Objective: Microalgal pharmaceutical biotechnology is mainly dependent on the biomass yield and also the final concentration of the obtained lipids. β-carotene is one of the most precious nutraceuticals, of both preventive and therapeutics importance in pharmacy and medicine. Dunaliella salina is known as famous β-carotene producer which could accumulate the β-carotene up to 10% of its dry cell weights. The amount of different macro and micronutrients in D. salina culture medium defines its productivity and β-carotene content. Methods: In this study, the effects of sulfur, iron and manganese deprivation, on cell growth and β-carotene biosynthesis in a naturally isolated strain of D. salina was examined. Besides, the fatty acid profile of the naturally isolated strain was also investigated. Results: Sulfur, iron and manganese deprivation caused a noticeable decrease in the cell growth of D. salina. On the other hand, in nutrient depleted media, the maximum β-carotene concentration was significantly improved (14.616 mg L-1 in sulfur starvation, 14.994 mg L-1 in iron starvation and 10.119 mg L-1 in manganese starvation media) compared with initial values (6.753 mg L-1) in basic culture medium. The obtained fatty acids from the studied microalgal strain found to be some important saturated, monounsaturated and polyunsaturated fatty acids. Conclusion: Owing to its significant growth rate, β-carotene contents and fatty acid profile; the naturally isolated microalgal strain could be exploited as a potential producer strain. Besides, the nutrient limitation strategy could be effectively employed to improve the β-carotene production procedure in D. salina.
Key words: Nutrient starvation, Dunaliella salina, β-carotene production, Fatty acid profile, Nutraceuticals.