title: Immobilization of enzymes on spongy polyvinyl alcohol cryogels: the example of beta-galactosidase from Aspergillus oryzae.
abstract: The catalytic properties of a beta-galactosidase from Aspergillus oryzae, entrapped into a spongy polyvinyl alcohol cryogel, were studied. This polymeric matrix was selected because of its mild conditions of preparation and its stability, biocompatibility, structural strength and diffusive properties. The enzyme was entrapped, in high percentage, into cryogel sponges and its activity and kinetic parameters were determined and compared with those of the free enzyme, using as substrates o-nitrophenyl-beta-galactopyranoside (ONPG) or lactose. The immobilized enzyme showed a reduced activity with ONPG and lactose, probably because of substrate diffusion limitations through the matrix, but it was more stable to temperature, pH and ionic strength than the free enzyme. Lactose hydrolysis under continuous experimental conditions was performed using the matrix-enzyme cited above.
authors.affiliation: Centro Universitario di Ricerca Interdisciplinare sui Biomateriali, Naples, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Rossi
authors.forename: A
authors.initials: A
authors.lastname: Morana
authors.forename: I D
authors.initials: ID
authors.lastname: Lernia
authors.forename: A
authors.initials: A
authors.lastname: Di tombrino
authors.forename: M
authors.initials: M
authors.lastname: De Rosa
mesh_terms: D000818:Animals; D001236:Aspergillus oryzae / Q000201:enzymology*; D002384:Catalysis; D004795:Enzyme Stability; D004800:Enzymes, Immobilized; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D007785:Lactose / Q000378:metabolism; D009598:Nitrophenylgalactosides / Q000378:metabolism; D009994:Osmolar Concentration; D011142:Polyvinyl Alcohol; D001616:beta-Galactosidase / Q000378:metabolism*
chemical_list: D004800:Enzymes, Immobilized; C055012:2-nitrophenylgalactoside; D009598:Nitrophenylgalactosides; D011142:Polyvinyl Alcohol; D001616:beta-Galactosidase; D007785:Lactose