What is the Difference Between Lactobacillus and Bifidobacterium

The main difference between Lactobacillus and Bifidobacterium is that Lactobacillus is a genus of rod-shaped, facultative anaerobic bacteria whereas Bifidobacterium is a genus of often branched anaerobic bacteria. Furthermore, Lactobacillus is a significant component of microbiota in the digestive, urinary, and genital system in humans while Bifidobacterium is the prominent, beneficial form of bacteria in the intestine in mammals. Moreover, Lactobacillus produces lactic acid, decreasing the pH and preventing the growth of bad bacteria while Bifidobacterium produces both lactic acid and acetic acid.  

Lactobacillus and Bifidobacterium are two important forms of the microbiota of the gastrointestinal tract. They are significant forms of probiotics. 

Key Areas Covered 

1. What is Lactobacillus
     – Definition, Features, Importance
2. What is Bifidobacterium
     – Definition, Features, Importance
3. What are the Similarities Between Lactobacillus and Bifidobacterium
     – Outline of Common Features
4. What is the Difference Between Lactobacillus and Bifidobacterium
     – Comparison of Key Differences

Key Terms 

Acetic Acid, Bifidobacterium, Gut Microbiota, Lactic Acid, Lactobacillus, Probiotics

Difference Between Lactobacillus and Bifidobacterium - Comparison Summary

What is Lactobacillus 

Lactobacillus is a genus of Gram-positive bacteria. It is a type of non-spore-forming bacteria that is rod-shaped. In addition, it is a type of facultative anaerobe that converts sugar into lactic acid. Generally, Lactobacillus belongs to the microbiota of mammals, occurring in the gastrointestinal tract and vaginal systems.

Difference Between Lactobacillus and Bifidobacterium

Figure 1: Lactobacillus  

Furthermore, Lactobacillus has probiotic characteristics. The main form of Lactobacillus with probiotic characteristics is Lactobacillus acidophilus. Therefore, it is commercially used in dairy products such as yogurts and cheese. However, by the production of lactic acid, they lower the pH, preventing the growth of bad bacteria in the gut. 

What is Bifidobacterium 

Bifidobacterium is the main form of microbiota in the gastrointestinal tract of mammals. It also occurs in the mouth and vagina of mammals. Moreover, it is a type of anaerobic bacteria that can convert carbohydrates into lactic acid, acetic acid, and short-chain fatty acids. This type of fermentation allows the digestion of indigestible forms of milk and plant carbohydrates.  Bifidobacterium cells have a branched shape. It also accounts for 25% of fecal bacteria in adults.

Main Difference - Lactobacillus vs Bifidobacterium

Figure 2: Bifidobacterium

Moreover, yogurts with Bifidobacterium is more potent than regular yogurts. Regular yogurts contain both Lactobacillus delbrueckii subsp. bulgaricus and another form of facultative anaerobe, Streptococcus thermophilus. Basically, Bifidobacterium in yogurts increases bowel movements. 

Similarities Between Lactobacillus and Bifidobacterium 

  • Lactobacillus and Bifidobacterium are two major genera of bacteria in the gut microbiota of mammals. 
  • They occur in the genital system as well. 
  • Both are Gram-positive, non-spore-forming, anaerobic bacteria that are rod-shaped. 
  • They are acid-producing bacteria that decrease the pH of the gut, preventing the growth of Gram-negative, bad bacteria. 
  • Both produce lactic acid. Also, they can produce short-chain fatty acids from carbohydrates. 
  • Moreover, they are probiotics, which strengthen the immune system, prevent diarrhea, lose weight, lower cholesterol, etc. 
  • Both have health-promoting and immunomodulatory properties. 
  • They are used in people with irritable bowel syndrome and ulcerative colitis while improving vaginal health. 
  • Furthermore, both are susceptible to antibiotics. 

Difference Between Lactobacillus and Bifidobacterium 


Lactobacillus refers to a rod-shaped bacterium that produces lactic acid through the fermentation of carbohydrates while Bifidobacterium refers to a genus of Gram-positive, nonmotile, anaerobic bacteria that live in the gastrointestinal tract and vagina of mammals. 


While Lactobacillus belongs to the phylum Firmicutes, Bifidobacterium belongs to the phylum Actinobacteria. 


Moreover, Lactobacillus is rod-shaped while Bifidobacterium is rod, clubs or branched rods. 


Lactobacillus is nonmotile while Bifidobacterium is motile.  


In addition, Lactobacillus is among the first colonizers in the intestine immediately after birth while Bifidobacterium colonizes later. 


Lactobacillus accounts for 1% of gastrointestinal microbiota while Bifidobacterium is the major form of the gastrointestinal microbiota. 

Oxygen Sensitivity 

Lactobacillus is a facultative anaerobic bacteria while Bifidobacterium is anaerobic. 


Furthermore, Lactobacillus produces lactic acid while Bifidobacterium produces both lactic acid and acetic acid. 


Lactobacillus occurs in regular yogurt while yogurts with Bifidobacterium are more potent than regular yogurts.  


Basically, Lactobacillus is a type of acid-producing bacteria, living as gut microbiota. It is also one of the first colonization forms of microbiota and is a facultative anaerobe. Significantly, it produces lactic acid, which prevents the growth of bad bacteria by decreasing pH. In contrast, Bifidobacterium is the main form of microbiota in the gut. However, they are anaerobes. They produce lactic acid and acetic acid. Meanwhile, yogurts with Bifidobacterium is more potent than the regular yogurts, which contain Lactobacillus. Therefore, the main difference between Lactobacillus and Bifidobacterium is their importance. 


1. Vlasova, Anastasia N et al. “Comparison of probiotic lactobacilli and bifidobacteria effects, immune responses and rotavirus vaccines and infection in different host species.” Veterinary immunology and immunopathology vol. 172 (2016): 72-84. doi:10.1016/j.vetimm.2016.01.003
2. Nguyen, Jennifer. “Understanding Probiotics: Bifidobacterium vs Lactobacillus.” Gene Food, 6 Sept. 2019, Available Here.

Image Courtesy:

1. “Lactobacillus sp 01” By Photo Credit: Janice CarrContent Providers(s): CDC/Dr. Mike Miller (Public Domain) via Commons Wikimedia   
2. “Bifidobacterium adolescentis Gram” By Y tambe – Y tambe’s file (CC BY-SA 3.0) via Commons Wikimedia    

About the Author: Lakna

Lakna, a graduate in Molecular Biology and Biochemistry, is a Molecular Biologist and has a broad and keen interest in the discovery of nature related things. She has a keen interest in writing articles regarding science.

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