Cross-linked enzyme aggregates of alginate lyase: A systematic engineered approach to controlled degradation of alginate hydrogel

Abstract

An enzyme aggregate of alginate lyase (EC 4.2.2.3) from flavobactierium was prepared using ammonium sulfate. The resultant aggregates upon cross-linking with glutaraldehyde produced insoluble and catalytically active cross-linked enzyme aggregate (CLEA) enzyme. The catalytic activity and stability of the cross-linked enzyme aggregate of alginate lyase (CLEA-AL) was studied in the presence of various pH, temperatures and organic solvents. Reusability, storage stability and surface morphology of the CLEA-AL were also studied. The native enzyme and CLEA-AL exhibited maximum enzyme activity at pH of 6.3 and at a temperature of 40°C. The CLEA-AL has good stability in nonpolar organic solvents and is thermally stable up to 50°C over a period of 8h. By encapsulating CLEA-AL into alginate hydrogel, we demonstrate that alginate hydrogels can be enzymatically degraded in a controlled fashion. The results also showed that degradation of alginate hydrogel with CLEA-AL incorporated beads is slower than native enzyme and therefore, CLEA-AL can be used for controlled degradation and release of various biologics from the degrading gel.

Keywords: Alginate hydrogel; Alginate lyase; Cross-linked enzyme aggregate; Enzyme immobilization; Enzyme-assisted degradation.