Accumulation of Carotenoid and Lipid in Microalgae Dunaliella bardawil DCCBC 15 Cultivated under Nitrogen Starved Conditions

Dunaliella bardawil is a unicellular green microalgae that can accumulate large amounts of carotenoids under adverse culture conditions, so it has high commercial value and is used as a functional food. Nutrient starvation, especially nitrogen starvation, induces carotenoid and lipid production in algal cells. Dunaliella bardawil cells were grown in MD4 medium after 12 cultural days reaching maximum cell density (1,4x106 cells/mL) that changed to four stress conditions—nitrogen replete, nutrient starvation, and half and fully nitrogen-depleted conditions—to investigate the carotenoid and lipid contents of D. bardawil microalgae. The results showed that the cell density D. bardawil decreased significantly under cultural conditions. High amounts of carotenoids were detected under fully nitrogen-depleted conditions (14.631 pg/cell; car/chl: 12.346). D. bardawil was able to overproduce lipids under both nitrogen-free (351.580 pg/cell; lipid/chl: 219.792) and fully nitrogen-free (373.136 pg/cell; lipid/chl 321.401) conditions. Therefore, fully nitrogen-depleted conditions of cultivation stimulate significantly D. bardawil cells accumulating a large amounts lipid and carotenoid.