''Pediococcus damnosus'' is a species of Gram-positive

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

. The genus ''Pediococcus'' is a spherical cocci shaped bacteria with nonmotile, non spore-forming and homofermentative properties. ''P. damnosus'' is a chemo-organotrophic, catalase negative, facultative anaerobe. Strains of this species frequently grow in wine and beer, where they overproduce

glucan A glucan is a polysaccharide derived from D-glucose, linked by glycosidic bonds. Glucans are noted in two forms: alpha glucans and beta glucans. Many beta-glucans are medically important. They represent a drug target for antifungal medications of ...

and spoil products by increasing their

viscosity The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the inte ...

. ''P. damnosus'' is a lactic acid bacteria (LAB), that can tolerate the low pH and higher ethanol levels that are found in beer. The ability to grow in beer is a strain specific characteristic of the species ''P. damnosus''.Behr, Jürgen, et al
"The Identification of Novel Diagnostic Marker Genes for the Detection of Beer Spoiling ''Pediococcus damnosus'' Strains Using the BlAst Diagnostic Gene FindEr"
''PLOS ONE''. ''Pediococcus damnosus LMG 28219'' is a lactic acid bacterium that has proved to be capable of growing in beer.

Characteristics

Growth in wine

Increased viscosity in wines is known as ropiness. Ropiness is a common type of spoilage in wines. Ropy wines have an oily or slimy appearance and higher viscosity due to the production of extracellular polysaccharide glucan. Lactic acid bacteria do not often produce glucan and only a few strains of lactic acid bacteria have been reported to produce glucan. ''P. damnosus'' also produces acetic acid and biogenic amines. In alcohol fermentation the presence of acetic acid inhibits the fermentation of ethanol. Increased levels of biogenic amines are correlated to compounds in wine that are indicative of wine spoilage. At increased concentrations, biogenic amines have an enhanced level of toxicity, affecting the hygienic quality of wine.

Growth conditions for ''P. damnosus''

''P. damnosus'' has been reported to grow successfully on MRS (CECT 8) medium with 40% beer or wine added to the culture medium with a reported pH of 5.8 and incubated at 26 °C in an anaerobic chamber for 48+ hours. CECT 8 is a growth medium designed to support the growth of lactic acid bacteria. It was designed by de Man, Rogosa, and Sharpe in 1960.

Genome analysis

Spoilage identification of ''P. damnosus''

Identification of spoilage associated diacetyl in strains of ''P. damnosus'' can be used to determine the risk of spoilage in the brewery environment. Diacetyl is a plasmid encoded trait that can be identified through diagnostic marker genes (DMG). Diagnostic marker genes are used for the identification of different bacterial groups. BIAst Diagnostic Gene findEr (BADGE) is a tool used to predict DMG's in bacteria. It offers a straightforward procedure to

comparative genomics Comparative genomics is a field of biological research in which the genomic features of different organisms are compared. The genomic features may include the DNA sequence, genes, gene order, regulatory sequences, and other genomic structural lan ...

. BADGE is used to successfully identify a DMG called fabZ. fabZ is used to discriminate between strains of ''P. damnosus'' capable of growing in beer.

References

External links

Type strain of ''Pediococcus damnosus'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
Lactobacillaceae Bacteria described in 1904 {{lactobacilli-stub