Effective lipid extraction from undewatered microalgae liquid using subcritical dimethyl ether

Abstract Background Recent studies of lipid extraction from microalgae have focused primarily on dewatered or dried samples, and the processes are simple with high yield. Yet, dewatering drying step is energy intensive, which makes input during production more than output obtained lipid. Thus, exploring an technique for just a thickened sample without dewatering, auxiliary operation (such as cell disruption) very significant. Whereas complicated by water content involved, traditional solvent, hence, cannot work well. Dimethyl ether (DME), green featuring affinity both organic compounds ability to penetrate walls has potential achieve this goal. Results This study investigated energy-saving method using DME solvent entrainer solution (ethanol acetone) flocculation-thickened microalgae. Extraction efficiency was evaluated in terms time, dosage, ethanol:acetone ratio. Optimal occurred after 30 min 4.2 mL per 1 microalgae, dosage 8% at 1:2 ethanol:acetone. Raw yields its component (represented fatty acid methyl ester) contents were compared against those common methods (Bligh Dryer, Soxhlet). Thermal gravimetry/differential thermal analysis, Fourier-transform infrared spectroscopy, C/H/N elemental analyses used examine differences lipids extracted each methods. Considering influence trace metals biodiesel utilization, inductively coupled plasma mass spectrometry atomic emission spectroscopy quantify raw lipids, revealed relatively concentrations Mg, Na, K, Fe. Conclusions Our DME-based recovered 26.4% total 54.4% esters first remnants being 2nd extraction. In additional, approach economical other methods, because it enabled simultaneous no disruption required. The indicated purification demand subsequent refining process.