Microbiologically influenced corrosion (MIC) presents growing challenges across industrial sectors such as oil and gas, cooling water systems, and utilities. Defined as corrosion influenced by microbial presence or activity, MIC is a complex, interdisciplinary phenomenon, including also elements of solid-state science. Despite advances in understanding microbial mechanisms and contributing factors, the field remains fragmented, and the translation of laboratory findings to real-world systems is limited due to the artificial nature of many experimental setups.

This presentation will describe a laboratory experiment designed to investigate MIC using carbon steel coupons exposed to drinking water and corrosion products from a distribution system affected by severe corrosion. Molecular microbiological methods (ATP biomass measurement and shotgun metagenomics) and chemical analyses (redox potential, dissolved oxygen, pH, iron, manganese, and other parameters) were combined with SEM-EDX and 3D optical microscopy, the latter ones performed in the Wigner RCP.

The results show that while the addition of culture media seems to accelerate corrosion, the underlying mechanisms differ significantly from those observed under field-relevant conditions. Notably, a high relative abundance of an iron-reducing bacterium—previously unreported in drinking water corrosion—was detected in nutrient-free conditions. This finding expands our understanding of the microbial diversity potentially involved in drinking water-related MIC and highlights the need for further investigation.