Microbes shuttle electrons into and out of their cells in a process called extracellular electron transfer (EET). Microbes sense their environment using extracellular electron transfer. If connected to an electrode, these organisms could also generate electrical currents. One major challenge to harnessing electrical currents from microbes is the inability to precisely control extracellular electron transfer. This project is focused on developing a genetic toolkit that would allow extracellular electron transfer activity to be programmed. In computer programming, logical operations like "AND" and "OR" can be combined with other operations to create a set of instructions. Genetic elements that perform regulatory functions can be created that mimic logical operations. This project will develop those elements and combine them to program the behavior of the extracellular electron transfer system. This project will include an education and outreach program that expands student access to project-based learning through the creation of a freshman research program. These efforts will contribute to the development of a highly skilled STEM workforce.

Extracellular electron transfer has implications for microbial catalysis and biomanufacturing. Unlocking these applications will require strict genetic control over extracellular electron transfer flux. To address this challenge, the primary goal of this research project is to program extracellular electron transfer flux through the optimized expression of critical extracellular electron transfer proteins in the model electroactive bacterium, Shewanella oneidensis. To accomplish this objective, the project researchers will pursue several major objectives. The first goal will be to develop libraries of promoter/ribosome binding sites that will drive the production of specific extracellular electron transfer proteins. Another aim will be to design genetic logic gates that will respond to externally applied signals. Overall, the results will provide fundamental insights into extracellular electron transfer. This outcome, in turn, will establish Shewanella oneidensis as a potentially transformative organism for biomanufacturing, bioenergy, and biosensing applications.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

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University of Texas Austin
United States
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