Melibiose is a reducing disaccharide formed by an α-1,6 linkage between galactose and glucose (D-Gal-α(1→6)-D-Glc).[1][2] It differs from lactose in the chirality of the carbon where the galactose ring is closed and that the galactose is linked to a different point on the glucose moiety. It can be formed by invertase-mediated hydrolysis of raffinose, which produces melibiose and fructose. Melibiose can be broken down into its component saccharides, glucose and galactose, by the enzyme alpha-galactosidase, such as MEL1 from Saccharomyces pastorianus (lager yeast).

Melibiose structure.svg
IUPAC name
3D model (JSmol)
MeSH Melibiose
Molar mass 342.297 g·mol−1
Melting point 84–85 °C (183–185 °F; 357–358 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Melibiose cannot be used by Saccharomyces cerevisiae[3] (ale yeast), this is one test to differentiate between the two yeast species.


  1. ^ Thisbe K. Lindhorst (2007). Essentials of Carbohydrate Chemistry and Biochemistry (1 ed.). Wiley-VCH. ISBN 3527315284.
  2. ^ John F. Robyt (1997). Essentials of Carbohydrate Chemistry (1 ed.). Springer. ISBN 0387949518.
  3. ^ Bokulicha. Nicholas A. & Bamforth. Charles W. (1 June 2013). "The Microbiology of Malting and Brewing". American Society for Microbiology. pp. 157–172. Retrieved 2 May 2015.