title: [Immobilization of laccase on magnetic chitosan microspheres and study on its enzymic properties].
abstract: Laccase was immobilized on magnetic chitosan microspheres by using glutaraldehyde as cross-linking reagent. The immobilization conditions and characterization of the immobilized enzyme were investigated. immobilization conditions for laccase were: 10mL of 0.8mg/mL of laccase in phosphate buffer(0.1mol/L, pH 7.0) reacted with 50mg of magnetic chitosan microspheres at 25 degrees C for 1h and subsequently was kept at 4 degrees C for 2h. The immobilized enzyme exhibited the maximal activity at pH 3.0. The optimal temperatures for immobilized enzyme were 10 degrees C and 55 degrees C. The Km value of immobilized laccase for ABTS was 171.1 micromol/L in pH 3.0 phosphate buffer at 37 degrees C. Compared with free enzyme, the thermal, operational, and storage stabilities of the enzyme were increased after the immobilization.
authors.affiliation: Key Laboratory of Fiber Optic Sensing Technology and Information Processing, Ministry of Education, Fiber Optic Sensing Technology Research Center, Wuhan University of Technology, Wuhan 430070, China.
authors.forename: De-Sheng
authors.initials: DS
authors.lastname: Jiang
authors.forename: Sheng-Ya
authors.initials: SY
authors.lastname: Long
authors.forename: Jun
authors.initials: J
authors.lastname: Huang
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Xiao
authors.forename: Ju-ying
authors.initials: JY
authors.lastname: Zhou
mesh_terms: D048271:Chitosan / Q000737:chemistry*; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D042845:Laccase / Q000737:chemistry / Q000378:metabolism*; D008280:Magnetics; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D013696:Temperature
chemical_list: D004800:Enzymes, Immobilized; D048271:Chitosan; D042845:Laccase