Production of Lipids Rich in Omega 3 Fatty Acids from the Halotolerant Alga Dunaliella salina

The effect of nitrogen limitation and salt stress on total lipid and unsaponifiable contents as well as fatty acid composition of Dunaliella salina were studied. The contents of total lipids, unsaponifiables and fatty acid composition were basically depend on NaCl and nitrogen concentration in the culture. The highest yield of total lipids (37.69%) and unsaponifiables (29.02%) was obtained in cells grown at 16% NaCl combined with 2.5 mM nitrogen. While, minimum yield occurred in cells grown in a culture containing 8% NaCl and 5 mM N. Cells grown at 16% NaCl combined with 2.5 mM N produced relatively higher proportion of polyunsaturated fatty acids (PUFAs), in particular C18:3w3 and C16:4w3. Increasing NaCl combined with decreasing N levels in the growth medium increased the total unsaturated fatty acids (TU) at the expense of total saturated fatty acids. At higher salinity, the total amounts of carotenoids and α-tocopherol in unsaponifiable fraction were significantly increased to reaching up to 12.03 and 4.10%. The results obtained suggest that D. salina cells containing high amount of total lipid, rich in w3 polyunsaturated fatty acids and antioxidant compounds in unsaponifiable lipid fraction may used as a supplemental ingredient or as a complete food to enhance the performance and state of the human body or improve a specific bodily function.