Kinetics of the supercritical fluid extraction of carotenoids from microalgae with CO2 and ethanol as cosolvent

The kinetics of the supercritical fluid extraction of carotenoids from microalgae has been studied. The solvent systems used were supercritical carbon dioxide and CO2 + 5% ethanol as a cosolvent. A penetration model developed by other authors was applied that, due to the spherical form of the cellular microalgae, was based on the application of the mass balance to a spherical particle. The fit of the model is satisfactory and it was able to predict in a reasonable way the extraction yield of the process. The comparison between experimental and calculated data provided a value for the internal diffusion coefficient and this allowed an analysis of the influence of the different variables in the extraction process.