title: Thermal deactivation kinetics of Pseudomonas fluorescens lipase entrapped in AOT/isooctane reverse micelles.
abstract: Thermostability of the lipase (EC 3.1.1.3) was found to be increased by the enzyme-entrapment in 50 mM AOT/isooctane reverse micelles. The half-life (15.75 h) of Pseudomonas fluorescens lipase entrapped in reverse micelles at 70 °C was 9.72- and 11.41-fold longer than those solubilized in a glycerol pool or in 10 mM phosphate buffer (pH 8.0), respectively. The enzyme deactivation model considering a two-step series-type was employed, and deactivation constants for the second step (k₂) at all temperatures were drastically decreased after the lipase was entrapped in reverse micelles. In particular, k₂ (0.0354 h⁻¹) at 70 °C in reverse micelles was 12.33- and 13.14-fold lower than in a glycerol pool or in the phosphate buffer, respectively. The deactivation energies (from k₁, k₂) for the lipase entrapped in the reverse micelles, solubilized in a glycerol pool, or in the aqueous buffer were 7.51, 26.35 kcal/mol, 5.93, 21.08 kcal/mol, and 5.53, 17.57 kcal/mol, respectively.
authors.affiliation: Department of Agricultural Biotechnology, Seoul National University , Seoul 151-742, Republic of Korea.
authors.forename: Kyung Min
authors.initials: KM
authors.lastname: Park
authors.forename: Chang Woo
authors.initials: CW
authors.lastname: Kwon
authors.forename: Seung Jun
authors.initials: SJ
authors.lastname: Choi
authors.forename: Young-Hwan
authors.initials: YH
authors.lastname: Son
authors.forename: Seokwon
authors.initials: S
authors.lastname: Lim
authors.forename: Yoonjung
authors.initials: Y
authors.lastname: Yoo
authors.forename: Pahn-Shick
authors.initials: PS
authors.lastname: Chang
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D055162:Biocatalysis; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D006358:Hot Temperature; D006868:Hydrolysis; D007700:Kinetics; D008049:Lipase / Q000737:chemistry / Q000378:metabolism*; D008066:Lipolysis; D008823:Micelles; D009795:Octanes / Q000737:chemistry; D011551:Pseudomonas fluorescens / Q000201:enzymology*; D013386:Succinates / Q000737:chemistry; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry; D014304:Triolein / Q000737:chemistry / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004800:Enzymes, Immobilized; D008823:Micelles; D009795:Octanes; D013386:Succinates; D013501:Surface-Active Agents; C511925:bis(2-ethylhexyl)sulfosuccinate; D014304:Triolein; D008049:Lipase; C045798:2,2,4-trimethylpentane