Construction Of Magnetic Hydroxy Microspheres And Application In Immobilized Penicillin Acylase

The immobilized enzymes have more stability, more use times and easier separation from substrate and product than enzymes in bulk solution. But current immobilization methods have many disadvantage, such as much enzyme activity lose after immobilization and high cost. So only a few immobilized enzymes have been used in industry widely though immobilized enzyme have been studied for about thirty years. In order to resolve these disadvantages, new enzyme carriers and immobilization methods need to be explored. In this paper we put forward some solutions and synthesized a kinds of new enzyme carriers.The immobilized penicillin G acylase (PGA) has played an important role in the manufacture of semi synthetic antibiotics. Much effect is being made to develop new types of carrier to improve the catalytic efficiency of the enzyme and reduce the cost of the supports. With suspension polymerization, taking above nanometer magnetic Fe₃O₄ particles as nucleus, and the copolymers of 2-hydroethyl methylate and styrene as macromolecular shell, hydroxyl magnetic microspheres were synthesized and activated with epoxyl chloropropane. Epoxy groups of copolymer supports can couple with amino groups of PGA under mild conditions so that the enzyme molecules can be immobilized on the surface of the supports. The effects of amount of crosslinking agent and immobilized conditions such as pH, time, temperature and amount of PGA on the binding efficiency, expression and activity of immobilized enzyme were investigated. The results showed that the polymer with crosslink density 30% can be used as a perfect immobilization enzyme support, and the appropriate immobilization conditions of PGA are pH 8.0, the temperature 35°C, the reaction time 24 h, and the amount of PGA 2000IU/g (dry weight). Under the above conditions the immobilized enzyme activity, binding efficiency and expression are 782. 2U/g (dry...