Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/5/2002
Publication Date: 9/1/2002
Citation: IRIMESCU, R., IWASAKI, Y., HOU, C.T. STUDY OF TRIACYLGLYCEROL ETHANOLYSIS TO 2-MONOACYLGLYCEROLS BY IMMOBILIZED CANDIDA ANTARCTICA LIPASE. JOURNAL OF THE AMERICAN OIL CHEMISTS SOCIETY. 2002. V. 79 (9). P. 879-883. Interpretive Summary: Lipases are enzymes that catalyze the breakdown of oils (TGs) to glycerol and fatty acids. Together with amylase and protease, it is one the three major known digestive enzymes. A type of compound derived from oils called 2-monoacylglycerols (2-MGs) is useful for industrial applications. However, these compounds are very difficult to synthesize using standard chemical methods. It is also possible to produce these compounds, although not in good yield, using an enzyme called lipase. This particular study used immobilized lipase (Novozym 435). The unique aspect of this study was the finding that Novozym 435 reacts differently in ethanol. Based on this finding, we successfully synthesized 2-MGs and neutraceutical structured lipids. This process now appears feasible for scale-up of industrial production of 2-MGs and structure lipids from vegetable oils at a cheaper cost.
Technical Abstract: Regiospecific ethanolysis of homogenous triacylglycerols (TGs) with immobilized Candida antarctica lipase (Novozym 435) was studied using trioleoylglycerol (TO) as a model substrate. Optimization of the reactant weight ratio revealed that the 2-monoacylglycerol (2-MG) yield became higher when a larger amount of ethanol was used. These results suggested that Novozym 435, which had been believed to be a non-regiospecific enzyme, showed stricter regiospecificity in an excess amount of ethanol. The process optimization (reaction temperature and reactant molar ratio) and a study of lipase specificity for various substrates were performed. Under the optimized conditions (ethanol/TO weight ratio = 4/1 and 25 degrees C), 2-monooleoylglycerol (2-MO) was obtained in more than 98% content among glycerides of the reaction mixture and approximately 88% yield in 4 h. The above reaction conditions were applied for ethanolysis of tridocosahexaenoylglycerol, trisicosapentaenoylglycerol, triarachidonoylglycerol, trilinolenoylglycerol and trilinoleoylglycerol. Yields ranging from 71.9 to 93.7% were obtained in short reaction times (2.5 to 8 h). Purified (>98%) 2-MO and 2-monodocosahexaenoylglycerol (2-MD) were reesterified with caprylic acid by immobilized Rhizomucor miehei lipase (Lipozyme IM) to afford symmetrical structured TGs. At stoichiometric ratio of 2-MG/caprylic acid, 25 degrees C and 2-5 mm Hg vacuum, the final glyceride composition of the esterification mixture was made of approximately 95% 1,3-dicapryloyl-2-oleoylglycerol (COC) at 4 h, and 96% 1,3-dicapryloyl-2- docosahexaenoylglycerol (CDC) at 8 h. The regioisomeric purity of both COC and CDC was 100%.