Lactococcus lactis

Lactococcus lactis
Scientific classification
Kingdom: Bacteria Phylum: Firmicutes Class: Bacilli Order: Lactobacillales Family: Streptococcaceae Genus: Lactococcus Species: L.lactis
Binomial name
Lactococcus lactis

Description and significance

"Lactococcus Lactis" is a non pathogenic,Gram-positive bacteria known as one of the most important microbes in dairy food production. Lactococci lactis, which is closely related to the strptococcus genus, has two subspecies,L. lactis subsp. and Lactococcus cremoris subsp. They are used to make soft and hard cheese respectively. L.Lactis group in pairs or short chains with a length of about 1.2µm by 1.5µm. Lactococci are immotile, nonsporelating, and are usually spherical or ovoid cells. L. Lactis is the starter culture for the production of fermented dairy products such as milk, cheese, yogurt, etc.Lactococcus is considered a opurtunistic pathogen, because of its ability to convert almost all it's sugar into lactic acid. Lactic acid produced by the the microbe curdles the milk which seperates into curds inturn are used to produce cheese and whey.In nature, L. lactis is found to be inactive on plant surfaces and on to multiply in the gastrointestinal tract after being swallowed by an animal.

Genome structure

 L. lactis genome has been sequenced  to investigate its essential role in dairy fermentation. Unexpected features of the analyzed genome have been disclosed such as genes that suggest the bacterium can perform aerobic respiration and can undergo horizontal gene transmission by the process of transformation. The continued research unveils the characteristics of L.lactis that can be manipulated, in particular those that can improve the flavor, texture, and preservation of 10 million tons of cheese produced annually. Knowledge of the genome sequence will also facilitate current and future work that aims to exploit Lactococcus lactis for a variety of medical and health maintenance applications.
  L. lactis  is a circular chromosome, its genome contains 2,365,589 base pairs. Protein-coding genes represent 86% of the genome, stable RNA 1.4%, and noncoding regions 12.6%. These percentages are very similar to other bacteria genome. Biological functions have been assigned to 64% of the genome, 20.1% have similar genome to other unknown proteins, however, 15% of the genome is unidentifiable. This 15% is hypothesized to contain the traits specific to L.lactis.

References

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