The study of microalgae Nannochloropsis salina fatty acid composition of the extracts using different techniques. SCF vs conventional extraction

The extraction of lipids and other valuable components from microalgae (Nannochloropsis salina) has been performed using various conditions: pure SC-CO2; SC-CO2 + acetone (at 32 MPa and 40 °C); Soxhlet apparatus with n-hexane; and Soxhlet apparatus with chloroform. Small amounts of co-solvents (3.2 wt.% of acetone) were added to modify the polarity and solvent strength of the supercritical CO2 to increase the solute solubility and to minimize operating costs of the extraction process. The extractions of lipids from algae were performed using a laboratory scale SCF extraction experimental apparatus. High pressure supercritical reactor with volume of 993 cm3, which made from stainless steel, was used. The flow rate of SCF was maintained constant (1.5 ± 0.05 kg/h). The extraction time was within 1.5 h. Four extracted lipid fractions were collected separately for each extraction conditions (for pure CO2 and CO2 + co-solvents) and analyzed using GC-MS. The experimental results showed that extraction technique is negligible small affecting on total extract yields and fatty acids content.