A uniform bacterial growth potential assay for different water types

Area of Science:

• Environmental microbiology
• Water quality assessment
• Microbial ecology

Background:

• Bacterial regrowth in water systems is a significant concern for water quality.
• Nutrient availability, particularly organic carbon, is a primary driver of bacterial growth potential.
• Accurate measurement tools are crucial for routine bacterial growth potential assessment.

Purpose of the Study:

• To develop a universal bacterial growth potential assay applicable to diverse water types and soil extracts.
• To utilize indigenous microbial communities as inocula, avoiding pure culture limitations.
• To compare Flow Cytometry (FCM) and Adenosine Tri-Phosphate (ATP) as methods for growth potential measurement.

Main Methods:

• Assayed bacterial growth potential in six different water/soil samples using indigenous microbial communities.
• Measured bacterial growth in response to increasing carbon concentrations.
• Employed Flow Cytometry (FCM) and Adenosine Tri-Phosphate (ATP) for growth quantification.

Main Results:

• Indigenous bacterial communities exhibited standard batch growth kinetics with available organic carbon.
• The assay detected organic carbon spikes as low as 10 μg/L.
• Bacterial growth was proportional to carbon concentration across tested samples, measurable by both FCM and ATP.

Conclusions:

• The proposed assay using indigenous communities provides a fast, stable, and accurate method for monitoring water biological stability.
• This approach overcomes limitations of previous assays by not requiring specific cultures.
• The assay can help identify growth limitations caused by factors beyond organic carbon.