cultivability

Culturability is the capacity of an organism to be cultivated in a laboratory culture under defined conditions. It is often expressed as the proportion of cells in a sample that can form colonies or exhibit detectable growth under specified media, temperature, and incubation. Culturability is distinct from viability, because cells can be viable but not readily culturable under standard conditions (the viable but non-culturable, or VBNC, state).

Measuring culturability typically uses plate counts, most probable number assays, or dilution-to-extinction methods, and compares these results with total cell counts obtained by microscopy or flow cytometry. The difference between total abundance and cultivable cells is known as the great plate count anomaly, highlighting gaps in conventional culture methods.

A variety of factors influence culturability, including nutrient adequacy, oxygen levels, pH, and temperature, as well as the presence of growth factors or signaling compounds. Ecological interactions and dependencies on other species, secreted metabolites, or co-culture can be essential. Sample history and the choice of media strongly bias which taxa are recoverable.

Understanding culturability is central to microbial ecology, biotechnology, and health research. It underpins attempts to isolate and characterize new organisms, discover natural products, and study community structure. Innovations such as diffusion chambers, microfluidic isolation, and in situ cultivation are expanding the range of organisms that can be cultured.

Culturability is not an intrinsic property of a microbe alone but a function of the organism, the environment, and the culture system used.