title: Immobilization of Aspergillus oryzae β-galactosidase in an agarose matrix functionalized by four different methods and application to the synthesis of lactulose.
abstract: Aspergillus oryzae β-galactosidase was immobilized in monofunctional glyoxyl-agarose and heterofunctional supports (amino-glyoxyl, carboxy-glyoxyl and chelate-glyoxyl agarose), for obtaining highly active and stable catalysts for lactulose synthesis. Specific activities of the amino-glyoxyl agarose, carboxy-glyoxyl agarose and chelate-glyoxyl agarose derivatives were 3676, 430 and 454IU/g biocatalyst with half-life values at 50°C of 247, 100 and 100h respectively. Specific activities of 3490, 2559 and 1060IU/g were obtained for fine, standard and macro agarose respectively. High immobilization yield (39.4%) and specific activity of 7700IU/g was obtained with amino-glyoxyl-agarose as support. The highest yields of lactulose synthesis were obtained with monofunctional glyoxyl-agarose. Selectivity of lactulose synthesis was influenced by the support functionalization: glyoxyl-agarose and amino-glyoxyl-agarose derivatives retained the selectivity of the free enzyme, while selectivity with the carboxy-glyoxyl-agarose and chelate-glyoxyl-agarose derivatives was reduced, favoring the synthesis of transgalactosylated oligosaccharides over lactulose.
authors.affiliation: School of Biochemical Engineering, Pontificia Universidad Católica de Valparaíso (PUCV), Valparaíso, Chile. Electronic address: c.siancas@gmail.com.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Guerrero
authors.affiliation: Department of Biology, Faculty of Chemistry and Biology, Universidad de Santiago de Chile (USACH), Santiago, Chile.
authors.forename: Carlos
authors.initials: C
authors.lastname: Vera
authors.affiliation: School of Biochemical Engineering, Pontificia Universidad Católica de Valparaíso (PUCV), Valparaíso, Chile.
authors.forename: Nestor
authors.initials: N
authors.lastname: Serna
authors.affiliation: School of Biochemical Engineering, Pontificia Universidad Católica de Valparaíso (PUCV), Valparaíso, Chile.
authors.forename: Andrés
authors.initials: A
authors.lastname: Illanes
mesh_terms: D001236:Aspergillus oryzae / Q000201:enzymology*; D001709:Biotechnology / Q000379:methods*; D004795:Enzyme Stability / Q000187:drug effects; D004800:Enzymes, Immobilized / Q000378:metabolism*; D006031:Glycosylation / Q000187:drug effects; D006038:Glyoxylates / Q000494:pharmacology; D007792:Lactulose / Q000096:biosynthesis*; D010316:Particle Size; D012685:Sepharose / Q000494:pharmacology*; D013696:Temperature; D001616:beta-Galactosidase / Q000378:metabolism*
chemical_list: D004800:Enzymes, Immobilized; D006038:Glyoxylates; C070399:glyoxyl agarose; D007792:Lactulose; D012685:Sepharose; D001616:beta-Galactosidase
keywords: Agarose matrix; Aspergillus oryzae; Immobilization; Lactulose; β-Galactosidase