Determination fucoxanthin content of marine microalgae Nitzschia thermalis and Isochrysis galbana under different stress conditions.

Fucoxanthin is a primary carotenoid present in microalgae and macroalgae and has pharmaceutical properties such as antitumor, antioxidant and antiobesity. Like other carotenoids, synthesis of fucoxanthin can be triggered in microalgae under various environmental or biological stress conditions. In this study, specific growth rate, doubling time, lipid content, fatty acid and fucoxanthin amounts of two marine microalgae Nitzschia thermalis (EGEMACC-56) and Isochrysis galbana (EGEMACC-86) were determined at different nitrogen (0 mg/L- 75mg/L- 200mg/L) and different iron (0 mg/L-3.15 mg/L-15.8 mg/L) concentrations. Maximum specific growth rates was obtained 0.47±0.03 day-1 in high nitrogen concentration for N.thermalis and 0.49±0.02 day-1 in high iron concentration for I. galbana. In addition, highest amount of fucoxanthin were found 7,57 ± 0,83 mg/g biomass and 10,09 ± 0,45 mg/g biomass for N.thermalis and I.galbana, respectively. The highest lipid contents was found 26.93±1.8% and 33.49±2.2% in the absence of nitrogen for N.thermalis and I. galbana, respectively.