Effects of salinity on growth and fatty acid composition of green microalgae Dunaliella bardawil as a candidate source for biofuel production

Microalgae as a source of saturated and unsaturated fatty acids, pigments, pharmaceutical and food metabolites, has received more focus by biological researchers at last decades. The amount and composition of fatty acids produced by microalgae depended on biomass production and environmental factors such as changes in salinity, light and nutrient availability. In this study, the green microalgae Dunaliella bardawil isolated from Chabahar Bay was cultured under different salinities (35, 70 and 105 g/L) using Conway medium. All treatments with air pump at 25±2 ° C and 12L: 12D (h) photoperiod and aerated. Effect of different salinity on the growth rate, lipid production and fatty acid composition of algal biomass were examined. ANOVA results showed that the highest growth rate and lipid content in the salinity of 70 g/L was obtained which are 933 and 206 milligrams per liter, respectively. Maximum and minimum lipid content of D. bardawil measured, 24.5 and 19 percent, at 105 and 35 ppt, respectively. Due to reduced cell density in 105 grams of salt per liter of fat produced per unit volume decreased to 65mg/L. The results show that D. bardawil purification from Chabahar Bay with degree unsaturation between 95-73 has great potential for biodiesel production.