API is the recommended formula by the American Petroleum Institute in the API-RP38 standard for monitoring SRB in oil and gas systems. API has both solid iron (in the form a nail), and diluted iron to facilitate the reaction from a clear, transparent media to black in the presence of sulfate reducing bacteria. API is one the most popular media worldwide for the detection of SRB and its formulation hasn’t changed significantly for the past 30 years. Biotechnology Solutions TX also provides different variations of the API media with minor modifications to its formulation in order to customize it for different environmental conditions.
Frequently Asked Questions
1-If MPB is better for the detection of SRB, why is API still offered?
API has been around for decades and many people in the oil and gas industry are used to seeing an iron nail in the media that is used for the detection of SRB. API is effective and simple to use as well, but it is because it so popular around the world that some customers still feel comfortable using it. Biotechnology Solutions TX will continue to offer this product because we prioritize our customer’s needs over everything else.
2- What is the difference between media like API, and SRB2/SRB3?
API, SRB2 and SRB3 are media that look pretty much the same. All look clear with an iron nail; however, SRB2/SRB3 have some extra ingredients that make them more effective for certain systems. Different carbon sources or extra oxygen scavengers are what make SRB2/SRB3 a little bit more efficient than API under certain conditions. If you are not sure if SRB2/SRB3 media is a viable option for you, please contact a Biotechnology Solutions TX representative and we’ll recommend the best media for your needs.
3-I have noticed that some API vials have faint “black lines” or even the nails look a little dark in certain areas, why is this? Should I ask for my media to be replaced?
All bacterial media that is shipped out to our customers have passed rigorous quality controls, and API is not the exception. Faint “black lines” can be formed during the sterilization process due to a minimal amount of oxygen interacting with iron traces dissolved in the media. When oxygen interacts with iron it will start forming iron oxide (rust) that becomes fully inactive by the sterilization process, and leaving sometimes a faint black line due to the high temperatures. These marks just confirm that there is no active form of oxygen inside the vial that could compromise the media or the bacterial growth. There is no need to request a media replacement, but if there are other issues with the media feel free to contact Biotechnology Solutions TX and request a different batch of API.
4-Can I incubate this media at high temperatures in order to mimic the conditions I find in my system?
Yes, API can be incubated at higher temperatures if needed. There are some SRB species that thrive under high temperatures so it is understandable to incubate them under conditions that mimic their natural habitat as closely as possible. Most chemicals will remain functional at high temperatures; however, at around 55°C some will become less effective causing the growth rate to slow down and even accelerating the expiration time of the vials. If you plan on changing the incubation parameters from the ones recommended by the manufacturer and NACE standards, please contact a Biotechnology Solutions TX representative to guide you during the inoculation and incubation processes.
5- I need to culture some SRB, but I do not need the media to turn black. Is there an alternative I could acquire from you?
Yes, we can a provide a modified API that won’t turn black, but it’ll still provide all the nutrients sulfate reducing bacteria need to grow. The media is clear as well, but it’ll turn turbid once SRB’s concentration increases.