Immobilized Of α-amylase Using Magnetic Carrier

Amylase(Amylase, E.C.3.2.1.1) is widely distributed in nature as a biological catalyst, whether higher plants or microorganisms can produce amylase. Therefore, the industrial production and application of the amylase more than other enzyme preparations. However, in the process of industrial production, often need to use a large number of enzyme catalytic reaction, but the product and free enzyme is often difficult to effective separation, resulting in a serious waste of enzyme preparation. Since the 90’s of last century, immobilized enzyme technology has been full researched, and has made some progress, especially using magnetic composite carrier to fix enzyme. Compared with the free enzyme, the immobilized enzyme can be separated with reaction products by simple and easy method in the catalytic reaction. The result is that the immobilized enzyme can be reused which could reduce cost.In this experiment, to prepare magnetic composite carrier particles by using covalent cross-linking method, we used chitosan powder to ambed nano Fe3O4 particles. The reaction conditions which the mass ratio of chitosan and Fe3O4 was 1:2, and stirring speed was 700 r/min, and amount of glutaraldehyde was 1 mL were the best to prepare magnetic composite carrier particles. By using scanning electron microscopy(SEM) and Fu Liye transform infrared spectrometer(FT-IR) to analyze magnetic composite carrier, the results showed that the magnetic composite carrier particles were balck balls and uniform size and well dispersion. Used the magnetic composite carrier particles to fix with a-amylase and optimized the immobilization reaction conditions. The study found when magnetic composite carrier particles were by 1.5% glutaraldehyde activating 60 min, at pH 6, temperature is 20℃, time is 8 h, immobilized amylase activity reached 14,654 U/g and the maximum immobilization efficiency was 81%.In this experiment, we also studied the physicochemical properties of immobilized amylase. The results showed that the optimum pH was 6, consistent with the free amylase. Compared with the free enzyme, the optimum reaction temperature of immobilized amylase is 60 which higher 20 than the ℃ ℃the free amylase. After reusing 10 times, the residual activity of immobilized amylase was also reached 50%. When the immobilized amylase and the free amylase were presrvated in the refrigerator at 4℃, after 40 days,the residual activity of immobilized amylase was 73%, but the free amylase was almost no activity. In summary, the immobilized amylase is much better than the free amylase in many ways, such as the optimuml reaction temperature, reusability and bin stability, which will provide some technical methods and reference resources for later industrial production and application.