Surprising Enhancement of Extracellular Electron Transfer (EET) from Electroactive Bacteria to Charge Collectors by Fumarate and Further Enhancement of EET by Functionalized Carbon Nanotubes (CNTs)

We are witnessing the convergence of organic electronics with applied microbial electrochemistry for applications of energy harvesting, biosensing, electrosynthesis and others. In other words, biocompatible films made of conducting organic molecules interface electroactive (and other) bacteria in electronic and electrochemical devices, such as microbial electrochemical cells, biobatteries and transistors. Recently we have contributed to these efforts by creating a 3D hybrid bioelectrode based on PEDOT:PSS and <i>Shewanella oneidensis</i> MR-1 for enhancing the output of MESs[1], and by the first demonstration of amplification of EET by organic electrochemical transistors [2]. After shortly introducing these two papers, we will discuss two ways EET can be enhanced to yield MESs with electrical performances closer to realistic applications. More concretely, we have been investigating the effect of chemically-functionalized CNTs, as well as the biomolecule fumarate, on the magnitude and temporal dynamics of EET. We observed distinctively different effects on EET based on the chemical agent for functionalization of CNTs, and an unexpected role of fumarate in EET dynamics.<br/><br/>References:<br/>[1] Zajdel, Baruch, Méhes (equal contributions), <i>et al</i>. Sci. Rep., 2018, 8, 15293, 1–12.<br/>[2] Méhes, Roy, Strakosas (equal contributions), <i>et al</i>. Adv. Science, 2020, 7, 2000641(1–8).