Methods to Assess Microbial Populations

Microbial populations are groups of the same species found in the same environment. They are assessed using various methods.

A culture-based method called viable plate count estimates living cells by plating diluted samples on agar, where each viable cell forms a visible colony.

In the most probable number method, progressively diluted samples are inoculated in replicates. Then, the number of tubes showing growth is used to estimate the microbial density in the samples.

Biochemical tests assess microbial activity by tracking traits like enzyme production, linking populations to ecological roles.

For instance, cellulase-producing microbes most likely serve as key decomposers in forests.

Fluorescence in situ hybridization uses fluorescent probes that bind to rRNA sequences unique to specific microbes.

This enables microscopic identification and quantification of microbial taxa.

Flow cytometry analyzes microbes by passing them through a laser beam one at a time.

It assesses traits like cell size, complexity, and viability, enabling high-throughput quantification and sub-population assessment within complex communities.