title: Encapsulation in a sol-gel matrix of lipase from Aspergillus niger obtained by bioconversion of a novel agricultural residue.
abstract: Lipase from Aspergillus niger was obtained from the solid-state fermentation of a novel agroindustrial residue, pumpkin seed flour. The partially purified enzyme was encapsulated in a sol-gel matrix, resulting in an immobilization yield of 71.4 %. The optimum pH levels of the free and encapsulated enzymes were 4.0 and 3.0, respectively. The encapsulated enzyme showed greater thermal stability at temperatures of 45 and 60 °C than the free enzyme. The positive influence of the encapsulation process was observed on the thermal stability of the enzyme, since a longer half-life t 1/2 and lower deactivation constant were obtained with the encapsulated lipase when compared with the free lipase. Kinetic parameters were found to follow the Michaelis-Menten equation. The K m values indicated that the encapsulation process reduced enzyme-substrate affinity and the V max was about 31.3 % lower than that obtained with the free lipase. The operational stability was investigated, showing 50 % relative activity up to six cycles of reuse at pH 3.0 at 37 °C. Nevertheless, the production of lipase from agroindustrial residue associated with an efficient immobilization method, which promotes good catalytic properties of the enzyme, makes the process economically viable for future industrial applications.
authors.affiliation: Department of Food Technology, Federal University of Sergipe, Avenida Marechal Rondon s/n, São Cristóvão, Sergipe, CEP: 49100-000, Brazil.
authors.forename: Claudia
authors.initials: C
authors.lastname: Zubiolo
authors.forename: Rafaela Cristiane Andrade
authors.initials: RC
authors.lastname: Santos
authors.forename: Nayara Bezerra
authors.initials: NB
authors.lastname: Carvalho
authors.forename: Cleide Mara Faria
authors.initials: CM
authors.lastname: Soares
authors.forename: Alvaro Silva
authors.initials: AS
authors.lastname: Lima
authors.forename: Luciana Cristina Lins
authors.initials: LC
authors.lastname: de Aquino Santana
mesh_terms: D001234:Aspergillus niger / Q000201:enzymology*; D028464:Cucurbita / Q000378:metabolism*; D004795:Enzyme Stability; D005285:Fermentation; D005782:Gels; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008049:Lipase / Q000378:metabolism*; D013696:Temperature
chemical_list: D005782:Gels; D008049:Lipase