title: Immobilization of laccase by Cu(2+) chelate affinity interaction on surface-modified magnetic silica particles and its use for the removal of 2,4-dichlorophenol.
abstract: Magnetic Cu(2+)-chelated silica particles that employ polyacrylamide as a metal-chelating ligand were developed and used to immobilize laccase by coordination. The particles were characterized by scanning electron microscope and Fourier transform infrared spectroscopy. The preparation, the enzymatic properties of the immobilized laccase, and its catalytic capacity for 2,4-dichlorophenol degradation were systemically evaluated. The results showed that immobilized laccase exhibited maximum enzyme activity when it was immobilized for 1 h at a pH of 4.0 and a temperature of 5 °C. The optimum laccase dose was 20 mg/g of carrier. In comparison to free laccase, the immobilized laccase had better acid adaptability and thermal stability. Higher activity was observed for immobilized laccase at a pH range of 2.0 to 3.5 and temperatures from 25 to 40 °C. The immobilized laccase that was prepared for this work exhibited a good catalytic capacity for removing 2,4-dichlorophnol from aqueous solutions.
authors.affiliation: The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing, 100875, People's Republic of China. wangying_21cn@yahoo.com.cn
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Chen
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.forename: Furong
authors.initials: F
authors.lastname: He
authors.forename: Ran
authors.initials: R
authors.lastname: Wang
mesh_terms: D002733:Chlorophenols / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D004800:Enzymes, Immobilized; D042845:Laccase / Q000737:chemistry* / Q000378:metabolism*; D008280:Magnetics; D008855:Microscopy, Electron, Scanning; D015394:Molecular Structure; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000378:metabolism; D018508:Water Purification
chemical_list: D002733:Chlorophenols; D004800:Enzymes, Immobilized; D014874:Water Pollutants, Chemical; D012822:Silicon Dioxide; D003300:Copper; D042845:Laccase; C004762:2,4-dichlorophenol