title: Substrate specificity and enzyme recycling using chitosan immobilized laccase.
abstract: The immobilization of laccase (Aspergillus sp.) on chitosan by cross-linking and its application in bioconversion of phenolic compounds in batch reactors were studied. Investigation was performed using laccase immobilized via chemical cross-linking due to the higher enzymatic operational stability of this method as compared to immobilization via physical adsorption. To assess the influence of different substrate functional groups on the enzyme's catalytic efficiency, substrate specificity was investigated using chitosan-immobilized laccase and eighteen different phenol derivatives. It was observed that 4-nitrophenol was not oxidized, while 2,5-xylenol, 2,6-xylenol, 2,3,5-trimethylphenol, syringaldazine, 2,6-dimetoxyphenol and ethylphenol showed reaction yields up 90% at 40 °C. The kinetic of process, enzyme recyclability and operational stability were studied. In batch reactors, it was not possible to reuse the enzyme when it was applied to syringaldazne bioconversion. However, when the enzyme was applied to bioconversion of 2,6-DMP, the activity was stable for eight reaction batches.
authors.affiliation: Laboratório de Tratamento de Águas e Efluentes, Departamento de Engenharia Ambiental, Universidade do Estado de Santa Catarina, Lages 88520-000, Brazil. skoronski@cav.udesc.br.
authors.forename: Everton
authors.initials: E
authors.lastname: Skoronski
authors.affiliation: Laboratório de Engenharia Bioquímica, Departamento de Engenharia Química e Engenharia de Alimentos, Universidade Federal de Santa Catarina, Florianópolis 88040-900, Brazil. mylena.fernandes@gmail.com.
authors.forename: Mylena
authors.initials: M
authors.lastname: Fernandes
authors.affiliation: Laboratório de Bioquímica, Departamento de Produção Animal e Alimentos, Universidade do Estado de Santa Catarina, Lages 88520-000, Brazil. maria.borba.magalhaes@gmail.com.
authors.forename: Maria de Lourdes Borba
authors.initials: Mde L
authors.lastname: Magalhães
authors.affiliation: Laboratório de Bioquímica, Departamento de Produção Animal e Alimentos, Universidade do Estado de Santa Catarina, Lages 88520-000, Brazil. gustavo.silva@udesc.br.
authors.forename: Gustavo Felippe
authors.initials: GF
authors.lastname: da Silva
authors.affiliation: Grupo de Catálise Enzimática e Síntese Orgânica, Departamento de Engenharia Química, Universidade do Sul de Santa Catarina, Tubarão 88704-900, Brazil. jair.joao@unisul.br.
authors.forename: Jair Juarez
authors.initials: JJ
authors.lastname: João
authors.affiliation: Laboratório de Avaliação Exotoxicológica, Departamento de Bioquímica, Universidade Federal de Santa Catarina, Florianópolis 88040-900, Brazil. chsoares@ccb.ufsc.br.
authors.forename: Carlos Henrique Lemos
authors.initials: CH
authors.lastname: Soares
authors.affiliation: Laboratório de Engenharia Bioquímica, Departamento de Engenharia Química e Engenharia de Alimentos, Universidade Federal de Santa Catarina, Florianópolis 88040-900, Brazil. agenor@enq.ufsc.br.
authors.forename: Agenor Fúrigo
authors.initials: AF
authors.lastname: Júnior
mesh_terms: D048271:Chitosan / Q000737:chemistry*; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D042845:Laccase / Q000737:chemistry / Q000378:metabolism*; D010636:Phenols / Q000737:chemistry / Q000378:metabolism*; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D004800:Enzymes, Immobilized; D010636:Phenols; D048271:Chitosan; D042845:Laccase