Journal of Supercritical Fluids, Vol.108, 89-95, 2016
Lipid content and fatty acid profile of Nannochloropsis oculata before and after extraction with conventional solvents and/or compressed fluids
The lipid content and fatty acid profile of freshly harvested Nannochloropsis oculata was characterized before and after extraction with both conventional solvents and compressed fluids. Among the conventional solvents, ethanol was the most efficient, yielding 11.33 g of fatty acids methyl esters per 100 g(-1) of dry microalga biomass. The addition of ethanol as co-solvent at a mass ratio of 1:1 improved the extraction performance of both subcritical propane and supercritical CO2. At 200 bar and 80 degrees C, the extraction of N. oculata with propane in the presence of ethanol resulted in the best yield of 7.53 g of fatty acid methyl esters per 100 g of the desalted biomass. By replacing propane by carbon dioxide, this yield dropped 45.8%. However, under the conditions used in this study, both conventional and compressed fluid extractions did not remove the entirety of the microalga fatty acids, demonstrating that these processes toned to be optimized to avoid mass transfer limitations. Even so, the use of compressed fluids reduced the amount of solvent used when compared to extraction with a conventional Soxhlet apparatus. (C) 2015 Elsevier B.V. All rights reserved.
Keywords:Nannochloropsis oculata;Pressurized fluids;Carbon dioxide;Propane;Ethanol;Fatty acid methyl esters