20 Microorganisms Associated with MIC: Species, Functions and Corrosion Evidence
MIC is a process influenced by microorganisms, not a diagnosis attached to a species name. This overview brings twenty widely discussed or practically relevant organisms into one cluster, with a separate article for each and a clear distinction between direct experiments, indirect associations and field interpretation.
A guide to species identity, microbial functions and evidence at the material surface.
Which microorganisms are associated with MIC?
MIC-related research and investigations include sulfate reducers such as Desulfovibrio, methanogenic Archaea such as Methanococcus maripaludis, sulfur and iron oxidizers, biofilm-forming bacteria and fungi such as Amorphotheca resinae. Their relevance differs by strain, environment and material.[1][2][3][4]
This is a representative top-20 reading list, not a measured ranking of prevalence, reputation or corrosivity. Use the table to find the right species article, then connect the biological evidence to the sampled surface and independently measured damage.
Key takeaways
How should this top-20 list be used?
There is no single scientifically established top twenty that applies to pipelines, sewers, cooling water, marine structures and fuel tanks alike. This pillar is an editorial selection that covers different mechanisms and evidence levels. The numbering makes the cluster easy to navigate; it does not imply that number one is more common or more damaging than number twenty.
Some entries have direct species- or strain-level corrosion experiments. Others are important because they form deposits or biofouling, change local chemistry or provide a useful mechanistic research model. Those distinctions are retained in the overview and developed in the linked articles.
The list includes bacteria, Archaea and a fungus. It also retains two familiar research designations, D. ferrophilus IS5 and D. corrodens IS4. Check the actual identification resolution when comparing a field finding with a published research strain.
The top-20 overview: choose an organism and its evidence
| No. | Organism and article | Functional context | Evidence to keep in view |
|---|---|---|---|
| 1 | Desulfovibrio vulgaris Current combination: Nitratidesulfovibrio vulgaris | Sulfate-reducing bacterium | Iron-corrosion experiments; hydrogen-mediated research. |
| 2 | Desulfovibrio desulfuricans | Sulfate-reducing bacterium | Stainless-steel experiments; strain and culture interpretation. |
| 3 | Desulfovibrio ferrophilus | Sulfate-reducing research isolate | IS5: pronounced iron-corrosion research; mechanism needs precision. |
| 4 | Desulfopila corrodens | Sulfate-reducing research isolate | IS4: iron-corrosion and mineral-crust research. |
| 5 | Desulfovibrio alaskensis Current combination: Oleidesulfovibrio alaskensis | Sulfate-reducing bacterium | G20 reference and taxonomic continuity; identity is not a corrosion phenotype. |
| 6 | Desulfotomaculum nigrificans | Spore-forming sulfate reducer | Corrosion experiments; dormancy and recovery questions. |
| 7 | Archaeoglobus fulgidus | Sulfate-reducing archaeon | Iron-corrosion experiments at elevated temperature. |
| 8 | Methanococcus maripaludis | Methanogenic archaeon | Strain-specific iron corrosion and extracellular hydrogenases. |
| 9 | Methanosarcina barkeri | Methanogenic archaeon | Condition-dependent anaerobic stainless-steel experiments. |
| 10 | Acidithiobacillus thiooxidans | Acidophilic sulfur oxidizer | Acidic sewer-concrete communities and deterioration. |
| 11 | Acidithiobacillus ferrooxidans | Acidophilic iron/sulfur oxidizer | Acidic carbon-steel corrosion and iron redox cycling. |
| 12 | Thiobacillus thioparus | Sulfur oxidizer | Cementitious-material research; changing surface chemistry. |
| 13 | Thiothrix nivea | Filamentous sulfur oxidizer | Mainly genus-level biofouling and indirect association. |
| 14 | Gallionella ferruginea | Iron oxidizer | Deposition and fouling context; indirect corrosion hypothesis. |
| 15 | Leptothrix discophora | Metal-associated bacterium | Steel-corrosion and manganese-biofilm electrochemical research. |
| 16 | Mariprofundus ferrooxydans | Marine iron oxidizer | Marine mild-steel and mixed-culture corrosion experiments. |
| 17 | Shewanella oneidensis | Iron/nitrate-reducing bacterium | Condition-dependent corrosion and local protection in split-cell studies. |
| 18 | Pseudomonas aeruginosa | Biofilm-forming bacterium | Nitrate/carbon-dependent carbon-steel corrosion experiments. |
| 19 | Clostridium acetobutylicum | Fermentative bacterium | Acidogenic hypothesis and purified-enzyme research; limited field causation. |
| 20 | Amorphotheca resinae Historical name: Hormoconis resinae | Fuel-associated fungus | Aluminum-alloy corrosion experiments and contamination context. |
Each linked article explains the organism's role, the supporting study context, sampling choices, interpretation limits and the molecular question to discuss. For weaker or indirect associations, the article makes that limitation explicit rather than assigning a universal MIC label.
