Oxygen microenvironments in E. coli biofilm nutrient transport channels : insights from complementary sensing approaches

Tools

Bottura, Beatrice and McConnell, Gail and Florek, Lindsey and Smiley, Marina and Martin, Ross and Eana, Ash and Dayton, Hannah and Eckartt, Kelly and Price-Whelan, Alexa and Hoskisson, Paul and Dietrich, Lars and Rooney, Liam (2025) Oxygen microenvironments in E. coli biofilm nutrient transport channels : insights from complementary sensing approaches. Microbiology. ISSN 1465-2080 (In Press) (https://doi.org/10.1099/mic.0.001543)

[thumbnail of Bottura-etal-Microbiology-2025-Oxygen-microenvironments-in-E-coli-biofilm-nutrient-transport-channels] Text. Filename: Bottura-etal-Microbiology-2025-Oxygen-microenvironments-in-E-coli-biofilm-nutrient-transport-channels.pdf
Accepted Author Manuscript
Restricted to Repository staff only until 1 January 2099.
Download (887kB) | Request a copy

Abstract

Chemical gradients and the emergence of distinct microenvironments in biofilms are vital to the stratification, maturation and overall function of microbial communities. These gradients have been well characterised throughout the biofilm mass but the microenvironment of recently discovered nutrient transporting channels in Escherichia coli biofilms remains unexplored. This study employs three different oxygen sensing approaches to provide a robust quantitative overview of the oxygen gradients and microenvironments throughout the biofilm transport channel networks formed by E. coli macrocolony biofilms. Oxygen nanosensing combined with confocal laser scanning microscopy established that the oxygen concentration changes along the length of biofilm transport channels. Electrochemical sensing provided precise quantification of the oxygen profile in the transport channels, showing similar anoxic profiles compared with the adjacent cells. Anoxic biosensing corroborated these approaches, providing an overview of the oxygen utilisation throughout the biomass. The discovery that transport channels maintain oxygen gradients contradicts the previous literature that channels are completely open to the environment along the apical surface of the biofilm. We provide a potential mechanism for the sustenance of channel microenvironments via orthogonal visualisations of biofilm thin sections showing thin layers of actively growing cells. This complete overview of the oxygen environment in biofilm transport channels primes future studies aiming to exploit these emergent structures for new bioremediation approaches.

ORCID iDs

Bottura, Beatrice, McConnell, Gail ORCID logoORCID: https://orcid.org/0000-0002-7213-0686, Florek, Lindsey, Smiley, Marina, Martin, Ross, Eana, Ash, Dayton, Hannah, Eckartt, Kelly, Price-Whelan, Alexa, Hoskisson, Paul ORCID logoORCID: https://orcid.org/0000-0003-4332-1640, Dietrich, Lars and Rooney, Liam ORCID logoORCID: https://orcid.org/0000-0002-2237-501X;
CORE (COnnecting REpositories)