P. SHARMA, M.B. KHETMALAS AND G.D TANDON
Abstract
An indigenous strain of Chlorella ellipsoidea isolated from freshwater pond was evaluated for its potential to produce biodiesel and bioethanol. It was characterized for its growth, carbohydrates, lipid and fatty acid composition. Specific growth rate was determined to be 2.32 x 104 cells/day with lipid productivity of 560 mg/L/day. Lipids were determined qualitatively by fluorescence microscopy using Nile Red. Algal oil extracted from dried biomass was transesterified and analyzed by GCMS to determine the fatty acid spectrum and the suitability of its TGAs as biodiesel. Hexadecanoic acid (46.50 %) and Heptadecanoic acid (3.88 %) were present as saturated fats. 1, 19-Eicosadiene (42.42 %) and Phytol (3.81 %) were detected as volatile compounds. The carbohydrates from the defatted, residual algal biomass were converted to bioethanol by subjecting the biomass to pretreatments, enzymatic hydrolysis and fermentation by a strain of Saccharomyces cerevisiae. Acidic pretreatments proved to be more promising as compared to alkaline treatments. Hydrolysis by a cocktail of enzymes yielded higher saccharification rates (98. 17 %) with 44 % of bioethanol conversion yields as compared to the individual enzymes. The study explored C. ellipsoidea for its complete biomass utilization.