Formulation of a Suitable Production Medium for Improved Lutein Production by Marine Microalgae Dunaliella Sp.

Abstract

The biosynthesis of lutein and lipid in microalgae is significantly influenced by the media components, which either increase the key enzyme concentrations or act as cofactors for the enzymes involved in lutein and lipid metabolic pathways. In this study, a medium formulation strategy, involving Plackett-Burman design for screening the modified zarrouk's media components was implemented for improving the lutein productivity of Dunaliella sp. along with lipid as a co-product. An increase in lutein productivity was observed with the upper value of sodium bicarbonate (500 mg/L). The Pareto chart indicated 7 significant components out of the eleven components selected for the Plackett-Burman design. Magnesium sulfate, sodium bicarbonate, copper sulfate, and sodium molybdate were observed to have a significant influence on the biomass yield of microalgae. Using the optimized media from the Placket-Burman design a biomass yield of 1.8 ± 0.1 g/L was obtained which was two times higher as compared to the control. A 61% increase in lutein productivity (0.208 ± 0.021 mg/L/day) was recorded with the optimized media. With the spike in biomass, nitrate utilization was observed to be 13% higher in optimized media as compared with the control. Lipid % was observed to be 14.78%, which was two percent higher than the control. 3.7% carbohydrate and 4.13% protein yield were also recorded. These results further open future prospects for precision media optimization for lutein product from the microalgal biomass of Dunaliella sp. Keywords: Plackett-Burman design, Dunaliella sp., lutein productivity, biomass yield, and nitrate utilization.