Production of natural pigment by Dunaliella salina: Key factors screening through Placket-Burman design

The distinctive biological and technical characteristics of Dunaliella, including the need for cheap culture medium, fast growth rate, simple genetic manipulation, and easy scale-up methods, have made this microorganism the prime candidate for molecular agriculture, and a suitable host for the production of antibodies, vaccines and valuable compounds such as carotenoids, glycerol, unsaturated fats, vitamins, proteins, and bioactive substances. Therefore, this alga may be one of the most appropriate models to investigate and utilize to produce useful compounds by optimizing its environment. This study investigated the feasibility of high biomass and pigment (chlorophyll a, chlorophyll b, and carotenoids) accumulation in a species of Dunaliella salina native to Iran by creating mixotrophic conditions using the Placket-Burman screening design. In this design, the effects of 10 variables, including pH, light intensity, carbon source (date waste), Nitrogen source, NaCl, Fe (ferrous sulfate), vitamin B1, vitamin B12, Incubation time and Inoculum concentration were investigated. The results showed the significant effects of carbon source, sodium chloride, pH, inoculum concentration, and incubation time on biomass accumulation the value of which varied from 1.90-8.54 g/100. All variables except vitamins had a significant effect on the accumulation of chlorophyll and increased its amount from 0.60-1.35 mg/l. While variables such as pH, incubation time, sodium chloride, light intensity, and iron effected the accumulation of chlorophyll b significantly. pH, carbon source, sodium chloride, nitrogen source, and light intensity affected the accumulation of carotenoids, and the highest amounts of chlorophyll b and carotenoids were obtained as 2.8 and 8.6 mg/l, respectively.