- Abstract The polyunsaturated fatty acid eicosapentaenoic acid (EPA) has attracted increased attention due to its pharmaceutical properties. The main source is marine fish oil which contains approximately 15% EPA. However, pharmaceutical applications of EPA will probably require higher concentrations, perhaps as high as 90%. The red microalga Porphyridium cruentum is a potential source, because its EPA content approaches 44.1% of the total fatty acids. Three methods were attempted for EPA concentration and arachidonic acid (AA) removal from the oil of this alga. Separation of the glycolipids, formation of a urea inclusion complex and reverse phase chromatography on C-18 Sep-Pak filters resulted in an EPA concentrate of 97% purity. Similar methods resulted in an AA concentrate of 80% purity.