higher than free cellulase under 5% (v/v) IL, and achieved 12.3%, which was found to be higher than free one in 25% (v/v) IL. Moreover, for estimating reusability, relative enzymatic activity on the 6th cycle retained over 85.2%. This novel immobilization system possessed a remarkable preservation to cellulase in hydrolysis contained interferences, e.g. IL, suggesting a noticeable practical potential in hydrolysis of cost-effective sustainable biomass materials.