Urban circular carbon economy through electrochemically influenced microbiomes

Leininger, Aaron; Chen, Jinjin; Ramaswami, A.; Ren, Zhiyong Jason

doi:10.1016/j.oneear.2023.02.011

Cited by 5 publications

(1 citation statement)

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“…EET is pivotal in diverse environments, contributing to Earth's biogeochemical cycles [7][8][9] and microbial community dynamics in mammalian gastrointestinal tracts 10,11 . Moreover, EET pathways can connect electronics and living cells, enabling the electrical modulation of energy metabolism, gene expression, and overall cellular physiology [12][13][14][15][16] . E. coli is conventionally regarded as a non-exoelectrogen and, because of its importance as a biotechnology workhorse, has been the focus of extensive engineering efforts to introduce EET [17][18][19][20][21][22] .…”

Section: Introductionmentioning

confidence: 99%

Extracellular Respiration is a Latent Energy Metabolism inEscherichia coli

Kundu,

Krishnan,

Szubin

et al. 2024

Preprint

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Diverse microbial species utilize redox shuttles to exchange electrons with their environment through mediated extracellular electron transfer (EET). This process maintains redox homeostasis and supports anaerobic survival across diverse microbial communities. Although mediated EET has been extensively leveraged for bioelectrocatalysis and bioelectronics for decades, fundamental questions remain about how these redox shuttles are reduced within cells and their bioenergetic implications. This knowledge gap limits our understanding of the physiological roles of mediated EET in various microbes and hampers the development of efficient microbial electrochemical technologies. To address this, we developed a methodology integrating genome editing, electrochemistry, and systems biology to investigate the mechanism and bioenergetic implications of mediated EET in bacteria. Using this approach, we uncovered a mediated EET mechanism inEscherichia coli. In the absence of alternative electron sinks, the redox cycling of 2-hydroxy-1,4-naphthoquinone (HNQ) via a cytoplasmic nitroreductase enabledE. colito respire and grow on an extracellular electrode. Genome-scale metabolic modeling suggested that HNQ- mediated EET offers a more energetically favorable route for supporting anaerobic growth than canonical fermentation. Transcriptome analysis revealed redox perturbations in response to HNQ and identified rapid metabolic adaptations that support growth. This work demonstrates thatE. colican grow independently of classical electron transport chains and fermentative pathways, unveiling a new type of anaerobic energy metabolism.

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