Ionic liquids assisted microalgal lipids extraction and characterization

Microalgal lipids are sustainable sources of biofuel production offering a cost-effective and eco-friendly alternative to fossil fuels. This study explores the use of ionic liquids (ILs) as a non-toxic replacement for conventional solvents in lipid extraction. Lipid extraction was optimized by varying the algae:IL ratio, with hexane used as the extraction solvent. Phytochemical analysis confirmed the presence of sterols, and high-performance thin-layer chromatography (HPTLC) identified sitosterol as a possible component. The optimal IL concentration (1:2), yielded 44.6 mg.g −1 of lipids, corresponding to an extraction efficiency of 4.46%. The selected IL-Tetrabutyl Ammonium Iodide (TBAI) remained effective despite increased water content. FT-IR analysis confirmed the presence of lipids through characteristic peaks at 2873.50 cm −1 , 2925.17 cm −1 and 1379.34 cm −1 corresponding to free fatty acids, -CH 2 stretching in lipids, and CH 3 bending, respectively. GC-MS analysis revealed diverse fatty acids, with a predominance of saturated types. Tridecanoic (C13:0) and Dodecanoic (C12:0) acids were the most abundant with their high saturated fatty acid content enhancing the fuel properties of the extracted lipids due to superior combustion characteristics. Future research will focus on optimizing TBAI recyclability and further improving extraction efficiency.