As bacteria are a very disparate group of microbes that can exist in a wide range of environments, and can be split into a number of different nutritional groups with very different prerequisites for growth, the ingredients in the medium will depend on the individual species. The common requirements of all bacteria are water, a source of energy, carbon, nitrogen, essential inorganic ions such as phosphate, sulfate, sodium, calcium, magnesium, potassium and iron and a number of trace elements (zn, Mn, Mo, Se, Co, Cu Ni, W). For heterotrophs, energy and carbon can be derived from the same moleculeAs bacteria are a very disparate group of microbes that can exist in a wide range of environments, and can be split into a number of different nutritional groups with very different prerequisites for growth, the ingredients in the medium will depend on the individual species. The common requirements of all bacteria are water, a source of energy, carbon, nitrogen, essential inorganic ions such as phosphate, sulfate, sodium, calcium, magnesium, potassium and iron and a number of trace elements (Zn, Mn, Mo, Se, Co, Cu, Ni, W). For heterotrophs, energy and carbon can be derived from the same molecule