The purpose of subculturing in microbiology is to grow and sustain a microbe sample suitable for experimentation and tests. Subculturing prolongs the lifespan of the cells or microorganisms, allowing for long-term maintenance and observation of the culture.
The process of subculturing involves transferring microbes from one growth container to another, providing the microbes with a fresh supply of nutrients on a solid or liquid medium. Subculturing enables the analyst to change the parameters of a microbe’s habitat, such as its temperature and physical environment, to obtain information used in species identification. Understanding where a microbial culture lives or dies helps to isolate its strain. In some instances, a microbial culture can be identified based on the length of time needed for new growth to appear after the subculture transfer.
Petri dishes with agar, a gelatinous substance made from seaweed, are used as a solid environment to grow microorganisms. When a liquid environment is needed, an artificial nutrient broth is used. Cultures with mixed microorganisms that are grown in a broth need to be subcultured onto a solid media to isolate colonies for accurate identification. Once on the agar surface, each microbe colony represents a single species of microorganism, originating from the multiplication of a single cell. This defined and isolated colony is called a pure culture and is an essential starting point in microbiological research.