Supercritical CO2 extraction of Mortierella alpina single cell oil: Comparison with organic solvent extraction

► Extraction method and pretreatment notably influence lipid recovery in M. alpina. ► Higher mass transfer in the treated cells results in rapid extraction. ► Maximum cell wall disruption occurred with enzyme as evidenced by the SEM images. ► Differential solubility of fatty acids was influenced by the mode of pretreatment. ► Prominent cis-stretching vibration noticed in the FT-IR spectra. Analysis of supercritical fluid extracted (SFE) and organic solvent extracted lipids from freeze dried Mortierella alpina biomass was carried out. The effect of biomass pre-treatment on effectual lipid recovery was also investigated. Results indicated that the methods employed viz., SFE and organic solvent (Sox Tec™) exhibited significant variation in lipid extraction efficacy. Efficacy of SFE on lipid recovery (38.73%) was significantly lower when compared to that of Sox Tec™ method (51.47%) because the organic solvent can also extract polar lipids. Biomass pretreatment by enzymatic method resulted in a substantial increase in lipid recovery. Maximum disruption of cell wall evidenced by scanning electron microscopy of treated cells warranted their higher mass transfer and efficient extraction. Characterisation of the extracted lipids by GC and GC–MS revealed considerable variation in the fatty acid profile. The FT-IR spectrum indicated a prominent cis-stretching vibration, no evident trans- stretching vibration and no major discrepancies between the SFE and Sox Tec™ extracts.