1. Adenosine Triphosphate (ATP) Assay:
- The ATP assay measures total microbial biomass by detecting ATP, the energy carrier molecule in all living cells. The ATP levels correlate with microbial activity, thus offering a rapid estimate of microbial presence. This method is widely used in the oilfield industry due to its rapid response and simplicity, particularly in assessing the effectiveness of biocides and general microbial activity.
- However, ATP degrades rapidly, which can limit its accuracy under certain conditions, such as during biocide treatment where delayed ATP degradation was observed. The ATP assay lacks specificity, as it cannot differentiate between microbial species and may overlook specific groups like SRB that contribute to corrosion
2. Bactiquant
- Bactiquant technology relies on a fluorometric method to measure general bacterial activity. This tool filters samples through a membrane that retains microbial particles; a reaction with a substrate yields fluorescence, which is quantified to produce a Bactiquant value. It has shown robust repeatability and efficiency, validated by the EPA for potable water monitoring, and it requires minimal training, making it suitable for field use.
- Like the ATP assay, Bactiquant measures overall microbial activity without species differentiation, which limits its utility in corrosion-specific applications, where identification of particular microbes, such as SRB, is critical. Additionally, Bactiquant results are not directly comparable to colony-forming units (CFU), necessitating further conversion efforts for standard reporting
3. Quantitative Polymerase Chain Reaction (qPCR):
- qPCR is a molecular method that detects and quantifies specific DNA sequences in microbial populations, allowing precise identification of microbial communities, including sulfate-reducing bacteria (SRB) and other corrosion-related microorganisms. This precision provides a clear advantage over ATP and Bactiquant, especially when identifying specific corrosive microorganisms, as it can target genes related to sulfate reduction directly. Especially with the distinction between high and low corrosive
- qPCR offers high specificity, and quantitative capabilities to create baselines and set KPI’s
- A common mentioned disadvantage is that it required specialized equipment and expertise in the past. This was limiting its application primarily to controlled lab settings rather than immediate field deployment. MICBUSTERS however, offers a complete and easy to use field kit that can be used with very limited training.
Summary
In summary, while each technique has its strengths, the choice of method depends on the specific requirements of the microbiological monitoring context. For general microbial activity, ATP and Bactiquant offer quick results especially for biocide efficacy testing. For more targeted monitoring, particularly where SRB or corrosion-inducing microorganisms are concerned, qPCR provides detailed species-level information.
MICBUSTERS offers an easy and comprehensive field kit that allows also operators with limited experiences with molecular technologies to work with qPCR and get reliable results.
