Visualisation and quantification of biofilm-substrate interface microenvironments based on a fungal-bacterial interaction model: An in-depth investigation into microbially mediated corrosion processes

Abstract

This study analyses the role of pH and H₂O₂ microenvironments accumulated underneath H₂O₂-producing bacteria and acid-producing fungi and their symbiotic biofilms in material corrosion. The results show that corrosion is driven by the microenvironments beneath the biofilm, that are dependent on species. Mixed bacterial gel-like EPS ensured continuous acidity within the biofilm, which weakened the passivation film and increased metal ion release. H₂O₂ in the microenvironment affected the bilayer structure of the passivation film, leading to a shift from pitting to uniform corrosion of the Ti-based material. Furthermore, the microenvironmental gradient under the biofilm promoted EET-MIC to some extent.