CENSUS® qPCR is a DNA based molecular microbiological method (MMM) to accurately quantify total bacteria, total archaea, and specific microorganisms like sulfate reducing bacteria (SRB) that are commonly responsible for microbiologically influenced corrosion (MIC) and souring. Also consider QuantArray®, an advanced qPCR method that can simultaneously quantify a broad spectrum of targets in a single run.
CENSUS qPCR MIC ADVANTAGES:
ACCURATE
Since the overwhelming majority (>99%) of microorganisms cannot be grown in artificial media, traditional methods (e.g. MPNs and plate counts) are not accurate and may vastly underestimate MIC threats. With CENSUS®qPCR, DNA is extracted directly from the field sample removing the need to grow the bacteria and eliminating biases associated with plate counts and MPNs.
QUANTITATIVE
Absolute quantification of the concentrations of total bacteria, total archaea, and specific microbial groups like sulfate reducing bacteria (SRB) to monitor abundances over time or in response to biocides or other MIC mitigation efforts. Results reported as cells/mL, cells/g, etc.
SENSITIVE
Practical Detection Limits (PDL) are as low as 100 cells per sample with a dynamic range over seven orders of magnitude.
SPECIFIC
Target specific bacterial groups (e.g., sulfate reducing bacteria, methanogens, iron reducing bacteria) responsible for MIC.
COST EFFECTIVE
Fast turnaround time (7-10 days), with rush service available, so you can make decisions and take action quickly. CENSUS® qPCR is inexpensive and ultimately saves money by allowing corrosion engineers and operators to make more informed MIC mitigation decisions.
FLEXIBLE
Analysis can be performed on almost any type of sample (water, solids, corrosion coupons, swabs, pigging solids, scrapings, and others).
CUSTOMIZABLE
Assays are available for quantification of many different MIC associated microbes. Custom assays can also be developed to fit your needs.
HOW TO USE CENSUS® qPCR MIC:
For MIC threat assessment, routine monitoring, and evaluating the effectiveness of biocides or other mitigation activities, CENSUS® qPCR quantification of total and specific MIC causing microorganisms provides the actionable data needed to make decisions.
Use CENSUS® qPCR to help answer…
- Is MIC a threat?
- Are concentrations of total bacteria, SRB, and other MIC associated microorganisms increasing?
- Was the biocide effective?
- Did concentrations of MIC associated microorganisms decrease after treatment?
- Have concentrations of MIC causing microorganisms rebounded?
RESOURCES
AVAILABLE CENSUS® qPCR ASSAYS TO HELP WITH MIC, SOURING AND MITIGATION
| TARGET | MI CODE | RELEVANCE / DATA INTERPRETATION |
|---|---|---|
| Total Eubacteria | EBAC | MIC is initiated by growth of a biofilm on the material surface. Monitoring total bacteria provides a general measure for evaluating bacterial growth in the system. |
| Total Archaea | ARC | Archaea are another general group of single celled microorganisms which, like bacteria, can initiate and contribute to MIC. Depending upon types and environmental conditions, total archaea can outnumber total bacteria and be a more important factor in MIC. |
| Sulfate Reducing Bacteria | APS | Sulfate reducing bacteria (SRB) consume hydrogen, produce hydrogen sulfide and are the group of microorganisms most commonly implicated in the pitting corrosion of various metals. |
| Sulfate Reducing Archaea | SRA | Sulfate reducing archaea consume hydrogen, produce hydrogen sulfide and have been implicated in MIC at elevated temperatures. |
| Methanogens | MGN | Methanogens utilize hydrogen for growth, can contribute to cathodic depolarization and can cause corrosion rates comparable to sulfate reducing bacteria. |
