''Sphaerotilus natans'' is an aquatic periphyton organism associated with polluted water. It forms colonies commonly known as "sewage fungus", but later identified as tightly sheathed filamentous bacteria.

Morphology

Straight or smoothly curved filaments 1.5 µm in diameter and 100 to more than 500 µm in length are formed by rod-shaped cells with clear septa growing within a long, tubular sheath. An adhesive basal element at one end of the filament can aid attachment to solid surfaces. The sheath offers some protection from predators, and the ability to anchor in flowing water allows access to a passing stream of food and nutrients. Individual mature cells swarm out of the protective tube to colonize new sites.Hammer p.55 Each motile mature cell has an intertwined bundle of

flagella A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates. A microorganism may have f ...

appearing as a single flagellum consisting of a long filament with a short hook and a basal body complex, but it is distinguishable by electron microscope as 10 to 30 strands with diameters of 12.5 to 16 nm each. ''S. natans'' stores reserves of poly- ''beta'' -hydroxybutyrate as internal globules making up 30 to 40% of the dry weight of a colony. Gram and Neisser staining reactions are negative.

Habitat

''S. natans'' requires dissolved simple

sugar Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose, fructose, and galactose. Compound sugars, also called disaccharides or double ...

s or

organic acid An organic acid is an organic compound with acidic properties. The most common organic acids are the carboxylic acids, whose acidity is associated with their carboxyl group –COOH. Sulfonic acids, containing the group –SO2OH, are rel ...

s as a food supply, but needs less phosphorus than many competing organisms and can tolerate low oxygen concentrations. Capability to deposit elemental

sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...

intracellularly in the presence of

hydrogen sulfide Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. The unde ...

is believed to be a detoxifying mechanism. ''S. natans'' requires either cobalamin or

methionine Methionine (symbol Met or M) () is an essential amino acid in humans. As the precursor of other amino acids such as cysteine and taurine, versatile compounds such as SAM-e, and the important antioxidant glutathione, methionine plays a critical ro ...

as a trace nutrient. ''S. natans'' filaments can aid development of a periphyton biofilm trapping suspended particles and stabilizing colonies of other organisms including '' Klebsiella'' and '' Pseudomonas''.

Significance

''Sphaerotilus natans'' is often associated with a buoyant floc (or "bulking sludge") causing poor solids separation in activated sludge clarifiers of secondary sewage treatment. Metal surfaces covered with ''S. natans'' may experience accelerated corrosion if the slime creates a barrier causing differential oxygen concentrations.Betz pp.288&289 ''S. natans'' slimes may reduce quality of paper produced by

paper mill A paper mill is a factory devoted to making paper from vegetable fibres such as wood pulp, old rags, and other ingredients. Prior to the invention and adoption of the Fourdrinier machine and other types of paper machine that use an endless belt, ...

s using recycled water streams.

References

External links

Type strain of ''Sphaerotilus natans'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
{{Taxonbar, from=Q290696 Aquatic ecology Gram-negative bacteria Comamonadaceae Water pollution

Morphology

Habitat

Significance

References

Further reading

External links