title: Screening of Dowex anion-exchange resins for invertase immobilization.
abstract: Commercial yeast invertase (Bioinvert) was immobilized by adsorption on anion-exchange resins, collectively named Dowex(R) (1x8:50-400, 1x4:50-400, and 1x2:100-400). Optimal binding was obtained at pH 5.5 and 32 degrees C. Among different polystyrene beads, the complex Dowex-1x4-200/invertase showed a yield coupling and an immobilization coefficient equal to 100%. The thermodynamic and kinetic parameters for sucrose hydrolysis for both soluble and insoluble enzyme were evaluated. The complex Dowex/invertase was stable without any desorption of enzyme from the support during the reaction, and it had thermodynamic parameters equal to the soluble form. The stability against pH presented by the soluble invertase was between 4.0 and 5.0, whereas for insoluble enzyme it was between 5.0 and 6.0. In both cases, the optimal pH values were found in the range of the stability interval. The Km and Vmax for the immobilized invertase were 38.2 mM and 0.0489 U/mL, and for the soluble enzyme were 40.3 mM and 0.0320 U/mL.
authors.affiliation: Department of Biochemical and Pharmaceutical Technology, Pharmaceutical Sciences School, University of São Paulo, Brazil.
authors.forename: Ester Junko
authors.initials: EJ
authors.lastname: Tomotani
authors.forename: Michele
authors.initials: M
authors.lastname: Vitolo
mesh_terms: D001709:Biotechnology / Q000379:methods*; D002384:Catalysis; D002411:Cation Exchange Resins / Q000737:chemistry; D002852:Chromatography, Ion Exchange / Q000379:methods*; D004800:Enzymes, Immobilized / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D011137:Polystyrenes / Q000737:chemistry; D013395:Sucrose / Q000737:chemistry; D013696:Temperature; D013816:Thermodynamics; D013997:Time Factors; D043324:beta-Fructofuranosidase / Q000737:chemistry*
chemical_list: D002411:Cation Exchange Resins; D004800:Enzymes, Immobilized; D011137:Polystyrenes; D013395:Sucrose; D043324:beta-Fructofuranosidase