History and Naming

In 1989, under the species Lacticaseibacillus casei, five different subspecies were recognized: L. casei subsp. casei, L. casei subsp. alactosus, L. casei subsp. pseudoplantarum, L. casei subsp. tolerans, and L. casei subsp. rhamnosus.

With advancements in molecular biology and the advent of DNA–DNA hybridization techniques, these subspecies were later reclassified as separate species:

(i) L. casei ( former L. casei subsp. casei);

(ii) L. paracasei, comprising two subspecies 

  •  L. paracasei subsp. paracasei (former L. casei subsp. alactosus and L. casei subsp. pseudoplantarum) 

  • L. paracasei subsp. tolerans (former L. casei subsp. tolerans)

(iii) L. rhamnosus ( former L. casei subsp. rhamnosus).

Although Lacticaseibacillus casei, Lacticaseibacillus paracasei, and Lacticaseibacillus rhamnosus share a close genetic relationship, functional similarities, and a common ancestry, they are now classified as distinct species. Because of their shared traits and the collective term “Lacticaseibacillus casei group,” these bacteria are often confused, and the names L. casei and L. paracasei are sometimes used interchangeably - a bit of a “potato, potahto” situation! However, despite their similarities, Lacticaseibacillus paracasei possesses unique properties and is now recognized as a separate species.

Health Benefits

Lacticaseibacillus paracasei is a common inhabitant of the oral cavity and gastrointestinal tract. However they are transient in nature and are not the dominant bacterial species in the gut. Having said that, their presence contributes to a better gut environment and fosters the growth of beneficial bacteria. Hence Lacteicaseibacillus paracasei alone or with other probiotics are supplemented to relieve the symptoms of various health concerns. Several strains of Lacticaseibacillus paracasei  have been shown to improve the symptoms of severe infections of gastrointestinal tract like acute gastroenteritis ,symptomatic diverticulitis and diarrhoea in C. difficile. Apart from digestive issues, L .paracasei supplementation along with the conventional treatment has shown to relieve the symptoms associated with atopic dermatitis. Interestingly it has also shown to restore the scalp microbiome and reduce dandruff while improving skin barrier integrity and skin hydration. Topical application of Lacticaseibacillus paracasei derived probiotic lotion has shown to reduce the acne vulgaris due to its anti-inflammatory properties. A study observed that L. paracasei supplementation improved the endothelial function by reducing the cholesterol levels thereby mitigating the risk of cardiovascular diseases. Another study showed that it reduces fat storage by regulating the expression of genes involved in metabolism. Administration of L. paracasei in animal models has shown to prevent type 2 diabetes through the regulation of glucose metabolism. It is also observed that supplementation of L. paracasei along with L. plantarum reduced the episodes of recurring common cold suggesting that it might play a role in boosting the immunity. The latest interest in microbiome sciences is to understand the effect of the microbial composition and their functions in athletes. Scientists are exploring the ways and developing formulations/supplementation which can increase athletes performance and fasten the exercise induced recovery process. In this quest, studies are focusing on positive effects of probiotics on the post-exercise recovery process. A recent clinical trial has shown that supplementation of live and heat killed L. paracasei PS23 reduced the blood markers associated with muscle damage and inflammation in addition to  speedy recovery and lesser exhaustion after exercise.

Applications

Several studies have provided evidence that supplementation with strains of Lacticaseibacillus paracasei offers numerous health benefits. These bacteria are also naturally found in many fermented products such as kefir, various types of cheese, koumiss, and pickles. The food industry has recognized the positive impact of this probiotic and is actively experimenting with developing foods and beverages fortified with L. paracasei.

It has been observed that yogurt co-fermented with Lacticaseibacillus paracasei ZFM54 not only improves the flavor and texture of the yogurt but also enhances gut ecology when consumed. There have also been attempts to incorporate probiotics into ice cream bars, chocolate mousse, and fruit juices.

Although the beneficial effects of L. paracasei are well established, incorporating them into functional foods remains a challenge, as their chances of surviving the manufacturing process, transportation, and storage are low.

Fun Fact

Heard of beer made with the same bacteria responsible for producing cheese and yogurt?  It turns out we’ve underestimated the versatility of certain Lactobacillus species, such as Lacticaseibacillus paracasei, traditionally used in fermented dairy products.

The major drawback of using Lactobacilli as a starter culture in beer brewing is that they are usually killed by the acids and alcohol produced during fermentation. However, Mei Zhi Alcine Chan et al. took a creative deviation from the conventional brewing process by co-fermenting Saccharomyces cerevisiae (brewer’s yeast) and Lacticaseibacillus paracasei for the first time, they were able to produce beer with high numbers of viable probiotics! The Lactobacilli add a tart, sour flavor to the beer while also offering potential health benefits. 

Cheers to this innovation - a guilt-free, gut-friendly beer experience might just be on tap for the future!

Taxonomic Classification

Domain: Bacteria

Phylum: Bacillota

Class: Bacilli

Order: Lactobacillales

Family: Lactobacillaceae

Genus: Lacticaseibacillus

Species: Lacticaseibacillus paracasei

Microbe Profile

Shap : Rod      

Gram nature: Positive

Spore formation: No

Biofilm formation: Yes

Oxygen requirement: Facultative anaerobe

Optimal temperature: 30 - 37 °C

Optimal pH: 5.5-6.2

Nutrient usage: Fructooligosaccharides, Galactooligosaccharides

-Khushi. C

References

Ou, S. J. L., Yusri, H., Yang, D., Khoo, C. M., & Liu, M. H. (2024). Effects of Moderate Consumption of a Probiotic-Fermented Sour Beer on the Inflammatory, Immunity, Lipid Profile, and Gut Microbiome of Healthy Men in a Participant-Blinded, Randomized-Controlled Within-Subject Crossover Study. Food science & nutrition, 12(12), 10867–10880. https://doi.org/10.1002/fsn3.4627

Sathikulpakdee, S., Kanokrungsee, S., Vitheejongjaroen, P., Kamanamool, N., Udompataikul, M., & Taweechotipatr, M. (2022). Efficacy of probiotic-derived lotion from Lactobacillus paracasei MSMC 39-1 in mild to moderate acne vulgaris, randomized controlled trial. Journal of cosmetic dermatology, 21(10), 5092–5097. https://doi.org/10.1111/jocd.14971

Dang, F., , Jiang, Y., , Pan, R., , Zhou, Y., , Wu, S., , Wang, R., , Zhuang, K., , Zhang, W., , Li, T., , & Man, C., (2018). Administration of Lactobacillus paracasei ameliorates type 2 diabetes in mice. Food & function, 9(7), 3630–3639. https://doi.org/10.1039/c8fo00081f

Chen, X., Zhu, Z., Zhang, X., Chen, L., Gu, Q., & Li, P. (2024). Lactobacillus paracasei ZFM54 alters the metabolomic profiles of yogurt and the co-fermented yogurt improves the gut microecology of human adults. Journal of dairy science, 107(8), 5280–5300. https://doi.org/10.3168/jds.2023-24332

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