title: Covalent immobilization of Kluyveromyces fragilis β-galactosidase on magnetic nanosized epoxy support for synthesis of galacto-oligosaccharide.
abstract: The novel magnetic nanobeads with epoxy groups on the surface were prepared from glycidyl methacrylate (GMA), ethylene glycol dimethacrylate (EGDMA) and hydroxyethyl methacrylate (HEMA) via emulsifier-free emulsion polymerisation, and they were characterized by scanning electron microscopy and vibrating sample magnetometer. The magnetic poly(GMA-EDGMA-HEMA) nanobeads were used as support for covalent immobilization of Kluyveromyces fragilis β-galactosidase, the maximum amount enzyme attached onto the support was 145.6 mg/g with activity recovery of 72.6%. The loading capacity of this novel support for K. fragilis β-galactosidase was improved 2.6-folds compared with Eupergit® C (commercial epoxy support). The immobilized K. fragilis β-galactosidase exhibited high catalytic activity for the reaction of galacto-oligosaccharide (GOS) synthesis, and a total of 2,240 g GOS were produced per gram of immobilized enzyme during consecutive batch reaction of 10 times. The immobilized biocatalyst retained 81.5% of its original activity after 10 reaction cycles.
authors.affiliation: Agricultural Information Institute of Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.forename: Jianfu
authors.initials: J
authors.lastname: Liu
authors.forename: Bin
authors.initials: B
authors.lastname: Tan
authors.forename: Fenjuan
authors.initials: F
authors.lastname: Zhou
authors.forename: Yan
authors.initials: Y
authors.lastname: Qin
authors.forename: Ruijin
authors.initials: R
authors.lastname: Yang
mesh_terms: D004800:Enzymes, Immobilized / Q000737:chemistry*; D004852:Epoxy Compounds / Q000737:chemistry; D005656:Fungal Proteins / Q000737:chemistry*; D005690:Galactose / Q000737:chemistry; D007716:Kluyveromyces / Q000201:enzymology*; D008689:Methacrylates / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D009844:Oligosaccharides / Q000096:biosynthesis / Q000737:chemistry; D001616:beta-Galactosidase / Q000737:chemistry*
chemical_list: D004800:Enzymes, Immobilized; D004852:Epoxy Compounds; D005656:Fungal Proteins; D008689:Methacrylates; D009844:Oligosaccharides; C005044:hydroxyethyl methacrylate; C004919:ethylene dimethacrylate; D001616:beta-Galactosidase; C007870:glycidyl methacrylate; D005690:Galactose