title: Reversible immobilization of glucoamylase onto magnetic chitosan nanocarriers.
abstract: A simple preparation process for the monodispersed pH-sensitive core-shell magnetic microspheres was carried out consisting of chitosan self-assembled on magnetic iron oxide nanoparticles. Meanwhile, glucoamylase was immobilized as a model enzyme on this carrier of Fe(3)O(4)/CS microspheres by ionic adsorption. The morphology, inner structure, and high magnetic sensitivity of the resulting magnetic chitosan microspheres were studied, respectively, with a field emission scanning electron microscope (SEM), transmission electron microscope (TEM), FT-IR spectroscopy, thermogravimetric analysis (TGA), and a vibrating sample magnetometer (VSM). Subsequently, the properties of glucoamylase immobilized on the regenerated supports were also investigated by determining storage stability, pH stability, reusability, magnetic response, and regeneration of supports. The results from characterization and determination remarkably indicated that the immobilized glucoamylase obtained presents excellent storage stability, pH stability, reusability, magnetic response, and regeneration of supports. Therefore, this kind of magnetic Fe(3)O(4)/CS microspheres with perfect monodispersity should be an ideal support for enzyme immobilization.
authors.affiliation: State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Institute of Biochemical Engineering & Environmental Technology, Lanzhou University, Lanzhou 730000, China.
authors.forename: Jianzhi
authors.initials: J
authors.lastname: Wang
authors.forename: Guanghui
authors.initials: G
authors.lastname: Zhao
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Li
authors.forename: Xiao
authors.initials: X
authors.lastname: Liu
authors.forename: Pingping
authors.initials: P
authors.lastname: Hou
mesh_terms: D048271:Chitosan / Q000737:chemistry*; D004800:Enzymes, Immobilized / Q000737:chemistry*; D005087:Glucan 1,4-alpha-Glucosidase / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008280:Magnetics; D008855:Microscopy, Electron, Scanning; D036103:Nanotechnology; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry
chemical_list: D004800:Enzymes, Immobilized; D048271:Chitosan; D005087:Glucan 1,4-alpha-Glucosidase