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Lookup NU author(s): Dr Hannah Bird, Dr Ben AllenORCiD, Dr Sharon Velasquez OrtaORCiD, Dr Elizabeth HeidrichORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© The Author(s) 2025. Abstract: Microbial fuel cells (MFCs) offer a promising alternative for sustainable wastewater treatment and energy recovery. However, the mechanisms underpinning electrogenic biofilm formation remain poorly understood. This study investigates the spatial and temporal dynamics of microbial community assembly using a novel multi-electrode MFC design under two substrate conditions: acetate and starch. Pre-inoculation of three designated electrodes led to successful current generation within 110 h in both MFCs, while a dispersed inoculation strategy failed to establish electrogenic biofilms despite equivalent inoculum volume. Electrode positioning significantly influenced start-up, with vertical alignment above inoculated electrodes facilitating faster colonisation and current generation than lateral spacing. Notably, starch-fed MFCs exhibited more rapid and widespread biofilm proliferation, suggesting that complex microbial consortia may disperse more efficiently than single-function electrogens. Community sequencing revealed spatial heterogeneity and a shift from diverse to more optimised anodic communities over time. Geobacter initially dominated, but community succession was shaped by substrate complexity, competition, and spatial structure. Interestingly, non-inoculated electrodes often outperformed inoculated ones, indicating that deterministic selection pressures favoured more efficient biofilms. However, long-term current production declined, particularly under batch conditions, suggesting that population drift and limited microbial renewal limited sustained performance. This study is the first to characterise electrogenic biofilm assembly in a multi-electrode MFC, highlighting the interplay between stochastic dispersal and deterministic selection. These findings underscore the importance of inoculation strategy, substrate selection, and continuous microbial replenishment for optimising MFC performance and real-world applicability. Key points: • Substrate complexity shaped colonisation and distinct microbial communities. • Vertical electrode positioning enhanced colonisation and start-up efficiency. • Temporal succession led to specialised but less diverse electrogenic biofilms.
Author(s): Bird H, Allen B, Velasquez-Orta SB, Heidrich E
Publication type: Article
Publication status: Published
Journal: Applied Microbiology and Biotechnology
Year: 2025
Volume: 109
Online publication date: 08/12/2025
Acceptance date: 15/11/2025
Date deposited: 22/12/2025
ISSN (print): 0175-7598
ISSN (electronic): 1432-0614
Publisher: Springer Nature
URL: https://doi.org/10.1007/s00253-025-13653-5
DOI: 10.1007/s00253-025-13653-5
Data Access Statement: The sequencing data that support the findings of this study have been deposited in the European Nucleotide Archive (ENA) under the accession number PRJEB95057.
PubMed id: 41359120
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