Hydrolysis of cellulose using cellulase physically immobilized on highly stable zirconium based metal-organic frameworks.

Developing a new cellulase-MOF composite system with enhanced stability and reusability for cellulose hydrolysis was aimed. Physical adsorption strategy was employed to fabricate two cellulase composites, and the activity of composite was characterized by hydrolysis of carboxymethyl cellulose. The NH functionalized UiO-66-NH MOF exhibited higher protein loading than the precursor UiO-66, due to the extra anchor sites of NH groups. The immobilized cellulase showed enhanced thermostability, pH tolerance and lifetime. The maximum activity attained at 55 °C could be kept 85% when used at 80 °C, and the residual activities were 72% after ten cycles and 65% after 30 days storage. The abundant NH and COOH groups of MOF adsorb cellulase and enhance its stability, and the resulted heterogeneity offered the opportunity of recovering composite via mild centrifuge. The findings suggest the promising future of developing cellulase-MOF composite with ultrahigh activities and stabilities for practical application.