Majumder, Abir B; Shah, Shweta; Gupta, Munishwar N
Kinetic resolution; Enzyme; Water molecules; Organic compounds
Background: Use of enzymes in low water media is now widely used for synthesis and kineticresolution of organic compounds. The frequently used enzyme form is the freeze-dried powders.It has been shown earlier that removal of water molecules from enzyme by rinsing with n-propanolgives preparation (PREP) which show higher activity in low water media. The present workevaluates PREP of the lipase (from Rhizomucor miehei) for kinetic resolution of (R,S)-β-citronellol.The acylating agent was vinyl acetate and the reaction was carried out in solvent free media.Results: The PREP, with 0.75% (v/v, reaction media) water, was indeed found to be more efficientand gave 95% conversion to the ester. Using this PREP, with no added water, 90% ee for (R)-(+)-β-citronellyl acetate at 45% conversion (E = 42) was obtained in 4 h. The control with freeze-driedenzyme, with zero water content, gave 78% ee at 30% conversion (E = 13). FT-IR analysis showedthat PREP had retained the α-helical content of the enzyme. On the other hand, freeze-driedenzyme showed considerable loss in the α-helical content.Conclusion: The results show that PREP may be a superior biocatalyst for enantioselectiveconversion by enzymes in low-water media.