Lipase Reactions in Supercritical Fluids

Abstract

The supercritical fluids (SCF) have several excellent solvent properties such as low viscosity, high diffusivity and high dependence of solubility on pressure and temperature. The critical temperature of carbon dioxide is 304.1 K, low enough to treat thermally labile biomaterials without decomposition, and CO2 is non-toxic to human beings. Supercritical carbon dioxide (SCCO2) have been used in extraction of flavor substance from hop and other flavors and also in removal of undesirable substances such as caffeine in coffee beans and in removal of residual organic solvent in powdery medical raw materials.The interest in the applications of SCF is now enlarged from extraction to the other areas such as chemical and enzymatic reactions, material processings, formation of fine particles etc. Most of the enzymes are stable in anhydrous SCCO2, consequently the lipase reactions in SCF have been studied in the examples of modification of the physical property of triacylglycerols, resolution of optical isomers, syntheses of flavor esters etc. In this review the characteristics of SCF as solvent of enzymatic reactions are summarized with the main results so far obtained for the lipase reactions in SCF.