Production of green and renewable biodiesel from marine brown alga <i>Sargassum tenerrimum</i>

Abstract

The present research work demonstrates the production of biodiesel from the oily content of marine macroalga <i>Sargassum tenerrimum</i> via mechanical stirring and microwave irradiations. The algal oil as well as direct algal biomas were subjected to methanolysis and ethanolysis using Na metal, NaOH and H₂SO₄ as catalysts. Mechanical stirring was found to be relatively slow but more feasible method for transesterification while microwave irradiation was observed to be too fast method with certain limitations like vigorous bumping that would be uncontrolable on large scale. Na metal was the most reactive catalyst that produced FAME (82%) and FAEE (80%) by mechanical stirring at room temperature whereas it produced FAME (88%) and FAEE (85%) by microwave heating within 1-5 minutes. Na metal was found to be very reactive, NaOH was the moderate while H₂SO₄ was the slowest catalyst for transesterification. Methanol was found to be more reactive due to its smaller size as compared to ethanol. Algal oil produced significant amount of biodiesel as compared to the algal biomass due to maximum interaction of reactants with oil. Biodiesel production was confirmed by TLC examination and by comparing the fuel properties of biodiesel with the ASTM standard limits of biodiesel.