Microbial Metabolism and Antimicrobial Production in Gut Microbiota

The human gut is colonised by a densely populated community of bacteria, archaea and fungi that cooperate and compete through an array of metabolic processes. Many gut residents ferment dietary carbohydrates to yield short-chain fatty acids (SCFAs) such as acetate, propionate and butyrate, which nourish intestinal cells, regulate immune function and influence systemic metabolism. In parallel, certain microbes convert glycerol and other substrates into potent antimicrobial agents, including 3-hydroxypropionaldehyde (reuterin) and its reactive by-product acrolein. These compounds shape community composition by inhibiting pathogens and modulating interspecies interactions. Biosynthesis of antimicrobial metabolites often depends on gene clusters encoding cobalamin-dependent enzymes, which link vitamin B12 availability to both microbial growth and defensive chemistry. Collectively, microbial metabolism and antimicrobial production in the gut are essential for colonisation resistance, maintenance of barrier integrity and the fine-tuning of host–microbe symbiosis, with implications for infectious disease control, metabolic health and the development of novel bioactive compounds.

Research from Nature Portfolio

Recent analyses have redefined the active agent of the reuterin system, demonstrating that acrolein rather than 3-hydroxypropionaldehyde is primarily responsible for antimicrobial activity and chemical conjugation with dietary toxins. Using a combination of advanced spectroscopic techniques and selective scavengers, investigators showed that acrolein formation occurs under physiological conditions in the colon and drives both microbial inhibition and detoxification of heterocyclic amines. This work reshapes our understanding of the biochemical dynamics of glycerol-derived antimicrobials and underscores the need to consider reactive intermediates when evaluating microbial defence strategies.

Microbial Metabolism and Antimicrobial Production in Gut Microbiota publication trend

The graph below shows the total number of articles in microbial metabolism and antimicrobial production in gut microbiota across all publications each year (not limited to Nature Index journals).

Technical terms

3-Hydroxypropionaldehyde (3-HPA, reuterin): A reactive aldehyde produced by certain lactic acid bacteria via glycerol dehydratase, exhibiting broad-spectrum antimicrobial activity.

Acrolein: A toxic unsaturated aldehyde formed from the spontaneous dehydration of reuterin; identified as the primary antimicrobial component within the reuterin system.

Short-chain fatty acids (SCFAs): Organic acids with fewer than six carbon atoms, produced by microbial fermentation of dietary fibres, vital for gut health and host metabolism.

Glycerol dehydratase (PduCDE): A cobalamin-dependent enzyme complex that catalyses the conversion of glycerol to 3-HPA, linking vitamin B12 biosynthesis to antimicrobial metabolite production.

Cobalamin (Vitamin B12): A cobalt-containing cofactor synthesised by gut bacteria, essential for the activity of enzymes involved in microbial metabolism and secondary metabolite formation.

References

1. Acrolein contributes strongly to antimicrobial and heterocyclic amine transformation activities of reuterin. Scientific Reports (2016).
2. Glycerol-derived reuterin regulates human intestinal microbiota and metabolites. Frontiers in Microbiology (2024).
3. Insights into the Mechanisms of Reuterin against Staphylococcus aureus Based on Membrane Damage and Untargeted Metabolomics. Foods (2023).