LACTOBACILLUS PLANTARUM: CHARACTERISTICS, MORPHOLOGY, APPLICATIONS - BIOLOGY - 2025

Lactobacillus plantarum is a short rod-shaped, Gram positive, catalase negative bacterium. It is also facultative heterofermentative, facultative aerobic and anaerobic. They are found in many environmental niches and are part of the microbiota of the gastrointestinal tract of humans and other animals.

It belongs to the group of Lactic Acid Bacteria (LAB). This is a functional group that comprises bacteria that produce lactic acid as the main metabolic product of carbohydrate fermentation.

Lactobacillus plantarum, Image credits: Nature. Taken and edited from

It has various applications, mainly in the fermentation of food to obtain products such as yogurt, cheeses, pickles, sausages and silage, among others.

characteristics

Lactobacillus plantarum is a Gram positive, non-spore-forming, catalase negative bacterium. It is tolerant aerobic and facultative anaerobic. It has a low GC content. It is capable of growing at a temperature range between 15 and 45 ° C. Tolerates pH values ​​between 4 and 9.

This bacterium is capable of producing lactic acid by fermentation of glucose using a metabolic pathway called EMP. Fermentation of hexoses by this metabolic pathway produces D- and L-lactic acids.

L. plantarum ferments more than 90% at least 10 types of carbohydrates, including mannitol, ribose, and sucrose. Arabinose and xylose are fermented between 11 and 89%.

Taxonomy

Lactobacillus plantarum was first described by Orla-Jennsen in 1919, naming it Streptobacterium plantarum. Later Pederson (1936) relocated it to the genus Lactobacillus. Taxonomically it is located in the phylum Firmicutes, class Bacilli, order Lactobacillales, and the family Lactobacillaceae.

Functionally it is included among Lactic Acid Bacteria (BAL) and is Generally Recognized As Safe (GRAS). GRAS is a designation granted by the Food and Drug Administration (FDA) of the United States of North America.

This designation is given to substances whose addition to food is considered safe by experts. GRAS are exempt from the Federal Food, Drug, and Cosmetic Law of that country.

The genus Lactobacillus is divided into three groups (A, B and C). Lactobacillus plantarum is included in group B. This group houses facultative heterofermentative species, capable of producing lactic acid by fermentation of glucose. Additionally, it belongs to a complex of species that bears his name and that contains four other species.

Morphology

Lactobacillus plantarum is a rod-shaped microorganism with rounded ends. It is approximately 0.9 to 1.2 µm wide by 1.0 to 8.0 µm long. It can grow solitary or forming short chains.

Its cell wall is high in peptidoglycans and lacks an outer cell membrane. It has a low proportion of GC and its genome is greater than that of the rest of the representatives of the Lactic Acid Bacteria group.

On its circular chromosome it contains 3,308,274 base pairs. It has three plasmids, called pWCFS101, pWCFS102 and pWCFS103.

Lactobacillus plantarum. Taken and edited from

Applications

Lactobacillus plantarum has a wide range of applications in the food industry as a starter culture and as a preservative. Recently, its use as a probiotic and in the fermentation of dairy products has increased. Its use has also been increased in the production of wines, meat products and fermented vegetables.

This bacteria is easy to grow and is considered a safe probiotic. It can suppress large number of pathogenic microorganisms from food products.

It is useful against diseases that can adversely affect humans. It has also shown a positive effect on the health, survival and weight gain of suckling cattle during weaning.

In the pharmaceutical industry

Lactobacillus plantarum is used, together with other LABs, for the production of some fermented foods, especially in the dairy industry.

These products are of high quality and have good properties of texture, taste and chemical content. The bacteria do not increase acidification during the milk fermentation and product storage processes.

Biopreservative

Lactobacillus plantarum is a BAL with high potential as a probiotic bioconservative, since it is part of the intestinal flora of humans. Another favorable aspect is that it has a long history of safe use as a starter culture in food fermentation.

Additionally, different strains of L. plantarum produce antimicrobial compounds with antagonistic activity against pathogenic and decomposing bacteria. It also produces antifungal compounds that can replace potentially harmful preservatives in food products.

Some strains of Lactobacillus plantarum produce bacteriocins, called plantaricins. Bacteriocins are protein toxins synthesized to inhibit the growth of other bacteria.

Plantaricins suppress the growth of at least five common foodborne pathogens. Among these pathogens are Escherichia coli and Salmonella typhimurium. In addition, they have antagonistic activity against bacteria responsible for diseases such as gastritis, ulcers, cavities and candidiasis.

Diseases

Lactobacillus species are part of the normal gastrointestinal flora of humans. Although very rarely, they have also been isolated from a variety of human infections, especially in people with weakened immune systems. Among the infections caused by bacteria of this genus are bacteremia, endocarditis, abscesses and meningitis.

Lactobacillus plantarum, for its part, has been associated with inflammation of the gallbladder, dental abscesses, cavities and peritonitis. The correct identification of this bacterium is difficult, however it is very important, since it is usually resistant to vancomycin and other antibiotics.

References

1. JC Goldstein, KL Tyrrell, DM Citron (2015). Lactobacillus Species: Taxonomic Complexity and Controversial Susceptibilities. Clinical Infectious Diseases
2. G. Melgar-Lalanne, Y. Rivera, H. Hernández-Sánchez (2012). Lactobacliilus plantarum: An overview with emphasis in biochemical and healthy properties. In: Lactobacillus: Classification, uses and health implications. Not going. Science Publishers.
3. A. Abdelazez, H. Abdelmotaal, Z.-T. Zhu, J. Fang-Fang, R. Sami, L.-J. Zhang, AR Al-Tawaha, Xi.-C. Meng, 2018. Potential benefits of Lactobacillus plantarum as probiotic and its advantages in human health and industrial applications: A review. Advances in Environmental. Biology.
4. H. Jurado-Gámez, C. Ramírez, J. Martínez (2013). In vivo evaluation of Lactobacillus plantarum as an alternative to the use of antibiotics in piglets. Magazine MVZ Córdoba.
5. SD Todorov, BD Franco. (2010). Lactobacillus plantarum: Characterization of the Species and Application in Food Production. Food Reviews International.
6. D. Tena, NM Martínez, C. Losa, C. Fernández, MJ Medina, & JA Sáez-Nieto (2013). Acute acalculous cholecystitis complicated with peritonitis caused by Lactobacillus plantarum. Diagnostic Microbiology and Infectious Disease.