Saprotrophic nutrition is a process of chemoheterotrophic
extracellular digestion involved in the processing of dead or decayed organic matter. It occurs
in saprotrophs or heterotrophs, and is most often associated with fungi and soil bacteria.
Saprotrophic microscopic fungi are sometimes called saprobes; saprotrophic plants or bacterial
flora are called saprophytes. The process is most often facilitated through the active
transport of such materials through endocytosis within the internal mycelium and its constituent
hyphae. Various word roots relating to decayed matter,
eating and nutrition, and plants or life forms produce various terms, such as detritivore,
detritophage, saprotroph, saprophyte, saprophage, and saprobe; their meanings overlap, although
technical distinctions narrow the senses. For example, usage distinctions can be made
based on macroscopic swallowing of detritus versus microscopic lysis of detritus. Process
Explanation As matter decomposes within a medium in which
a saprotroph is residing, the saprotroph breaks such matter down into its composites.
Proteins are broken down into their amino acid composites through the breaking of peptide
bonds by proteases. Lipids are broken down into fatty acids and
glycerol by lipases. Starch is broken down into simple disaccharides
by amylases. These products are re-absorbed into the hypha
through the cell wall via endocytosis and passed on throughout the mycelium complex.
This facilitates the passage of such materials throughout the organism and allows for growth
and, if necessary, repair. Conditions
In order for a saprotrophic organism to facilitate optimal growth and repair, favourable conditions
and nutrients must be present. Optimal conditions refers to several conditions which optimise
the growth of saprotrophic organisms, such as;
Presence of water: 80–90% of the fungi is composed of water by mass, and requires excess
water for absorption due to the evaporation of internally retent water.
Presence of oxygen: Very few saprotrophic organisms can endure anaerobic conditions
as evidenced by their growth above media such as water or soil.
Neutral-acidic pH: The condition of neutral or mildly acidic conditions under pH 7 are
required. Low-medium temperature: The majority of saprotrophic
organisms require temperatures between 1 °C and 35 °C, with optimum growth occurring
at 25 °C. The majority of nutrients taken in by such
organisms must be able to provide carbon, proteins, vitamins and in some cases, ions.
Due to the carbon composition of the majority of organisms, dead and organic matter provide
rich sources of disaccharides and polysaccharides such as maltose and starch, and of the monosaccharide
glucose. In terms of nitrogen-rich sources, saprotrophs
require combined protein for the creation of proteins, which is facilitated by the absorption
of amino acids, and usually taken from rich soil. Although both ions and vitamins are
rare, thiamine or ions such as potassium, phosphorus, and magnesium aid the growth of
the mycelium. See also Mycorrhizal fungi and soil carbon storage
Chemoautotrophic nutrition Detritivore
Holozoic nutrition Parasitic nutrition
Photoautotrophic nutrition Photosynthesis
Wood-decay fungus Notes
Clegg, C. J.; Mackean, D. G.. Advanced Biology: Principles and Applications, 2nd ed. Hodder