Fatty acid ethyl esters purification

Shimada, Y., Maruyama, K., Sugihara, A., Baba T., Komemushi, S., Moriyama, S., and Tominaga, Y. 1998. Purification of ethyl docosahexaenoate by selective alcoholysis of fatty acid ethyl esters with immobilized Rhizomucor miehei lipase. J. Am. Oil Chem. Soc., 75,1565-1571. 

This paper demonstrates the purification of fatty acid ethyl esters, FAEE, due to their chain length. 

Bernhardt TG, Cannistraro PA, Bird DA, Doyle KM, Laposata M. Purification of fatty acid ethyl esters by soUd-phase extraction and 1IPLC. J Chromatogr B 1996 675 189-196. 

Riley D.IS. Kyger EM, Spilburg CA, Lange LG. Pancreatic cholesterol esterases. 2. Purification and characterization of human pancreatic fatty acid ethyl ester synthase. Biochemistry 1990 29 3848-3852. 

B. S. Kaphalia, R. R. Fritz, G. A. S. Ansari, Purification and Characterization of Rat Liver Microsomal Fatty Acid Ethyl and 2-Chloroethyl Ester Synthase and Their Relationship with Carboxylesterase (p/ 6.1) , Chem. Res. Toxicol. 1997, 10, 211 -218. 

A large number of trialkylacetic acid esters have been prepared by mixed Kolbe electrolysis of ethyl malonates [164]. Crossed-coupling is also used for chain extension. Extension by two carbon atoms is achieved with benzyl succinates [153, 180-182], whereby the purification of the chain extended fatty acid is simphfied by using the benzyl half ester [181a]. 

Polyunsaturated fatty acids (PUFAs) have various physiological functions and are widely used as pharmaceuticals, neutraceuticals, and as food additives. The ethyl ester of eicosapentaenoic acid (EPA) has been used for the treatment of arteriosclerosis and hyperlipemia since 1991 in Japan (Hara, 1993). DHA possesses not only similar physiological activities to those of EPA, but also an important function in the brain and retina (Hung, 2007). In addition, DHA accelerates the growth of preterm infants as does arachidonic acid (Carlson et al., 1993 Lanting et al., 1994). From these reasons, DHA ethyl ester (DHAEE) is currently expected to be used as a medicine, and the development of the purification methods is desired. 

It is clear that moulds represent excellent sources of dietetically acceptable oils. The main difficulty is one of sales and marketing as it obviously is not easy to convince a suspicious public that mould oil is as good as a plant oil. Scientifically, there is no detriment to using mould oil. Indeed one positive advantage of the mould oil as a source of GLA is its much lower content of linoleic acid (18 2) than either of the plant sources. This makes the purification of GLA much easier than starting from the plant oils as the main problem is the separation of the two closely allied fatty acids. Simple urea adduct formation enables oils with 80-85% GLA to be produced. Solvent winterization has also been used but without great effect (Yokochi et al., 1990) although the best, but most expensive, procedure for purification is by use of zeolites where 98% pure GLA has been obtained as its ethyl ester (Arai et al., 1987). Enrichment... 

Purification of stearidonic acid and its derivatives with transition metals capable of forming tt-complexes has been demonstrated. Fatty acids of seed oil of Echiumplantagineum containing 12.2 wt% stearidonic acid were converted to ethyl esters and treated with silver nitrate solution. After various extraction procedures an ethyl ester phase containing 94.6 wt% stearidonic acid was obtained (Coupland and Newbould, 1997). 

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