Bacterial strain is a set of bacteria with equality in terms of their biological characteristics, that is, bacteria of the same species, they are called bacterial strains or colonies. For example, E. Coli is a bacterium that lives in the intestinal tract and does not live alone. It does so by forming strains or colonies.
It is important to highlight the fact that the characteristics of the colonies occur in various degrees and combinations that depend on the bacteria and are generally very uniform. They are used to identify bacteria in mixed cultures. However, in addition to these characteristics, they are also necessary to study the physiology and properties of the bacteria that allow a complete identification to be carried out.
The general characteristics of the bacterial strains are as follows:
- Stability genetics.
- Ease of cultivation.
- Maximum playback speed under chosen operating conditions.
- Metabolism oriented to the desired production with the highest possible yield.
- Easy to use.
- Ease of conservation.
An important aspect is the conservation of the bacterial strain. The preservation of bacterial strains happens by stopping or slowing the metabolic activity of cells. This can be done by drastically reducing the available water. This can be achieved through:
Freeze drying Freezing: at -178 oC with liquid nitrogen.
Colonial morphology is comparable to a statistic, as it is derived from an individual cell, but it is characteristic of the cell mass. So, for example, the pigmentation is evident in the colony, but not in the individual cell, in the case of the consistency of the mucosa of some colonies this is derived from the capsular substance in those bacteria with a very large capsule.
The measurement of the colonies, this characteristic is quite constant within the species and can vary from very small colonies to a diameter of several millimeters.
Shape. It is determined by its edge and its thickness.
In terms of consistency and texture, the consistency of the colonies can vary from a dry colony that can move on the agar with the handle, to a viscous colony that adheres to the handle and forms filaments or mucous threads when it comes to separating it from the handle. agar.
The surface can be uniformly shiny and smooth or it can be corrugated with concentric or broken notches. When examining the colony with transmitted light, it may appear granular or amorphous in texture.
