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Metal Corrosion and the Efficiency of Corrosion Inhibitors in Less Conductive Media
Published on: November 3, 2018
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Iron Corrosion via Direct Metal-Microbe Electron Transfer
Hai-Yan Tang1,2, Dawn E Holmes3,4, Toshiyuki Ueki1
1Department of Microbiology, Morrill IV Science Center, University of Massachusetts Amherst, Amherst, Massachusetts, USA.
Mbio
|May 16, 2019
Summary
This study demonstrates direct electron transfer from iron (Fe(0)) to anaerobic microorganisms, specifically Geobacter sulfurreducens. This finding clarifies microbial iron corrosion mechanisms and offers insights for future corrosion prevention strategies.
Area of Science:
- Microbiology
- Geochemistry
- Biotechnology
Background:
- Anaerobic microorganisms are known to accelerate iron corrosion, but direct electron transfer from Fe(0) has been difficult to prove.
- Previous studies were confounded by hydrogen (H2) production from Fe(0) oxidation, which could serve as an alternative electron source for microbes.
- Understanding direct metal-microbe electron transfer is crucial for addressing issues like iron structure corrosion.
Purpose of the Study:
- To definitively demonstrate direct electron transfer from Fe(0) to anaerobic microorganisms.
- To identify microbial components involved in direct electron transfer from Fe(0).
- To provide a foundation for developing strategies to mitigate microbially influenced iron corrosion.
Main Methods:
- Engineered Geobacter sulfurreducens strain ACL (ACLHF) lacking hydrogen and formate utilization pathways.
- Cultured ACLHF with Fe(0) as the sole electron donor and fumarate as the electron acceptor.
- Utilized transcriptomics to identify key outer surface c-type cytochromes (OmcS and OmcZ) involved in Fe(0) interaction.
- Created gene deletion mutants of OmcS and OmcZ to confirm their necessity for Fe(0) utilization.
Main Results:
- ACLHF grew using Fe(0) as the sole electron donor, with significant H2 accumulation, indicating minimal H2 utilization.
- ACLHF cells exhibited strong colonization of Fe(0) surfaces, with minimal planktonic growth.
- OmcS and OmcZ were identified as essential outer surface cytochromes for direct electron transfer from Fe(0).
- Mutants lacking OmcS or OmcZ could not grow with Fe(0), confirming their critical role.
Conclusions:
- Direct electron transfer from Fe(0) to Geobacter sulfurreducens is a viable mechanism for anaerobic respiration.
- Outer surface cytochromes OmcS and OmcZ are critical for direct electrical contact and electron uptake from Fe(0).
- This study provides a robust model for investigating direct metal-microbe electron transfer and its implications for iron corrosion.
Keywords:
Geobacterautotrophcytochromeelectromicrobiologyextracellular electron transferzero-valent ironMore Related Videos
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