Lactobacillus plantarum as a Versatile Probiotic Microorganism

Lactobacillus plantarum is a prominent species within the genus Lactobacillus, a group of bacteria known for their lactic acid production and their beneficial roles in food fermentation, probiotics, and human health. L. plantarum is highly versatile and has been extensively studied for its various applications, from food preservation to its use as a probiotic, as well as its potential in the field of biotechnology and medicine. In this discussion, we will delve into the multifaceted nature of L. plantarum, exploring its characteristics, roles in food production, health benefits, and emerging applications.

Taxonomy and General Characteristics

Lactobacillus plantarum belongs to the family Lactobacillaceae, within the phylum Firmicutes. It is a Gram-positive, non-spore-forming bacterium that is rod-shaped and anaerobic or facultative anaerobic, meaning it can thrive in both the presence and absence of oxygen. L. plantarum is characterized by its ability to ferment various sugars, particularly pentoses and hexoses, into lactic acid, which imparts acidity to its growth environment.

Role in Food Fermentation

L. plantarum has a long history of use in food fermentation, and it is renowned for its roles in preserving and enhancing the quality of a wide range of food products. Some of its notable contributions to food fermentation include:

• Fermentation of Vegetables: L. plantarum is a key player in the fermentation of vegetables, particularly in the production of sauerkraut, kimchi, and pickles. It helps maintain the acidity and inhibits the growth of spoilage and pathogenic microorganisms, thus extending the shelf life of these fermented products.
• Fermentation of Dairy Products: L. plantarum is used in the production of various dairy products, such as yogurt and kefir. Its ability to convert lactose into lactic acid contributes to the characteristic tangy flavor and texture of these products. Additionally, it can compete with potentially harmful bacteria, improving the safety and shelf life of dairy foods.
• Bread and Sourdough Fermentation: L. plantarum contributes to the fermentation of sourdough bread, imparting a unique flavor profile and improving the shelf life of bread. It accomplishes this by producing lactic acid and other metabolites, which reduce the pH of the dough and inhibit the growth of unwanted microorganisms.

Probiotic Potential

Lactobacillus plantarum has emerged as a promising probiotic microorganism, and several strains of L. plantarum are used in probiotic supplements and functional foods. Probiotics are live microorganisms that confer health benefits when consumed in adequate amounts. The potential health benefits associated with L. plantarum include:

• Gastrointestinal Health: L. plantarum strains have been shown to have a positive impact on gut health. They can help balance the gut microbiota, potentially improving digestion, reducing symptoms of irritable bowel syndrome (IBS), and preventing or alleviating diarrhea, including traveler’s diarrhea.
• Immune System Support: Some studies suggest that L. plantarum may enhance the body’s immune response by promoting the production of cytokines and antibodies. This immune modulation can help the host’s defense against infections and contribute to overall health.
• Anti-Inflammatory Effects: L. plantarum has been investigated for its anti-inflammatory properties, particularly in the context of gastrointestinal disorders. It may help reduce gut inflammation and alleviate symptoms in conditions such as inflammatory bowel disease (IBD).
• Metabolic Health: Research indicates that certain strains of L. plantarum may influence metabolic parameters. They can help in weight management, regulate blood sugar levels, and reduce the risk of obesity-related disorders.
• Oral Health: L. plantarum strains have been explored for their potential to support oral health by reducing the growth of harmful bacteria in the mouth and contributing to the prevention of dental caries.

Biotechnological Applications

Beyond its roles in food production and as a probiotic, Lactobacillus plantarum holds promise in various biotechnological applications. Some of these applications include:

• Biodegradation: L. plantarum strains have been investigated for their ability to degrade organic pollutants in wastewater, contributing to environmental remediation efforts. Their metabolic activity can help break down contaminants and improve water quality.
• Biopreservation: L. plantarum produces antimicrobial compounds, such as organic acids and bacteriocins, that inhibit the growth of spoilage and pathogenic microorganisms. This biopreservation potential is utilized in the food industry to extend the shelf life of products without the need for chemical preservatives. One of the most interesting antimicrobial peptides being suggested as a new food preservation agent in its own right is plantaricin (Abdulhussain Kareem & Razavi, 2020).
• Biofuel Production: L. plantarum can be engineered to produce biofuels, such as bioethanol and biohydrogen, through fermentation processes. Its ability to ferment various sugars into useful products makes it a candidate for sustainable biofuel production.
• Vaccine Delivery: L. plantarum has been investigated as a potential vector for vaccine delivery. By genetically engineering this bacterium, researchers aim to create oral vaccines that can stimulate immune responses in the gut, providing an alternative to traditional injection-based vaccination.

Emerging Medical Applications

In addition to its established probiotic applications, Lactobacillus plantarum is being explored for emerging medical applications:

• Functional Foods: L. plantarum strains are being incorporated into functional foods that target specific health conditions. For instance, these bacteria may be used in foods designed to support individuals with lactose intolerance or to enhance gut health.
• Mucosal Health: L. plantarum is being studied for its potential to improve mucosal health. It may have applications in addressing conditions that affect mucosal surfaces, such as urinary tract infections, respiratory infections, and oral health issues.
• Brain-Gut Axis: There is growing interest in the gut-brain axis and the potential influence of gut microbiota on brain health. L. plantarum strains are under investigation for their role in modulating this axis and addressing conditions like anxiety, depression, and cognitive health.

Safety and Regulatory Considerations

When using Lactobacillus plantarum for probiotic or biotechnological applications, safety and regulatory considerations are of paramount importance. Regulatory agencies, such as the U.S. Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA), provide guidelines for the safety and efficacy assessment of probiotic strains. Ensuring the strain’s identity, viability, and stability, as well as conducting safety assessments, is essential to meet regulatory standards.

What can we say now about Lactobacillus plantarum. It is a versatile microorganism with a rich history of contributions to food fermentation, probiotics, and human health. Its diverse applications, from food preservation to its use as a probiotic, reflect its adaptability and potential in various fields. As research on L. plantarum continues to advance, it is likely that new applications and benefits will emerge, further expanding its role in biotechnology, medicine, and sustainable solutions for a wide range of health and environmental challenges.

References

Abdulhussain Kareem, R., & Razavi, S. H. (2020). Plantaricin bacteriocins: As safe alternative antimicrobial peptides in food preservation—A review. Journal of Food Safety, 40(1), e12735. .