Fig. 5

The total carotenoids and total MAAs of Dunaliella tertiolecta cultured outdoors under different sodium bicarbonate concentrations in ATCC-1174 DA medium using rotating floating photobioreactor. a The changes in total carotenoid concentrations of D. tertiolecta under 0.02 mol L⁻¹ NaHCO₃ (filled red circle) and 0.10 mol L⁻¹ NaHCO₃ (filled blue triangle) as compared to the control, 0.00 mol L⁻¹ NaHCO₃ (filled black cube). b The changes in total MAA concentrations of D. tertiolecta culture under cultivation conditions mentioned in Fig. 5a. c The changes in total carotenoid productivity (g m⁻² day⁻¹) of D. tertiolecta culture under 0.02 mol L⁻¹ NaHCO₃ (red bar) and 0.10 mol L⁻¹ NaHCO₃ (blue bar) as compared to the control, 0.00 mol L⁻¹ NaHCO₃ (black bar). d The changes in total MAA productivity (g m⁻² day⁻¹) of D. tertiolecta culture under cultivation conditions mentioned in Fig. 5c. e The changes in total carotenoid/chlorophyll a ratio of D. tertiolecta culture under cultivation conditions mentioned in Fig. 5a. f The scanning spectrograph of D. tertiolecta from 300 to 750 nm; the yellow peak (319–350 nm) and green peak (630–679 nm) stand for the absorption peaks of total MAAs and chlorophyll a, respectively. The negative values of productivities calculated were all shown as 0 g m⁻² day⁻¹. Data were expressed as mean ± standard deviation of three independent experiments (n = 3)