|Acquisition Program: || Objective: ||Develop eukaryotic microorganisms for the production of energy-dense alcohols or hydrocarbons with a carbon number of four or greater via fermentation using existing commercial infrastructure.
|| Description: ||The development of alternative sustainable fuels is essential to maintain Army capabilities in the face of dwindling fossil fuel stores. Biofuels, derived from renewable biological sources, are an attractive option to fulfill this need. Such fuels could be used directly for soldier-borne power capabilities or could be converted into JP-8 for a sustainable source of logistics fuel. Ethanol has served as the first model for a commercial biofuel, but several limitations prevent widespread use, including limited energy density, incompatibility with the existing pipeline infrastructure, and the requirement to process food crops for fuel production. Therefore, recent efforts have focused on the production of more complex (C4 or greater) energy-dense hydrocarbons derived from non-food crops. Such higher chain molecules possess superior properties relative to ethanol, including increased energy density, low water absorption, low vapor pressure, and low corrosiveness. Moreover, these properties approach the capability of transporting such fuels through existing pipeline infrastructure. Energy-dense hydrocarbons can be blended with gasoline and even have the potential to be used as fuel replacements (e.g., butanol performs well in conventional gasoline engines).
The primary route for production of sustainable energy-dense hydrocarbons is the conversion of biological material by microorganisms. Genetically engineered bacteria have been developed that produce a variety of compounds including higher chain alcohols and hydrocarbons. However, the commercialization of fermentation processes that rely on bacterial microorganisms is hampered by low robustness to process conditions and incompatibility with existing infrastructure. In contrast, commercial fermentation processes utilizing eukaryotic microorganisms have already been established for various products, including ethanol and lactic acid, but not for higher chain alcohols or hydrocarbons. The goal of this topic is to develop eukaryotic microorganisms (single species monoculture or a microbial consortium) for production of energy-dense alcohols or hydrocarbons with a carbon number of four or greater via fermentation using existing commercial infrastructure.
|| ||PHASE I: Develop approaches for engineering eukaryotic microorganism(s) to produce energy-dense hydrocarbons in a commercially viable yield. The hydrocarbons produced must exhibit minimal water absorption, low vapor pressure, and low corrosiveness.
|| ||PHASE II: Integrate the eukaryotic microorganism(s) into commercial fermentation apparatus, demonstrate production of a minimum of 5 gallons of energy-dense alcohol or hydrocarbon for testing and analysis, and optimize yield.
|| ||PHASE III: The development of a system to produce energy-dense hydrocarbons using existing commercial fermentation apparatus will support capabilities for soldier-borne power systems driven by sustainable fuels. In addition, this system will provide a sustainable source of hydrocarbons for conversion to JP-8 in support of Army logistics. Commercial applications will have a significant positive impact on civilian life and the environment. A sustainable supply of fuel will reduce dependence on foreign oil supplies, increasing national energy security. Fuel that is less costly and clean-burning will enable enhanced civilian capabilities and reduce greenhouse gas emissions.
|| References: ||
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2. Alper, H. and Stephanopoulos, G. Engineering for biofuels: exploiting innate microbial capacity or importing biosynthetic potential? Nature Reviews Microbiology, v.7, p.715-723, 2009.
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4. Steen, E.J., Chan, R., Prasad, N., Myers, S., Petzold, C.J., Redding, A., Ouellet, M., and Keasling, J.D. Metabolic engineering of Saccharomyces cerevisiae for the production of n-butanol. Microbial Cell Factories, v.7, 2008.
5. Fortman, J.L., Chhabra, S., Mukhopadhyay, A., Chou, H., Lee, T.S., Steen, E., and Keasling, J.D. Biofuel alternatives to ethanol: pumping the microbial well. Trends in Biotechnology, v.26, p.375-381, 2008.|
|Keywords: ||eukaryotic microorganisms, fermentation, hydrocarbons, alcohols, biofuel|