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Importing Wikidata short description: "Genus of Cyanobacteria" (Shortdesc helper) |
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{{
{{Automatic taxobox
| image = SingleSpirulinaInMicroscope4WEB.jpg
| image_caption = A single ''Arthrospira platensis'' colony
| taxon = Arthrospira
| authority = Sitzenberger ex Gomont, 1892
| subdivision_ranks = Species
| subdivision = About 35.
*''[[Arthrospira ardissonei]]''
*''[[Arthrospira erdosensis]]''
*''[[Arthrospira fusiformis]]''
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*''[[Arthrospira platensis]]''
}}
[[File:Spira400xwetcr.jpg|300px|thumbnail|Spirulina powder
'''''Arthrospira''''' is a genus of free-floating filamentous [[cyanobacteria]] characterized by [[Cylinder (geometry)|cylindrical]], multicellular [[trichome]]s in an open left-hand [[helix]]. A [[dietary supplement]] is made from ''A. platensis'' and ''A. maxima'', known as [[Spirulina (dietary supplement)|spirulina]].<ref name="ciferri">{{Cite journal
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| pmc = 283708
| doi = 10.1128/MMBR.47.4.551-578.1983
}}</ref> The ''A. maxima'' and ''A. platensis'' species were once classified in the genus [[Spirulina (genus)|''Spirulina'']]. Although the introduction of the two separate genera
| last = Mühling
| first = Martin
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| url = http://etheses.dur.ac.uk/1198/
| access-date = 2016-01-23
|
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| url-status = live
| df = ymd
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==Taxonomy==
The common name, [[Spirulina (dietary supplement)|spirulina]], refers to the dried biomass of ''
At {{cite journal
| title = Genomic Structure of an Economically Important Cyanobacterium, ''Arthrospira'' (''Spirulina'') platensis NIES-39
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| author22 = Nobuyuki Fujita
| author23 = Masayuki Ohmori
|
| pmc = 2853384
| date = 2010-03-04
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| volume=17
| issue = 2
| journal=DNA
| pages=85–103
}} In its turn, it references:
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| year = 2007
| pages = 542–3
}}</ref> A 2019 analysis of ''Arthrospira'' species using [[16S ribosomal RNA|16S rRNA gene sequence]] suggests that certain species of this genus (''A.'' ''jenneri'') is much closer to ''[[Planktothrix]]'' [[Cladistics|clade]] than previously thought. It also lacks characteristics of mass produced species (such as preference of alkaline habitats). As a result, researchers proposed a new genus closer to ''Limnoraphis and Neolyngbya'' called '''''Limnospira''' comprising [[L. fusiformis]], [[Arthrospira maxima|L. maxima]]'' and ''[[Arthrospira indica|L. indica]]''.<ref>{{Cite journal |last=Nowicka-Krawczyk |first=Paulina |last2=Mühlsteinová |first2=Radka |last3=Hauer |first3=Tomáš |date=2019-01-24 |title=Detailed characterization of the Arthrospira type species separating commercially grown taxa into the new genus Limnospira (Cyanobacteria) |url=https://www.nature.com/articles/s41598-018-36831-0 |journal=Scientific Reports |language=en |volume=9 |issue=1 |pages=694 |doi=10.1038/s41598-018-36831-0 |issn=2045-2322 |pmc=6345927 |pmid=30679537}}</ref>
==Morphology==
The genus ''Arthrospira'' comprises helical [[Trichome|trichomes]] of varying size and with various degrees of coiling, including tightly
The helical parameters of the shape of ''Arthrospira'' is used to differentiate between and even within the same species.<ref>{{cite journal |last1=Rich |first1=F |title=Notes on ''Arthrospira platensis'' |journal=
▲journal|last1=Rich|first1=F|title=Notes on Arthrospira platensis|journal=Rev. Algol.|date=1931|volume=6|pages=75–79}}</ref><ref>{{cite journal|last1=Marty|first1=F|last2=Busson|first2=F|title=Données cytologiques sur deux Cyanophycées:Spirulina platensis (Gom.) Geitler et Spirulina geitleri J. de Toni|journal=Schweizerische Zeitschritf für Hydrologie|date=1970|volume=32|issue=2|pages=559–565|doi=10.1007/bf02502570}}</ref> These differences may be induced by changing environmental conditions, such as the growth temperature.<ref>{{cite journal|last1=Van Eykelenburg|first1=C|title=On the morphology and ultrastructure of the cell wall of Spirulina platensis|journal=Antonie van Leeuwenhoek|date=1977|volume=43|issue=2|pages=89–99|doi=10.1007/bf00395664|pmid=413479}}</ref> The helical shape of the trichomes is only maintained in a liquid environment.<ref name="ReferenceB">{{cite book|author=FAO Report|title=A review on culture, production and use of spirulina as food for humans and feeds for domestic animals and fish|date=2008|publisher=Food and agriculture organization of the united nations|location=Rome}}</ref> The filaments are solitary and reproduce by binary fission, and the cells of the trichomes vary from 2 to 12 μm and can sometimes reach 16 μm.
