Abstract

Algae biofuel have emerged as viable renewable energy sources and are the potential alternatives to fossil based fuels in recent times. Algae have the potential to generate significant quantities of commercially viable biofuel apart from treating wastewater. Three algal species viz. Chlorococum sp., Microcyctis sp. and Phormidium sp. proliferating in wastewater ponds were isolated and cultured in laboratory myxotrophically under similar wastewater conditions. Chlororcoccum sp. attained a mean biomass productivity of 0.09 gL^-1d^-1 with the maximum biomass density of 1.33 gL^-1 and comparatively higher lipid content of 30.55 % (w/w) on the 9^th day of the culture experiment. Under similar conditions Microcystis sp. and Phormidium sp. attained mean biomass productivities of 0.058 gL^-1d^-1 and 0.63 gL^-1d^-1 with a total lipid content of 8.88 % and 18.66 % respectively. Biochemical composition (carbohydrates, proteins, lipids and phosphates) variations and lipid accumulation studies were performed by comparison of the ratios of carbohydrate to protein (C/P); lipid to protein (L/P) and lipid to phosphates (L/phos.) by using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) which showed higher L/P ratio during the stationary phase of algal growth. The composition analysis of fatty acid methyl ester (FAME) has been performed through gas chromatography and mass spectrometry (GC-MS). The Chlorococcum sp. with higher productivity and faster growth rate have higher lipid content with  about 67 % of saturated fatty acid dominated by palmitate (36.3 %) followed by an unsaturate as linoleate (14 %) and has proved to be an economical and viable feedstock for biofuel production compared to the other wastewater grown species.

Keywords: Algae, lipid, wastewater, biofuel, fatty acid (FAME)