Macronutrients, micronutrients, and growth factors

Phosphorus, potassium, magnesium, calcium, and sulfur are all macronutrients required by fungi.  All but phosphorus are usually available to excess in the fungal environment. Phosphorus can sometimes be in short supply, particularly in soils, and fungi have the ability to produce extracellular phosphatase enzymes which allow them to access other- wise unavailable phosphate stores.

Micronutrients include copper, manganese, sodium, zinc, and molybdenum, all of which are usually available to excess in the environment. Iron is relatively insoluble and there- fore not easily assimilated, but fungi can produce siderophores or organic acids, which can chelate or alter iron solubility and improve its availability.

Some fungi may require preformed vitamins, for example, thiamin and biotin. Other requirements can be for sterols, riboflavin, nicotinic acid, and folic acid.