Fe/Mn bimetal-doped ZIF-8-encapsulated chitosanase for highly efficient synthesis of chitosan oligosaccharide

MOFs represent a promising platform for enzyme immobilization, yet the development of tailored strategies to accommodate both enzyme properties and MOF structures remains a challenge. In this study, we employed chitosanase BCC1 as a model enzyme and integrated Fe 2+ /Mn 2+ ions into the ZIF-8 to construct a bimetallic MOF-based immobilization system (BCC1@Fe/Mn-ZIF-8). Comprehensive characterization by SEM, FTIR, TGA confirmed the successful immobilization and structural integrity of the composite. The immobilized enzyme retained 97 % of its initial activity and exhibited enhanced stability under harsh thermal, pH, and solvent conditions. Notably, BCC1@Fe/Mn-ZIF-8 maintained 117 % activity after 14 days at 4 °C and 72 % residual activity after 14 reuse cycles, indicating excellent storage and reusability. This bimetallic MOF-based strategy offers a robust and efficient approach for enzyme immobilization, with strong potential in industrial biocatalysis.