title: Immobilization of laccase from Aspergillus oryzae on graphene nanosheets.
abstract: Laccase enzymes of Aspergillus oryzae were immobilized on graphene nanosheets by physical adsorption and covalent bonding. Morphological features of the graphene sheets were characterized via microscopy techniques. The immobilization by adsorption was carried out through contact between graphene and solution of laccase enzyme dissolved in deionized water. The adsorption process followed a Freundlich model, showing no tendency to saturation within the range of values used. The process of immobilization by covalent bonding was carried out by nitration of graphene, followed by reduction of sodium borohydride and crosslinking with glutaraldehyde. The process of immobilization by both techniques increased the pH range of activity of the laccase enzyme compared to the free enzyme and increased its operating temperature. On operational stability, the enzyme quickly loses its activity after the second reaction cycle when immobilized via physical adsorption, while the technique by covalent bonding retained around 80% activity after six cycles.
authors.affiliation: Universidade do Estado de Santa Catarina, Departamento de Engenharia Ambiental, Laboratório de Tratamento de Águas e Resíduos, Av. Luís de Camões, 2090, CEP 88520-000, Lages, Santa Catarina, Brazil. Electronic address: skoronski@cav.udesc.br.
authors.forename: Everton
authors.initials: E
authors.lastname: Skoronski
authors.affiliation: Universidade do Estado de Santa Catarina, Departamento de Engenharia Ambiental, Laboratório de Tratamento de Águas e Resíduos, Av. Luís de Camões, 2090, CEP 88520-000, Lages, Santa Catarina, Brazil.
authors.forename: Diego Hoefling
authors.initials: DH
authors.lastname: Souza
authors.affiliation: Universidade do Estado de Santa Catarina, Departamento de Engenharia Ambiental, Laboratório de Tratamento de Águas e Resíduos, Av. Luís de Camões, 2090, CEP 88520-000, Lages, Santa Catarina, Brazil.
authors.forename: Cyntia
authors.initials: C
authors.lastname: Ely
authors.affiliation: Universidade do Estado de Santa Catarina, Departamento de Engenharia Ambiental, Laboratório de Tratamento de Águas e Resíduos, Av. Luís de Camões, 2090, CEP 88520-000, Lages, Santa Catarina, Brazil.
authors.forename: Felipe
authors.initials: F
authors.lastname: Broilo
authors.affiliation: Universidade Federal de Santa Catarina, Departamento de Engenharia Química e Engenharia de Alimentos, Laboratório de Engenharia Bioquímica, Campus Universitário Trindade, CEP 88040-900, Florianópolis, Santa Catarina, Brazil.
authors.forename: Mylena
authors.initials: M
authors.lastname: Fernandes
authors.affiliation: Universidade Federal de Santa Catarina, Departamento de Engenharia Química e Engenharia de Alimentos, Laboratório de Engenharia Bioquímica, Campus Universitário Trindade, CEP 88040-900, Florianópolis, Santa Catarina, Brazil.
authors.forename: Agenor
authors.initials: A
authors.lastname: Fúrigo
authors.affiliation: Universidade Federal Rural de Pernambuco, Unidade Acadêmica do Cabo de Santo Agostinho, Rua Manoel de Medeiros, Dois Irmãos, CEP 52171-900, Recife, Pernambuco, Brazil.
authors.forename: Marcos Gomes
authors.initials: MG
authors.lastname: Ghislandi
mesh_terms: D000327:Adsorption; D001236:Aspergillus oryzae / Q000201:enzymology*; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism; D006108:Graphite / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D042845:Laccase / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry*; D019800:Phenol / Q000737:chemistry / Q000302:isolation & purification; D013696:Temperature
chemical_list: D004800:Enzymes, Immobilized; D019800:Phenol; D006108:Graphite; D042845:Laccase
keywords: Aspergillus oryzae; Graphene; Laccase