Cattle urine increases lipid content in Chlorella pyrenoidosa: A low cost medium for bioenergy application

Media requirement for microalgae cultivation adds most to the cost of biodiesel production at commercial scale. The present work aims to study the growth of green algae Chlorella pyrenoidosa under fogg`s medium and modified fogg`s medium by replacing KNO3 with urea at different concentrations 0.15, 0.20 and 0.25% (w/v). To reduce the cost of urea, cow urine (CU) was utilized to grow the Chlorella sp. in different volume fractions as 5, 7.5, 10, and 12.5 % (v/v). Biomass production in 7.5% cow urine was achieved 1.93 g l-1 that is almost double in comparison to normal Fogg’s medium (0.82 g l-1). Cellular biochemical components such as lipid, protein and carbohydrate are determined quantitatively. The lipid content is found to be 32.7 % in 10 % of cow urine and 22.7 % in 7.5 % cow urine that is much higher than the Chlorella sp. grown under Fogg`s media (7%). The protein content is enhanced to 50.17% and carbohydrate reduced by half in comparison to normal fogg’s medium cells. The extracted lipid is converted into fatty acid methyl esters (FAME) and characterized by GC-MS. The FAME produced from cow urine grown cells showed suitable composition to prove its application as biofuel.