In present scenario, microalgae have been used as a third generation promising source for production of biofuel. So it is necessary to screen microalgal strains rich in oil and adapt to variable environment conditions. The present study deals with cultivation of Chlorella pyrenoidosa in Fogg's media using urea and KNO 3 as nitrogen source. The effect of two different nitrogen sources at different concentration (0-2g/L) on biomass and lipid content was studied. The result showed that with

more »

... e of N-source in media biomass increased but lipid content decreases and vice versa. Moreover, at same concentration of urea and KNO 3 , biomass as well as lipid content was more in microalgal cell growing in urea. Urea at concentration of 0.1g/L gives optimum conditions for biomass production and lipid content in cells. At high concentration of urea due to ammonium toxicity growth rate decreased in algal culture. The optimum concentration of urea proves better than other nitrate source to culture Chlorella pyrenoidosa in order to increase lipid content and to use it as biofuel feed stock.