title: Increased enantioselectivity and remarkable acceleration of lipase-catalyzed transesterification by using an imidazolium PEG-alkyl sulfate ionic liquid.
abstract: Several types of imidazolium salt ionic liquids were prepared derived from poly(oxyethylene)alkyl sulfate and used as an additive or coating material for lipase-catalyzed transesterification in an organic solvent. A remarkably increased enantioselectivity was obtained when the salt was added at 3-10 mol % versus substrate in the Burkholderia cepacia lipase (lipase PS-C)-catalyzed transesterification of 1-phenylethanol by using vinyl acetate in diisopropyl ether or a hexane solvent system. In particular, a remarkable acceleration was accomplished by the ionic liquid coating with lipase PS in an iPr(2)O solvent system while maintaining excellent enantioselectivity; it reached approximately 500- to 1000-fold acceleration for some substrates with excellent enantioselectivity. A similar acceleration was also observed for IL 1-coated Candida rugosa lipase. MALDI-TOF mass spectrometry experiments of the ionic-liquid-coated lipase PS suggest that ionic liquid binds with lipase protein.
authors.affiliation: Department of Materials Sciences, Faculty of Engineering, Tottori University, 4-101 Koyama-minami, Tottori 680-8552, Japan. titoh@chem.tottori-u.ac.jp
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Itoh
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Matsushita
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Abe
authors.forename: Shi-Hui
authors.initials: SH
authors.lastname: Han
authors.forename: Shohei
authors.initials: S
authors.lastname: Wada
authors.forename: Shuichi
authors.initials: S
authors.lastname: Hayase
authors.forename: Motoi
authors.initials: M
authors.lastname: Kawatsura
authors.forename: Shigeomi
authors.initials: S
authors.lastname: Takai
authors.forename: Minoru
authors.initials: M
authors.lastname: Morimoto
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Hirose
mesh_terms: D002175:Candida / Q000201:enzymology; D002384:Catalysis; D004951:Esterification; D007093:Imidazoles / Q000737:chemistry*; D008049:Lipase / Q000378:metabolism*; D011092:Polyethylene Glycols / Q000737:chemistry*; D013237:Stereoisomerism; D013431:Sulfates / Q000737:chemistry*
chemical_list: D007093:Imidazoles; D013431:Sulfates; D011092:Polyethylene Glycols; D008049:Lipase