Optimization of Microalgae Lipid Extracts for the Production of Fuels

The new federal rules designed to reduce CO2 emissions from power plants demand innovation in the field of carbon capture and utilization. The use of algae to sequester CO2 from coal-fired power plants constitutes an interesting solution, particularly because algae can intermediate the conversion of these emissions into valuable fuels and chemicals. Our previous research showed that this approach was feasible from a technical standpoint, current work being focused on cost reduction. Past work has shown that oil can be extracted from algae and converted to hydrocarbon fuels that are fully compatible with existing infrastructure. To date efficient extraction of the oil has required that the algae are first subjected to an energy intensive and costly drying step. To improve the economics of the extraction process, we have investigated the extraction of oil from wet algae grown using the flue gas of a Kentucky coal-fired power plant. The research conducted in this project tested the extraction efficiency of sonication, mechanical disruption methods (milling and beating), suspension in supercritical hexanes and a modified Bligh-Dyer solvent extraction method (employing a CHCl3/CH3OH/H2O solvent system). From these studies it is concluded that the optimal methods in terms of the oil yield are suspension in supercritical hexanes and the modified Bligh-Dyer method. The lipid profile and elemental analysis of the oils extracted using these methods provide valuable insights regarding the effect of the extraction method on the composition of the oil obtained