Synthesis and Characterization of Beta-Glucosidase (EC 3.2.1.21) Magnetic Nanoparticle Bioconjugates for Biocatalyst Applications

Wednesday, November 10, 2010: 9:20 AM
Canyon B (Hilton)
Hee Joon Park, Chemical Engineering, University of Wyoming, Laramie, WY, Matt Kipper, Chemical and Biological Engineering, Colorado State University, Fort Collins, CO and Patrick A. Johnson, Chemical & Petroleum Engineering, University of Wyoming, Laramie, WY

Four different types of bioconjugates were developed using magnetic nanoparticles (MNPs) as the core solid support and β-glucosidase (βG) as the immobilized enzyme. MNPs were prepared by oxidation of Fe(OH)2 . βG was covalently bound on the surface of MNPs by two different methods. The first method used glutaraldehyde as a cross-linking agent between amine groups on MNP and enzymes. MNP surfaces were modified with 3-(aminopropyl)triethoxysilane (APTES) to express amine groups on the surface. The second method adds poly(ethylene glycol) (PEG) as a longer spacer between MNPs and βG. The surface of MNPs were functionalized with (3-glycidyloxypropyl)trimethoxysilane (GOPES) and three different molecular weight PEG compounds (200, 400, and 1000). The saturated magnetization (Ms) of the MNPs was 62.3 emu g-1 and was reduced 60.4 emu g-1 after immobilization process. The bioconjugates were thermally stable at 65 oC and tested for five consecutive recycling processes. In terms of total product conversion, the substrate conversion quantity by the bioconjugates was comparable to native βG after the fifth cycle.

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