effects of different nitrate levels on growth and fatty acid content in two species of freshwater microalgae

nitrogen as one of the important nutrients of microalgae has significant affect on the growth and nutrition value of the algae if the changes. in present study the growth and fatty acids content of the different concentration of nitrate (0, 0.62, 1.25, 2.5 and 5 mm from no3) was studied during a 12 day cultivation period of haematococcus sp. and desmodesmus cunaetus. at 22 °c in laboratory conditions. the results revealed that maximum count of algal cells(18.11×105 cell.ml-1) and growth rate of haematococcus sp.(0.22± 0.09 day-1) is seen while the algae exposed to 2.5 mm no3. in desmodesmus cunaetus, the maximum growth rate (36.00×105 cell.ml-1) and growth rate (0.31± 0.09 day-1) was found at1.25 mm no3. also a significant differentiation between high content of nitrate with increase in pufa (polyunsaturated fatty acid) and reduction of sfa (saturated fatty acids) was seen.