Direct Transesterification of Microalga Botryococcus braunii Biomass for Biodiesel Production

Microalgae biodiesel are reported to be better than fossil fuels in terms of life-cycle energy performance. Green alga, Botryococcus braunii symbolizes one of the most favorable resources of biodiesel due to relatively high lipid content. The present study focused on the cultivation of Botryococcus braunii with the fed-batch in 4 L labscale continuously stirred tank reactors (CSTRs) through inexpensive red Nile tilapia effluent medium (RNTEM), biomass growth, protein, carbohydrate, lipid, hydrocarbon production and fatty acids profiles. Additionally, in this study we have evaluated the feasibility of biodiesel production directly from B. braunii biomass at laboratory scale achieved through direct transesterification process. B. braunii growth confirmed the highest biomass yield (8.57 g L −1) and 35.32% hydrocarbon content was observed. Further, 47.59% lipids, 16.39% proteins and 38.21% carbohydrates were observed under laboratory conditions. Fatty acid methyl esters (FAME) synthesis by direct conversion of B. braunii biomass was carried out using sulfuric acid as a catalyst and methanol as solvent. The experimental results obtained in the present study proved that the production of B. braunii by RNTEM is potentially feasible.