New species of methane-producing archaea discovered in the human gut

Summary

Scanning electron micrograph of Methanobrevibacter smithii DSM 861 (=PST), Methanobrevibacter smithii DSM 2375 (=ALI), Methanobrevibacter smithii GRAZ-2 and WWM1085. Credit: International Journal of Systematic and Evolutionary Microbiology (2025). DOI: 10.1099/ijsem.0.006751 An international team of microbiologists from the Medical University of Graz, the DSMZ—German Collection of Microorganisms and Cell Cultures (Braunschweig, Germany)—and the University of Illinois (U.S.) has identified and described a previously unknown species of methane-producing archaea in the human gut: Methanobrevibacter intestini sp. nov. (strain WWM1085). In addition, a new variant of the species Methanobrevibacter smithii, which is referred to as GRAZ-2, was isolated. The scientists have thus taken another important step toward understanding the interaction between humans and the microbiome. The study is published in the International Journal of Systematic and Evolutionary Microbiology. Unknown original inhabitants of the gut: What is special about archaea Archaea are a distinct domain of life—along with bacteria and eukaryotes (i.e., organisms with a cell nucleus such as animals, plants and fungi). Although they appear similar to bacteria under the microscope, they differ in many basic aspects: for example, in their cell membrane, metabolic pathways and genetic characteristics. Archaea were originally discovered above all in extreme environments such as hot springs or salt lakes, but they are also found in the human body, especially in the gut. Methane-producing archaea, so-called methanogens, are a particularly exciting research area: They produce methane from simple substrates such as hydrogen and CO₂ and thus significantly contribute to microbial metabolic processes—in ruminants, for example, but also in the human gut. Their research is still in its infancy because they are extremely sensitive to oxygen and difficult to cultivate. Christine Moissl-Eichinger and Viktoria Weinberger. Cr...