Abstract

Microalgae is one of the best sources of renewable energy production, such as biofuels. The production of biodiesel from microalgae has several advantages, including the high productivity of lipid and the possibility of cultivating them on marginal land. One of the challanges in using microalgae for biodiesel production is the complexities process of lipids extraction by organic solvents followed by transesterification. The aim of this work is to optimize this process by a single extraction and conversion step. The reaction was carried out for different parameters such as; various oil to methanol ratios, concentration of catalyst, temperature and time reaction. The lipid content of Nannochloropsis gaditana microalgae was 0.19 g/g biomass. The best yield of fatty acid methyl ester (65.6%) was obtained at 150 min duration for algae drying, 60% (wt./wt. oil) H₂SO₄ as catalyst concentration, and 1:8 algae biomass to methanol ratio (w/v). The algal biodiesel samples were analyzed with gas chromatography mass spectrometry (GC-MS) and Fourier transform infrared spectroscopy (FT-IR). N. gaditana microalgae investigated in this study, proved to be suitable as raw material for biodiesel production, due to their high cetane number (69.68). From the FT-IR result and fatty acid profile, it was implied that marine microalgae, N. gaditana in this study can be considered as potential feedstock for biodiesel production to fight the future energy crisis.

Key words: Biodiesel, fatty acid methyl ester, microalgae, Nannochloropsis gaditana, transesterification.