Expanded ethanol with CO2 and pressurized ethyl lactate to obtain fractions enriched in γ-Linolenic Acid from Arthrospira platensis (Spirulina)

In the present work, two extraction techniques and two green solvents have been tested to obtain γ-linolenic acid (GLnA)-enriched fractions from Arthrospira platensis (Spirulina). Expanded ethanol with CO2 (gas expanded liquid extraction, GXL) and pressurized liquid extraction (PLE) using mixture of ethanol:ethyl lactate were tested and optimized chemometrically. Results obtained allow understanding the effects of the different factors involved in the tested processes and providing the optimum conditions to achieve the maximum total yield of lipids and also maximum GLnA recovery (%, w/w). Total yields up to 20.7% (w/w), were obtained under optimum PLE conditions considering 20.7 MPa pressure, 180 °C temperature and 15 min extraction time and a solvent composition of ethanol:ethyl lactate (50:50, v/v), under which GLnA recoveries of 68.3% from the original amount was achieved. GXL provided total yields of 7.4% (w/w) and GLnA recovery of 35.3%, both of which were lower than those obtained by PLE.