What are the main functional groups?
Sulfate-reducing microorganisms
Sulfate reducers can affect reduced-sulfur chemistry and surface processes. Some strains have been investigated for pronounced iron corrosion, including systems with substantial mineral products. Evidence from one strain should not be applied indiscriminately to every sulfate-reducing organism.[5]
Include sulfate-reducing Archaea when relevant: “SRB” is narrower than “SRM.” The SRB versus SRM guide explains this analytical distinction.
Methanogenic Archaea
Some methanogen strains possess corrosion-associated extracellular hydrogenase systems. Their presence is a separate question from broadly detecting methane-metabolism genes. Bacterial-only monitoring can leave this organism group outside the panel.[2][6]
Sulfur and iron oxidizers
These organisms can transform sulfur or iron and change the environment near a surface. The material consequence varies: acidic concrete deterioration, iron-rich fouling and marine steel experiments are different contexts. Sulfur-oxidizing succession has been documented on sewer concrete, and marine iron oxidizers have been investigated on mild steel.[3][7]
Biofilms, fermenters and fungi
Biofilm distribution and metabolic products can matter as much as the name of a detected species. Split-cell research with Shewanella demonstrates spatially different effects. Purified-enzyme studies require a separate level of interpretation, while fungal aluminum-corrosion experiments show material dependence.[8][9][4]
Why separate species identity, function and damage?
| Evidence layer | Example question | What it cannot establish alone |
|---|---|---|
| Identity | Is the covered species or lineage present? | Its strain-specific phenotype, activity or causal role |
| Functional genetic context | Are the selected sulfur- or methane-metabolism sequences present? | The direction or rate of every metabolic process |
| Narrower corrosion-associated target | Is the covered MicC or MicH sequence present? | Gene expression, enzyme behavior or corrosion rate |
| Local environment | Do chemistry and deposits support the hypothesis? | A unique responsible species |
| Material outcome | Is the surface losing metal or otherwise deteriorating? | The mechanism without supporting exposure and biological evidence |
A complete investigation combines these layers. An organism can arrive in water without growing on the damaged surface. A gene can be present without being expressed. A pit can have several possible explanations. The task is to test their connection rather than use any single layer as a complete diagnosis.
Pathway context matters too. Reverse dsr pathways occur in sulfur oxidation, including within Thiothrix. A generic sequencing annotation should not automatically be interpreted as sulfate reduction.[10]
Where do MicC and MicH fit in the cluster?
MicC and MicH add narrower corrosion-associated genetic questions to broader functional monitoring. Research describes a conserved multi-heme cytochrome cluster in severely corrosive sulfate-reducer biofilms and hydrogenase-associated severe corrosion in oilfield-water systems.[11][6]
A selected dsrAB assay, a selected mcrA assay, a MicC assay and a MicH assay each have their own target and coverage. They should not be treated as interchangeable counts. A positive species identification does not automatically establish a positive corrosion-associated marker, and a negative marker does not exclude every possible MIC route.
