Levan polysaccharide

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Levan polysaccharide
Names
Other names
Polyfructose
Identifiers
ChEBI
ChemSpider
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Levan in the linear form with beta 2,6 glycosidic linkages.
Levan in the branched from with beta 2,1 glycosidic linkages.

Levan is a naturally occurring fructan present in many plants and microorganisms.[1] This polymer is made up of fructose, a monosaccharide sugar, connected by 2,6 beta glycosidic linkages. Levan can have both branched and linear structures of relatively low molecular weight.[2] Branched levan forms a very small, sphere-like structure[3] with basal chains 9 units long. The 2,1 branching allows methyl ethers to form and create a spherical shape. The ends of levan also tend to contain a glucosyl residue.[4] Branched levan tends to be more stable than linear polysaccharides.[5] However, the amount of branching and length of polymerization tends to vary among different species.[4] The shortest levan is 6-kestose, a chain of two fructose molecules and a terminal glucose molecule.

Discovery

Levan was first discovered through research on

polarized light
.

Production

Levan is synthesized in

fructosyltransferase in the vacuole which creates the beta 2,6 linkages to form the linear form of levan.[5] Bacteria also use a fructosyltransferase known as levansucrase to form levan.[5] These enzymes in bacteria form the 2,1 linkages in the linear basal chains of levan to allow for branching points to occur.[5] Many bacteria produce levan in the cell exterior.[5] This production can be sensitive to temperature, oxygen concentration, pH, and other factors.[5] Levan production in bacteria is typically a sign of growth in population.[5] There are also possible ways to produce by fracturing soybean mucilage.[citation needed
]

Levans are produced by microbes during colonization of a food

exopolysaccharides).[8]

Properties

The beta 2,6 linkages of levan allow for it to be soluble in both water and oil; however, the water temperature varies the degree of solubility.[9] Levan also is insoluble in many organic solvents such as methanol, ethanol, and isopropanol.[4] The branching of levan allows it to have a high tensile and cohesive strength, while the hydroxyl groups contribute to adhesion with other molecules.[4] The intrinsic viscosity n, a measure of the substance effect on viscosity of a solution, tends to be very low for levan.[4] This allows levan to be utilized in a pharmaceutical setting.

Real world implications

Many industries such as

eye irritation, has not shown any allergenic effects, and poses no threat of cytotoxicity.[10]

Food

In the food industry, levan is incorporated due to its

cholesterol lowering ability, and adhesive properties.[4] It also occurs naturally in low amounts in food for human consumption.[4] Levan is also included in many dairy products as fiber or sweetener.[4] Commercial, non-alcoholic beverages use levan as well in ultra-high-fructose-syrups.[11] Interestingly, levan causes useful bacterial growth and proliferation which can be especially important in the gut because it causes a decrease in population of the pathogenic bacteria.[12]

Cosmetics

Levan can be used for

melanogenesis.[5]

Medicine

Levan has shown uses for burned tissue,

phagocytic removal.[15] Levan produced by Pantoea agglomerans ZMR7 was reported to decrease the viability of rhabdomyosarcoma (RD) and breast cancer (MDA) cells compared with untreated cancer cells. In addition, it has high antiparasitic activity against the promastigote of Leishmania tropica[16]

See also

References

  1. PMID 25624035
    , retrieved 2020-05-10
  2. ISSN 1542-6238
    .
  3. ISSN 0144-8617
    .
  4. ^
    PMID 25662693
    .
  5. ^
    PMID 27178733
    .
  6. ISSN 0365-9496
    .
  7. PMID 22672649
    .
  8. S2CID 132210454
    .
  9. PMC 3747740
    .
  10. ^ "Montana Polysaccharides Corp". www.polysaccharides.us. Retrieved 2019-05-15.
  11. PMID 11518326
    .
  12. PMID 12753971
    .
  13. ISSN 1300-3070
    .
  14. ISBN 9783319967998
  15. PMID 17158064
    .
  16. PMID 33820887
    .
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