title: Immobilization of Aspergillus niger lipase on chitosan-coated magnetic nanoparticles using two covalent-binding methods.
abstract: Aspergillus niger lipase immobilization by covalent binding on chitosan-coated magnetic nanoparticles (CMNP), obtained by one-step co-precipitation, was studied. Hydroxyl and amino groups of support were activated using glycidol and glutaraldehyde, respectively. Fourier transform infrared spectrometry, high-resolution transmission electron microscopy and thermogravimetric analysis confirmed reaction of these coupling agents with the enzyme and achievement of a successful immobilization. The derivatives showed activities of 309.5 ± 2.0 and 266.2 ± 2.8 U (g support)(-1) for the CMNP treated with glutaraldehyde and with glycidol, respectively. Immobilization enhanced the enzyme stability against changes of pH and temperature, compared to free lipase. Furthermore, the kinetic parameters K m and V max were determined for the free and immobilized enzyme. K m value quantified for enzyme immobilized by means of glutaraldehyde was 1.7 times lowers than for free lipase. High storage stability during 50 days was observed in the immobilized derivatives. Finally, immobilized derivatives retained above 80% of their initial activity after 15 hydrolytic cycles. The immobilized enzyme can be applied in various biotechnological processes involving magnetic separation.
authors.affiliation: Cuerpo Académico (CA) de Nanobiociencia, Universidad Autónoma de Coahuila, Boulevard V. Carranza y José Cárdenas Valdés, 25280, Saltillo, COAH, Mexico.
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Osuna
authors.forename: José
authors.initials: J
authors.lastname: Sandoval
authors.forename: Hened
authors.initials: H
authors.lastname: Saade
authors.forename: Raúl G
authors.initials: RG
authors.lastname: López
authors.forename: José L
authors.initials: JL
authors.lastname: Martinez
authors.forename: Edith M
authors.initials: EM
authors.lastname: Colunga
authors.forename: Gabriela
authors.initials: G
authors.lastname: de la Cruz
authors.forename: Elda P
authors.initials: EP
authors.lastname: Segura
authors.forename: Fernando J
authors.initials: FJ
authors.lastname: Arévalo
authors.forename: María A
authors.initials: MA
authors.lastname: Zon
authors.forename: Héctor
authors.initials: H
authors.lastname: Fernández
authors.forename: Anna
authors.initials: A
authors.lastname: Ilyina
mesh_terms: D001234:Aspergillus niger / Q000201:enzymology*; D048271:Chitosan / Q000737:chemistry*; D004800:Enzymes, Immobilized / Q000737:chemistry*; D005656:Fungal Proteins / Q000737:chemistry*; D005976:Glutaral / Q000737:chemistry; D008049:Lipase / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*
chemical_list: D004800:Enzymes, Immobilized; D005656:Fungal Proteins; D048271:Chitosan; D008049:Lipase; D005976:Glutaral