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α-Amylase Immobilization on Nanocomposite Magnetic Silica Particles and Characterization of the Prepared Nanobiocatalysts

Sayyahmanesh, Maryam | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 45655 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Mashayekhan, Shohreh; Arpanaei, Ayyoob
  7. Abstract:
  8. Enzymes are widely used in industry, however, the expensive cost, low stability, and the limited activity in a certain range of temperature and pH, have limited the usage of such bio-catalists. In addition to increasing and preserving their activity under different conditions, the enzyme immobilization can improve its stability in different pH, temperature values and increase its thermostability, storage stability and the possibility of their recycling. Meanwhile, utilizing the super-magnetic systems could be very helpful as well. For instance, separation of the the magnetic nano-particles like Fe3O4 from reaction system using an external magnetic field is easily possible. In this study, α-amylase was covalently immobilized onto amino group functionalized magnetite-silica particles, magnetite-silica-polyethyleneimine & magnetite-silica-polyacrylic acid. The amount of covalently bound α-amylase was found 80%, 90% & 92% respectively. Magnetite nano composites were characterized using Fourier transform infrared spectroscopy (FT-IR), Scannining electron microscopy (SEM), X-ray diffraction (XRD), Thermogravimetric & zeta potentional analyses. Immobilized α-amylases on magnetite-silica particles, magnetite-silica-polyethyleneimine have better activity than free enzymes but α-amylase Amino group immobilized onto magnetite-silica-polyacrylic acid have been seen no activity. in following amin functionalized magnetite-silica & magnetite-silica-polyethyleneimine¬ particles were named Amin-magnetite-silica nanoparticles (MSP-A) & Polyamin-magnetite-silica nanoparticles (MSP-PA) respectively . The optimum pH value for the free & immobilized α-amylase was at pH 6. The immobilized α-amylase on MSP-A & MSP-PEI was stable up to 16 days and lost only 50% & 30% of initial their activity. The covalently bound enzyme demonstrated more than 70% & 90% activity after 5 runs, 35% & 70% activity after 10 runs
  9. Keywords:
  10. Enzyme Stabilization ; Magnetic Nanodot ; Alpha-amylase Enzyme ; Polyethylenimine ; Magnetic Silica Nanoparticles ; Magnetic Silica Nanoparticle-Polyethylene-Imine

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