| Acid Producing Bacteria | AGN | Acetogenic bacteria are strict anaerobes that produce acetate from the conversion of H2-CO2, CO, or formate. Hydrogen mediated acetogenesis has been demonstrated in high pressure natural gas pipelines confirming the in situ activity of this bacterial group. Further, the presence of acetic acid is known to exacerbate carbon dioxide corrosion of carbon steel. |
| Fermenters | FER | Anaerobic bacteria produce organic acids and hydrogen. Acid production can lead to localized drops in pH facilitating corrosion while hydrogen production can support growth of other MIC associated organisms including SRB. |
| Iron Reducing Bacteria (other) | IRB | Iron reducing bacteria reduce insoluble ferric iron to soluble ferrous iron potentially facilitating the removal of protective corrosion products formed on exposed iron alloy surfaces. However, other studies have suggested that the actions of IRB can inhibit corrosion through a variety of mechanisms. This assay targets iron reducing bacteria such as Deferribacter, Ferrimonas, Geopsychrobacter, Geothermobacter, Geothrix, Geovibrio, Geothermobacterium and Albidiferax. Please note that Geobacter and Shewanella are also common iron reducing bacteria which need to be ordered as separate assays. |
| Iron Reducing Bacteria (Geobacter) | GEO | Iron reducing bacteria reduce insoluble ferric iron to soluble ferrous iron potentially facilitating the removal of protective corrosion products formed on exposed iron alloy surfaces. This assay targets a common iron reducing bacteria, Geobacter. |
| Iron Reducing Bacteria (Shewanella) | SHW | Anaerobic bacteria which can utilize cathodic hydrogen as an energy source, reduce ferric iron and sulfite to ferrous iron and sulfide indicating that it can play a role in MIC. |
| Iron Reducing Archaea | IRA | Targets two genera of iron reducing archaea, Ferroglobus and Geoglobus. |
| Iron Oxidizing Bacteria | FeOB | Iron oxidizing bacteria are a group of microorganisms commonly implicated in metal deposition and tubercle formation. |
| Manganese Oxidizing Bacteria | MnOB | Like iron oxidizing bacteria, manganese oxidizing bacteria are capable of making deposits of metal oxides. |
| Sulfur Oxidizing Bacteria | SOB | Often aerobic bacteria oxidize sulfide or elemental sulfur producing sulfuric acid. Commonly implicated in the corrosion of concrete. |
| Nitrate Reducing Bacteria | DNF | Increasingly, nitrate addition is being used to stimulate growth of nitrate reducing bacteria as a bioexclusion strategy to combat SRB-mediated reservoir souring and MIC. The DNF assay quantifies target genes encoding enzymes responsible for a key step in biological nitrate reduction. |
| Archaeal Nitrite Reducing Bacteria | ADNF | Similar to the DNF assay, ADNF quantifies the two types of nitrite reductase genes (nirS and nirK) found in archaeal organisms. |
| Ammonia Oxidizing Bacteria | AOB | Ammonia oxidation or nitrification produces nitric acid causing corrosion of concrete and natural stone. Depending on alkalinity levels, nitrification in water systems can increase lead contamination and increase copper solubility. |
| Nitrite Oxidizing Bacteria | NOR | Targets the gene encoding the enzyme responsible for the last step in nitrification. |
| Nitrogen Fixing Bacteria | NIF | Nitrogen fixation converts nitrogen gas into ammonia which can be assimilated by organisms. Nitrogen fixation may become increasingly important in mature biofilms. |
| Exopolysaccharide Production | BCE | Gene involved in the production of exopolysaccharide (EPS) and biofilm formation by some Burkholderia spp. |
| Deinococcus spp. | DCS | Genus of bacteria considered very efficient primary biofilm formers and therefore have been implicated in slime formation and biofouling. |
| Meiothermus spp. | MTS | Like Deinococcus spp., Meiothermus spp. are efficient primary biofilm formers and frequently implicated in slime formation and biofouling. |
