title: The comparative study of a laccase-natural clinoptilolite-based catalyst activity and free laccase activity on model compounds.
abstract: For the first time a laccase from Trametes versicolor was immobilized on a natural clinoptilolite with Si/Al=5 to obtain a biocatalyst for environmental applications. Immobilization procedures exploiting adsorption and covalent binding were both tested, and only the last provided enough activity for practical applications. The optimal conditions for the immobilization of the enzyme on the support and the kinetic parameters for the free and covalent bonded laccase were determined. The laccase bonded to the zeolitic support showed a lower activity than the free laccase, but the pH and thermal stability were greater. 20 mg of dry biocatalyst containing 1 U of laccase were able to remove in 50h 73-78% of 2-chlorophenol and 2,4-dichlorophenol in relatively concentrated aqueous solutions (100 μmol L(-1)).
authors.affiliation: Institute of Chemical Methodologies of CNR (IMC), Research Area of Rome 1, Via Salaria Km 29,300, 00015 Monterotondo, Rome, Italy.
authors.forename: Enrica
authors.initials: E
authors.lastname: Donati
authors.affiliation: Institute of Chemical Methodologies of CNR (IMC), Research Area of Rome 1, Via Salaria Km 29,300, 00015 Monterotondo, Rome, Italy. Electronic address: chiara.polcaro@cnr.it.
authors.forename: Chiara M
authors.initials: CM
authors.lastname: Polcaro
authors.affiliation: Institute of Chemical Methodologies of CNR (IMC), Research Area of Rome 1, Via Salaria Km 29,300, 00015 Monterotondo, Rome, Italy.
authors.forename: Piero
authors.initials: P
authors.lastname: Ciccioli
authors.affiliation: Institute of Agro-Environmental and Forest Biology of CNR (IBAF), Research Area of Rome 1, Via Salaria Km 29,300, 00015 Monterotondo, Rome, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Galli
mesh_terms: D000327:Adsorption; D002384:Catalysis; D002733:Chlorophenols / Q000737:chemistry; D004800:Enzymes, Immobilized / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D042845:Laccase / Q000737:chemistry*; D013696:Temperature; D055454:Trametes / Q000201:enzymology; D017641:Zeolites / Q000737:chemistry*
chemical_list: D002733:Chlorophenols; D004800:Enzymes, Immobilized; C083175:clinoptilolite; D017641:Zeolites; D042845:Laccase; C004762:2,4-dichlorophenol
keywords: 2,4-Dichlorophenol; 2-Chlorophenol; Biocatalyst; Laccase; Natural clinoptilolite