Effect of light intensity, pH, and temperature on triacylglycerol (TAG) accumulation induced by nitrogen starvation in Scenedesmus obliquus

Microalgae-derived lipids in the form of triacylglycerols (TAGs) are considered an alternative resource for the production of biofuels and food commodities. Large scale production of microalgal TAGs is currently uneconomical. The cost price could be reduced by improving the areal and volumetric TAG productivity. The economic value could be increased by enhancing the TAG quality. To improve these characteristics, the impact of light intensity, and the combined impact of pH and temperature on TAG accumulation were studied for Scenedesmus obliquus UTEX 393 under nitrogen starved conditions. The maximum TAG content was independent of light intensity, but varied between 18% and 40% of dry weight for different combinations of pH and temperature. The highest yield of fatty acids on light (0.263 g/mol photon) was achieved at the lowest light intensity, pH 7 and 27.5 °C.