Knockout Sudoku: An Investigation of the Genetic Basis Behind Extracellular Electron Transfer in Shewanella oneidensis MR-1

Abstract

Our present society’s rampant consumption of coal, oil, and natural gas will leave us not only largely bereft of fossil fuel stocks by the year 2100 but also mired in environmental, societal, and health concerns impacting all segments of civilization. Our desire to mitigate these problems opens up a variety of possibilities in the way of sustainable energy. One especially promising solution, known as electrosynthesis, seeks to merge the energy capture efficiency of modern-day photovoltaics with the metabolic flexibility of electroactive microorganisms that are capable of harnessing photovoltaic electrons by extracellular electron transfer (EET). Currently, however, our largest obstacle hindering our ability to maximize the efficiency of electrosynthesis for widespread use is our incomplete understanding of the genes and genetic networks underlying EET. To address this concern, our lab invented Knockout Sudoku, a novel method relying on transposon mutagenesis for creating highly complete and annotated whole genome knockout collections. With this technique, we created a knockout collection of the electroactive bacterium Shewanella oneidensis and have begun to extract valuable information concerning the genetic basis behind EET. This work and future research, including the potential to create many more knockout collections at a low-cost and rapid scale, will inform our ability to apply biological organisms toward a more sustainable future in energy.