Q. Source of nutrients and energy of Microorganisms?

Microorganisms use foods as a source of nutrients and energy. Each kind of microorganism has a definite range of food requirements. For some species that range is wide and growth takes place in a variety of substrates e.g. coliform bacteria; but others, e.g., many of the pathogens, being fastidious in their nutrient requirements can grow in limited kinds of substrates. The better the medium for an organism, the wider the ranges of temperature, pH, and aw over which growth can take place.

The food based on their nutrient composition can be classified as

(1) foods for energy,

(2) foods for growth, and

(3) accessory food substances, or vitamins, which may be necessary for energy or growth.