''Oenococcus oeni'' (known as ''Leuconostoc oeni'' until 1995) is a Gram-positive bacterial species in the genus of ''

Oenococcus ''Oenococcus'' is a genus of gram-positive bacteria, placed within the family Lactobacillaceae. The only species in the genus was ''Oenococcus oeni'' (which was known as ''Leuconostoc oeni'' until 1995). In 2006, the species ''Oenococcus kitahar ...

''. It was the only species in the genus until 2006, when the species ''

Oenococcus kitaharae ''Oenococcus'' is a genus of gram-positive bacteria, placed within the family Lactobacillaceae. The only species in the genus was ''Oenococcus oeni'' (which was known as ''Leuconostoc oeni'' until 1995). In 2006, the species '' Oenococcus kitaha ...

'' was identified. As its name implies, ''Oe. oeni'' holds major importance in the field of oenology, where it is the primary bacterium involved in completing the

malolactic fermentation Malolactic conversion (also known as malolactic fermentation or MLF) is a process in winemaking in which tart-tasting malic acid, naturally present in grape must, is converted to softer-tasting lactic acid. Malolactic fermentation is most often ...

.Kunkee, R. E. 1973. Malo-Lactic Fermentation and Winemaking. In, The Chemistry of Winemaking, Adv. Chem. Ser. 137, A. D. Webb, Ed. American Chemical Society. Washington DC.

Diacetyl

Diacetyl Diacetyl (IUPAC systematic name: butanedione or butane-2,3-dione) is an organic compound with the chemical formula (CH3CO)2. It is a yellow liquid with an intensely buttery flavor. It is a vicinal diketone (two C=O groups, side-by-side). Diacet ...

in wine is produced by

lactic acid bacteria Lactobacillales are an order of gram-positive, low-GC, acid-tolerant, generally nonsporulating, nonrespiring, either rod-shaped (bacilli) or spherical (cocci) bacteria that share common metabolic and physiological characteristics. These bacte ...

, mainly ''Oe. oeni''. In low levels, it can impart positive nutty or caramel characters, but at levels above 5 mg/L, it creates an intense buttery or

butterscotch Butterscotch is a type of confectionery whose primary ingredients are brown sugar and butter, but other ingredients are part of some recipes, such as corn syrup, cream, vanilla, and salt. The earliest known recipes, in mid-19th century Yorkshir ...

flavour, where it is perceived as a flaw. The sensory threshold for the compound can vary depending on the levels of certain wine components, such as sulfur dioxide. It can be produced as a metabolite of

citric acid Citric acid is an organic compound with the chemical formula HOC(CO2H)(CH2CO2H)2. It is a colorless weak organic acid. It occurs naturally in citrus fruits. In biochemistry, it is an intermediate in the citric acid cycle, which occurs in t ...

when all of the

malic acid Malic acid is an organic compound with the molecular formula . It is a dicarboxylic acid that is made by all living organisms, contributes to the sour taste of fruits, and is used as a food additive. Malic acid has two stereoisomeric forms ...

has been consumed. Diacetyl rarely taints wine to levels where it becomes undrinkable.Gibson, George; Farkas, Mik
Flaws and Faults in Wine
URL accessed on 12 March 2006.

References

External links

Type strain of ''Oenococcus oeni'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
Lactobacillaceae Bacteria described in 1995 {{Lactobacilli-stub