How do fungi decompose wood and other complex materials?

Fungi decompose wood and other complex organic materials through a process known as absorptive nutrition. Because they cannot ingest solid food, fungi function as saprotrophs by secreting powerful digestive enzymes directly onto their growth substrate.123

These enzymes act as biological catalysts that break down complex, insoluble polymers—such as cellulose, hemicellulose, lignin, and proteins—into simpler, soluble molecules. Once the material is converted into a solution, it is absorbed directly through the walls of the fungal hyphae.23

This extracellular digestion allows fungi to efficiently recycle nutrients back into the ecosystem. By breaking down the tough cell-wall material of plants, fungi play a vital role in the carbon cycle, transforming complex organic matter into nutrients that can be utilized by other organisms. While this process is essential for environmental health, it can also lead to the decay of structural timber and stored food products.13