Introduction to Bacillus coagulans

In 1915, Hammer discovered Bacillus coagulans from spoiled milk. Due to its dual characteristics of both lactic acid bacteria and spore-forming bacteria, there has been ongoing controversy in the academic community regarding its classification. In 1974, the eighth edition of the Bergey's Manual of Determinative Bacteriology classified it into the genus Bacillus. Because of its ability to produce coagulants, it was officially named Bacillus coagulans in 1980. In 2012, the U.S. Food and Drug Administration (FDA) approved Bacillus coagulans as a safe edible strain. In 2016, Bacillus coagulans was included in the list of strains that can be used in food published by the National Health and Family Planning Commission of China.

Biological Characteristics

Bacillus coagulans is a Gram-positive bacterium, facultatively anaerobic, homofermentative, and positive for catalase. The colonies are opaque, white, and round, with rod-shaped cells approximately 2.5-5μm long and 0.6-1μm wide, bluntly rounded at both ends, producing terminal spores, without flagella, and exhibiting some motility. Bacillus coagulans has relatively loose growth conditions, capable of normal growth at 30-55°C, with an optimal growth temperature of 37-45°C and an optimal pH of 6.6-7.0. The spores of Bacillus coagulans are highly resistant to stress, heat, gastric acid, and bile salts. Experiments have shown that after 90°C, 60 minutes of moist heat treatment, the number of viable bacteria only decreased by one order of magnitude; when placed in simulated gastric juice at pH 2.5 for 12 hours, the survival rate was 71.9%; in simulated intestinal fluid with a bile salt concentration of 0.3% and pH 8.0 for 12 hours, the survival rate was 84.4%.

Probiotic Effects and Mechanisms

Although Bacillus coagulans is not part of the inherent intestinal flora, its strong resistance of spores allows it to pass through the harsh acidic and digestive enzyme environment of the gastrointestinal tract, colonizing within the host and exerting its probiotic effects.

1. Inhibiting harmful bacteria and maintaining intestinal flora balance

After colonizing in the intestine, Bacillus coagulans forms a biological barrier on the surface of small intestinal epithelial cells, competing for binding sites with harmful bacteria; it secretes lactic acid to lower the pH, inhibiting the growth of harmful bacteria; at the same time, it rapidly consumes free oxygen in the environment, providing favorable growth conditions for anaerobic probiotics such as lactic acid bacteria and bifidobacteria.

Research by Katsutoshi Ara et al. showed that after adding Bacillus coagulans to the diet, the levels of bifidobacteria and lactic acid bacteria in human feces increased, while the number of Clostridium difficile decreased, and the fecal pH also significantly lowered.

On the other hand, Bacillus coagulans has the ability to secrete bacteriocins. Coagulins are similar to bacteriocin peptides secreted by Lactobacillus, which significantly inhibit harmful bacteria such as Escherichia coli, Listeria, Staphylococcus aureus, and Helicobacter pylori. In recent years, another bacteriocin, Lactosporin, has been isolated, which is an anionic antimicrobial substance that can penetrate the surface of pathogenic bacteria, causing leakage of amino acids and inorganic salt ions from within the cells, thereby inhibiting harmful bacteria.

2. Secreting digestive enzymes to improve nutrient utilization

Bacillus coagulans can secrete digestive enzymes including β-galactosidase, protease, and lipase, improving the body's utilization of protein and carbohydrates. β-galactosidase can hydrolyze lactose into glucose and galactose, increasing the absorption rate of milk in lactose-intolerant patients and alleviating their symptoms. Experiments by Asokan S et al. demonstrated that the plant proteases secreted by Bacillus coagulans significantly improved the conversion rate of protein from peas, soybeans, and rice in the human body, reducing the production of toxic metabolites.

3. Antioxidant function, enhancing host immunity

Antioxidant capacity is an important guarantee for the normal functioning of the immune system. Once the oxidative stress in the host reaches a certain level, the body will be damaged, potentially leading to a series of inflammatory responses. The level of malondialdehyde can reflect the degree of oxidative damage in the body, and multiple experimental studies have proven that Bacillus coagulans can increase the activity of antioxidant enzymes in serum and liver while reducing malondialdehyde levels, thereby alleviating the damage of free radicals to host cells and reducing the likelihood of disease occurrence.

In in vitro antioxidant experiments, it was found that the extracellular polysaccharides produced by Bacillus coagulans also have strong abilities to scavenge free radicals and reduce malondialdehyde levels.

Bacillus coagulans can enhance the intestinal mucosal barrier function in animals, promote the proliferation and differentiation of T lymphocytes and B lymphocytes, stimulate the secretion of cytokines from helper T cells 1 (Th1) and helper T cells 2 (Th2), and enhance the activity of natural killer cells (NK cells) and phagocytes, thereby improving humoral and cellular immunity levels. Gitte S Jensen et al. found that the cell wall and metabolic products of Bacillus coagulans can induce the production of Th2 cytokines IL-4, IL-6, and IL-10; subsequent studies also found that Bacillus coagulans can alleviate inflammatory conditions to some extent by regulating the nuclear transcription system. Sudha et al. showed that Bacillus coagulans can inhibit the inflammatory cell COX-2, thereby inhibiting the RelA protein and suppressing the expression of pro-inflammatory factors IL-12, TNF-α, and IFN-γ.

Applications and Prospects

Due to its good probiotic effects and resistance, Bacillus coagulans has broad application prospects. However, the current domestic market mainly focuses on feed and pharmaceuticals, with food-related applications starting relatively late. Moreover, some probiotic mechanisms of Bacillus coagulans remain to be studied, but it is undeniable that its related probiotic products will inevitably develop.

Note: This article is for informational purposes only and should not be considered medical guidance.