Electrical Access to (Non)-Electroactive Bacteria by Redox Polymer-Based Artificial Molecular Conduits

Through extracellular electron transfer (EET), metabolic energy conversion of bacteria has the potential to be harnessed for industrial processes, such as electricity generation, wastewater treatment, bioelectrosynthesis, bioremediation. While electroactive bacteria (EB), such as <i>Shewanella oneidensis</i>, possess natural molecular conduits to transfer electrons to or from electrodes, many other bacteria cannot efficiently interface electrode surfaces, greatly limiting the range of accessible reactions for utilization. To solve this issue, redox polymers (RPs) have recently surfaced to be able to mediate charge transfer between non-EB and electrodes[1].<br/>Here, we report on our investigations of extracting EET-derived electrical currents from both the EB <i>S. oneidensis</i>MR-1 and the non-EB <i>E.coli</i> using a ferrocene-based RP as an artificial molecular conduit. Through the use of mainly standard electrochemical techniques, including chronoamperometry, scanning voltmmetry and electrochemical impedance spectroscopy, we characterize the magnitude and nature of the observed signal. Importantly, by employing EB, our investigations revealed a different mechanism of current extraction between RP-coated and non-coated electrodes. Finally, as a follow-up on our earlier works[2,3], I will show our initial results on combining RP with the well-known conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) aiming at maximizing the extracted EET. Our results intend to stress the yet unexplored possibilities and capabilities of the microbes surrounding us for utilization in processes beneficial for society.<br/><br/>References:<br/>[1] Nagamine K., Ueki A., Makino D. Electrochemical Society of Japan (ECSJ) Fall meeting 2022.<br/>[2] Zajdel T. J., Baruch M., Méhes G., Stavrinidou E., Berggren M., Maharbiz M. M., Simon D. T., Ajo-Franklin C. M. Scientific Reports, 2018, 8, 15293.<br/>[3] Méhes G., Roy A., Strakosas X., Berggren M., Stavrinidou E., Simon D. T. Advanced Science, 2020, 7, 2000641.