Which Vitamin Does Lactobacillus Produce? An In-Depth Look

December 15, 2025 •

4 min read

According to scientific studies, certain strains of probiotic bacteria, including some species of Lactobacillus, are capable of producing water-soluble B-group vitamins, such as riboflavin (B2), folate (B9), and cobalamin (B12). This biosynthesis helps fortify fermented foods and contributes to the nutritional content available in the human gut.

Quick Summary

Several Lactobacillus species synthesize B-group vitamins like B2, B9, and B12, along with vitamin K2, playing a vital role in human nutrition and gut health. Strain-specific differences and metabolic pathways determine vitamin production capabilities among these probiotic microorganisms. Optimized fermentation processes can enhance the vitamin content in fermented foods.

Key Points

Specific Strains Produce Vitamins: Not all Lactobacillus species produce the same vitamins; this ability is highly strain-specific and dependent on genetic makeup.
Producers of B-Group Vitamins: Key vitamins synthesized include riboflavin (B2), folate (B9), and cobalamin (B12), which are all essential for human health.
Vitamin K2 Synthesis: Some Lactobacillus strains, notably L. fermentum, are also capable of producing vitamin K2, which is important for bone and heart health.
Enhance Fortified Foods: Vitamin-producing strains are used as starter cultures in fermented foods like yogurt and cheese to naturally enhance their nutritional value.
Impact Gut Microbiome: The vitamins produced contribute to the microbial balance in the gut, supporting other beneficial bacteria, although direct human absorption is complex.
Potential for Bioengineering: Researchers can use metabolic engineering to create strains that overproduce specific vitamins, offering new avenues for nutritional supplements and fortified foods.
Synergistic Health Benefits: Combining B vitamins with certain probiotics may lead to synergistic effects, promoting greater nutrient absorption and overall health benefits.

Understanding Lactobacillus and Its Role in Vitamin Production

Lactobacillus, a genus of lactic acid bacteria (LAB), is widely recognized for its pivotal role in the food industry and human health. As probiotics, these bacteria ferment sugars into lactic acid, which gives many foods their characteristic tangy flavor and acts as a natural preservative. Beyond their role in food preservation, the metabolic activities of various Lactobacillus strains have a significant impact on human health, including the synthesis of essential vitamins. It is important to note that the ability to produce these vitamins is highly strain-specific and not a universal trait across the entire genus.

The B-Group Vitamins Produced by Lactobacillus

The most prominent vitamins produced by specific Lactobacillus strains are from the B-group, which are water-soluble and crucial for human metabolism. These include:

Riboflavin (Vitamin B2): This vitamin is a precursor to the coenzymes FMN and FAD, which are essential for cellular energy production. Some Lactobacillus species, such as Lactobacillus fermentum, are known to produce riboflavin, enriching fermented products like milk with this vital nutrient.
Folate (Vitamin B9): Folates are indispensable for DNA and RNA synthesis and for repairing DNA damage. While many lactobacilli possess the genes for folate synthesis, some require the precursor para-aminobenzoic acid (pABA) to complete the process. Some Lactobacillus plantarum strains, for instance, are predicted to be folate producers under the right conditions.
Cobalamin (Vitamin B12): Vitamin B12 is a complex vitamin that is vital for red blood cell formation, neurological function, and DNA synthesis. Humans cannot produce it, making bacterial synthesis in the gut or dietary intake from animal products critical. While historically considered auxotrophic for B12, recent research has confirmed that certain strains, like Lactobacillus reuteri and Lactobacillus rossiae, do possess the complete biosynthetic pathway for producing this vitamin.

Vitamin K2 Production by Lactobacillus

Beyond the B vitamins, some Lactobacillus species are also capable of synthesizing long-chain menaquinones, a form of vitamin K2. Vitamin K2 plays a key role in bone metabolism and cardiovascular health. The production of K2 is particularly noted in strains used in fermented dairy products, where it contributes to the overall nutritional quality of the food. A study identified a novel strain, Lactobacillus fermentum LC272, as being capable of producing vitamin K2, which has promising applications in fortifying fermented foods.

Comparison of Key Vitamin-Producing Lactobacillus Species

This table highlights the diverse vitamin-producing capabilities of different Lactobacillus species, showcasing the strain-specific nature of this metabolic activity.


