All microorganism require water, source of energy, carbon, nitrogen, and other elements. This requirement vary depending on the organism as well as environmental factors to which they are exposed. The differences in nutritional requirements between microorganism reflects differences in their synthetic ability which in turn are determined by the genetic makeup of the cell. 
The ability to utilize a given compound as a source of energy or various inorganic materials depends upon the presence of a series of enzymes, without which the cell of organisms becomes more demanding or exacting nutritionally.
In the laboratory, microorganism are grown (cultured), cultivated in media that contain appropriate kinds of concentrations of nutrients required for their growth and reproduction such a medium is referred to as "culture media". The following conditiin s are necessary for the optimum growth of microorganisms in the laboratory cture media.
The culture media must contain all necessary substance in utilizable form and no inhibitory substance (chemicals)must be present.
It must contain a source of energy. I.e food, organic matter, carbohydrate e.t.c
The pH and temperature of incubation must be optimum for and reproduction.
The gaseous environment must be suitable.
Competition by other microorganisms as in the case of contamination must be eliminated except where a study is designed.
Kool