The Journal of

  Background: Concerns about energy crisis coupled with climate change and increased global warming is drawing more attention to producing biodiesel from microalgae. Cell growth, biomass production and lipid accumulation in microalgae determine economic performance of biodiesel . The aim of this study was to investigate the role of medium to enhance the efficiency factors.

  Methods: Microalgae were cultured in four culture media of Walne, F/2, Sato and TMRL. Cell growth was determined by spectrophotometry on a daily basis by measuring the cell density. Biomass production and lipid accumulation of microalgae in the logarithmic growth phase and stationary growth measurements and constituents were identified by gas chromatography. Quality of oil extracted from each culture for biodiesel production was determined by iodine values through standards.

  Results: The results showed the highest rate of cell growth and biomass production in walne culture media to be 0.2616 day^-1 and 2.652gl^-1 respectively. Most amount of converting biomass into lipids in TMRL culture media equal to 37.22% of the cell dry weight was obtained. Walne culture media is also the most efficient lipid the productivity of which equaled 0.1057 gl^-1day^-1 and the highest amount of polyunsaturated fatty acids (PUFA) was obtained in Walne culture media in the logarithmic growth phase and equal to 42.99% of the fatty acids. The highest amount of triacylglyceride was obtained in Sato medium in the stationary growth phase and equal to 75.25% of the fatty acids.

  Conclusion: Nannochloropsis Oculata show maximum efficiency for aquaculture purposes and human consumption and biodiesel production, respectively, in the logarithmic growth phase and stationary growth in Walne medium.