Supercritical CO2 extraction of γ-linolenic acid and other lipids from Arthrospira (Spirulina)maxima: Comparison with organic solvent extraction

Freeze-dried biomass of Arthrospira maxima Setchell & Gardner was submitted to supercritical CO2 extraction using a flow type apparatus at a temperature of 50 °C and a pressure of 250 bar.To increase the yield in either lipids or GLA (γ-linolenic acid), which is mostly contained in the glycolipid fractions, a polar co-solvent (ethanol) was added to the CO2 and the corresponding supercritical fluid extraction was carried out at temperatures of 50 and 60 °C and at 250 and 350 bar. The use of the co-solvent increased both lipid and GLA yields relative to the extraction with pure CO2. On the other hand, the increase of pressure and temperature also had a positive effect on the extraction of GLA.Supercritical extraction was compared with organic solvent extraction, regarding lipid yields, fatty acid composition of total lipids and lipid classes, as well as the distribution of lipids by their classes (neutral lipids, glycolipids and phospholipids).