Study On Immobilization Of Lipase Bacterial Cellulose

Bacterial cellulose is high purity cellulose that is obtained by the acetobacter xylinum. Bacterial cellulose have many unique properties, for example nanofiber-network structure, higer crystallinity, high strength and biological adaptability and so on. In recent years, immobilized lipase become one of the focus in the international researches. In this paper, the methods of immobilization of lipase on the bacterial cellulose membrane carriers and the characterization of the immobilized lipase on the bacterial cellulose membrane carriers, bacterial cellulose pellets and hydroxypropyl bacterial cellulose carriers, respectively.Preparation of bacterial cellulose membrane was studied. Lipase was immobilized on the bacterial cellulose membrane by adsorption and adsorption-crosslink. The experiment evaluated the effects of different membrane size, adsorption time and the amount of lipase on immobilized lipase. There five targets:immobilized enzyme activity, specific activity, percent of adsorption, activity recovery and protein binding capacity. Some characters such as optimum temperature, optimum pH value, the thermal stability, the pH stability, the operation stabilities and the reuse stability have been studied. The result of the experiment prove that the optimum temperature of immobilized lipase was 50℃, the optimum pH was 5. The thermal stability, the pH stability, the operation stabilities and the reuse stability were improved.Preparation of bacterial cellulose pellets was studied. Lipase was immobilized on the bacterial cellulose pellets. The optimum temperature of immobilized lipase was 50℃, the optimum pH was 5. After the heating was continued for 3 hours, the residual activity was still 70%. Reused after 8 times, residual activity was 45%. Storage of 30 days, the residual activity was 70%.Preparation of hydroxypropyl bacterial cellulose was studied. Lipase was immobilized on the hydroxypropyl bacterial cellulose carriers. By comparison of the characters of the free lipase, the immobilized lipase on the bacterial cellulose membrane, bacterial cellulose pellets and hydroxypropyl bacterial cellulose. The results show that:the immobilized lipase was the best in enzymatic properties and stability on the hydroxypropyl bacterial cellulose.The research work that has been studied in the paper widens the application fields of bacterial and provides necessary experimental and theoretical base for the further development of the immobilized lipase.