Author:

Abstract:

In the quest for sustainable commercial production of bioproducts such as lipids, pigments and proteins and for pollution mitigation and CO2 abatement, microalgae are increasingly receiving an attention due to their high growth rate, high CO2 sequestration and their lack of requirement for fertile soil surface compared to conventional crops. Because microalgal biomass consists of individual cells with rigid cell walls, extraction of useful components from the biomass is often problematic. Extraction and processing with supercritical fluids (SCF) is increasingly gaining importance in the food, pharmaceutical and chemical industries and can be a solution for these specific problems. Carbon dioxide is the most common supercritical fluid due to its moderate critical temperature (31.3 oC) and pressure (72.9 atm) and hence particularly desirable for the extraction of thermally labile natural products. Since the extraction conditions are relatively mild, the residual algal biomass can still be maximally valorized. Because CO2 is gaseous at room temperature, it yields a solvent free extract. Moreover, carbon dioxide is a non toxic, non flammable, odorless, tasteless and inexpensive gas. The goal of this work is to investigate the possibility of using supercritical carbon dioxide extraction to obtain the lipids and other valuable products from microalgae. The supercritical fluid extractions are carried out at different temperatures, pressures as well as with different extraction times and carbon dioxide flow rates. Both the lipid yield and composition are considered in order to optimize the supercritical carbon dioxide extraction and to compare its efficiency with the conventional extraction methods.