Saprotrophs, also known as detritivores, saprobes, or saprophytes, feed on the non-living organic matter - detritus. They participate in a typical decaying process of most of the dead animals, plants and some biological wastes. The etymology of the word Saprotrophs is derived from the Greek word sapros meaning- rotten and trophe means nourishment. Saprotrophs are the most essential organisms in the process of energy cycle because they help to convert a lot of waste into decayed matter thereby releasing energy into the system. Saprotrophism demands a lot of biochemical assistance from outside. Some of the most common Saprotrophic organisms are fungi, few bacteria and fungus-like organisms called water molds. During the saprotrophic process, nutritional substrate such as dead organisms and other nonliving organic matter is directly digested by a variety of enzymes released by the Saprotrophs. Some enzymes assist to convert the detritus into simpler molecules. The biological phenomena in which the saprotrophic feeding occur is called saprotrophism.
Fungi are the most effective saprotrophs among all. They are capable of decomposing the most complex organic molecules in a short span. Saprotrops also assist in recycling the nutrients thereby allowing them back into the ecosystem. The bulk of the plant tissues are made up of the cell-wall with cellulose- a complex carbohydrate. The structural complexity of the cellulose cannot be degraded by ordinary organisms but the fungus can even degenerate them. The most common fungi used to decompose the leaves and twigs are Marasmius and some forest mushrooms.
Bacteria are also well-known for decomposing dead animal`s flesh. They are active in converting the animal tissues into simpler organic compounds. Some of the most common decomposing bacteria that decompose the animal tissues are Escherichia coli and Spirochaeta cytophaga.
Water molds ( oomycetes ) are found in freshwater and saltwater aquatic systems throughout the world. They assist in decomposing both plant`s and animal`s organic material.
Process of decomposition
As the waste gets decomposed, the saprotrophs breaks the complex material into simpler ones. The starch found in the dead matter is broken down into pieces of simple disaccharides with the help of an enzyme- amylase. The protein material in the decaying matter is broken down into sub-units I.e. Amino acid composites. The underlying mechanism involved in protein decay is the breaking of peptide bonds by the enzyme protease. Similarly, complex lipids are broken down into fatty acids and glycerol with the help of lipases. The simpler units are re-absorbed into the hypha found in the cell wall of saprotrophs and the process of absorption is enabled by endocytosis occur all around the mycelium complex.
Conditions required for decomposition
For saprotrophism, materials like water, oxygen and neutral to mildly acidic conditions -pH (below 7 ) is essential. The temperature must be between 1 °C to 35 °C, with optimum growth occurring at 25 °C. The carbon content of the majority of organisms gives away the disaccharides and polysaccharides such as maltose, starch, as well as the monosaccharides in the form of glucose.