Multi-factor effects of culture conditions on lutein and β-carotene production in Iranian Dunaliella sp. isolates

Carotenoids, including lutein and β-carotene, are valuable natural pigments with extensive applications in the food, pharmaceutical, and nutraceutical industries. In the current study, using the factorial experimental design, the biomass and carotenoid production in three Iranian Dunaliella sp. isolates (ABRIINW-B8, ABRIINW-G23, ABRIINW-I44) under combinations of light regime, salinity, nitrate, and copper supplementation, and cultivation time were surveyed. Significant strain and treatment-dependent differences were observed in biomass accumulation and pigment production. Within the tested experimental ranges, strain B8 showed the highest carotenoid accumulation under a light regime (1200 µmol photons m⁻² s⁻¹), 1 M NaCl, 0.5 M KNO₃, and 0.05 mM CuSO₄·7 H₂O, reaching 11.5 mg g⁻¹ DW lutein (7.36 mg L⁻¹) and 63.5 mg g⁻¹ DW β-carotene (40.64 mg L⁻¹). Strain G23 exhibited the highest chlorophyll content. These findings demonstrate the capacity of Iranian Dunaliella isolates to produce high-value carotenoids and identify culture conditions that enhance lutein and β-carotene accumulation.