Experimental comparison of biodiesel production performance of two different microalgae

In this study, the fresh water green microalga Scenedesmus dimorphus and the marine golden Isochrysis aff. galbana were compared at the laboratory scale for their potential in biodiesel production. For this purpose, the microalgal strains were grown over five days under the Bristol and Erdschreiber's media conditions. The cultures were supplied with 1.5% carbon dioxide (CO2) and 16:8 light to dark cycle at fixed temperature. The research performed contained the following stages: 1) Growth monitoring (analysis of growth rate), 2) Microalgae harvesting (lab-scale lipid extraction), 3) Biodiesel production and 4) Determination of biodiesel quantity and quality. The results show that the total lipids (% dry weight biomass) from Scenedesmus dimorphus and Isochrysis aff. galbana cultures were found to be 15.87 and 42.65%, respectively. The obtained yields of the transesterification reactions were 87.4% (Scenedesmus dimorphus) and 94.6% (Isochrysis aff. galbana). The methyl esters of Isochrysis aff. galbana contained higher percentage of saturated fatty acids than Scenedesmus dimorphus and its fatty acid composition improved the basic fuel properties. The overall finding of the study suggested that Isochrysis aff. galbana can be considered as more viable source for biodiesel production, in part due to the relative ease in producing a high oil yield.