Application of Hierarchically Porous Chitosan Monolith for Enzyme Immobilization

Abstract

Enzyme immobilization is a crucial technique for improving the stability of enzymes. Compared with free enzymes, immobilized enzymes offer several advantages in industrial applications. Efficient enzyme immobilization requires a technique that integrates the advantages of physical absorption and covalent binding while addressing the limitations of conventional support materials. This study offers a practical approach for immobilizing α-amylase on a hierarchically porous chitosan (CS) monolith. An optimized CS monolith was fabricated using chemically modified chitin by thermally induced phase separation. By combining physical adsorption and covalent bonding, this technique leverages the amino and hydroxy groups present in CS to facilitate effective enzyme binding and stability. α-Amylase immobilized on the CS monolith demonstrated excellent stability, reusability, and increased activity compared to its soluble counterpart across various pH levels and temperatures. In addition, the CS monolith exhibited a significant potential to immobilize other enzymes, namely, lipase and catalase. Immobilized lipase and catalase exhibited higher loading capacities and enhanced activities than their soluble forms. This versatility highlights the broad applicability of CS monoliths as support materials for various enzymatic processes. This study provides guidelines for fabricating hierarchical porous monolith structures that can provide efficient enzyme utilization in flow systems and potentially enhance the cost-effectiveness of enzymes in industrial applications.