Chitosan-Based metal-organic framework for Stabilization of p-glucosidase: Reusability and storage stability

Enzyme immobilization is a powerful tool for protecting enzymes from harsh reaction conditions and improving enzyme activity, stability, and reusability. In this study, metal organic frameworks (MIL-Fe composites) were synthesized via solvothermal reactions and then modified with chitosan (CS). p-Glucosidase was immobilized on the chitosan-metal organic framework (CS-MIL-Fe), and the resulting composites were characterized with various analytical techniques. The p-glucosidase immobilized on a CS-MIL-Fe composite had an immobilization yield of 85 % and a recovered activity of 74 %. The immobilized enzyme retained 81 % of its initial activity after ten successive cycles and preserved 69 % of its original activity after 30 days of storage at 4 degrees C. In contrast, the free enzyme had only preserved 32 % of its original activity after 30 days. Under various temperature and pH conditions, the immobilized enzyme showed greater stability than the free enzyme, and the optimal temperature and pH were 60 degrees C and 6.0 for the immobilized enzyme and 50 degrees C and 5.0 for the free enzyme. The kinetic parameters were also determined, with the Km values of 13.4 and 6.98 mM for the immobilized and free p-glucosidase, respectively, and Vmax values of 3.96 and 1.72 U/mL, respectively. Overall, these results demonstrate that the CS-MIL-Fe@pglucosidase is a promising matrix showing high catalytic efficiency and enhanced stability.