Decomposer

[3] After allowing the enzymes time to digest the material, the decomposer then absorbs the nutrients from the environment into its cells.

[5] The definition of "decomposer" therefore centers on the outcome of the decomposition process, rather than the types of organisms performing it.

"Decomposer" as a category, therefore, would include not just fungi and bacteria, which perform external digestion, but also invertebrates such as earthworms, woodlice, and sea cucumbers that digest dead matter internally and release nutrients locally via their feces.

The paired processes are akin to what occurs in mammal digestive tracts: food is mechanically ground up by teeth, and then chemically broken down by enzymes.

Enzymes for the digestion of molecules like fats, proteins, and starch are widespread and many organisms, from microbes to mammals, have them.

[11][12] Unlike bacteria, which are unicellular organisms and are decomposers as well, most saprotrophic fungi grow as a branching network of hyphae.

[13] These two factors make fungi the primary decomposers in forests, where litter has high concentrations of lignin and often occurs in large pieces like fallen trees and branches.