Microbiologically Influenced Corrosion of Metallic Materials

Microbiologically influenced corrosion (MIC) refers to the degradation of metallic materials resulting from the activities of microorganisms, often through the formation of biofilms that alter electrochemical conditions at the metal–solution interface. This phenomenon affects a broad array of sectors, including marine infrastructure, oil and gas pipelines, water treatment systems and medical implants, leading to substantial economic costs and safety hazards. Key mechanisms include the production of corrosive metabolites such as sulphide and organic acids, the formation of conductive mineral crusts, and direct extracellular electron transfer between microbial cells and metal surfaces. Environmental parameters—such as nutrient availability, flow regime, temperature and pH—govern microbial community composition and activity, influencing corrosion rates and patterns, including uniform attack, pitting and crevice formation. A multidisciplinary approach combining microbiology, electrochemistry, materials science and engineering is essential for understanding MIC processes and developing effective mitigation strategies, such as tailored biocides, surface coatings and monitoring of active microbial populations.

Research from Nature Portfolio

Recent studies have demonstrated that extracellular electron transfer between bacteria and stainless steel can be bidirectional and switchable, mediated by riboflavin molecules that shuttle electrons to and from the metal surface. Enhanced bioanodic and biocathodic processes were shown to compromise the passive film on stainless steel, accelerating pitting corrosion under biofilm coverage. In another investigation, the corrosion resistance of a hyper-duplex stainless steel alloy in marine environments was evaluated in the presence of a Pseudomonas aeruginosa biofilm. Electrochemical measurements revealed shifts in corrosion potential and increased current density, while surface analyses indicated depletion of key alloying elements beneath the biofilm. Although pit depths remained small over short durations, the findings underscored that even highly resistant alloys are susceptible to MIC under realistic marine conditions.

Microbiologically Influenced Corrosion of Metallic Materials publication trend

The graph below shows the total number of articles in microbiologically influenced corrosion of metallic materials across all publications each year (not limited to Nature Index journals).

Technical terms

Microbiologically Influenced Corrosion (MIC): Degradation of metals driven or accelerated by microbial activity, often via biofilm formation and metabolite production.

Biofilm: Structured microbial community embedded in an extracellular matrix that adheres to surfaces, modifying local chemistry and electrochemistry.

Extracellular Electron Transfer (EET): Process by which microbes exchange electrons directly or via mediators with inorganic substrates such as metals.

Passive Film: Thin, protective oxide layer formed on metal surfaces that slows corrosion under normal conditions.

Pitting Corrosion: Localised form of corrosion characterised by the creation of small cavities or “pits” on a metal surface, often initiated under biofilms or at defects in the passive film.

References

1. Microbiologically influenced corrosion—more than just microorganisms. FEMS Microbiology Reviews (2023).
2. Adaptive bidirectional extracellular electron transfer during accelerated microbiologically influenced corrosion of stainless steel. Communications Materials (2021).
3. Microbiologically Influenced Corrosion of 2707 Hyper-Duplex Stainless Steel by Marine Pseudomonas aeruginosa Biofilm. Scientific Reports (2016).
4. Nutrient Level Determines Biofilm Characteristics and Subsequent Impact on Microbial Corrosion and Biocide Effectiveness. Applied and Environmental Microbiology (2020).
5. Iron Corrosion via Direct Metal-Microbe Electron Transfer. mBio (2019).