RSI Research Seminar

Join us every other Monday at noon for lunch and a 30-minute research talk, presented by Resnick Sustainability Institute Graduate Fellows and Caltech researchers funded by the Resnick Sustainability Institute. To see the full schedule of speakers, visit the RSI Research Seminar web page. Seminars currently take place in a hybrid format, both in-person (Jorgensen building first-floor conference room) and via Zoom. For more information and to get the Zoom login info, please reach out to [email protected]

Understanding Biological Electron Transfer in Electro-Active Bacteria

Interfacing microbes with electrodes has been explored in a variety of contexts, including engineered biosensors, microbial fuel cells, and more recently microbial electrosynthesis. The ability to directly deliver charge equivalents (electrons) from an externally controlled electrode bypasses the need to feed microbes expensive sugars, thus overcoming mass-transport limitations, high cost, and low energy efficiencies that have historically plagued whole-cell biocatalysis. However, to date the methods of probing microbe-electrode electron transfer are limited, and the biochemical pathway(s) that an electrode-derived electron take within cells is poorly understood. We have recently succeeded in utilizing fluorescence lifetime imaging microscopy (FLIM) to interrogate how electrode-derived electrons impact the redox pool of the model electro-active bacteria Shewanella oneidensis. We find qualitative differences in the NADH bound / free fraction, which provides an indicator of how the redox pool and metabolic state of these organisms are perturbed under polarization. The use of FLIM for electro-active bacteria opens new avenues for probing the spatio-temporal impact of charge transfer at the electrode-microbe interface.