title: Chemical improvement of chitosan-modified beads for the immobilization of Enterococcus faecium DBFIQ E36 L-arabinose isomerase through multipoint covalent attachment approach.
abstract: D-tagatose is produced from D-galactose by the enzyme L-arabinose isomerase (L-AI) in a commercially viable bioprocess. An active and stable biocatalyst was obtained by modifying chitosan gel structure through reaction with TNBS, D-fructose or DMF, among others. This led to a significant improvement in L-AI immobilization via multipoint covalent attachment approach. Synthetized derivatives were compared with commercial supports such as Eupergit(®) C250L and glyoxal-agarose. The best chitosan derivative for L-AI immobilization was achieved by reacting 4 % (w/v) D-fructose with 3 % (w/v) chitosan at 50 °C for 4 h. When compared to the free enzyme, the glutaraldehyde-activated chitosan biocatalyst showed an apparent activity of 88.4 U g (gel) (-1) with a 211-fold stabilization factor while the glyoxal-agarose biocatalyst gave an apparent activity of 161.8 U g (gel) (-1) with an 85-fold stabilization factor. Hence, chitosan derivatives were comparable to commercial resins, thus becoming a viable low-cost strategy to obtain high active L-AI insolubilized derivatives.
authors.affiliation: Grupo de Ingeniería de Alimentos y Biotecnología, Instituto de Desarrollo Tecnológico para la Industria Química, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional del Litoral (UNL), Colectora RN 168 km 472 "Paraje El Pozo" S/N, (S3000GLN), Santa Fe, Argentina.
authors.forename: Ricardo M
authors.initials: RM
authors.lastname: Manzo
authors.affiliation: Departamento de Engenharia Química, Universidade Federal do Ceará, Campus do Pici, Bloco 709, Fortaleza, CE, CEP 60455-760, Brazil.
authors.forename: Marylane
authors.initials: M
authors.lastname: de Sousa
authors.affiliation: Grupo de Ingeniería de Alimentos y Biotecnología, Instituto de Desarrollo Tecnológico para la Industria Química, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional del Litoral (UNL), Colectora RN 168 km 472 "Paraje El Pozo" S/N, (S3000GLN), Santa Fe, Argentina.
authors.forename: Cecilia L
authors.initials: CL
authors.lastname: Fenoglio
authors.affiliation: Departamento de Engenharia Química, Universidade Federal do Ceará, Campus do Pici, Bloco 709, Fortaleza, CE, CEP 60455-760, Brazil. lrg@ufc.br.
authors.forename: Luciana Rocha Barro
authors.initials: LR
authors.lastname: Gonçalves
authors.affiliation: Grupo de Ingeniería de Alimentos y Biotecnología, Instituto de Desarrollo Tecnológico para la Industria Química, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional del Litoral (UNL), Colectora RN 168 km 472 "Paraje El Pozo" S/N, (S3000GLN), Santa Fe, Argentina. ejoma@intec.unl.edu.ar.
authors.forename: Enrique J
authors.initials: EJ
authors.lastname: Mammarella
mesh_terms: D019747:Aldose-Ketose Isomerases / Q000737:chemistry* / Q000378:metabolism; D048271:Chitosan / Q000737:chemistry*; D016984:Enterococcus faecium / Q000201:enzymology*; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism; D005632:Fructose / Q000737:chemistry; D005976:Glutaral / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008863:Microspheres; D012995:Solubility; D013696:Temperature
chemical_list: D004800:Enzymes, Immobilized; D005632:Fructose; D048271:Chitosan; D019747:Aldose-Ketose Isomerases; C019715:L-arabinose isomerase; D005976:Glutaral
keywords: Chitosan; D-Galactose; D-Tagatose; Immobilization; L-Arabinose isomerase; Multipoint covalent attachment