Effect of nitrogen, phosphorus and sodium bicarbonate on lipid production and fatty acid profile in Coelastrella terrestris

This study reveals the combined impact of nitrogen (N) and phosphorus (P) with the addition of sodium bicarbonate (NaHCO3) on lipid productivity and lipid content in chlorophycean microalgae Coelastrella terrestris. The N50P50 limited cells showed maximum productivity of lipid (LP) (2.45 μg/ml/d), which is 3.88-folds higher than control (0.63 μg/ml/d). The N00P00 combination yields 21.47% lipid content, which is higher than control (3.04%) and N50P50 (11.98%). However, biomass productivity is also very important in addition to the lipid content. In this regard, N50P50 combination found to have better biomass productivity (Bp) and lipid content along with highest lipid productivity among all the combinations. Gas chromatographic analysis of trans-esterified microalgal oil showed higher amount of saturated fatty acids under N50P50 (1.14-folds higher) than control. This increment in saturation has positive impact on stability of biodiesel. Present study reveal that cooperative effect of N and P limited conditions positively increase the amount of useful fatty acids and lipid content with supplementation of sodium bicarbonate in C. terrestris.