Euglena as a potential natural source of value-added metabolites. A review

Microalgae-derived functional materials, such as food supplements, drugs, and biofuels have gained a great deal of attention in recent times. Among the several microalgae investigated for biomaterials production, Euglena spp. are particularly attractive due to their easiness to grow in cultures and the ability to produce numerous bioactive compounds through extremely complex metabolic pathways. The genus Euglena comprises more than 300 species of unicellular, predominantly freshwater flagellates of worldwide distribution. The plastids in Euglena cells have been recognized as a site of the production of proteins, fatty acids, and many other value-added metabolites. Euglena is one of the few microorganisms that simultaneously produces antioxidants, such as beta-carotene, L-ascorbic acid, and alpha-tocopherol, along with wax esters, phytotoxins and polyunsaturated fatty acids (PUFAs), that are useful in the manufacture of pharmaceuticals, cosmeceuticals, and nutraceuticals. Nevertheless, the biotechnological potency of Euglena for industrial production has been exploited limitedly. This review summarizes the major value-added compounds obtained from the protist genus Euglena and their potential and prospects for commercial production.