Streak plate technique-

The inoculum is streaked or spread over the surface of a solid medium. The streaking process accomplishes a thinking out of the population. There is no uniform distribution of the organism. Where they are thickly populated, they will grow in mass, but where only few are present, they develop distinct colonies. These isoalated colonies are the progenies of single cells and whether they are so may be verified from microscopic examination. Pure culture may be recurred by the transfer of a part of such colonies to a container with suitable culture medium.

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.