title: An alkaline lipase from organic solvent tolerant Acinetobacter sp. EH28: Application for ethyl caprylate synthesis.
abstract: A mesophilic bacterium producing a thermostable alkaline lipase was isolated from oil rich soil sample and identified as Acinetobacter sp. EH28. The lipase was partially purified by ammonium sulphate precipitation followed by hydrophobic interaction chromatography with 24.2-fold purification and 57.1U/ml specific activity. The partially purified enzyme exhibited maximum activity at pH 10.0 and at 50 degrees C and was highly stable at 50 degrees C retaining 100% of its activity up to 90min. It was highly stable and retained more than 80% of its initial activity upon exposure to various organic solvents. The EH28 lipase was used for synthesis of the flavor ester ethyl caprylate in organic solvents, thus providing a concept of application of Acinetobacter sp. lipase in non-aqueous catalysis. Reaction parameters best suited for this esterification reaction were 40 degrees C reaction temperature, 1.3:1 ratio of caprylic acid to ethanol and cyclohexane as the medium.
authors.affiliation: BRD School of Biosciences, Sardar Patel Maidan, Vadtal Road, Satellite Campus, P.O. No. 39, Sardar Patel University, Vallabh Vidyanagar 388 120, Gujarat, India. eltayib1974@yahoo.com
authors.forename: Eltayib Hassan
authors.initials: EH
authors.lastname: Ahmed
authors.forename: Tripti
authors.initials: T
authors.lastname: Raghavendra
authors.forename: Datta
authors.initials: D
authors.lastname: Madamwar
mesh_terms: D000150:Acinetobacter / Q000201:enzymology*; D001483:Base Sequence; D002210:Caprylates / Q000378:metabolism*; D002853:Chromatography, Liquid; D017931:DNA Primers; D004951:Esterification; D008049:Lipase / Q000378:metabolism*; D009930:Organic Chemicals; D016133:Polymerase Chain Reaction; D012997:Solvents; D013696:Temperature
chemical_list: D002210:Caprylates; D017931:DNA Primers; D009930:Organic Chemicals; D012997:Solvents; C549324:ethyl caprylate; D008049:Lipase