Technological Advances and Remaining Challenges to Make Biofuels from Algae a Reality

Production of biofuels such as jet fuel and biodiesel from algae has shown a step change in the amount of research in the last 3 years. The field is advancing at a rapid pace, everything from understanding fundamental algal biology to cultivation through conversion to fuels and coproducts. The major technological advances including: algal strain sequence information; molecular biological toolboxes; novel bioreactor strategies; new processes for dewatering, harvesting, extracting, and conversion; and the potential for food co-products will be highlighted. The base case pathway involves open pond cultivation, centrifugation, solvent extraction, fatty acid or lipid clean up and conversion to biodiesel via acid transesterfication or to jet fuel via hydrocracking. Nutrient recycle is often included in any economic analysis. Alternative harvesting technologies that do not require chemical addition include filtration, acoustic focusing, and electrolytic coagulation. Combined extraction and conversion technologies include microwave transesterification, super critical processes, hydrothermal liquefaction, and catalytic hydrothermal gasification. These various scenarios will be compared and contrasted. The technological and economic challenges will be discussed.