Everything about Lactobaccillus totally explained
Lactobacillus is a
genus of
Gram-positive facultative anaerobic or
microaerophilic bacteria. They are a major part of the
lactic acid bacteria group, named as such because most of its members convert
lactose and other
sugars to
lactic acid. They are common and usually benign. In humans they're present in the
vagina and the
gastrointestinal tract, where they're
symbiotic and make up a small portion of the
gut flora. Many species are prominent in decaying plant material. The production of lactic acid makes its environment acidic which inhibits the growth of some harmful bacteria. Several members of the genus have had their
genome sequenced.
Food production
Some
Lactobacillus species are used industrially for the production of
yogurt,
cheese,
sauerkraut,
pickles,
beer,
wine,
cider,
kimchi,
chocolate and other
fermented foods, as well as animal feeds, such as
silage.
Sourdough bread is made using a "starter culture" which is a symbiotic culture of
yeast and
lactic acid bacteria growing in a
water and
flour medium. Lactobacilli, especially
L. casei and
L. brevis, are some of the most common beer spoilage organisms.
The species operate by lowering the pH of the fermenting substance by creating the lactic acid, neutralising it to the desired extent.
Taxonomy
The genus
Lactobacillus currently consists of over 125 species and encompasses a wide variety of organisms. The genus is
polyphyletic, with the genus
Pediococcus dividing the
L. casei group, and the species
L. acidophilus,
L. salivarius, and
L. reuteri being representatives of three distinct subclades. The genus
Paralactobacillus falls within the
L. salivarius group. In recent years, other members of the genus
Lactobacillus (formerly known as the Leuconostoc branch of Lactobacillus) have been reclassified into the genera
Atopobium,
Carnobacterium,
Weissella,
Oenococcus, and
Leuconostoc.
Dental cavities
Although considered beneficial, some
Lactobacillus species have been associated with
dental caries.
(External Link
) Lactobacillus count in saliva has been used as a "caries test" for many years.
(External Link) This is one of the arguments used in support of the use of
fluoride in
toothpaste and
lozenges.
(External Link)
Metabolism
Many lactobacilli are unusual in that they operate using homofermentative metabolism (that is, they produce only lactic acid from sugars) and are aerotolerant despite the complete absence of a respiratory chain. This aerotolerance is
manganese-dependent and has been explored (and explained) in
Lactobacillus plantarum. Many lactobacilli don't require
iron for growth and have an extremely high
hydrogen peroxide tolerance.
According to metabolism,
Lactobacillus species can be divided into three groups:
- Obligately homofermentative (Group I)
- Facultatively heterofermentative (Group II)
- Obligately heterofermentative (Group III)
Further Information
Get more info on 'Lactobaccillus'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://lactobacillus.totallyexplained.com">Lactobacillus Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |
