Previous reports have demonstrated that the lipid production by oleaginous microorganisms is heavily influenced by the carbon-to-nitrogen (C/N) molar ratio As shown in Figure 3A, when the (NH4)2SO4 was increased from 0.1 to 10 g/l corresponding to a decrease of the C/N ratio from 200 to 2, the optical density increased from 2.1 to approximately 4.0. After 36 hrs of cultivation, higher amounts of nitrogen