A Microbial Consortium Enabling Complete Feedstock Conversion
The aviation industry requires energy-dense, carbon-based fuels, which are difficult to achieve biologically because of low yields and poor carbon conversion efficiency. The University of California, Berkeley, will engineer an approach to reach near 100% carbon conversion efficiency. A single organism can be limited by CO2 loss from core metabolic reactions. Coupling a heterotroph (an organism that cannot produce its own food like an animal) with an autotroph (an organism that produces its own food using light, water and carbon dioxide like a plant) will enable CO2 recycling and complete feedstock conversion. The proposed systems will use a heterotrophic production strain to convert sugar substrates into biofuels via a carbon-conserving synthetic metabolism, co-cultured with a phototrophic strain engineered to be chemotrophic to enable CO2 utilization. In combination, the two strains re-capture and recycle CO2 released during the sugar fermentation. These changes combined will ensure complete carbon conservation into liquid fuel, making biofuels competitive with fossil fuels. Although the proposed work targets aviation fuel, the platform will be designed to swap in various strains to generate different biofuel products.
The application of biology to sustainable uses of waste carbon resources for the generation of energy, intermediates, and final products---i.e., supplanting the “bioeconomy”—provides economic, environmental, social, and national security benefits and offers a promising means of carbon management.