Effect of organic solvents and ionic liquids on resolution of 2-epoxyhexane by whole cells of Rhodotorula glutinis in a two-liquid phase system

Abstract

BACKGROUND: Enantiopure epoxides and diols have attracted much attention as important building blocks for the production of flavorings, agrochemicals and pharmaceutical products. Enantioselective hydrolysis reaction of rac-epoxide in a biphasic system using whole cell catalysts is one of the promising methods to obtain enantiopure compounds. RESULTS: The kinetic resolution of racemic 1,2-epoxyhexane was carried out using whole cell biocatalyst in a hydrophobic solvent/buffer biphasic system and the effect of organic solvents and ionic liquids on the initial reaction rate of (R)-enantiomer, rR0 and enantiomeric ratio, E was examined. In the case of using hydrophobic hydrocarbons, rR0 increased with the hydrophobicity of hydrocarbon (log PO/W), and a linear correlation was observed between rR0 and log PO/W. On the other hand, there were no correlations between rR0 and log PO/W of ionic liquids. Moreover, effects on E were small in both solvents. However, the addition of 1-heptanol to dodecane was very effective at increasing E value. The kinetic data correlated well with the reaction kinetic model, considering the distribution between two liquid phases and competitive product inhibition. CONCLUSION: The high enantiomeric ratio of (R)-diol (E>100) without significant decrease in the reactivity was accomplished by adding 1-heptanol in minute amounts to dodecane. © 2013 Society of Chemical Industry.