Determine Nitzschia sp. and Nanofrustulum shiloi lipid content under different stress condition

Microalgae are microscopic organisms with commercial value that constitute the first pace of the food chain. Diatoms, substation of microalgae, are eukaryotic organisms and live in a colony or single cell. Their most important feature is that they contain plenty of silica. It has commercial value and is very popular in petroluem Works, sea water pollution rate determination, cosmetic product, food industry and construction industry. In addition, the oil content that it possesses has led to various studies in the production of biodiesel. In this study, batch culture of Nitzschia sp. and Nanofrustulum shiloi are aimed to determine the specific growth rates of different chemical concentrations, such as light and nitrogen, iron and copper, as well as the changes in the content of carotenoid, biomass and fatty acids content. Morphological and biochemical contents of cultures prepared under different culture conditions and different stress conditions of the species have been determined optical density, cell count, fucoxanthin, chlorophyll-a, amount of total fatty acids were measured. The changes in carotenoids with the help of HPLC-DAD and the total fatty acids content were determined with ARGEFAR GC-FID. The cultures were incubated at ambient temperature of 20 ± 1ºC and pH 8.2-8.5 with light intensity of 30 to 300 μmol m-2 sec-1, nitrogen 0 to 2 g L-1, iron 0 to 15.8 mg L-1, copper 0 to 1.49 mg L-1 concentrations were used. As a result of the study, Nitzschia sp., the best specific growth rate was 0.27 days-1 under the stress condition that the nitrogen concentration was 2 g L-1. The best specific growth rate for the Nanofrustulum shiloi was 0.36 days-1 in the stress condition where the nitrogen concentration was 2 g L-1. The best value for the doubling time of Nitzchia sp. is 2.54 days-1 where stress condition that the nitrogen concentration was 2 g L-1. It was determined that the nitrogen concentration for the Nanofrustulum shiloi was 1.88 days under the stress condition of 2 g L-1. For biomass weights, the best value for Nitzschia sp. is 0.27 g L-1 where copper concentration was 1.49 mg L-1 and the best value for Nanofrustulum shiloi is 0.68 g L-1 where nitrogen concentration is 0.68 g L-1. HPLC measurements showed that Nitzschia sp. the highest value was measured as 8.47 mg mL-1 at low light intensity and 7.83 mg mL-1 at the stress condition where the highest iron concentration was 15.8 g L-1 for the Nanofrustulum shiloi. The fat content for Nitzschia sp. was found to be 37.8% in 2 g L-1 nitrogen concentration. For Nanofrustulum shiloi was found to be 17.8% in 15.8 g L-1 iron concentration. The highest percentage of saturated fatty acid in the Nitzschia sp. was found to be 67.3% in the stress condition with the light intensity of 30 μmol m-2 sec-1, the highest percentage of monounsaturated fatty acid was 63,6% in the stress condition of copper concentration was 1.49 mg L-1, the highest percentage of polyunsaturated fatty acid was 9.71% in the stress comdition of iron concentration was 0 g L-1. The highest percentage of saturated fatty acid in the Nanofrustulum shiloi was found to be 74.4% in the stress condition of copper concentration was 1,49 mg L-1, the highest percentage of monounsaturated fatty acid was 37.4% in the stress condition of nitrogen concentration was 0 g L-1, the highest percentage of polyunsaturated fatty acid was 20.2% in the stress comdition of copper concentration was 1.49 mg L-1.