Sphingomonas
Encyclopedia
Sphingomonas was defined in 1990 as a group of Gram-negative
, rod-shaped, chemoheterotrophic, strictly aerobic
bacteria. They possess ubiquinone 10 as their major respiratory quinone
, contain glycosphingolipids (GSLs) instead of lipopolysaccharide
in their cell envelopes, and typically produce yellow-pigmented colonies.
By 2001, the genus included more than 20 species that were quite diverse in terms of their phylogenetic, ecological, and physiological properties. As a result, the Sphingomonas were subdivided into four genera: Sphingomonas, Sphingobium
, Novosphingobium
, and Sphingopyxis
.
These genera are commonly referred to collectively as sphingomonads. The sphingomonads are widely distributed in nature, having been isolated from many different land and water habitats, as well as from plant root systems, clinical specimens, and other sources.
Some of the sphingomonads (especially Sphingomonas paucimobilis) also play a role in human disease, primarily by causing a range of mostly nosocomial, non-life-threatening infection
s that typically are easily treated by antibiotic
therapy. Due to their biodegradative and biosynthetic capabilities, sphingomonads have been utilised for a wide range of biotechnological applications, from bioremediation of environmental contaminants to production of extracellular polymers such as sphingans (e.g., gellan
, welan, and rhamsan) used extensively in the food and other industries. One strain, Sphingomonas sp. 2MPII, can degrade
2-methylphenanthrene
In May 2008, Daniel Burd, a 16-year-old Canadian, won the Canada-Wide Science Fair
in Ottawa after discovering that Sphingomonas can degrade over 40% of the weight of plastic bags (Polyethylene
) in less than three months.
A Sphingomonas sp. strain BSAR-1 expressing a high activity alkaline phosphatase (PhoK) has also been applied for bioprecipitation of uranium from alkaline solutions. The precipitation ability was enhanced by overexpressing PhoK protein in E. coli. This is the first report of bioprecipitation of uranium under alkaline conditions, adding another feather in the cap of the Sphingomonads.
Gram-negative
Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...
, rod-shaped, chemoheterotrophic, strictly aerobic
Aerobic organism
An aerobic organism or aerobe is an organism that can survive and grow in an oxygenated environment.Faculitative anaerobes grow and survive in an oxygenated environment and so do aerotolerant anaerobes.-Glucose:...
bacteria. They possess ubiquinone 10 as their major respiratory quinone
Quinone
A quinone is a class of organic compounds that are formally "derived from aromatic compounds [such as benzene or naphthalene] by conversion of an even number of –CH= groups into –C– groups with any necessary rearrangement of double bonds," resulting in "a fully conjugated cyclic dione structure."...
, contain glycosphingolipids (GSLs) instead of lipopolysaccharide
Lipopolysaccharide
Lipopolysaccharides , also known as lipoglycans, are large molecules consisting of a lipid and a polysaccharide joined by a covalent bond; they are found in the outer membrane of Gram-negative bacteria, act as endotoxins and elicit strong immune responses in animals.-Functions:LPS is the major...
in their cell envelopes, and typically produce yellow-pigmented colonies.
By 2001, the genus included more than 20 species that were quite diverse in terms of their phylogenetic, ecological, and physiological properties. As a result, the Sphingomonas were subdivided into four genera: Sphingomonas, Sphingobium
Sphingobium
Sphingobium species are different from other sphingomonads in that they are commonly isolated from soil, however Sphingobium yanoikuyae was isolated from a clinical specimen...
, Novosphingobium
Novosphingobium
Novosphingobium is a genus of Gram-negative bacteria that includes N. taihuense, which can degrade aromatic compounds such as phenol, aniline, nitrobenzene and phenanthrene. The species N. aromativorans, which was first found in Ulsan Bay, similarly degrades aromatic molecules of two to five rings....
, and Sphingopyxis
Sphingopyxis
Sphingomonas is one of the four genera of sphingomonads.Sphingomonas alaskensis and S. flavimarisis are the dominant bacteria in some marine oligotrophic environments. S. chilensis degrades chlorophenol. S. macrogoltabida and S. terrae degrade polyethylene glycol, and S. witflariensis was isolated...
.
These genera are commonly referred to collectively as sphingomonads. The sphingomonads are widely distributed in nature, having been isolated from many different land and water habitats, as well as from plant root systems, clinical specimens, and other sources.
Some of the sphingomonads (especially Sphingomonas paucimobilis) also play a role in human disease, primarily by causing a range of mostly nosocomial, non-life-threatening infection
Infection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
s that typically are easily treated by antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
therapy. Due to their biodegradative and biosynthetic capabilities, sphingomonads have been utilised for a wide range of biotechnological applications, from bioremediation of environmental contaminants to production of extracellular polymers such as sphingans (e.g., gellan
Gellan gum
Gellan gum is a water-soluble polysaccharide produced by Pseudomonas elodea, a bacterium.-Chemical structure:The repeating unit of the polymer is a tetrasaccharide, which consists of two residues of D-glucose and one of each residues of L-rhamnose and D-glucuronic acid...
, welan, and rhamsan) used extensively in the food and other industries. One strain, Sphingomonas sp. 2MPII, can degrade
Biodegradation
Biodegradation or biotic degradation or biotic decomposition is the chemical dissolution of materials by bacteria or other biological means...
2-methylphenanthrene
Phenanthrene
Phenanthrene is a polycyclic aromatic hydrocarbon composed of three fused benzene rings. The name phenanthrene is a composite of phenyl and anthracene. In its pure form, it is found in cigarette smoke and is a known irritant, photosensitizing skin to light...
In May 2008, Daniel Burd, a 16-year-old Canadian, won the Canada-Wide Science Fair
Canada-Wide Science Fair
The Canada-Wide Science Fair is an annual science fair in Canada coordinated by . Started in 1962, it is the highest level of competition in Canada, and approximately 400 projects and 500 students are judged at the fair...
in Ottawa after discovering that Sphingomonas can degrade over 40% of the weight of plastic bags (Polyethylene
Polyethylene
Polyethylene or polythene is the most widely used plastic, with an annual production of approximately 80 million metric tons...
) in less than three months.
A Sphingomonas sp. strain BSAR-1 expressing a high activity alkaline phosphatase (PhoK) has also been applied for bioprecipitation of uranium from alkaline solutions. The precipitation ability was enhanced by overexpressing PhoK protein in E. coli. This is the first report of bioprecipitation of uranium under alkaline conditions, adding another feather in the cap of the Sphingomonads.
External links
- Article describing the discovery of Sphingomonas as a biodegrader of plastic bags Kawawada, Karen, The Record (May 22 2008).