Selective Extraction of Neutral Lipids and Pigments from Nannochloropsis salina and Nannochloropsis maritima Using Supercritical CO2 Extraction: Effects of Process Parameters and Pre-treatment

Abstract Supercritical CO2 extraction experiments were conducted to investigate the effects of pretreatment and process parameters on neutral lipids, chlorophylls and carotenoids recovery on two species of Nannochloropsis. For Nannochloropsis maritima, a factorial experimental design was performed (P: [100 - 300] bar, T: [313 - 333] K). The highest extraction yields were obtained at the highest pressures and temperatures. Two drying modes, ring drying and air flow drying, were compared. Although total extraction yield and extraction kinetics were observed to be greater using air flow dried microalgae, extracts from this drying method resulted in partial degradation of glycerides in free fatty acids. Ring dried extracts maintained the same neutral lipid composition as the initial biomass. Based on these results, ring dried Nannochloropsis salina was extracted using supercritical CO2 at 333 K and both 300 - 400 bar. Extraction curves were modelled using the Sovova’s mathematical model.