Large-scale production of Nannochloropsis-derived EPA: Current status and perspectives via a biorefinery context

The rapid rise in global population and increase in food demands have significantly propelled mass production of plant- and animal-based conventional foods, which require substantial arable lands, water, and time. Microalgae have the potential to be a sustainable and promising alternative sources of nutrient-rich food supplement, amongst which Nannochloropsis is highlighted by its high concentration of nutrient rich metabolites. Most significantly, ∼30–40% of lipids synthesized by Nannochloropsis constitute polyunsaturated fatty acids (PUFA), in which 20–30% of total fatty acids account for eicosapentaenoic acid (EPA), an essential omega-3 supplement required for human health. Nevertheless, the incorporation of whole biomass of Nannochloropsis into functional foods often imparts negative tastes and odor. Therefore, EPA could be extracted by utilizing green, sustainable methods, including microwave and ultrasound pretreatment, supercritical fluid extraction, green solvents, and purified through urea complexation. Moreover, the defatted residual biomass could be valorized to various co-products, namely biofuels, sugars, and proteins, within a zero-waste biorefinery model. Amongst the multitude of biorefinery routes available, processes starting with high value EPA extraction followed by synthesis of peptides from a protein-rich residual biomass appear to be most lucrative. Hence, the current review provides a holistic outlook on large-scale production of Nannochloropsis-derived EPA by assessing various extraction and purification methods, and functional food applications, while scrutinizing the viability of biorefining for an economically viable and sustainable commercialization.