sapro

Sapro- is a combining form derived from the Greek sapros meaning rotten. In biology and ecology, it is used to form terms that describe decay-related processes and organisms that obtain nutrients from decaying organic matter. The most common usages are saprotroph, saprobe, and saprotrophy.

A saprotroph, also called a saprobe, is an organism that feeds on dead organic material by secreting extracellular enzymes and absorbing the resulting nutrients. Saprotrophy is the nutritional mode that involves external digestion of dead matter. Saprotrophic organisms include many fungi (notably wood-decaying basidiomycetes and many molds), numerous bacteria, and some protists. They play a central role in nutrient cycling by breaking down complex polymers such as cellulose, hemicellulose, and lignin, releasing inorganic nutrients back into ecosystems.

Ecologically, saprotrophs are often contrasted with detritivores, which physically ingest dead matter, whereas saprotrophs derive nutrients from the dissolved or absorbed products of decomposition. Through this metabolism, saprotrophs contribute to soil formation, fertility, and carbon cycling, influencing the availability of nutrients and the breakdown of organic carbon.

The prefix sapro- appears in a range of terms beyond saprotrophy, including saprobe (an organism that lives on dead matter), saprobic (describing organisms that are saprotrophic), and related enzymes. While the term is widely used across biology, its exact application can vary by discipline and literature.