The Hansen theory to choose the best cosolvent for supercritical CO2 extraction of β-carotene from Dunaliella salina

Abstract

The Hansen solubility theory was used to predict the best cosolvent for supercritical carbon dioxide (sc-CO2) to achieve the selective extraction of β-carotene from Dunaliella salina. Among four organic cosolvents, ethanol was predicted to be the best based on minima Ra values. The predictions were validated through equilibrium data and extraction curves from the microalgae. The addition of ethanol reduced the bubble pressures, and therefore increased the solubility of the β-carotene. With 5% mass fraction, at 318.15 K and 20 MPa, the extraction yield was 25 g carotenoids kg microalgae−1, much more than in pure sc-CO2 (6 g).