Which probiotic produces lactic acid?

January 13, 2026 •

3 min read

Lactic Acid Bacteria (LAB) are a vast group of over 60 bacterial genera recognized for producing lactic acid through fermentation. Understanding which probiotic produces lactic acid is key to identifying the microorganisms responsible for many fermented foods and their specific health benefits for gut and immune support.

Quick Summary

Bacterial strains, including Lactobacillus and Bifidobacterium, produce lactic acid by fermenting carbohydrates. This creates an acidic gut environment that aids digestion and suppresses pathogens. These beneficial bacteria are in fermented foods and probiotic supplements.

Key Points

Lactic Acid Bacteria (LAB): A broad category of microorganisms, including many probiotics, that produce lactic acid as a byproduct of carbohydrate fermentation.
Key Genera: The most common lactic acid-producing probiotics are from the Lactobacillus and Bifidobacterium genera, known for their gut and immune benefits.
Two Fermentation Types: LAB are either homofermentative, producing only lactic acid, or heterofermentative, producing lactic acid plus other compounds like ethanol and CO2.
Health Benefits: Lactic acid lowers gut pH, inhibiting pathogens and aiding mineral absorption, which contributes to a healthy gut microbiome and enhanced immunity.
Sources: Probiotics that produce lactic acid are found in fermented foods like yogurt, kefir, and sauerkraut, as well as in dietary supplements.
Strain Specificity: Probiotic effects can be species and strain-specific, so it is important to choose products containing strains clinically shown to support your health goals.

The Science Behind Lactic Acid Production

Lactic acid bacteria (LAB) produce lactic acid as the primary end-product of carbohydrate metabolism. This metabolic process, known as fermentation, is fundamental to their survival and their beneficial effects on humans. Depending on the pathway used, LAB are classified into two main groups:

Homolactic Fermenters: These bacteria, such as many strains of Lactococcus and some Lactobacillus species, convert glucose almost exclusively into lactic acid. This high yield is particularly valuable in industrial settings for pure lactic acid production.
Heterolactic Fermenters: These species, which include genera like Leuconostoc and some Lactobacillus, produce a mix of lactic acid, ethanol, and carbon dioxide from glucose. This additional gas production is responsible for the characteristic bubbles and unique textures in certain fermented products like kefir.

Key Lactic-Acid-Producing Probiotic Genera

While many bacterial genera produce lactic acid, the following are the most well-known probiotics in the health and food industries:

*Lactobacillus spp.: This is the most common and extensively studied genus of probiotic lactic acid bacteria. Species such as L. acidophilus, L. rhamnosus, L. casei, and L. plantarum are widely used in supplements and fermented foods. They are valued for their ability to survive in the acidic conditions of the stomach and for their various beneficial effects, from aiding digestion to supporting immune function.
*Bifidobacterium spp.: A key inhabitant of the human gut, Bifidobacterium species produce both lactic and acetic acid. This acid production helps lower the intestinal pH, creating an inhospitable environment for many pathogens. Common probiotic species include B. bifidum and B. animalis ssp. lactis.
Streptococcus thermophilus: This bacterium is a homolactic fermenter and a co-starter culture with Lactobacillus bulgaricus in yogurt production. While it produces lactic acid, its primary role in probiotics is often in combination with other strains, creating a symbiotic effect.
*Enterococcus spp.: Some Enterococcus strains, including E. faecium, are also used as probiotics and are homolactic fermenters. They are a natural part of the human microbiome.

How Lactic Acid Benefits Gut Health

The lactic acid produced by these probiotics has several profound benefits for intestinal health:

Pathogen Inhibition: By lowering the intestinal pH, lactic acid creates an unfavorable environment for many harmful, acid-sensitive bacteria, which helps prevent infections and crowd out pathogens.
Nutrient Absorption: The slightly acidic environment created by lactic acid and other metabolites aids in the absorption of key minerals like iron.
Immune System Modulation: Lactic acid bacteria stimulate immune activity within the gut mucosa, helping to regulate the body's immune response and reduce inflammation.
Mucosal Barrier Support: Probiotics help reinforce the gut's mucosal barrier, a physical line of defense that prevents foreign substances from entering the bloodstream.

