Abstract: Immobilizing enzyme by ion exchange adsorption is easy and inexpensive, but its stability is poor. For improving operational stability of immobilized enzyme by biosensor encapsulation resin the chicken liver-esterase was encapsulated by alginate. Influences on activity rate of enzyme in different SA (Sodium alginate) concentrations, CaCl2 (calcium chloride) concentration and other operational conditions have been investigated. Activity rate of immobilized enzyme was compared with the entrapped calcium alginate under real condition. The results showed that the operational stability was obviously enhanced in 0.2% SA, 0.1mol/L CaCl2 and 30 minutes standing. Moreover, attempt of adding 0.025mol/L Ca+ into Tris buffer would also improve the stability of alginate gel.

Key words: operational stability, immobilized enzyme, encapsulating, ion exchange adsorption