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How do fungi obtain nutrients through osmotrophic nutrition?

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A herd of African elephants stands at the edge of the Chobe River in Botswana, drinking water with a backdrop of dry hills and scattered green trees. — life A herd of African elephants (*Loxodonta africana*) drinking from the Chobe River, Botswana.

Fungi obtain nutrients through a process known as osmotrophic nutrition, which involves the external digestion of organic matter. Because fungi cannot ingest solid food, they secrete enzymes directly onto the surface on which they are growing.12

These biological catalysts break down complex polymers—such as proteins, starches, cellulose, and lignin—into simpler, soluble forms like glucose and amino acids. Once the food is dissolved in water, it is absorbed directly through the walls of the hyphae. The entire mycelial surface is capable of this absorption, though some fungi utilize specialized structures like rhizoids for anchoring and absorption, or haustoria to penetrate and extract nutrients from living host tissues.231

This extracellular digestion allows fungi to thrive as saprotrophs on dead organic material or as parasites on living organisms.12