Numerical taxonomy-

Isolation of pure culture-
Growth of microbes in or on a laboratory medium is known as “Culture”. A growth of this type on a solid medium, which has originated from a single cell or spore is termed “colony”. A culrure, which contains only one species of microbe is termed a “ pure culture” and one which consists of several species is called a “mixed culture”.
Microbes are ubiquitous. It is very difficuly to obtain pure cultures of bacteria in nature.they usually exist as mixed cultures in their natural habitats, but it is essential to have pure culture of an organism before one can study its charasteristics. To obtain organisms in pure cultures various techniques have been employed.