title: Neutrase immobilization on alginate-glutaraldehyde beads by covalent attachment.
abstract: Neutrase, a commercial preparation of Bacillus subtilis , was covalently immobilized on alginate-glutaraldehyde beads. Immobilization conditions and characterization of the immobilized enzyme were investigated. Central composite design and response surface methods were employed to evaluate the effects of immobilization parameters, such as glutaraldehyde concentration, enzyme loading, immobilization pH, and immobilization time. Under optimized working conditions (2% alginate, 6.2% glutaraldehyde, 61.84 U mL(-1) Neutrase, pH 6.2, and 60 min) the immobilization yield was about 50%. The immobilized enzyme exhibited higher K(m) compared to the soluble enzyme. The pH-activity profile was widened upon immobilization. The optimum temperature was shifted from 50 to 60 degrees C, and the apparent activation energy was decreased from 47.7 to 22.0 kJ mol(-1) by immobilization. The immobilized enzyme also showed significantly enhanced thermal stability.
authors.affiliation: Department of Biotechnology and Food Science, Area of Biochemistry and Molecular Biology, University of Burgos, Plaza Misael Banuelos, Burgos, Spain. nortega@ubu.es
authors.forename: Natividad
authors.initials: N
authors.lastname: Ortega
authors.forename: Manuel
authors.initials: M
authors.lastname: Perez-Mateos
authors.forename: María C
authors.initials: MC
authors.lastname: Pilar
authors.forename: María D
authors.initials: MD
authors.lastname: Busto
mesh_terms: D000464:Alginates; D004795:Enzyme Stability; D004800:Enzymes, Immobilized; D020723:Glucuronic Acid; D005976:Glutaral; D006603:Hexuronic Acids; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008666:Metalloendopeptidases / Q000378:metabolism; D008863:Microspheres; D013997:Time Factors
chemical_list: D000464:Alginates; D004800:Enzymes, Immobilized; D006603:Hexuronic Acids; D020723:Glucuronic Acid; D008666:Metalloendopeptidases; C044194:microbial metalloproteinases; D005976:Glutaral