Utilization of microalgae for bio-jet fuel production in the aviation sector: Challenges and perspective

Aviation sector discharges approximately 2% of the global anthropogenic CO2, and the proportion is growing. The search for cost-effective and environmental-friendly bio-jet fuels derived from natural resources is gaining momentum. The microalgae cultivation conditions including temperature, pH, light intensity and nutrients have shown significant influence on the microalgae growth rate and chemical composition, which create the opportunities to enhance the yield and quality of microalgae bio-jet fuel. This review is focused on the hydroprocessing method for converting microalgae oil into bio-jet fuel, as well as the novel conceptual approaches for bio-jet fuel production such as gasification with Fischer-Tropsch and sugar-to-jet. Fischer-Tropsch synthesis of biomass is one of the best alternative ways to replace natural aviation fuel due to the high maximum energy efficiency and low emission of greenhouse gas. In addition, hydroprocessing with the aid of Ni and zeolites catalysts has successfully converted the microalgae biodiesel to bio-jet fuel with high yield and alkane selectivity. Among these techniques, hydroprocessing used the lowest production cost with the longest duration, whereas the bio-jet fuel with high selectivity (C8–C16) could be produced by using gasification with the Fischer-Tropsch process. Consequently, gasification and Fischer-Tropsch and sugar-to-jet can become the future alternative process to convert microalgae to bio-jet fuel. The development of microalgae bio-jet fuel will increase the security of energy supply and reduce the fuel expenses in aviation industry.