Alver, ErolMetin, Aysegul Ulku2020-06-252020-06-252017closedAccess0964-83051879-0208https://doi.org/10.1016/j.ibiod.2017.07.012https://hdl.handle.net/20.500.12587/6845Immobilization improves the stability and reusability of enzymes. In this study, laccase, which is a green biocatalyst, was immobilized onto Cu (II)-chelated chitosan nanoparticles via adsorption and successfully applied to remove phenol from aqueous solution. Cu (II)-chelated chitosan-graft-poly (glycidyl methacrylate) nanoparticles were prepared using poly (ethylene imine), PEI, which is employed as both a spacer arm and metal chelator and used to immobilize laccase by coordination. Properties of chitosan based nanoparticles were characterized using FTIR, TGA, SEM and zeta-sizer analysis. The maximum laccase loading capacity of Cu (II)-chelated chitosan based nanoparticles (CHT-PGMA-PEI-Cu (II) NPs) was calculated as 65.75 +/- 2.51 mg/g. This immobilized system exhibited broad pH and temperature profiles, and better stability and reusability than free enzyme; after eight cycles of continuous use, the activity of the immobilized enzyme remained above 50 +/- 0.62%. The K-m and V-max values of free and immobilized laccase were 0.055 mM, 0.070 mM, and 0.19 U/mg, 0.14 U/mg, respectively. The catalytic efficiencies (V-max/K-M) of the free and immobilized laccase were 3.45 and 2.0, respectively. Feasibility of the laccase immobilized system in the removal of phenol was investigated in a batch system. The results showed that the CHT-PGMA-PEI-Cu (II) NPs have great potential for industrial applications. More than 96% of phenol was removed with laccase immobilized metal chelated NPs in the presence of mediator, ABTS, indicating that the metal-chelated chitosan based NPs is a promising support for both laccase immobilization and further applications in the removal of phenolic compounds. (C) 2017 Elsevier Ltd. All rights reserved.eninfo:eu-repo/semantics/closedAccessChitosanNanoparticlesLaccaseCu (II)PhenolArticle12523524210.1016/j.ibiod.2017.07.0122-s2.0-85027095920Q1WOS:000414878300026Q1