Synthesis of triacylglycerol from polyunsaturated fatty acid by immobilized lipase

More than 95% of polyunsaturated acid (PUFA) was converted to triacylglycerol by immobilized lipase fromCandida antarctica orRhizomucor miehei. The esterification was carried out at 50–60°C with shaking and dehydration for 24 h. The substrates consisted of glycerol and free fatty acid or ethyl esters of the fatty acid at a 1∶3 molar ratio. The docosahexaenoic acid (DHA) or eicosapentaenoic acid (EPA) in the substrate polymerized during the reaction, and they required 5–10% more than the stoichiometric amount to compensate for the PUFA loss. On the contrary, ethyl esters of DHA and EPA were not polymerized. Pure tridocosahexaenoyl, trieicosapentaenoly and triarachidonoyl glycerol were isolated after passing the product through a basic aluminum oxide column. Industrial feasibility of this process was discussed for the ethyl ester as substrate. Portions of this article were presented at the annual meeting of the Japan Society for Bioscience, Biotechnology, and Agrochemistry and at the annual meeting of The Japan Oil Chemists' Society held in Kyoto, Japan, March 31, 1991, and in Hamamatsu, Japan, October 4, 1991, respectively.