Pediococcus damnosus

Genus/species (aliases): Pediococcus damnosus

Gram Stain: Positive


  • Cell: Spherical cells (0.3-0.6 mm in diameter) that form short chains or tetrads. Non-motile, do not form spores or capsules.
  • Colony:  Round colonies with cream coloring.
  • Liquid Growth: dispersed


Physiological Traits:

Pediococcus damnosus is a homofermentative organism and will metabolize glucose, sucrose, and galactose. Some strains of these bacteria will ferment maltose and sucrose.  Though these bacteria can only ferment sugars they are able to do so with equal success in the presence or absence of oxygen. Pediococci ferment glucose to dl-lactate via the Embden-Meyerhof-Parnas pathway. This particular species converts pyruvate to acetoin/diacetyl. Pediococci are unable to reduce nitrate, are nonproteolytic and catalase negative. P. Damnosus will not hyrdolize arginine, arabinose, xylose or lactose. This species is sensitive to temperature and pH as it is unable to grow at pH 8 or at 35 C. The optimum growth conditions are at 22 C and pH 5.5. P. Damnosus is also sensitive to environments that contain NaCl and will not exhibit growth at 4%.

Ecological Traits:

Pediococci are found in plant material, fruits and fermented foods.

Distinguishing Features:

  Species of Pediococci are often hard to distinguish from one another; however, some characteristics of P. Damnosus that can be used to identify the strain are the ability to produce diacetyl from pyruvate, the inability to grow in the presence of NaCl and the inability for the species to survive at higher pH levels. This species exhibits a lower optimum growth temperature of 22 C when compared to other Pediococci.

Role in wine: 

Often P. Damnosus is considered a spoilage bacteria in the wine making and brewing fields because of the production of diacetyl which leaves unwanted buttery off-flavors. Also causes unwanted viscosity in wine due to glucan synthesis.


  • SO2:
  • Sorbate­­­­­:
  • DMDC:
  • pH: x
  • Acids:
  • Ethanol:
  • Anaerobiosis:
  • Heat: x


Gindreau, E., et al. Direct polymerase chain reaction detection of ropy Pediococcus damnosus strains in wine.  Journal of Applied Microbiology. 2001 Apr: 90(4); 535-42.