''Sphaerotilus natans'' is an aquatic

periphyton Periphyton is a complex mixture of algae, cyanobacteria, heterotrophic microbes, and detritus that is attached to submerged surfaces in most aquatic ecosystems. The related term Aufwuchs ( German "surface growth" or "overgrowth", ) refers to the ...

bacterial organism associated with polluted water. These tightly sheathed filamentous

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

colonies are commonly but inaccurately known as " sewage fungus"

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 SEPTA, the Southeastern Pennsylvania Transportation Authority, is a regional public transportation authority that operates bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly four million people througho ...

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 (; : flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores ( zoospores), and from a wide range of microorganisms to provide motility. Many pr ...

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 An electron microscope is a microscope that uses a beam of electrons as a source of illumination. It uses electron optics that are analogous to the glass lenses of an optical light microscope to control the electron beam, for instance focusing it ...

as 10 to 30 strands with diameters of 12.5 to 16 nm each. ''S. natans'' stores reserves of poly- ''beta'' -hydroxybutyrate as internal

bioplastic Bioplastics are plastic materials produced from renewable biomass sources. Timeline of plastic development, Historically, bioplastics made from natural materials like shellac or Celluloid, cellulose had been the first plastics. Since the end of ...

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 Glucose is a sugar with the Chemical formula#Molecular formula, molecul ...

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 re ...

s as a food supply, but needs less

phosphorus Phosphorus is a chemical element; it has Chemical symbol, symbol P and atomic number 15. All elemental forms of phosphorus are highly Reactivity (chemistry), reactive and are therefore never found in nature. They can nevertheless be prepared ar ...

than many competing organisms and can tolerate low

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

concentrations. Capability to deposit elemental

sulfur Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...

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 toxic, corrosive, and flammable. Trace amounts in ambient atmosphere have a characteristic foul odor of rotten eggs. Swedish chemist ...

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

cobalamin Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in metabolism. One of eight B vitamins, it serves as a vital cofactor (biochemistry), cofactor in DNA synthesis and both fatty acid metabolism, fatty acid and amino a ...

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

as a trace nutrient. ''S. natans'' filaments can aid development of a periphyton

biofilm A biofilm is a Syntrophy, syntrophic Microbial consortium, community of microorganisms in which cell (biology), cells cell adhesion, stick to each other and often also to a surface. These adherent cells become embedded within a slimy ext ...

trapping suspended particles and stabilizing colonies of other organisms including ''

Klebsiella ''Klebsiella'' is a genus of Gram-negative, oxidase-negative, rod-shaped bacteria with a prominent polysaccharide-based capsule. ''Klebsiella'' is named after German-Swiss microbiologist Edwin Klebs (1834–1913). Carl Friedlander described ' ...

'' and ''

Pseudomonas ''Pseudomonas'' is a genus of Gram-negative bacteria belonging to the family Pseudomonadaceae in the class Gammaproteobacteria. The 348 members of the genus demonstrate a great deal of metabolic diversity and consequently are able to colonize a ...

''. ''S. natans'' is described as a key taxon in sewage fungus, a polymicrobial

that proliferates in rivers with a high organic loading such as from sewage discharges, industrial effluents or runoff from airport de-icing. It is also implicated in active sludge bulking

Significance

''Sphaerotilus natans'' is often associated with a buoyant floc (or "bulking sludge") causing poor solids separation in

activated sludge The activated sludge process is a type of biological wastewater treatment process for treating sewage or Industrial wastewater treatment, industrial wastewaters using aeration and a biological floc (biofilm), floc composed of bacteria and protozoa ...

clarifier Clarifiers are settling tanks built with mechanical means for continuous removal of solids being deposited by Sedimentation (water treatment), sedimentation. A clarifier is generally used to remove solid particulates or suspended solids from li ...

s of secondary sewage treatment. Metal surfaces covered with ''S. natans'' may experience accelerated

corrosion Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engine ...

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 that use recycled water.

References

External links

Type strain of ''Sphaerotilus natans'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
{{Authority control Aquatic ecology Gram-negative bacteria Comamonadaceae Water pollution

Morphology

Habitat

Significance

References

Further reading

External links