Effect of salinity on growth, biochemical composition, and lipid productivity of Nannochloropsis oculata CS 179

Effect of salinity (15, 25, 35, 45, and 55 parts per thousand) on growth, biochemical composition, and lipid productivity of Nannochloropsis oculata CS 179 was investigated under controlled cultivation in a 19-day study. The results demonstrate that the dry biomass of N. oculata was the highest at a salinity of 25 parts per thousand among the treatments in the first 10-day cultivation (P<0.05). During days 1419 (stage III), the dry biomass productivity was the highest at a salinity of 35 parts per thousand (P<0.05). The algae had the highest chlorophyll a content (26.47 mg g-1) at 25 parts per thousand in stage I, and it decreased continuously at stage III. Protein content (as% of dry biomass) of algae reached the highest value of 42.25 +/- 2.10% at 15 parts per thousand, and the lipid content was the highest of 32.11 +/- 1.30% of dry biomass at 25 parts per thousand. However, the lipid productivity of these algae was the highest at 35 parts per thousand (64.71 mg L-1 d-1; P<0.001). C16 series content was the highest among the total fatty acid methyl esters (FAME), and eicosapentaenoic acid C20:5n-3 (EPA) content was high at the low salinity. Fatty acid profiles of N. oculata varied significantly under different salinities.