Accumulation of carotenoid, lipid, phenolic and antioxidant capacity of microalgae Dunaliella salina ccap 19/18 cultivated under temperature stress regimes

Abstract

Microalgae Dunaliella salina is considered a source of biologically active substances such as carotenoids specially beta-carotene, phenolics, and nutrients like lipids, glycerol, and carbohydrates under abiotic and biotic stress conditions. Dunaliella salina CCAP 19/18 was cultured two stages, the growth stage the microalgae cultivated in RM2 medium for 12 days to reach maximum cell density. The stress stage, after 12 days of cultivation, Dunaliella salina was exposed systematically to three distinct temperature conditions 10°C, 25°C (control), and 45°C. The analysis of carotenoid, lipid, phenolic compound and antioxidant capacity every 3 days at two different daily exposure durations: 3 and 6 hours. The results showed that the temperature stress cultivated conditions were induced the accumulation of biological active compounds rapidly, carotenoid, lipid and phenolic in Dunaliella salina cells. Specially, under the culture condition of 10oC for 6 hours/day, the accumulation of carotenoids (1.531 pg/cell), lipids (29.209 pg/cell), phenolics (1.197 pg GAE/cell) and antioxidant capacity (29.255 I%/cell) of microalgae D. salina CCAP 19/18 reached the highest concentration on day 12 after inhibition. However, under inhibitory culture conditions at 45oC, no microalgae cell survival was recorded after 3 days of inhibition. The temperature factor and stress regimes are known key markers for strategy to increase accumulation of carotenoid, lipid and phenolic compounds in cultivating microalgae Dunaliella salina in Viet Nam.