| Cladosporium spp. | CLAD | The fungus Cladosporium resinae is such a common fuel contaminant that it has been described as the "kerosene fungus". C. resinae grows on hydrocarbons including alkanes to produce organic acids often linked to the corrosion of aluminum fuel tanks. |
| Sporomusa spp. | SSPH | Genus of anaerobic, acetic acid producing bacteria (homoacetogens). Acetic acid is known to exacerbate carbon dioxide corrosion of carbon steel. Moreover, one Sporomusa species, S. sphaeroides, has been shown to grow with iron as the sole electron donor enhancing corrosion. |
| Acetic Acid Bacteria | AAB | Quantifies the alcohol dehydrogenase (adhA) genes from acetic acid bacteria (Acetobacter, Gluconobacter, and Komagataeibacter). adhA catalyzes the oxidation of ethanol to acetic acid which can be a potential cause of corrosion. |
| Glycerol Utilizing Bacteria | GLK | Microbial degradation of glycerol, a byproduct of biodiesel production from fats, leads to the generation of VFAs (lactic and propionic acid) both of which have been observed at high concentrations in diesel tanks. VFA production can substantially reduce local pH and also supports the growth of other microbial groups commonly implicated in corrosion. The GLK assay targets a key functional gene in glycerol uptake and utilization. |
| Perchlorate reductase Sedimenticola spp. | pcrAS | Quantifies the gene encoding perchlorate reductase in Sedimenticola spp. which catalyzes the initial, rate-limiting step in the biodegradation of perchlorate as well as the reduction of chlorate to chlorite. |
| MIC Hydrogenase | MicH | Targets the gene encoding a NiFe (MIC) Hydrogenase found in some methanogens which is involved in electrical microbial influenced corrosion (EMIC), a proposed process for the acceleration of iron corrosion. It can be used to help distinguish highly corrosive biofilms. |
| TatC Translocase | TatC | Targets the gene encoding TatC translocase which is coexpressed with MicH. It helps export MicH out cells where it can come into contact with iron and cause corrosion. |
| Glycolipid Biosurfactants | SurG | Glycolipid surfactants are composed of lipids with a carbohydrate attached by a glycosidic bond. The SurG assay quantifies two genes from Pseudomonas spp. responsible for the production of rhamnolipids which are involved in the uptake of low polarity hydrocarbons. These glycolipid biosurfactants are useful in Microbial Enhanced Oil Recovery (MEOR) and the bioremediation of petroleum hydrocarbons. |
| Lipopeptide Biosurfactants | SurP | Lipopeptide biosurfactants are composed of a lipid connected to a peptide molecule. The SurP assay quantifies the SrfAC, licC, aprE genes involved in the production of Surfactin, lichenysin, and Subtilisin in Bacillus spp. as well as the visC gene involved in the production of viscosin in Pseudomonas spp. Surfactin is currently considered as one of the most effective biosurfactants. These lipopeptide biosurfactants are useful in Microbial Enhanced Oil Recovery (MEOR) and the bioremediation of petroleum hydrocarbons. |
| Liposaccharide Biosurfactants | SurL | Liposaccharide biosurfactants are high molecular weight, water soluble compounds composed of a hydrophobic lipid section, a hydrophilic core polysaccharide chain, and a repeating hydrophilic oligosaccharide side chain. The SurL assay quantifies the weeA and alnB genes involved in the production of emulsan and alasan in hydrocarbon degrading Acinetobacter spp. These liposaccharide biosurfactants are useful in Microbial Enhanced Oil Recovery (MEOR) and the bioremediation of petroleum hydrocarbons. |
| Trehalose Biosurfactants | SurT | This is a specific group of glycolipid biosurfactants that are produced by Rhodococcus and Mycobacterium spp. and are involved in the uptake of low polarity hydrocarbons. The SurT assays quantifies two genes responsible for the production of these biosurfactants. These trehalose biosurfactants are useful in Microbial Enhanced Oil Recovery (MEOR) and the bioremediation of petroleum hydrocarbons. |