The interest in microalga as a food supplement has grown due their high contents of carotenoids, polyunsaturated fatty acids and proteins. This study evaluated the effect of different temperatures (22, 27 or 32 °C) and sodium nitrate concentrations (12, 24, 36, 48 or 60 mg L -1 of N-ND 3 ) in culture medium on Heterochlorella luteoviridis biomass production and composition. The highest biomass concentration (3.35 g L -1) was observed at the highest N-ND 3 concentration. The N-ND 3 concentration positively affected protein, carbohydrate and carotenoids contents of biomass. Dn the other hand, cells cultured at the lowest N-ND 3 concentration showed a slight increment in lipid content. The major carotenoid was lutein (30.7 ± 1.4% of total carotenoids), and the polyunsaturated fatty acids were 37 ± 2% of total fatty acids. Low temperature improved the biosynthesis of ω3 type fatty acids by lowering the ω6:ω3 ratio. Dverall, our results indicate H. luteoviridis can yield high biomass concentration under autotrophic growth, resulting in a biomass rich in carotenoids, mainly lutein, and ω3 polyunsaturated fatty acids.Keywords: nitrogen; temperature; lipids; omega-3; carotenoids; microalga.Practical Application: Microalgae can be used as food supplement and is a vegan source of omega-3 fatty acids.

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The microalgae H. luteoviridis and D. tertiolecta are excellent sources of lutein that could be commercially exploited by the food and pharmaceutical industries. Moreover, it was confirmed that both microalgae are good sources of protein, lipids and calcium. © 2016 Society of Chemical Industry.