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This content will become publicly available on December 12, 2026

Title: Cultivation of Methanonezhaarchaeia, the third class of methanogens within the phylum Thermoproteota
Methane is a potent greenhouse gas, largely produced by methanogenic archaea, contributing to Earth’s dynamic climate and biogeochemical cycles. In the past decade, metagenomics revealed that lineages outside of the Euryarchaeota superphylum encode genes for methanogenesis. This was recently confirmed through the cultivation of two classes of methanogenic Thermoproteota. Thus far, all methanogens within the Thermoproteota are predicted or were shown to be methylotrophic. The only exception to this are the Nezhaarchaea, for which metagenomic predictions suggest they are CO2-reducing methanogens. Here, we demonstrate methanogenic activity in a third class of Thermoproteota, the Methanonezhaarchaeia. Contrary to genomic predictions for this class, we cultivated a methylotrophic species,CandidatusMethanonezhaarchaeum fastidiosum YNP3N, highlighting the importance of testing metagenomic hypotheses through experimentation. We investigate the metabolic diversity of Methanonezhaarchaeia, including metabolic modifications accompanying frequent loss of methanogenesis in this class. This highlights gaps in our understanding of the biochemistry, diversity, and evolution of thermoproteotal methanogens and their contributions to carbon cycling.  more » « less
Award ID(s):
2049445
PAR ID:
10660009
Author(s) / Creator(s):
; ;
Publisher / Repository:
Science
Date Published:
Journal Name:
Science Advances
Volume:
11
Issue:
50
ISSN:
2375-2548
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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