Lactobacillus plantarum belongs to the lactic acid bacteria group and is a Gram-positive, facultatively anaerobic bacterium. It does not form spores and appears as straight rods with rounded ends, existing singly, in pairs, or in short chains. Lactobacillus plantarum can produce both D- and L-lactic acid. Its optimal growth temperature is 30–35°C, it can grow within a pH range of 4.5–9.5, with the optimal pH around 6.5.
During growth and reproduction, Lactobacillus plantarum can produce a variety of bioactive compounds, including organic acids, small peptides, hydrogen peroxide, and bacteriocins. These substances help regulate gut microbiota, inhibit the growth of harmful bacteria, and provide certain health benefits. Due to its stability and functional versatility, Lactobacillus plantarum is widely used in medical research, fermented food processing, and silage production, making it a highly valuable probiotic strain.
Lactobacillus plantarum is a native bacterium of the human gut and one of the dominant intestinal microbes, playing an important role in maintaining gut microecological balance. It is highly acid-tolerant, which makes it particularly useful in the late-stage fermentation of foods to improve nutritional value and extend shelf life. It is also commonly used in silage fermentation and as a component in biopreservatives.
Functional Characteristics of Lactobacillus plantarum
1. Antimicrobial Activity
Lactobacillus plantarum can inhibit both Gram-positive and Gram-negative bacteria. It exhibits strong intestinal adhesion, allowing it to compete with pathogens for binding sites on the gut lining and protect the host. Additionally, it suppresses pathogenic bacteria through nutrient competition. Its metabolic products, such as lactic acid and bacteriocins, inhibit harmful bacterial growth, balancing and optimizing the gut microbiota, thereby achieving antimicrobial effects.
2. Immune Regulation
Lactobacillus plantarum can enhance the nonspecific immune function of the mucosal immune system. This effect is related not only to the live bacteria themselves but also to their metabolic products. Even inactivated bacterial cells can exert immune-modulating effects.
3. Efficient Lactose Conversion
As a homofermentative lactic acid bacterium, Lactobacillus plantarum converts lactose primarily into lactic acid with high efficiency. It can also utilize residual proteins in whey and is relatively salt-tolerant. Furthermore, it works synergistically with other lactic acid bacteria, giving it advantages that other strains cannot match.
4. Nutritional Benefits
Lactobacillus plantarum produces α-galactosidase, which hydrolyzes large sugar molecules into small compounds that can be absorbed by the small intestine. It also produces bile salt hydrolase, generating free bile acids that precipitate with cholesterol, thereby reducing cholesterol levels in the medium and in serum.
Lactobacillus plantarum is widely found and plays important roles in human and animal health. With ongoing scientific research and technological development, the range of applications for Lactobacillus plantarum is expected to expand continuously, and its use in various fields will likely increase.