One Man’s Poop is Another Man’s Treasure: The Metabolic Systems of Rare Syntrophic Organisms

Unfortunately, in our world cow feces aren’t very tasty or appealing to most, and typically when thinking of waste, all that is seen is useless byproducts or even pollutants that have no immediate use in the world. However, just as humans have found a practical use for manure, it seems the rare ecosystems of extremophiles have beat humans to the punch. Many rare bacteria and archaea have evolved to survive extreme and specific conditions, thanks to their versatility and speedy evolutionary properties, which is why we see so many unique kinds of metabolisms different from the more familiar glucose pathways.

In 2025, researchers at the University of British Columbia discovered a new species of bacterium called Syntrophacetatiphaga Salishiae (STPS), which roughly translates to ‘syntrophic organism that eats acetate from another organism.’ Acetate is a commonly seen salt, also seen as the main component in vinegar, so it is very different from the glucose we use in our metabolic processes. However, through syntrophic acetate oxidation a bacteria can “oxidize acetate and produce H₂ and CO₂, or formate… [where they] can serve as interspecies electron carriers” (Timmers et al. 2018) by their partner species, according to the study Metabolism and Occurrence of Methanogenic and Sulfate-Reducing Syntrophic Acetate Oxidizing Communities in Haloalkaline Environments.

In this kind of metabolism, where the starting source is carbon based, is oxidized into acetyl coenzyme A and into pyruvate which are similarly found in carbohydrate metabolism, except in this system it operates in the reverse direction. Cellular carriers accept electrons from the redox reactions and take them to the further down reactions, and finally forms formate, which is the final product of its metabolism, but the electron carrier for other organisms, and the exergonic reactions that take place and release energy into the cell is used for its cellular processes. This process is shown in the figure below.

STPS is not an organism to underestimate, it is essential to its ecosystem. The study that discovered it also noted how crucial it was in its environment: “[STPS] accounted for a majority of acetate flux, suggesting that the oxidative glycine pathway is an important route for anaerobic carbon transformation and is probably central to community metabolism in natural and engineered ecosystems” (Friedline et al. 2025). All these processes are really special and rare; fermenting bacterium break down food waste into smaller substances like fatty acids or amino acids, including acetate, then STPS, an anoxic bacteria eats the acetate to make formate, and other anoxic bacterium will use that formate to make methane which is either released for the ecosystem, or can potentially be harvested as a natural gas resource.

In conclusion, STPS’s as a microorganism cooperating with other species in its metabolic processes are incredibly unique and a huge essential in its unique environment for ensuring the health and survival of its ecosystem. Microbial life is persistently adaptable, and humans are still discovering more and more about extreme environments, unique microbe metabolism, and the wonders of syntrophic systems.

References

Friedline, S., McDaniel, E.A., Scarborough, M. et al. Activity-targeted metaproteomics uncovers rare syntrophic bacteria central to anaerobic community metabolism. Nat Microbiol 10, 2749–2767 (2025). https://doi.org.libaccess.lib.mcmaster.ca/10.1038/s41564-025-02146-w

Timmers, Peer H. A., Charlotte D. Vavourakis, Robbert Kleerebezem, et al. “Metabolism and Occurrence of Methanogenic and Sulfate-Reducing Syntrophic Acetate Oxidizing Communities in Haloalkaline Environments.” Frontiers, October 27, 2026. https://doi.org/10.3389/fmicb.2018.03039.