Publications

Journal articles

July 2024

Mixed Conducting Polymers Alter Electron Transfer Thermodynamics to Boost Current Generation from Electroactive Microbes

Agee, Alec; Pace, Gordon; Yang, Victoria; Segalman, Rachel; Furst, Ariel L.

Abstract

Electroactive microbes that can release or take up electrons are essential components of nearly every ecological niche and are powerful tools for the development of alternative energy technologies. Small-molecule mediators are critical for this electron transfer but remain difficult to study and engineer because they perform concerted two-electron transfer in native systems but only individual, one-electron transfers in electrochemical studies. Here, we report that electrode modification with ion- and electron-conductive polymers yields biosimilar, concerted two-electron transfer from Shewanella oneidensis via flavin mediators. S. oneidensis biofilms on these polymers show significantly improved per-microbe current generation and morphologies that more closely resemble native systems, setting a new paradigm for the study and optimization of these electron transfer processes. The unprecedented concerted electron transfer was found to be due to altered mediator electron transfer thermodynamics, enabling biologically relevant studies of electroactive biofilms in the lab for the first time. These important findings pave the way for a complete understanding of the ecological role of electroactive microbes and their broad application in sustainable technologies.

Acknowledgements

We would like to thank Nadia Zaragoza and Dr. Thomas Gill for support with AFM and SEM imaging. Research reported in this publication was supported by funding from the Army Research Office (W911NF-22–1–0106), the U.S. Department of Energy, Office of Science, Basic Energy Sciences (DE-SC0016390), the UC Santa Barbara Materials Research Science and Engineering Center (MRSEC, NSF DMR 1720256), the National Institutes of Health-NIEHS (Core Center Grants P42-ES027707 and P30-ES002109), and the MIT Energy Initiative (Seed Grant). A.A. and G.P. are supported by the National Science Foundation Graduate Research Fellowship Program under grants DGE 1650114 and DGE 2141064, respectively.