Photosynthetic microalgae have considerable promise as biological catalyst for the conversion of carbon dioxide (CO2) into lipid-rich biomass which can serve as a feedstock for biodiesel production. A major barrier for converting microalgae to biodiesel on a large scale is the need to dry the algae and extract the oil components. The proposed research will develop the scientific and engineering knowledge to convert algal biomass directly to biodiesel in its natural wet state through a two step process without the need for drying or extraction. The first step is a mild hydrothermal carbonization treatment that hydrolyzes the intracellular lipids into fatty acids and coalesces them into easy-to-filter solids. The second step is biodiesel synthesis through noncatalytic and catalytic approaches, including the uncatalyzed esterification of the lipids in the wet hydrolysis solids with supercritical ethanol, or the metal-triflate-catalyzed esterification of the lipids in the wet hydrolysis solids with subcritical ethanol. The reaction pathways and kinetics of each step will be elucidated to assess how the process variables (temperature, concentrations, time, etc.) influence the biodiesel product yields.
The proposed activities are designed to provide educational opportunities for students within the context of the proposed research. Undergraduate students, particularly women and underrepresented minorities, will be recruited through the Marian Sarah Parker Scholars Program and Summer Research Opportunity Program at the University of Michigan to conduct research on algal biodiesel in collaboration with the PhD student who will be trained as part of this project. Renewable energy concepts will be incorporated into a sophomore level Sustainable Engineering course offered though the College of Engineering at the University of Michigan.