Lactobacillus rhamnosus
Probiotics & Enzymes
Overview
- Lactobacillus rhamnosus is a Gram-positive, non-spore-forming, rod-shaped bacterium belonging to the lactic-acid-producing Lactobacillus genus.
- It is a well-studied probiotic strain (most commonly the GG/ATCC 53103 isolate).
- When ingested in sufficient numbers, it can survive gastric transit, temporarily colonize the intestinal mucosa, and modulate host physiology for health-promoting effects.
Chemistry
- Lactobacillus rhamnosus is a living microorganism, not a single chemical entity.
- Its cell envelope comprises a thick peptidoglycan layer (Gram-positive) linked to teichoic acids (e.g., wall-teichoic acid with D-alanine residues) and a cytoplasmic membrane rich in phospholipids (phosphatidylglycerol, cardiolipin).
- The genome of the reference GG strain is ~2.99 Mbp, encoding ~2,900 proteins, with a GC content of ~46 %.
- The major metabolic product is L-lactic acid (C₃H₆O₃, IUPAC: (S)-lactate), generated via homolactic fermentation of carbohydrates via the Embden–Meyerhof pathway.
- The bacterium also synthesizes exopolysaccharides (EPS) composed of glucose, galactose, and rhamnose units, contributing to biofilm formation and immune modulation.
Sources & Quality
- Commercially, L. rhamnosus is cultivated from the well-characterized GG/ATCC 53103 strain, isolated originally from a healthy human gastrointestinal tract in 1983.
- Production involves anaerobic fermentation in dairy-based media (e.g., skim-milk or soy-based broth) under controlled pH (≈ 5.5) and temperature (≈ 37 °C) to achieve high viable counts.
- After fermentation, cells are harvested, washed, and lyophilized with cryoprotectants (e.g., trehalose) to maintain viability.
- Quality control includes strain verification by 16S-rRNA sequencing, CFU enumeration, and absence of contaminants (e.g., E. coli, Staphylococcus spp.).
- Good Manufacturing Practices (GMP) and third-party testing (e.g., USP, NSF) ensure purity, potency, and stability.
- Natural sources include fermented dairy (yogurt, kefir), fermented vegetables, and some probiotic-enriched foods, though supplement formulations provide standardized, high-dose CFU counts that are difficult to achieve via diet alone.
Where to Buy Lactobacillus rhamnosus
Affiliate Disclosure: We earn a commission if you purchase through these links at no additional cost to you. This helps us maintain our research and provides you with the best supplement information.