title: Immobilization and characterisation of a lipase from a new source, Bacillus sp. ITP-001.
abstract: A new source of lipase from Bacillus sp. ITP-001 was immobilized by physical adsorption on the polymer poly(3-hydroxybutyrate-co-hydroxyvalerate) (PHBV) in aqueous solution. The support and immobilized lipase were characterised, compared to the lyophilised lipase, with regard to the specific surface area, adsorption-desorption isotherms, pore volume (V(p)) and size (dp) by nitrogen adsorption, differential scanning calorimetry, thermogravimetric analysis, chemical composition analysis, Fourier transform infrared spectroscopy and biochemical properties. The immobilized enzyme displayed a shift in optimum pH towards the acidic side with an optimum at pH 4.0, whereas the optimum pH for the free enzyme was at pH 7.0; the optimum temperature of activity was 80 and 37 °C for the free and immobilized enzyme, respectively. The inactivation rate constant for the immobilized enzyme at 37 °C was 0.0038 h⁻¹ and the half-life was 182.41 h. The kinetic parameters obtained for the immobilized enzyme gave a Michaelis-Menten constant (K(m)) of 49.10 mM and a maximum reaction velocity (V(max)) of 205.03 U/g. Furthermore, the reuse of the lipase immobilized by adsorption allowed us to observe that it could be reused for 10 successive cycles, duration of each cycle (1 h), maintaining 33 % of the initial activity.
authors.affiliation: Universidade Tiradentes, Av. Murilo Dantas, 300, Bairro Farolândia, 49032-490, Aracaju-SE, Brazil.
authors.forename: Rebeca Y
authors.initials: RY
authors.lastname: Cabrera-Padilla
authors.forename: Matheus
authors.initials: M
authors.lastname: Albuquerque
authors.forename: Renan T
authors.initials: RT
authors.lastname: Figueiredo
authors.forename: Alini T
authors.initials: AT
authors.lastname: Fricks
authors.forename: Elton
authors.initials: E
authors.lastname: Franceschi
authors.forename: Alvaro S
authors.initials: AS
authors.lastname: Lima
authors.forename: Onelia A
authors.initials: OA
authors.lastname: A Dos Santos
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Silva
authors.forename: Cleide M F
authors.initials: CM
authors.lastname: Soares
mesh_terms: D000327:Adsorption; D001407:Bacillus / Q000201:enzymology*; D002152:Calorimetry, Differential Scanning; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000378:metabolism*; D006207:Half-Life; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008049:Lipase / Q000378:metabolism*; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013818:Thermogravimetry
chemical_list: D004800:Enzymes, Immobilized; D008049:Lipase