title: Purification and biochemical characterization of a halotolerant Staphylococcus sp. extracellular lipase.
abstract: We have isolated a lipolytic halotolerant bacterium, designated as CJ3, that was identified as a Staphylococcus sp. Culture conditions were optimized and the highest extracellular lipase production amounting to 5 U/ml was achieved after 24 h of cultivation. The extracellular lipase was puriﬁed 24-fold by ammonium sulfate precipitation and a Sephacryl S-200 chromatography, and its molecular mass was found to be around 38 kDa, as revealed by SDS-PAGE and gel filtration. The lipase substrate specificity was investigated using short (tributyrin) and long (olive oil) chain triglyceride substrates. The lipase was inhibited by submicellar concentrations of Triton X-100, and maximum specific activities were found to be 802 U/mg on tributyrin and 260 U/mg on olive oil at pH 8.0 and 45 °C. The lipase was fairly stable in the pH range from 6.0 to 9.0, and about 69% of its activity was retained after incubation at 45 °C for 60 min. The enzyme showed a high tolerance to a wide range of salt concentration and a good stability in organic solvents, especially in long-chain alcohols.
authors.affiliation: University of Sfax, ENIS - Laboratory of Biochemistry and Enzymatic Engineering of Lipases, 3038 Sfax, Tunisia.
authors.forename: Lobna
authors.initials: L
authors.lastname: Daoud
authors.forename: Jannet
authors.initials: J
authors.lastname: Kamoun
authors.forename: Madiha Bou
authors.initials: MB
authors.lastname: Ali
authors.forename: Raida
authors.initials: R
authors.lastname: Jallouli
authors.forename: Rim
authors.initials: R
authors.lastname: Bradai
authors.forename: Tahar
authors.initials: T
authors.lastname: Mechichi
authors.forename: Youssef
authors.initials: Y
authors.lastname: Gargouri
authors.forename: Yassine Ben
authors.initials: YB
authors.lastname: Ali
authors.forename: Ahmed
authors.initials: A
authors.lastname: Aloulou
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification*; D002850:Chromatography, Gel; D008049:Lipase / Q000737:chemistry* / Q000302:isolation & purification*; D008970:Molecular Weight; D013210:Staphylococcus / Q000201:enzymology*; D013379:Substrate Specificity / Q000502:physiology; D014280:Triglycerides / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D014280:Triglycerides; D008049:Lipase