Quantifying bacterial concentration in water and sand media during flow-through experiments using a non-invasive,...

Area of Science:

• Environmental microbiology
• Biogeochemistry
• Porous media science

Background:

• Understanding bacterial dynamics in porous media is crucial for environmental science.
• Bacterial transport and interactions with environmental factors require accurate quantification methods.

Purpose of the Study:

• To develop and validate a non-invasive, real-time method for quantifying bioluminescent bacteria in water and sand.
• To compare bioluminescent counting with traditional viable counts.

Main Methods:

• Conducted 27 column experiments using a real-time bioluminescent imaging system.
• Quantified bacterial concentration using both viable counts and a novel bioluminescent counting method.
• Investigated the influence of surface coating, pore water velocity, and ionic strength on bioluminescent counting accuracy.

Main Results:

• A strong linear correlation was found between bioluminescent counts and viable counts.
• Bioluminescent counting proved reliable for quantifying bacteria in water (10^6 to 2 × 10^8 cells/mL) and sand (5 × 10^6 to 5 × 10^8 cells/cm^3).
• Surface coating and ionic strength significantly affected counting accuracy, while pore water velocity had minimal impact.

Conclusions:

• Bioluminescent counting is a reliable and efficient method for enumerating bacteria in porous media.
• This technique offers a novel approach for in situ bacterial monitoring in 2D devices like flow cells and microfluidics.