This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
Summary Intellectual Merit: This proposal will investigate the factors that result in optimal production of high energy lipids and biopolymers in the microalgal and cyanobacteria species of the genera Botryococcus, Nannochloropsis, Synechocystis, and Nostoc. The overall goal of this project is to develop a technical and economically feasible method to obtain and extract high energy storage products from microalgae through environmentally friendly processes. The large scale experimentation will be performed using the Hydraulically Integrated Serial Turbidostat Algal Reactor (HISTAR). HISTAR incorporates inoculums generation, biomass production and harvesting in a series of reactors, allowing for a high local dilution rate to mitigate contaminant introduction and low system dilution rate to increase productivity. The design of the system has shown to have higher yields and reduced problems commonly observed in closed bioreactors such as wall growth, heat accumulation and poor gas exchange. The goal will be achieved by testing the following hypothesis: 1) bench scale microalgae or cyanobacteria culture results can be scaled to commercial levels within HISTAR; 2) lipids and PHA can be co-produced in certain cyanobacteria species; 3) C:N ratio will impact the lipid and PHA content of the algal cells; 4) lipid and PHA extraction efficiency (and thus cost) will vary with the extraction method used; 5) the use of nanostructured metals can enhance the extraction processes; and 6) a microalgal productivity model can adequately predict lipid and PHA yields from intensive, continuous microalgal cultures. These objectives will be tested in four phases: 1) production of biomass, lipid and PHA in batch systems; 2) culture of one microalgae and one cyanobacteria species in the HISTAR system; 3) evaluation of extraction methods for the lipids and PHA, as well as quantification of the total energy content of the biomass produced, and 4) cost:benefit analysis of each process pathway via modeling. The outcomes from this work will provide a better scientific understanding of the processes dictating successful microalgal culture for biofuels and foundation for a commercial approach to cultivating microalgae with increased energy content (PHA) and/or lipids (oil extraction). Broader impact: This proposal topic lends itself to several formal/informal educational activities, several of which will be disseminated through the Louisiana Sea Grant College Program (Ocean Commotion), Cain Center for Science, Technology, Engineering and Mathematics Literacy (Teacher Prep), Office of Diversity Programs in Engineering (REHAMS and XCITE) and American Chemical Society (Super Science Saturday). The results of this work will be disseminated through technical meetings, journal papers and through web based documents. Society benefits expected from this project is the increase of production of biomass based high energy products to reduce the consumption of oil based fuels and polymers and thus reduces the dependency on foreign oil.
