Nutrition & Digestion

Fungi do their digestion outside their own body. This style of feeding is called saprotrophic nutrition:

1. The fungus grows a tangled mesh of thread-like cells called hyphae (collectively the mycelium) into a piece of dead organic matter (a fallen leaf, an old log, a slice of bread).
2. The hyphae secrete digestive enzymes onto the surrounding food. Carbohydrases, proteases and lipases are released, just like the ones in your gut.
3. The enzymes break down the large food molecules into small soluble ones right there in the substrate.
4. The fungus then absorbs the small soluble molecules through the cell wall of each hypha.

Because they break down dead material and recycle the nutrients, fungi are essential decomposers in every ecosystem. Without them, dead leaves, animals and other waste would simply pile up.