Promotion of a lipase-catalyzed esterification in supercritical carbon dioxide in the near-critical region

Abstract

The ester syntheses from acyl donors and terpene alcohols catalyzed by Candida cylindracea(CCL) lipase have been carried out in supercritical carbon dioxide (SCCO 2). In the near-critical region, the rate of esterification showed a sharp maximum and l-terpene esters were stereoselectively synthesized from acyl donors and a primary alcohol such as ( dl)-citronellol. It was found that, in very limited pressure range near the critical point, the interactions between carbon dioxide and enzyme molecules are greatly increased and allowed to provoke drastic conformational changes of the enzyme, causing active sites to emerge and catalyze the stereoselective syntheses. Supercritical carbon dioxide medium in the near-critical region should be a trigger to the activation of the enzyme by causing the movement of the surface groups and creating an active site, producing stereoselective machinery.