==Biochemical composition==
{{Further|Spirulina (dietary supplement)}}
''Arthrospira'' is very rich in [[protein]]s
Its protein harbours all [[Essential amino acid|essential amino acids]].<ref name="
==Occurrence==
Species of the genus ''Arthrospira'' have been isolated from alkaline [[Brackish water|brackish]] and [[Saline water|saline waters]] in tropical and subtropical regions. Among the various species included in the genus,'' A. platensis'' is the most widely distributed and is mainly found in Africa, but also in Asia. ''A. maxima'' is believed to be found in California and Mexico.<ref name=":0"/> ''A. platensis'' and ''A. maxima'' occur naturally in tropical and subtropical lakes with alkaline [[pH]] and high concentrations of [[carbonate]] and [[bicarbonate]].<ref name="FAO Spirulina Review">{{cite web|title=A Review on Culture, Production and Use of Spirulina as Food dor Humans and Feeds for Domestic Animals and Fish|url=ftp://ftp.fao.org/docrep/fao/011/i0424e/i0424e00.pdf|publisher=Food and Agriculture Organization of The United Nations|
==Present and future uses==
Spirulina is widely known as a [[
==Cropping systems==
Growth of ''
In summer the main limiting factor of spirulina growth is light.
When growing in water depths of 12–15 cm, self-shading governs the growth of the individual cell.
However, research has shown, that growth is also photoinhibited, and can be increased through shading.<ref>{{cite book|last1=Vonshak|first1=A|last2=Guy|first2=R|title=Photoinhibition as a limiting factor in outdoor cultivation of Spirulina platensis. In Stadler et al. eds. Algal Biotechnology|date=1988|publisher=Elsevier Applied Sci. Publishers|location=London}}</ref> The level of photoinhibition versus the lack of light is always a question of cell concentration in the medium.
The optimal growth temperature for ''A. platensis'' is
One of the major hurdles for
==Cultivation systems==
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===Open pond===
Open pond systems are the most common way to grow ''A.
Another problem
===Closed system===
Closed systems have the advantage of being
==
Cultivation of
Especially as a small-scale crop, ''Arthrospira'' still has considerable potential for development, for example for nutritional improvement.<ref name="smart fish">{{cite journal|date=2011|title=Spirulina – a livelihood and a business venture|journal=Report: SF/2011|author=Smart Fish}}</ref> New countries where this could happen, should dispose of alkaline-rich ponds on high altitudes or saline-alkaline-rich groundwater or coastal areas with high temperature.<ref name="FAO Spirulina Review" /> Otherwise, technical inputs needed for new spirulina farms are quite basic.<ref name="smart fish" />
The international market of spirulina is divided into two target groups: the one includes NGO’s and institutions focusing on malnutrition and the other includes health conscious people. There are still some countries, especially in Africa, that produce at a local level. Those could respond to the international demand by increasing production and [[economies of scale]]. Growing the product in Africa could offer an advantage in price, due to low costs of labour. On the other hand, African countries would have to surpass quality standards from importing countries, which could again result in higher costs.<ref name="smart fish" />
== References ==
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== External links ==
* {{AlgaeBase genus|name=Arthrospira|id=
{{Taxonbar|from=Q987596}}
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