Kangaroo Gut Bacteria Reveal New Hydrogen Management Strategies
- Authors
- Kate L Bowerman, Yang Lu, Harley McRae, James G Volmer, Julian Zaugg, Phillip B Pope, Philip Hugenholtz, Chris Greening, Mark Morrison, Rochelle M Soo, Paul N Evans
- Journal
- mSystems
- Year
- 2025
- DOI
- 10.1128/msystems.01608-25
- Study Type
- Kangaroo
- Outcome
- Neutral
- Peer Reviewed
- Yes
- Country
- Australia
- Health Condition
- Digestive Health
- Body System
- Digestive System
TL;DR
Marsupial gut microbes use different hydrogen-management strategies, including pathways that divert hydrogen away from methane production, which may explain why some species produce less methane.
Key Finding
Marsupial gut microbiomes employ diverse hydrogen management strategies, with some species enriched in methane-producing genes while others favor alternative hydrogen-uptake pathways that reduce methane production.
Summary
Researchers studied the gut bacteria of 14 marsupial species (like kangaroos and wallabies) to understand why they produce less methane than similar-sized livestock. They found that different marsupial species use different strategies to manage hydrogen—a byproduct of digestion—with some favoring methane production and others using alternative pathways that don't produce methane. This variation exists even within the same species, suggesting that individual differences in gut bacteria composition, rather than species type alone, determine how much methane each animal produces.
Practical Takeaway
This is a foundational microbiology study of marsupial digestion with no direct application to hydrogen water for humans. While it demonstrates that hydrogen management by gut bacteria influences methane production in animals, the study does not investigate hydrogen water consumption or its effects on human health or microbiota.
Abstract
Methane is an end product of plant biomass digestion by gut microbiota, though the amount produced and/or released varies between hosts. On a per-unit-of-feed basis, macropodid marsupials (e.g., kangaroos) have been reported to emit less methane than ruminant livestock, despite a similar diet, although measurements exist for only a subset of macropodid species. Competition for hydrogen within the gut microbiome, particularly through alternative hydrogen sinks to methanogenesis, influences methane production; therefore, characterizing hydrogen management strategies within a host system can provide insights into methane emission profiles. In this study, we analyzed 33 fecal microbiomes of 14 marsupial species (predominantly captive animals) to provide the first systematic characterization of methanogen types and hydrogen-cycling genetic capacity across marsupial gut microbiomes. We recovered 1,394 metagenome-assembled genomes and identified host-associated bacterial signatures that varied significantly between marsupial species. Comparative analysis with fecal microbiomes from high- and low-methane-emitting mammals revealed that marsupials display heterogeneous hydrogen management strategies: some harbor elevated methanogenesis genes (mcrA, methanogen-specific hydrogenases), while others show enrichment of bacterial hydrogen-uptake hydrogenases and alternative electron acceptor pathways (nitrate/nitrite reduction, sulfite reduction). This predicted functional variation occurs both between and within marsupial families and gut types, suggesting that hydrogen management capacity may differ within taxonomic and anatomical classifications. These results demonstrate that marsupial gut microbiomes cannot be treated as a functionally homogenous group regarding methane emissions and highlight the need for species-specific measurements to accurately assess their methanogenic potential and inform ecological models of greenhouse gas production.IMPORTANCEHerbivorous marsupials such as kangaroos and wallabies have been reported to produce significantly lower methane emissions than ruminant livestock despite eating a similar diet, yet the microbial mechanisms underlying this difference remain poorly understood. Here, we conduct a comparative study of fecal microbiomes of 14 marsupial species to provide the first investigation of hydrogen-cycling genetic capacity across these animals. Through comparative analysis with fecal microbiomes of high- and low-methane-producing animals, we identify enrichment of bacterial genes for alternative hydrogen uptake and disposal pathways in some marsupials, supporting competition for hydrogen playing a role in the level of methane production. These data also indicate variation in hydrogen management between marsupials, including within species, suggesting methane emission capacity may vary at the level of the individual.