Q. Foods for Growth in microorganisms?

Microorganisms differ in their ability to use various nitrogenous compounds as a source of nitrogen for growth. The primary nitrogen sources utilized by heterotrophic microorganisms are amino acids. A large number of other nitrogenous compounds may serve this function for example, nucleotides, free amino acids, peptides and proteins. Simple compounds such as amino acids will be utilized by most of the organisms before they utilize complex compounds. The nitrogen requirements of some bacteria such as Pseudomonas spp. may be satisfied by simple compounds like ammonia or nitrates.

Many molds are proteolytic, but comparatively few bacteria and very few yeast are actively proteolytic. Proteolytic bacteria grow best at pH values near neutrality and are inhibited by acidity. Only exceptions are the acid-proteolytic bacteria that hydrolyze protein while producing acid. Carbon for growth for most of the microorganisms is derived from organic compounds but some can use carbon dioxide also. The minerals required by microorganisms are nearly always present at the low levels required.