Nitrate Reducing Bacterial Broth

The Nitrate Reducing Bacterial Broth has been designed for the detection of nitrate reducing bacteria in the oil and gas industry following the NACE standard TMO194-2014. The media is slightly yellow in color and will become turbid with a higher concentration of nitrite due to the reduction of nitrate. Even though nitrate reducing bacteria do not actively cause corrosion they can be a good indicator of other kinds of bacteria with more corrosive metabolisms.


Frequently Asked Questions

1-How can I know for sure that I have nitrate reducing bacteria in my system?

Even though the NRB media is not too selective and there is a slight chance for other bacteria to grow in this media, the higher concentration of nitrite when compared to nitrate is the definitive factor. If nitrate reducing bacteria are present, they will deplete all the nitrate available for them in the media; that nitrate will be reduced to nitrite which is not an ingredient. So, by simply using nitrate/nitrite strips it could easily be confirmed whether or not there is nitrate reducing bacteria in this media. Any other bacteria could probably use other ingredients for their metabolism, but the nitrate will remain untouched and there won’t be any nitrite.

The best way to use nitrate strips is by placing one drop of an inoculated vial with potential NRB on top of the nitrate/nitrite indicators. Most indicators will present an immediate color change that quantifies the concentration of either nitrate or nitrite.

2-What is the main difference between NRB media and NUB media?

NRB media is targeted for nitrate-reducing bacteria while NUB (nitrate-utilizing broth) is strictly manufactured for another group of microorganisms named denitrifying bacteria. This group of bacteria perform denitrification, which plays a key role in the nitrogen cycle. Denitrification is a process carried out by bacteria, fungi and other organisms where nitrate, nitrite, and other nitrogenous compounds are eventually reduced to molecular nitrogen (N2) and released back to the atmosphere. NRB is more restrictive than NUB, since it will only target a group of bacteria that transforms nitrate to nitrite; on the other hand, NUB is less specific but provides a wider range of nutrients for multiple organisms. In order to confirm that a denitrification process occurred inside a vial of NUB, it is necessary to use nitrate/nitrite strips. If both compounds are not detected by the strips, it has been proven that denitrifying organisms are present.

3-Should I use NRB with PRD or MPB/API?

There is no need to use NRB in conjunction with any other media. NRB helps to detect the presence of nitrate reducing bacteria that most of the time do not actively cause or influence corrosion. A significant concentration of nitrate reducing bacteria is an indicator that the probability of finding SRB is low given that most nitrate reducing bacteria out compete corrosive bacteria for resources.

4- Can NRB be customized to my needs?

Yes, absolutely. Given the diversity of nitrate-reducing organisms we are aware that customization of this media could be necessary depending on the environmental conditions of each field or system. For example, we have had costumers requesting NRB media with yeast extract as an alternative source of amino acids, or with reduced amounts of nitrates in order to adapt the media to their different needs. Please, feel free to contact a Biotechnology Solutions TX representative to obtain more information about the different alternatives of NRB media available for you.

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