(677b) Imaging Electron Transfers in Electro-Active Bacteria for Sustainable Chemical Synthesis

Interfacing microbes directly with electrodes has potential application in engineered biosensors, microbial fuel cells, and microbial electrosynthesis. However, methods of probing such microbe-electrode electron transfers are limited, leading to poorly understood mechanistic details of how electrode-derived electrons are utilized by a microbe. We hypothesize that both spatial and temporal heterogeneities in metabolomic response occur in electrode-attached microbes under polarization due to metabolic adaptations, which can be visualized by changes in metabolic flux. Here, we leverage fluorescence lifetime imaging (FLIM) of the redox shuttle NADH to image the impact of electrode-derived electrons on Shewanella oneidensis. Differences in the NADH bound/free fraction provide an indicator of how the redox pool and cell metabolic state are perturbed under polarization. The ability to directly image changes in a microbe’s redox state will allow for direct mapping of competing mass transport and charge transport effects in bio-electrocatalysis. Such insights will lead to better understanding of how cells consume electrode-derived cells, and how metabolic processes can be engineered for real-world application.