Microbiologically influenced corrosion

At NCIMB we offer 16S sequencing, qPCR and culture-based analyses to provide data that helps you understand the threat of microbiologically influenced corrosion and undertake failure investigations.

Why use NCIMB's microbiologically influenced corrosion services?

We have decades of microbiological experience and understanding of the strains that can influence corrosion.
We provide clear actionable reports with the data you need to to assess the threat of microbiologically influenced corrosion so you can make decisions on action required. Get in touch if you would like a copy of a sample report.
We work hard to make things easy for our customers. Our experienced scientific staff can guide you through the process, tailoring the service to suit your requirements, advising on the benefits of different analytical methods and giving guidance on interpretation of results.

What is microbiologically influenced corrosion?

Microorganisms are ubiquitous in nature and can quickly colonise the surfaces of man-made structures when they are introduced to the environment. The metabolic activity of microorganisms can accelerate corrosion reactions on the surfaces that they colonise. When microorganisms colonise surfaces they often form biofilms - these can be highly complex communities of different species, but their composition varies from site to site. The action of different groups of organisms within biofilms can influence corrosion in different ways. For example, the growth of some groups can create the conditions that allow the proliferation of others, which in turn produce corrosive waste products.

Impacts of microbiologically influenced corrosion

Microbiologically influenced corrosion accounts for a significant proportion of corrosion failures, and can have devastating impacts. Oil and gas production facilities, wind turbines, pipelines, cooling systems and power plants are all at risk of microbiologically influenced corrosion, and the action of microbes can affect both metal and concrete structures on land or in sea.

Methods for investigating microbial populations that can influence corrosion

Monitoring for the presence of groups of microorganisms known to influence corrosion can allow remedial action to be taken if numbers start to rise. At NCIMB we also have experience in analysing samples for the purpose of failure investigations.

A number of different methods can be used for determining the presence of microorganisms that influence corrosion and three options are described below. They can be used individually or in combination with each other - see our case study below.

Most probable number

This culture-based enumeration method, sometimes referred to as "bug bottles", is based on the inoculation of selective media to enumerate groups of microorganisms that can influence corrosion. A serial dilution is used to estimate the number of organisms in the initial sample. Inoculated vials are incubated for a period of time before results are obtained, and consequently the turnaround time can be longer than for other methods we offer. Groups of microorganims tested for include:

Sulphate reducing prokaryotes
Thermophilic sulphate reducing prokaryotes
General heterotrophic bacteria
Acid-producing general heerotrophic bacteria
Nitrite reducing bacteria.

qPCR

This method is used to quantify groups of microorganisms without any requirement for growth. It therefore gives faster results than the most probably number method and ensures that microbes that do not grow under laboratory conditions are included in the counts. Like the most probable number method, qPCR can be used to enumerate populations of different groups of microorganisms that can influence corrosion to build an in-depth understanding.

16S sequencing

This method, which is sometimes also referred to as "next generation sequencing" uses DNA sequencing to analyse the whole bacterial population from a single sample. It is a semi-quantitative method that determines the groups of organisms present in a sample and calculates their relative abundance as illustrated below.

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Desulfobacter curvatus has a relative abundance of 64%; relative abundance of Pseudodesulfovibrio aespoeensis is 10%. Desulfobacter psychrotolerans has a relative abundance of 2%. Paracubacteria has a relative abundance of 2%. All other groups present have a relative abundance of less than 2%

Figure 1: Bar chart showing groups of bacteria present and their relative abundance. Desulfobacteri curvatus accounts for 64% of the population present, followed by Pseudodeslfovibrio aespoeensis, which accounts for 10%.

Failure investigation case study

NCIMB took part in an investigation into the cause of an unexpected mooring chain failure on an FPSO offshore West Africa with CIU Ltd. The retrieved chains had been significantly affected by the phenomenon known as "meg pits". It was suspected that the main corrosion mechanism was microbiologically influenced corrosion but this was not the only possible explanation.

NCIMB provided a sampling kit and detailed instructions that enabled local crew to take samples and preserve them prior to transport to our laboratory for analysis. The analysis undertaken included:

Enumeration of total bacteria by qPCR
Enumeration of SRB by qPCR
16S sequencing to determine groups of organisms present
Sulphide (mg/cm²)

The qPCR results indicated the presence of moderate to high numbers of bacteria and archaebacteria. The 16S sequencing determined that a percentage of the organisms present were sulphate-reducing bacteria and other groups of bacteria involved in the sulphur cycle. Several samples also contained high concentrations of sulphide which is an indicator for SRB activity. Read the full case study here.

Sending samples for analysis

Please contact us to discuss your requirements prior to shipping samples.

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