Docosahexaenoic acid and eicosapentaenoic acid from microalgae: Extraction, purification, separation, and analytical methods

Functional foods and nutraceuticals have made significant progress in highlighting bioactive molecules' benefits for human health. Microalgae offer potential sources of new functional food due to their ability to synthesize eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Several studies have shown that EPA and DHA are beneficial for neurological disorders, inflammation, cardiovascular disease, and even cancer. This review summarizes and discusses the extraction and purification methods of EPA and DHA from microalgae species. We examined the yields of DHA and EPA from several microalgae species. For the extraction of EPA and DHA products, the optimal extraction and purification methods have been determined. Organic solvent extraction, solvent-free extraction, and supercritical fluid extraction (SFE) are the most common methods, while organic solvents have been widely used for extracting lipids from microalgae. We discuss various process parameters and extraction conditions that may improve process performance and yield high oil recovery rates. Supercritical fluid extraction (SFE) and supercritical fluid chromatography (SFC) are the most suitable lipids extraction and purification techniques with high DHA and EPA recovery. More studies are required to produce better quality EPA and DHA from microalgae species by using innovative and optimized techniques that can increase lipid yields and its health benefits and, hence proper utilization of these underutilized microalgae species.