Caspian Sea’s Navicula salinicola Hustedt 1939 and effect of the prolonged culture on its fatty acid profile

Diatoms are a potent source of polyunsaturated fatty acids. This study was conducted for screening a Naviculoid diatom strains from the southern Caspian Sea with analyzing its lipid production and accumulation potentials. The isolate was identified as Navicula salinicola strain IBRC-M 5083 based on micro-morphological characterization and analysis of 18S rRNA genomic region. Navicula salinicola were cultured in the f/2 medium under both normal and prolonged culture (21 days) conditions. Total lipid percentages of this strain were found to be 31.83% under normal condition and 43.72±1.4% in prolonged culture respectively on the basis of their dry cell weight (DCW). Also, the oil droplets were detected in 21 days’ cells as shown by Sudan Black B staining experiments. Furthermore, the main fatty acids were found by Gas Chromatography analyses of this strain under prolonged condition to be Eicosapentaenoic acid (25.58%TFA). Such oil accumulation capabilities seem to be promising for performing further studies on this strain as a source of Omega-3 in aquafeed, pharmaceutical and biofuel industries.