<p>In this work, magnetic microporous microspheres were prepared using glycidyl methacrylate (GMA) and ethyleneglycole dimethacrylate (EGDMA) monomers via suspension polymerization method. The MNP@poly(GMA-co-EGDMA) microspheres were characterized using FT-IR, SEM, VSM, and BET methods. The MNP@poly(GMA-co-EGDMA) microspheres were grafted with the tetraethylenepentamine (TEPA) ligand as a cationic ligand, and to serve as a spacer-arm and a chelating group. The TEPA ligand incorporated microspheres were used either in the covalent immobilization of laccase after glutaraldehyde (GA) activation or in the interaction of laccase with metal chelate after the incorporation of Cu(II) ions. The amount of covalently immobilized laccase on the MNP@poly(GMA-co-EGDMA)-TEPA-GA microspheres was 28.3&#xa0;mg/g. The amount of immobilized enzyme via metal chelate interaction on the MNP@poly(GMA-co-EGDMA)-TEPA, and MNP@poly(GMA-co-EGDMA)-TEPA-Cu(II) microspheres was 18.9&#xa0;mg/g and 37.8&#xa0;mg/g, respectively. The highest laccase activity yield was observed with MNP@poly(GMA-co-EGDMA)-TEPA-Cu(II)-Lac, about 69.7%, compared to MNP@poly(GMA-co-EGDMA)-TEPA-GA-Lac (52.9%) using syringaldazine as a substrate. The free laccase showed its maximum activity at pH 5.0. The degradation of Reactive Brown-10 (RB-10) dye using the MNP@poly(GMA-co-EGDMA)-TEPA-Cu(II)-Lac and MNP@poly(GMA-co-EGDMA)-TEPA-GA-Lac microspheres was also studied in the presence of acetosyringone mediator compound, and the degradation performance increased from 64.7% and 93.6%, and from 48.3% to 72.6%, respectively. The MNP@poly(GMA-co-EGDMA)-TEPA-Cu(II)-Lac showed 1.6-fold better catalytic activity for RB-10 dye compared to the MNP@poly(GMA-co-EGDMA)-TEPA-GA-Lac preparation. Furthermore, the MNP@poly(GMA-co-EGDMA)-TEPA-Cu(II)-Lac and MNP@poly(GMA-co-EGDMA)-TEPA-GA-Lac showed good reusability, with retained activities of 61% and 73% for RB-10 dye after five degradation cycles, respectively.</p>

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Immobilization Agaricus bisporus laccase via covalent attachment and metal chelate interaction: removal of reactive brown-10 dye

  • Gulay Bayramoglu,
  • Omur Celikbicak,
  • Mehmet Yakup Arica

摘要

In this work, magnetic microporous microspheres were prepared using glycidyl methacrylate (GMA) and ethyleneglycole dimethacrylate (EGDMA) monomers via suspension polymerization method. The MNP@poly(GMA-co-EGDMA) microspheres were characterized using FT-IR, SEM, VSM, and BET methods. The MNP@poly(GMA-co-EGDMA) microspheres were grafted with the tetraethylenepentamine (TEPA) ligand as a cationic ligand, and to serve as a spacer-arm and a chelating group. The TEPA ligand incorporated microspheres were used either in the covalent immobilization of laccase after glutaraldehyde (GA) activation or in the interaction of laccase with metal chelate after the incorporation of Cu(II) ions. The amount of covalently immobilized laccase on the MNP@poly(GMA-co-EGDMA)-TEPA-GA microspheres was 28.3 mg/g. The amount of immobilized enzyme via metal chelate interaction on the MNP@poly(GMA-co-EGDMA)-TEPA, and MNP@poly(GMA-co-EGDMA)-TEPA-Cu(II) microspheres was 18.9 mg/g and 37.8 mg/g, respectively. The highest laccase activity yield was observed with MNP@poly(GMA-co-EGDMA)-TEPA-Cu(II)-Lac, about 69.7%, compared to MNP@poly(GMA-co-EGDMA)-TEPA-GA-Lac (52.9%) using syringaldazine as a substrate. The free laccase showed its maximum activity at pH 5.0. The degradation of Reactive Brown-10 (RB-10) dye using the MNP@poly(GMA-co-EGDMA)-TEPA-Cu(II)-Lac and MNP@poly(GMA-co-EGDMA)-TEPA-GA-Lac microspheres was also studied in the presence of acetosyringone mediator compound, and the degradation performance increased from 64.7% and 93.6%, and from 48.3% to 72.6%, respectively. The MNP@poly(GMA-co-EGDMA)-TEPA-Cu(II)-Lac showed 1.6-fold better catalytic activity for RB-10 dye compared to the MNP@poly(GMA-co-EGDMA)-TEPA-GA-Lac preparation. Furthermore, the MNP@poly(GMA-co-EGDMA)-TEPA-Cu(II)-Lac and MNP@poly(GMA-co-EGDMA)-TEPA-GA-Lac showed good reusability, with retained activities of 61% and 73% for RB-10 dye after five degradation cycles, respectively.