Role of two polysaccharide matrices on activity, stability and recycling efficiency of immobilized fungal amyloglucosidase of GH15 family

Abstract

Current study deals with immobilization of amyloglucosidase using two different strategies (entrapment and covalent binding). Chitosan beads were prepared using neutralization method while alginate beads were synthesized by simple gelation. Results of this study showed that percent recovery of amyloglucosidase after covalent binding was 85% however in case of entrapment it was 66%. Immobilization was optimized by standardizing various conditions including concentrations of polysaccharide (alginate: 4%; chitosan: 3%), divalent ions (0.2M) and glutaraldehyde (5%). Slight shift in catalytic efficiency of soluble amyloglucosidase in terms of reaction time, pH and temperature was also noticed after immobilization. Activation energy decreased after immobilization due to which stability of amyloglucosidase increased for longer time period as compared to soluble enzyme. Results of recycling studies showed that covalently bound amyloglucosidase retained more enzymatic activity even after 15 cycles as compared to the entrapped enzyme that lost its activity within 10 cycles.