Immobilization of maltogenic amylase in alginate-chitosan beads for improved enzyme retention and stability

Abstract

Maltogenic amylase (Mag1) is a potent enzyme that hydrolyzes the glycosidic bond of polysaccharides to produce malto-oligosaccharides (MOS). However, the Mag1 enzyme has poor stability and reusability, leading to inefficient MOS production. Enzyme immobilization is a promising method to solve the enzyme stability problem. Entrapment and encapsulation technique was used in this study to immobilize Mag1 because of high biocompatibility and prevention of enzyme degradation, hence lesser loss of enzymatic activity. Chitosan was used as a coating membrane on the alginate matrix, preventing enzyme leaching from the beads. Mag1 entrapped in alginate-chitosan beads showed better performance compared to alginate beads in terms of thermostability, reusability and enzyme retention. Alginate-chitosan beads showed improvement of temperature stability of approximately 35%, 30% and 20% at a respective temperature of 30 °C, 40 °C and 50 °C. Reusability analysis showed immobilized Mag1 can be used up to at least eight cycles with retained activity of 80% and 70% from its initial activity for alginate-chitosan and alginate beads respectively. Enzyme leakage percentage in alginate-chitosan was 7-21%, while that in alginate was 12-35%. The overall findings envisage the promising application of alginate-chitosan beads immobilized Mag1 as a biocatalyst for MOS synthesis.