Lactobacillus Species	Key Vitamins Produced	Fermentation Process	Notes on Production	Potential Application
L. reuteri	B12, Folate	Anaerobic fermentation in the gut.	Confirmed to have the complete pathway for B12 synthesis.	Probiotic supplements, fermented products like sourdough.
L. plantarum	Folate, B2, B3, B6, B9	Fermentation of vegetables, sourdough, dairy.	Potential producers; some strains require pABA to produce folate.	Functional fermented foods, sourdough bread.
L. fermentum	B2, K2 (menaquinones)	Fermentation of milk, cereals.	Strain LC272 is known for high vitamin K2 production.	Fortified dairy products, fermented vegetables.
L. acidophilus	B3, B6, B9	Fermentation of dairy products like yogurt and milk.	Exhibits proteolytic effects that aid in nutrient production.	Probiotic capsules, yogurt, fermented dairy products.
L. paracasei	B3, B6, B9	Fermentation of yogurt and other dairy.	Studied for its role in developing fortified fermented products.	Functional fermented foods, cheese production.
L. coryniformis	B12 (pseudocobalamin)	Fermentation of silage.	Identified as a producer of a B12-like compound, pseudocobalamin.	Animal feed, niche fermented products.

The Impact of Lactobacillus on Gut Microbiota and Vitamin Availability

The human gut microbiome is a complex ecosystem where bacteria produce and consume vitamins in a dynamic interplay that can affect host health. The vitamins produced by probiotic Lactobacillus species can be utilized by other gut bacteria, or potentially by the human host, though the exact extent of absorption is an area of ongoing research. For example, studies have shown that vitamin B2 supplementation can influence the gut microbiota composition, increasing beneficial bacteria like Faecalibacterium prausnitzii. This highlights that the impact of Lactobacillus on vitamin availability is not a simple linear process but a complex interaction within the gut ecosystem.

Some research has also shown a synergistic effect when combining B vitamins and probiotics. A 2024 study demonstrated that a combination of B vitamins and three Lactobacillus strains promoted vitamin absorption more effectively than either alone. This suggests that the relationship between these bacteria and vitamins is mutually beneficial and can be harnessed for nutritional purposes.

Future Perspectives: Enhancing Vitamin Production

With advancements in metabolic engineering and genomics, researchers are exploring ways to enhance the vitamin-producing capabilities of lactic acid bacteria. By manipulating the biosynthetic pathways, it is possible to increase the yield of specific vitamins, creating more potent probiotic strains for functional foods and supplements. This can be particularly useful in regions where dietary deficiencies, such as vitamin B12 deficiency in vegan diets, are a concern. The ultimate goal is to leverage these natural bacterial abilities to create more nutritionally valuable and cost-effective fermented products. IntechOpen.com has extensive chapters on the biosynthesis of vitamins by probiotic bacteria, offering deeper scientific insight.

Conclusion

In conclusion, specific strains of Lactobacillus are confirmed producers of several vital B-group vitamins, including riboflavin, folate, and B12, as well as vitamin K2. This ability is not universal across all species within the genus and is influenced by environmental conditions and genetic makeup. These vitamin-producing probiotics contribute to the nutritional value of fermented foods and may have a direct or indirect impact on human health by modulating the gut microbiome. Ongoing research and technological advancements aim to optimize these natural capabilities for the development of enriched functional foods and targeted nutritional therapies. As we continue to unravel the complex interactions within the gut, the role of Lactobacillus as a microbial factory for essential nutrients remains a promising area of scientific inquiry.

Frequently Asked Questions

No, the vitamin-producing capabilities of Lactobacillus are highly strain-specific. A particular species, like L. reuteri, may produce B12, while another, such as L. plantarum, might be a folate producer, but this is not a universal trait across all Lactobacillus species.

While many lactobacilli cannot produce B12, some specific strains like Lactobacillus reuteri and Lactobacillus rossiae are exceptions and have been shown to possess the complete biosynthetic pathway for producing this complex vitamin.

While fermented foods can be a source of bacterially produced vitamins, relying on them as your sole source is not recommended. The vitamin content varies significantly based on the specific strain, fermentation process, and other factors, making consistent intake difficult to guarantee.

Yes, some Lactobacillus strains are known to produce menaquinones, a form of vitamin K2. This contributes to the nutritional value of fermented foods and offers potential health benefits related to bone and cardiovascular health.

Probiotics affect vitamin availability and absorption in the gut in a complex way. They produce vitamins for their own use and for other bacteria, but can also consume them. The overall effect on human host absorption is still a research area, but combining B vitamins and probiotics can have synergistic effects.

The B vitamins produced by bacteria are chemically identical to those from other dietary sources. The main difference lies in their bioavailability and location of synthesis within the body. Bacterial production occurs in the gut, whereas dietary sources are ingested through food or supplements.

Yes, vitamin-producing Lactobacillus strains are often used as starter cultures in the food industry to naturally fortify fermented products. Using them in home fermentation can increase the vitamin content, but the yield can vary widely depending on conditions and the specific strain used.