Comparing Lactic-Acid-Producing Probiotic Species


Probiotic Species	Fermentation Type	Key Benefits	Example Source
L. acidophilus	Homofermentative	Aiding digestion, reducing cholesterol, supporting vaginal health.	Yogurt, miso, supplements.
L. rhamnosus	Facultatively Heterofermentative	Preventing and treating various types of diarrhea, boosting immune function.	Yogurt, kefir, supplements.
B. bifidum	Produces Lactic and Acetic Acid	Alleviating IBS symptoms, supporting respiratory health.	Supplements, fermented dairy products.
L. plantarum	Facultatively Heterofermentative	Improving gut health diversity, alleviating anxiety, anti-tumor effects.	Sauerkraut, kimchi, pickles, sourdough bread.
S. thermophilus	Homofermentative	Improving lactose digestion, co-starters in yogurt production.	Yogurt, cheese.

Sources of Lactic-Acid-Producing Probiotics

These beneficial bacteria are readily available from a variety of sources:

Fermented Dairy Products: Yogurt, kefir, and certain cheeses are excellent sources of Lactobacillus and Streptococcus thermophilus. Look for labels indicating “live and active cultures”.
Fermented Vegetables: Sauerkraut, kimchi, and naturally fermented pickles contain numerous probiotic strains, particularly L. plantarum.
Supplements: Probiotic supplements are available in capsules, powders, and liquids, often containing specific, scientifically studied strains of Lactobacillus and Bifidobacterium.
Other Fermented Foods: Miso, tempeh, and sourdough bread also naturally contain lactic acid bacteria.

Conclusion

Lactic acid-producing probiotics are vital for a healthy gut microbiome, contributing significantly to digestive and immune health. While the Lactobacillus genus is the most prominent, a diverse group of bacteria, including Bifidobacterium, produce this beneficial organic acid. Whether sourced from fermented foods or targeted supplements, incorporating these probiotics into your diet can help maintain intestinal balance and offer a range of clinically validated health benefits. Choosing the right probiotic depends on your specific health goals, with many products clearly listing the active strains to ensure you get the desired effect.

Disclaimer: Always consult with a healthcare professional before starting any new supplement regimen, especially if you have underlying health conditions.

NIH.gov: Probiotics, D–Lactic acidosis, oxidative stress and strain specificity

Frequently Asked Questions

Lactic acid produced by probiotics helps lower the pH level in the gut, which creates an acidic environment hostile to many harmful, pathogenic bacteria. This helps to maintain a balanced and healthy gut microbiome.

No, not all probiotics produce lactic acid. While the largest group of probiotics, known as Lactic Acid Bacteria (LAB), are producers, some beneficial yeasts like Saccharomyces boulardii and other bacteria like certain Bacillus species do not.

The entire Lactobacillus genus consists of lactic acid bacteria. This includes widely recognized probiotic species such as L. acidophilus, L. rhamnosus, L. casei, and L. plantarum, all of which are known lactic acid producers.

Yes, Bifidobacterium species produce both lactic and acetic acid in the gut. This dual acid production is effective at lowering the pH and inhibiting the growth of undesirable microorganisms.

Health benefits include supporting a healthy gut flora, improving digestion, enhancing the immune system, and protecting against intestinal infections. These probiotics can also aid in the digestion of lactose in intolerant individuals.

You can get these probiotics by consuming fermented foods with 'live and active cultures,' such as yogurt, kefir, sauerkraut, kimchi, and miso. Dietary supplements containing specific probiotic strains are also a direct way to increase your intake.

Yes, for most healthy individuals, consuming probiotics that produce D-lactic acid is safe and is a normal part of fermenting carbohydrates. Concerns about D-lactic acidosis are primarily limited to individuals with short bowel syndrome who consume large quantities of fermentable carbohydrates.