title: Obtaining high transesterification activity for subtilisin in ionic liquids.
abstract: It is known that subtilisin shows poor transesterification activity in ionic liquids (ILs). The present work, taking subtilisin as the system, explores approaches for biocatalyst preparations, which are capable of yielding higher/adequate transesterification activity in these solvents. Of all the approaches tried, enzyme precipitated and rinsed with n-propanol (EPRP) gave the best results (about 10,000 times increase in initial rates in 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF(6)]) over what is obtained with pH tuned lyophilized powders). In case of water soluble ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF(4)]), pH tuned lyophilized subtilisin did not show any transesterification activity. EPRP, however, gave an initial rate (for transesterification) of 2.78 mmol mg(-1) h(-1).
authors.affiliation: Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
authors.forename: Shweta
authors.initials: S
authors.lastname: Shah
authors.forename: Munishwar N
authors.initials: MN
authors.lastname: Gupta
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004951:Esterification; D007477:Ions; D013381:Subtilisins / Q000378:metabolism*
chemical_list: D007477:Ions; D013381:Subtilisins