Enhanced Degradation of Insoluble Chitin: Engineering High-Efficiency Chitinase Fusion Enzymes for Sustainable Applications

N-acetyl-D-glucosamine and its dimer are degradation products of chitin waste with great potential in therapeutic and agricultural applications. However, the hydrolysis of insoluble chitin by chitinases remains a major bottleneck. This study investigated the biochemical properties and catalytic mechanisms of PoChi chitinase obtained from Penicillium oxalicum with a focus on enhancing its efficiency during the degradation of insoluble chitin. Recombinant plasmids were engineered to incorporate chitin-binding (ChBD) and/or fibronectin III (FnIII) domains. Notably, PoChi-FnIII-ChBD exhibited the highest substrate affinity (K