| Magnetic microspheres have developed several dozens of years as a new piece of big molecule function material. Especially, it applied in the immobilized enzyme that solved the difficult problems such as the free enzyme tend to lose its activity and was hard to be separated and used in industry. The magnetic immobilized enzyme can be quickly and effectively used in large-scale industrial production. To produce the magnetic immobilized enzyme with high activity and stability, the polymer that wrapped the magnetic microspheres was the key. By consulting the literature, we found the PF resin and the polyvinylbutryal have high capacity of binding enzyme and protein.We synthesized magnetic nanometer-sized PF microspheres, polyvinylbutryal microspheres by the method of co-precipitation, and immobilized a -amylse on them by the cross-linking method respectively.The kinds of magnetic immobilized enzymes were not reported. At the same time, we used XRD, TEM, IR spectra, Vibrating-sample Magnetometer, UR spectra which provided experimental basis. The major work is summarized as the following:(1) According to the experiments, some factors in the coprecipitating process such as concentration of bivalent and tervalent iron and precipitators, water-bath temperature, the pH value of the system were discussed. It was found that the concentration of bivalent and tervalent iron is the critical factor that affects the form of Fe3O4 bead. When n(Fe2+):n(Fe3+)=2:l, temperature=60 ℃, pH>10, reaction time^lh, the magnetic beads with high magnetism and small diameter can be obtained. The range of diameter was 10~20nm and the shapes of them were globosities proved by TEM.(2) The influence on binding protein capacity with varying prepartion condition of PF resins, magnetic PF micropheres and magnetic polyvinylbutryal micropheres and the immobilization conditions of immobilizing BSA were discussed. The optimum synthesization was temperature: 90℃, reaction time: Ih, formaldehyde: 30.0mL, hydroquinone: 11.0g, muriatic acid: 4mL. When the amount of PF resin=2g/0.01mol, pH=4, absorbing time=3h, magnetic PF microsphere has maximal binding protein capacity. And magnetic polyvinylbutryal microphere perform best if the amount of polyvinylbutryal was: 0.8g/0.01mol, pH: 6, immobilizing time: 3h. In conclusion, magnetic PFmicropheres and magnetic polyvinylbutryal micropheres have preferable binding protein capacity and can be used as good carriers to immobilize protein.(3) The influence on the activity of magnetic immobilized a -amylase and binding protein capacity with varying immobilization conditions were investigated. And we compared and confirm the optimum application conditions, stability etc. of the free enzyme and magnetic immobilized enzyme. The optimum preparation condition of immobilized a -amylase on magnetic PF microsphere by cross-linking method was pH: 5.11, temperature: 10癈, absorbing time:2h, cross-linking time: 4h, n^glutaraldehyde): 0.05%, the amount of a -amylase: 15mL. The activation condition of magnetic polyvinylbutryal micropheres was librating the magnetic bead in the buffer solution (pH=6.97) in a poor light for 4h and leaving it for one night. And the immobilization condition of magnetic polyvinylbutryal micropheres was as follows: pH: 6.07, temperature: 10@, immobilizing time: 3h, w (glutaraldehyde): 0.025%, the amount of enzyme: 15mL. At this time the magnetic immobilized a -amylases have preferable activity.In this dissertation, we found that the a -amylase didn't change its molecule structure and preserve its catalytic activity. When compared with the free a -amylase, the magnetic immobilized a -amylase has higher optimum temperature for use and can be used in wider pH and temperature range. The immobilization enhance a -amylase's ability to resist the protein denaturants and endow it with more higher stability. After long time preservation the immobilized enzyme still have high activity and can be separated easily from the reaction system and used repe...
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