Influence of citrate on Chlorella vulgaris for biodiesel production

The present study was carried out on microalgae Chlorella vulgaris to investigate the effect of citrate metabolite as a nutrient for biodiesel production. The oil obtained from C. vulgaris is a promising fuel substitute and can be used as biodiesel. C. vulgaris was cultured in conway medium at different concentrations of citrate, namely 0.5, 1.0 and 2 g/L were added to the culture medium in different experimental groups. Subsequently, the growth, proximate composition and biomass content of the cultured cells were analyzed. The maximum biomass (1.68±0.044 g/L) in the cultured cells was obtained at a citrate concentration of 2.0 g/L in the culture medium. However, the highest oil yield (28.62%) was obtained at the 1owest citrate concentration. Physico-chemical parameters such as pH, viscosity, density, acid and iodine values of the extracted oil were analyzed. In addition, a freeze-dried sample of the algae was analyzed to ascertain its biochemical composition. The maximum lipid content (37.03±±0.88%) was obtained at the minimum experimental concentration of citrate (0.5 g/L) in the culture media. An increase in citrate concentration in the media resulted in a decrease in total lipid content of the cells, but increased the carbohydrate content up to 29.43±0.72%. Fatty acid profiles of the control and experimental groups were analyzed. The present study was suggested that the presence of lowest concentration of citrate in the culture media can improve the accumulation of lipids in C. vulgaris.