- What is MicC? and MicC versus dsrAB develop the sulfate-reducer question.
- What is MicH? and MicH versus mcrA develop the methanogenic question.
- The combined MicC/MicH overview connects the target choices.
- Upstream oil-and-gas monitoring explains an operating context.
Confirm available assay coverage, specificity and matrix validation before selecting a panel. This content cluster does not imply that an off-the-shelf species assay is available for every listed organism.
Which samples should you collect?
Choose the compartment that represents the problem. Flowing water can describe a suspended population or transport. A defined attached sample is often more relevant to localized attack. Recovered pig debris provides useful solids information when its origin and recovery are documented.
| Problem | Sample to prioritize | Supporting information |
|---|---|---|
| Suspected localized steel MIC | Defined biofilm or deposit near the damage | Surface inspection, chemistry and exposure history |
| Population transport or souring | Representative water, with solids where relevant | Process conditions and sulfur chemistry |
| Concrete acidification | Affected surface or altered layer | Local pH, sulfur exposure and material condition |
| Iron-rich biofouling | Defined attached deposit or fouling material | Iron source, deposit composition and physical performance |
| Fuel-system fungal concern | Relevant water-bottom, interface or attached material | Phase identity, tank condition and exposed alloy |
Keep water, swabs and solids separate in reporting. Record area, volume or mass and the recovery method. Use the swab guide, pig-debris guide and sessile versus planktonic comparison to make trends interpretable.
How should a positive qPCR result be interpreted?
Standard DNA qPCR measures selected target DNA recovered from the sample. The target copy number is not automatically a cell count: gene copy number, extraction recovery and normalization influence the relationship. Detection also does not establish viability, current transcription or the rate of a chemical process.
Start by checking target scope, units, reporting capability, extraction performance and inhibition controls. Then ask whether the sample represents the relevant surface and whether the chemistry and damage record support the hypothesis. A negative result only narrows the covered target question under those sampling and analytical conditions.
For repeat monitoring, retain comparable sample types, locations and operating intervals. Annotate cleaning, pigging, treatment and method changes. Read the MicC/MicH sampling and interpretation guide and the post-biocide DNA explanation before treating a result change as treatment success or failure.
How do you build a useful monitoring panel?
- Define the decision. Clarify whether the question concerns souring, attached corrosion-associated populations, acidification, fouling or intervention follow-up.
- Map the location and material. Include temperature, water chemistry, deposits, alloy or concrete context and operating history.
- Select biological coverage. Include the relevant bacterial, archaeal or fungal groups and the intended identity or functional question.
- Confirm the assay scope. Check target sequences, specificity, matrix validation and reporting units.
- Collect connected evidence. Pair the molecular sample with appropriate chemistry and material measurements.
- Plan the follow-up. Compare repeat samples that support the same question and retain the independently assessed integrity outcome.
The MICBUSTERS on-site qPCR workflow can support selected rapid field measurements. Turnaround depends on the selected workflow and preparation; the biological result still needs interpretation within the asset investigation.
Which articles should you read next?
For anaerobic steel corrosion, begin with D. vulgaris, D. ferrophilus IS5, D. corrodens IS4 and M. maripaludis. For persistence or hot-system questions, add D. nigrificans and A. fulgidus.
For sulfur-exposed concrete, follow A. thiooxidans and T. thioparus. For conspicuous fouling, read Thiothrix nivea and Gallionella ferruginea; the Thiothrix literature supports a genus-level biofouling context.[12]
For electrochemical or nitrate-related questions, continue with L. discophora, S. oneidensis and P. aeruginosa. For a fuel-system concern, go directly to A. resinae. Each guide provides its own evidence and interpretation limits.
Turn the organism list into a practical MIC monitoring plan
MICBUSTERS can help connect your suspected mechanism, sample matrix and selected molecular targets to the operating decision you need to make. Discuss identity, functional coverage and MicC/MicH where relevant.
