Biological fixation of carbon dioxide and biodiesel production using microalgae isolated from sewage waste water

The present research investigates potential of microalgae isolated from sewage treatment plant to utilize sodium bicarbonate as carbon source for CO(2)sequestration and biodiesel production. Eight algal isolates were isolated from waste water of sewage treatment plant, Amity University Haryana, India. The most potent algal isolates were identified and characterized on the basis of growth and lipid content. The efficient isolates ASW1 and ASW2 were identified asChlorellasp. andArthronemasp. by 18srRNA and 16srRNA sequencing method. In both isolates, maximum growth was observed under 20-W fluorescent bulb (3500 flux light intensity) with continuous light cycle of 24 h at pH 9.0 and 25 degrees C on the 20th day of incubation period. CO(2)utilization efficiency of both algal isolates were observed in terms of total CO(2)consumption rate. Under optimized culture conditions, total lipid content and lipid yield was higher inArthronemasp. (180 mg l(-1); 32.14%) as compared toChlorellasp. (98 mg l(-1); 29.6%) in 50 mM NaHCO3. Transesterified lipids were analysed by GC-MS. The fatty acid methyl ester profile ofArthronemasp. was 34.42% saturated and 65.58% unsaturated fatty acid.Chlorellasp. produces 29.80% saturated and 70.20% unsaturated fatty acid. In both isolates, C16 and C18 fatty acids dominated, which is a promising component for biodiesel. Graphical abstract