Enhancement of Lipase-catalyzed Synthesis of Caffeic Acid Phenethyl Ester in Ionic Liquid with DMSO Co-solvent

Caffeic acid phenethyl ester (CAPE) is a natural and rare ingredient with several biological activities, but its industrial production using lipase-catalyzed esterification of caffeic acid (CA) and 2-phenylethanol (PE) in ionic liquids (ILs) is hindered by low substrate concentrations and long reaction time. To set up a high-efficiency bioprocess for production of CAPE, a novel dimethyl sulfoxide (DMSO)–IL co-solvent system was established in this study. The 2% (by volume) DMSO–[Bmim][Tf2N] system was found to be the best medium with higher substrate solubility and conversion of CA. Under the optimum conditions, the substrate concentration of CA was raised 8-fold, the reaction time was reduced by half, and the conversion reached 96.23%. The kinetics follows a ping-pong bi-bi mechanism with inhibition by PE, with kinetic parameters as follows: Vmax = 0.89 mmol · min− 1 · g− 1, Km,CA = 42.9 mmol · L− 1, Km,PE = 165.7 mmol · L− 1, and Ki,PE = 146.2 mmol · L− 1. The results suggest that the DMSO co-solvent effect has great potential to enhance the enzymatic synthesis efficiency of CAPE in ILs.

Graphical abstractCaffeic acid phenethyl ester (CAPE) is a natural and rare ingredient with several biological activities. To set up a high-efficiency bioprocess for obtaining CAPE, a novel dimethyl sulfoxide (DMSO)–IL co-solvent system was successfully established. The 2% (by volume) DMSO–[Bmim][Tf2N] was found to be the best medium with higher substrate solubility of CA and conversion. Under the optimum conditions, the substrate concentration of CA was raised 8-fold, the reaction time was reduced by half, and the conversion reached 96.23%. Thus, the DMSO co-solvent effect has great potential of enhancing the enzymatic synthesis efficiency of CAPE in ILs.Figure optionsDownload full-size imageDownload as PowerPoint slide