Leave your business email below and we will contact you about the monitoring objective, available assays and a suitable on-site qPCR workflow.
Frequently asked questions
Is this a ranking of the twenty most corrosive species?
No. It is a representative editorial list organized for reading and monitoring decisions. No universal quantitative ranking of prevalence or corrosivity is claimed.
Does detecting a listed organism prove MIC?
No. A detection result must be connected to a representative location, relevant chemistry and independently measured damage. Evidence strength also differs among organisms and strains.
Do all MIC-relevant organisms fit a bacterial test panel?
No. Relevant sulfate reducers and methanogens can be Archaea, and fuel-associated concerns can involve fungi. Confirm the panel's biological and sequence coverage.
Do MicC and MicH replace dsrAB and mcrA?
They answer narrower corrosion-associated target questions. Broader functional targets can provide complementary context, subject to assay coverage. No DNA target alone measures corrosion rate.
Sources and further reading
- Woodard TL, Ueki T, Lovley DR. H2 Is a Major Intermediate in Desulfovibrio vulgaris Corrosion of Iron. mBio. 2023.
- Tsurumaru H, et al. An extracellular [NiFe] hydrogenase mediating iron corrosion is encoded in a genetically unstable genomic island in Methanococcus maripaludis. Scientific Reports. 2018.
- Okabe S, Odagiri M, Ito T, Satoh H. Succession of Sulfur-Oxidizing Bacteria in the Microbial Community on Corroding Concrete in Sewer Systems. Applied and Environmental Microbiology. 2007.
- Shariat AH, et al. Comprehensive evaluation of fungal-induced corrosion in aluminum alloys by Amorphotheca resinae. Scientific Reports. 2024.
- Enning D, et al. Marine sulfate-reducing bacteria cause serious corrosion of iron under electroconductive biogenic mineral crust. Environmental Microbiology. 2012.
- Lahme S, Mand J, Longwell J, Smith R, Enning D. Severe Corrosion of Carbon Steel in Oil Field Produced Water Can Be Linked to Methanogenic Archaea Containing a Special Type of [NiFe] Hydrogenase. Applied and Environmental Microbiology. 2021.
- McBeth JM, et al. Neutrophilic Iron-Oxidizing Zetaproteobacteria and Mild Steel Corrosion in the Marine Environment. Applied and Environmental Microbiology. 2011.
- Miller RB II, Lawson K, Sadek A, Monty CN, Senko JM. Uniform and Pitting Corrosion of Carbon Steel by Shewanella oneidensis MR-1 under Nitrate-Reducing Conditions. Applied and Environmental Microbiology. 2018.
- Rouvre I, Basseguy R. Exacerbation of the mild steel corrosion process by direct electron transfer between [Fe-Fe]-hydrogenase and material surface. Corrosion Science. 2016.
- Ravin NV, et al. Comparative Genome Analysis of the Genus Thiothrix Involving Three Novel Species, Thiothrix subterranea sp. nov. Ku-5, Thiothrix litoralis sp. nov. AS and “Candidatus Thiothrix anitrata” sp. nov. A52, Revealed the Conservation of the Pathways of Dissimilatory Sulfur Metabolism and Variations in the Genetic Inventory for Nitrogen Metabolism and Autotrophic Carbon Fixation. Frontiers in Microbiology. 2021.
- Lahme S, Mand J, Longwell J, Enning D. Detection of a conserved multi-heme cytochrome gene cluster in severely corrosive sulfate-reducing biofilms. International Biodeterioration & Biodegradation. 2025.
- Brigmon RL, Martin HW, Aldrich HC. Biofouling of Groundwater Systems by Thiothrix spp.. Current Microbiology. 1997.
Primary studies establish observations under their stated conditions. The sampling examples and monitoring suggestions in this article are practical interpretations, not universal MIC limits.