Chemo-enzymatic production of omega-3 monoacylglycerides using sponge-like ionic liquids and supercritical carbon dioxide

Abstract

A clean chemo-enzymatic synthesis of omega-3 monoacylglycerides was carried out by two consecutive catalytic steps, the enzymatic transesterification of raw fish or linseed oil with solketal for producing fatty acid solketyl esters, followed by the hydrolysis of these solketal moieties catalysed by solid acids (e.g. zeolites) in either supercritical carbon dioxide (scCO2) or sponge-like ionic liquids (SLILs). By using scCO2 as reaction/extraction medium, an excellent performance of both coupled catalytic steps was observed when t-butanol was used as a co-solvent, resulting in a 100% monoacylglyceride yield for seven days under continuous operation and without any loss in catalytic activity. For discontunuous operation, the process involved two separated steps in SLIL and water, respectively, leading to 100% product yield and IL-free monoacylglyceride product by following a cooling and centrifugation protocol, which allow for the full recovery of the enzyme / SLIL / zeolite components of the reaction system that could be reused for at least 6 cycles with unchanged catalytic performance.