This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
The goal of this project is to develop metabolic engineering approaches for diatoms to enable induction of lipid accumulation by controllable manipulation of intracellular processes rather than from external environmental conditions, and to manipulate carbon partitioning within the cell between lipid and carbohydrate synthesis to enable both abundant biomass and lipid accumulation.
There are four specific objectives: 1) To perform comparative transcriptomic analyses in diatoms of lipid accumulation resulting from silicon, nitrogen, and selenium limitation, to identify key regulatory steps involved in controlling lipid accumulation and carbon partitioning. 2) To metabolically engineer the diatom cell to enable repression of silicon transport by simple manipulations, as a means to artificially starve the cells for silicon to trigger lipid accumulation. 3) To metabolically engineer the cell to enable repression of nitrate transport by simple manipulations, as a means to artificially starve the cells for nitrogen to trigger lipid accumulation. 4) To metabolically engineer the cell to alter carbon partitioning to enable abundant lipid accumulation along with high biomass production, without the need for nutrient limitation.
Intellectual Merit: The significance of this project is that it will enable greater control over lipid accumulation in diatoms for biofuels production by using manipulable intracellular processes rather than depending on variable environmental conditions, and it will possibly enable lipid accumulation under normal growth conditions. In microalgae, lipid accumulation generally occurs under nutrient limiting conditions, which are subject to environmental variability, and which prevents high biomass accumulation. Transferring control of lipid induction to intracellular processes will eliminate the variability, and identifying the key regulatory steps involved in controlling carbon partitioning in the cell coupled with metabolic engineering should enable greater partitioning of carbon into lipids during non-limiting nutrient growth conditions. These approaches are expected to have a substantial impact on the development of renewable biofuels technology.
Broader Impact: The involvement of undergraduate and high school students in this project will enable them to experience "hands on" laboratory research. This is critical in the development of a young person's mind, to be able to appreciate the practical and dynamic aspects of discovery, as apposed to just assimilating information via lectures or reading. This importance of this cannot be overemphasized, because it develops an appreciation for the level of effort and commitment that must be applied to any successful endeavor. The students will participate as part of local training programs that emphasize the involvement of underrepresented minorities. The societal benefits of the proposed research will be realized through the technological application of developing diatoms as a source of renewable fuels. The potential benefits include reduced CO2 production and subsequent benefit to climate change, decreased dependence on oil imports, and establishment of new jobs in this emerging technology industry.
