{{Chembox <!-- Images --> | ImageFile = Alternan.png | ImageSize = | ImageAlt = <!-- Names --> | IUPACName = | OtherNames = <!-- Sections --> | Section1 = {{Chembox Identifiers | CASNo = 136510-13-9 | PubChem = <!-- 102416773 fragment of alternan --> | SMILES = }} | Section2 = {{Chembox Properties | Formula = (C<sub>6</sub>H<sub>10</sub>O<sub>5</sub>)<sub>n</sub> | MolarMass = | Appearance = | Density = | MeltingPt = | BoilingPt = | Solubility = Highly soluble }} | Section3 = {{Chembox Hazards | MainHazards = | FlashPt = | AutoignitionPt = }} }}
'''Alternan''' is a branched α-d-glucan produced by microorganisms. This polymer was first discovered in the bacterium ''Leuconostoc mesenteroides'', which has since been genetically engineered to produce alternan. They genetically engineered the genes for alternansucrase, the enzyme that produces alternan, to get a pure sample. This gene of the enzyme alternansucrase had also been genetically engineered into ''E. coli.''<ref name=":0" />
This compound is highly soluble in water and has a low viscosity. These characteristics make it a prime candidate to use in the food and cosmetic industries.
== Biosynthesis == Alternan is an exopolysaccharide generated from the glucose monosaccharides of sucrose by the enzyme alternansucrase.<ref name=":0">{{Cite book |url=https://linkinghub.elsevier.com/retrieve/pii/C20180042450 |title=Handbook of Hydrocolloids |date=2021 |publisher=Elsevier |isbn=978-0-12-820104-6 |doi=10.1016/c2018-0-04245-0}}</ref> The polysaccharide is assembled with α-(1→6) and α-(1→3) glycosidic bonds.<ref>{{Cite journal |last=Leathers |first=Timothy D. |last2=Nunnally |first2=Melinda S. |last3=Côté |first3=Gregory L. |date=2010-07-07 |title=Optimization of process conditions for enzymatic modification of alternan using dextranase from Chaetomium erraticum |url=https://linkinghub.elsevier.com/retrieve/pii/S0144861710002006 |journal=Carbohydrate Polymers |volume=81 |issue=3 |pages=732–736 |doi=10.1016/j.carbpol.2010.03.030 |issn=0144-8617|url-access=subscription }}</ref> Alternansucrase was initially found in ''Leuconostoc mesenteroides'', a bacterial species used in the dairy industry.<ref>{{Citation |last=Hassan |first=A. N. |title=MICROORGANISMS ASSOCIATED WITH MILK |date=2011-01-01 |work=Encyclopedia of Dairy Sciences (Second Edition) |pages=447–457 |editor-last=Fuquay |editor-first=John W. |url=https://linkinghub.elsevier.com/retrieve/pii/B9780123744074003095 |access-date=2024-10-04 |place=San Diego |publisher=Academic Press |doi=10.1016/b978-0-12-374407-4.00309-5 |isbn=978-0-12-374407-4 |last2=Frank |first2=J. F.|url-access=subscription }}</ref> ''L. mesenteroides'' is a gram positive bacterium that performs fermentation. During fermentation the bacterium produces a very high amount of alternan and dextran, requiring a medium containing sucrose, nitrogen, glutamate, thiamine, and valine. The alternan is then extracted from the fermentation product through centrifugation or filtration.
==Industrial use== Alternan has numerous industrial uses. One of the valuable uses is in food production as an essential component of the sweetener sucromalt, also known as Xtend, which is commonly used in diabetic foods due to its low glycemic index.<ref name=":2">{{cite web |title=Xtend ® Sucromalt |url=https://www.cargill.com/food-bev/na/xtend-sucromalt |website=Cargill |publisher=Cargill Incorporated |access-date=23 October 2024}}</ref><ref name=":1">{{cite web |last1=Rich |first1=Joseph |title=Lactic Acid Bateria - Friend or Foe? Lactic Acid Bacteria in the Production of Polysaccharides and Fuel Ethanol |url=https://www.ars.usda.gov/research/publications/publication/?seqNo115=240820 |website=Agricultural Research Service U.S. DEPARTMENT OF AGRICULTURE |publisher=US Government |access-date=3 October 2024}}</ref> Alternan can also be used to add texture to food or cosmetics in place of fat or oil.<ref>{{Cite web |title=Unified Patents - Analytics Portal |url=https://portal.unifiedpatents.com/patents/patent/WO-2009109407-A3 |access-date=2024-10-07 |website=portal.unifiedpatents.com}}</ref>
Alternan has shown potential as a bulking agent as it has a low viscosity and high solubility. These properties are shared with other commonly used food extenders and binders.<ref>{{Cite web |title=Publication : USDA ARS |url=https://www.ars.usda.gov/research/publications/publication/?seqNo115=248634 |access-date=2024-10-23 |website=www.ars.usda.gov}}</ref> Few microorganisms have the ability to break down alternan, it is also able to retain its structure and properties when exposed to heat, making it a strong candidate to improve shelf-life of food products.<ref>{{Cite book |last=Wyckoff |first=Herbert A |title=Chemistry of novel foods |last2=Hayman |first2=G. Thomas |last3=Biely |first3=Peter |publisher=Allured Publishing Corporation |year=1997 |location=IL, USA |pages=95–110 |chapter=Low-viscosity polysaccharides as potential new food ingredients}}</ref>
== Future Applications == Alternan has shown promising applications in stem cell research. When treating mesenchymal stem cells (MSC) with alternan they showed increased proliferation and viability. Alternan stimulated toll-like receptors in the MSC that are important in differentiation of the cell as well as increased migration abilities of the MSC. Alternan could be a beneficial additive to stem cell therapies to improve outcomes.<ref>{{Cite journal |last=Charoenwongpaiboon |first=Thanapon |last2=Supraditaporn |first2=Kantpitchar |last3=Klaimon |first3=Phatchanat |last4=Wangpaiboon |first4=Karan |last5=Pichyangkura |first5=Rath |last6=Issaragrisil |first6=Surapol |last7=Lorthongpanich |first7=Chanchao |date=2019-01-30 |title=Effect of alternan versus chitosan on the biological properties of human mesenchymal stem cells |url=https://pubs.rsc.org/en/content/articlelanding/2019/ra/c8ra10263e |journal=RSC Advances |language=en |volume=9 |issue=8 |pages=4370–4379 |doi=10.1039/C8RA10263E |issn=2046-2069|pmc=9060545 }}</ref>
== References == {{reflist}}
*
Category:Wikipedia Student Program Category:Polysaccharides