Methane-producing archaea are among the oldest and most widespread microbes on Earth, living everywhere from the human gut to wastewater plants and many other environments, where they help regulate key biochemical processes. In a new study published in Nature, microbiologists led by the University of Vienna and the Institut Pasteur in Paris found a new enzyme that breaks down the cell wall of these microbes. They revealed something unexpected: the previously described structure of these microbes' cell walls was wrong. The new findings also have a wide range of applications in climate protection and biotechnology.
The discovery began with an enzyme. Nika Pende (University of Vienna) and Robert Smith (Institut Pasteur) identified and studied a new enzyme called "arminidase", which breaks down cell walls in archaea that produce the greenhouse gas methane. It plays a key role in cell division, separating the daughter cells that are still connected by the cell wall. Nika Pende, co-first author of the study, explains: "When analyzing the results to determine exactly where this enzyme attacks the cell wall, we found that the individual components of the cell wall structure differ from those previously described in the literature. We were so surprised by this result, that we initially thought it was an error in our analysis."
A wall built differently than previously thought
Most archaea do not have cell walls at all. Only two groups of methanogenic archaea share this characteristic with bacteria, whose cell walls are composed of similar components. This discovery was made more than 50 years ago. Like in bacteria, the archaeal cell wall consists of chains of two alternating sugars (glycans) linked by several amino acids (peptides), forming a net-like structure known as peptidoglycan. This structure gives the cells their rigidity and shape.
To check their surprising result, the team turned to highly specialized chemical and physical tools, including mass spectrometry and nuclear magnetic resonance. The results held up and went further: they had found a completely new sugar, never described before, plus a different linkage between sugars and peptides than the one published in the 1970s and 1980s. Every other methanogenic archaea species they tested shared the new sugar and revised structure.
"The use of more precise analytical methods and the new enzyme made it possible to revise the structure. Arminidase targets specific sites on the cell wall, this allows the peptidoglycan to be broken down into its individual components, making it easier to analyze and enabling us to discover the new sugar and overall structure", says Nika Pende.
Opening up new areas of biotechnological application
Because the enzyme targets the cell wall of methane-producing archaea so specifically, it opens the door to new tools that could weaken or disrupt it deliberately. That has real-world applications: cows are responsible for roughly a quarter to a third of the world's methane emissions, largely thanks to methane-producing archaea in their digestive systems. Compounds that interfere with the microbes' cell walls could help curb those emissions — a meaningful lever against climate change.
The findings also open new research directions on how these archaea interact with the human gut and could eventually help to develop biotechnological processes for the production of e.g., custom-made proteins or biopolymers, such as natural and biodegradable plastics.
Summary
- Methanogenic archaea are considered ecologically and economically important microorganisms that are widespread and among other things, play a role in the gut microbiome
- Microbiologists at the University of Vienna and the Pasteur Institute in Paris have identified and described a new enzyme that is important in the cell division of methanogenic archaea
- With the help of this enzyme, a new sugar was discovered, leading to a revision of the archaea cell wall structure
- The enzyme can also be used as a tool, as it specifically targets the cell wall of these particular microorganisms
- This could help reduce methane emissions, advance our understanding of human health, and enable the use of these microorganisms in biotechnology for added-value products
Reference: Smith & Pende et al., A methanogen hydrolase reveals the structure of archaeal peptidoglycan, Nature (2026). DOI: 10.1038/s41586-026-11028-y
Behind the paper: Pende, Cracking the Archaeal Cell Wall: How a hydrolase overturned a 50-year-old paradigm, communities.springernature.com/posts/cracking-the-archaeal-cell-wall-how-a-hydrolase-overturned-a-50-year-old-paradigm
Scientific contact:
Nika Pende, PhD
Department for Functional and Evolutionary Ecology, University of Vienna
1030 Vienna, Djerassiplatz 1
T: +43-4277-76527
https://archaea.univie.ac.at/team/pende/
