Structure and Physiology of Oenococcus oeni

    Oenococcus oeni is a gram-positive, rod-shaped

bacteria used in the secondary fermentation of wine.

Both its structure and physiology contribute to how

it adapts and functions in its environment.

    Structure

    The structure of O. oeni  is relatively basic.

The bacteria is in the Oenococcus family.

That alone tells us a few important things:

1.     The bacteria is gram-positive.
2.     The bacteria does not form endospores.
3.     The bacteria is round or elongated.
4.     The bacteria is anaerobic.

In this case, Oenocooccus oeni is gram-positive,

doesn't form spores, is elongated(rod-shaped), and

is a facultative anaerobe, meaning it survives with or

without oxygen. The fact that it is a facultative anaerobe

helps it to survive in the newly fermented wine, which

has a relatively low amount of oxygen. Being that it also

can survive with oxygen, O. oeni can continue to survive

as the wine gains oxygen over time. It varies whether

this bacteria has a flagella or not, but if it were to have

one, the overall structure would be something like this:

(6)

Gram-positive bacteria have a thick outer cell wall

made out of peptidoglycan, and a thin inner membrane

made of a lipid bilayer. On the outside are the flagella,

the pilli and the capsule. The inside is just as simple;

it contains genetic material, ribosomes, plasmid, and

cytoplasm.

    Physiology

    The physiology of this bacteria really makes it most

beneficial to humans. It has the ability to survive in lower

pH(high acidity) environments, such as newly fermented

wine, unlike many lactic acid bacteria(LAB). This ability

makes it a prime choice for wine-makers to use as a

converter of malic acid to lactic acid. How  this

conversion works is extremely complex, and is

near impossible to explain in simple terms.

The most basic way to explain this process is to

say that it takes in malic acid in its surroundings (the wine)

and puts out lactic acid, which has a lower pH than malic

acid. This gives the wine a more full, smooth flavor and

texture.

    Unfortunately, we were unable to find any information

about reproduction in Oenococcus oeni besides the fact

that it does not use endospores to reproduce. However,

we are assuming, based on our research, that this

bacteria reproduces asexually.

    The bacteria Oenococcus oeni's structure and physiology

greatly contribute to how beneficial it is to humans through

the improvement of wine quality.