The warmer their environment, the better they grow. The growth of molds depends heavily on moisture: they need lots of moisture to thrive. Like yeasts, molds depend on organic materials for food; this can be anything from cellulose to sugar to the starch that was in your bread. Sugars are found in soil and the glucose is used by most fungi as a source of carbon and energy. ... Synthesis of these enzymes depends on environmental conditions as well as the ability of each species and fungus strain.
