Bifidobacterium and Lactobacillus probiotics produce distinctly different peptide and metabolite profiles in their postbiotics, with Bifidobacterium generating nearly half its metabolites as amino acids and peptides.
48.44%of Bifidobacterium postbiotic metabolites were amino acids and peptides — significantly higher than Lactobacillus
What the researchers found
An untargeted metabolomic analysis of 14 probiotic strains identified 3,333 metabolites in their cell-free supernatants (postbiotics), with 1,262 metabolites shared across all strains. Bifidobacterium postbiotics contained significantly higher amino acid and peptide content (48.44%) compared to Lactobacillus, with glutamic acid peptides being particularly prevalent.
Indole derivatives — compounds important for immune regulation through the aryl hydrocarbon receptor — were found in all strains, but their types differed: 3-indoleacrylic acid was more concentrated in Lactobacillus, while indole-3-lactic acid was more prevalent in Bifidobacterium. These findings suggest different probiotic species produce distinct bioactive peptide and metabolite profiles.
Why it matters
Postbiotics — the beneficial substances produced by probiotic bacteria — are gaining attention as a way to deliver health benefits without requiring live bacteria. This study provides the first detailed metabolic fingerprint comparing what Bifidobacterium and Lactobacillus actually produce, revealing that the peptide and amino acid profiles differ substantially between these two major probiotic families. Understanding these differences could help researchers design more targeted probiotic or postbiotic therapies.
The numbers in context
14 probiotic strains · 3,333 metabolites identified · 1,262 shared across all strains · 62.5% linked to microbial metabolism · 48.44% amino acid/peptide content in Bifidobacterium CFS
How the study worked
The researchers grew 14 different probiotic strains (from Bifidobacterium and Lactobacillus families) and collected their cell-free supernatants — essentially the liquid left after removing the bacteria. They then used untargeted metabolomics to identify and compare all the small molecules, peptides, and other metabolites produced by each strain, using principal component analysis to map the differences.
Who was studied
14 probiotic strains (laboratory study)
What this study cannot tell us
This was an in vitro laboratory analysis — the metabolites were identified in culture conditions, not in the human gut. Whether these same peptides and metabolites are produced in meaningful amounts inside the body remains unknown. The study also did not test the biological activity of the identified peptides, only their presence.
How to read the evidence
This is a laboratory metabolomics study that identifies and catalogues metabolites but does not test their biological effects in living organisms. It provides strong analytical chemistry data but no direct evidence of health outcomes.
When this study was published
Published in 2026, this is a very recent study reflecting current advances in metabolomics technology applied to postbiotics research.
The bigger picture
The postbiotics field is rapidly growing as researchers recognize that many probiotic health benefits come not from the bacteria themselves but from the peptides and metabolites they produce. This study provides a foundational metabolic map that could guide the development of next-generation postbiotic supplements targeting specific health outcomes based on their peptide composition.
Questions still open
- Do these bacterial peptide profiles remain the same when produced inside the human gut rather than in lab culture?
- Could specific glutamic acid peptides from Bifidobacterium be isolated and used as standalone bioactive supplements?
- How do individual diet and microbiome composition affect the peptide output of these probiotic strains?
Common questions
What are postbiotics and how do they relate to peptides?
Does this mean Bifidobacterium probiotics are better than Lactobacillus?
Read the original research
Untargeted Metabolomics Reveals Shared and Unique Metabolites in Bifidobacterium and Lactobacillus Derived Postbiotics.
Journal of agricultural and food chemistry, 74(3), 2749-2760
Citation
Liu, Yue; Sun, Yuhang; Fang, Bing; Wang, Ran; Lan, Hanglian; Zhao, Wen; Hung, Wei-Lian; Zhao, Liang; Zhang, Ming. (2026). Untargeted Metabolomics Reveals Shared and Unique Metabolites in Bifidobacterium and Lactobacillus Derived Postbiotics.. Journal of agricultural and food chemistry, 74(3), 2749-2760. https://doi.org/10.1021/acs.jafc.5c10317