What is the Difference Between Lactobacillus and Bifidobacterium?

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Lactobacillus and Bifidobacterium are both genera of probiotic bacteria that are commonly found in the human gastrointestinal and urogenital tracts and have important roles in promoting good health. They share some common properties, such as being Gram-positive, non-spore-forming, and lactic acid-producing bacteria (LAPB). However, there are also differences between the two:

  1. Metabolism: Lactobacilli have limited biosynthetic abilities and ferment refined sugars, generating lactic acid as the major end product. Bifidobacteria, on the other hand, are important producers of short-chain fatty acids (SCFA).
  2. Taxonomy: Lactobacilli belong to the genus Lactobacillus in the phylum Firmicutes, while Bifidobacteria belong to the genus Bifidobacterium in the phylum Actinobacteria.
  3. Population: In adults, Firmicutes and Bacteroidetes phyla usually dominate the intestinal microbiota, whereas Actinobacteria, Proteobacteria, and Verrucomicrobia are considerably less abundant. However, in naturally delivered, breast-fed infants, Bifidobacteria (Actinobacteria) make up a significant portion of the intestinal microbiota.
  4. Application: Lactobacilli have been used to make dairy products like cheese and yogurt due to their high tolerance for low pH conditions, which allows them to travel through the gastrointestinal tract and survive the abrupt pH changes. Bifidobacteria reside in the gastrointestinal tract, vagina, and mouth of mammals, making up 25% of adult fecal bacteria and 80% in infants.

Despite these differences, both Lactobacillus and Bifidobacterium are known for their probiotic properties and have been used therapeutically to promote a healthy digestive tract and support vaginal health.

Comparative Table: Lactobacillus vs Bifidobacterium

Here is a table comparing the differences between Lactobacillus and Bifidobacterium:

Feature Lactobacillus Bifidobacterium
Classification Facultative anaerobic bacterial species Obligate anaerobic bacterial species
Metabolism Majority of species involve in homofermentative metabolism, and a minority of species involve in heterofermentative metabolisms Non-motile, gram-positive, rod-shaped (branched) bacterium
Microbiota Belongs to the genus Lactobacillus in the phylum Firmicutes Belongs to the genus Bifidobacterium in the phylum Actinobacteria
Fermentation Ferments refined sugars, generating lactic acid as the major end product Produces short chain fatty acids (SCFA)

Both Lactobacillus and Bifidobacterium are non-spore-forming, gram-positive, lactic acid producing bacteria (LAPB). They are important parts of the normal intestinal microbiota of various mammalian species and are recognized as probiotics, providing health benefits to the host.