Methanogenesis mediated by archaea is the major source of methane, a strong greenhouse gas, and thus is critical for understanding Earth’s climate dynamics. Recently, genes encoding diverse methanogenesis pathways were discovered in metagenome-assembled genomes affiliated with multiple archaeal phyla^1–7. However, all experimental studies on methanogens are currently restricted to cultured representatives of the Euryarchaeota. Here we show for the first time methanogenic growth by a member of the lineage Korarchaeia within the phylum Thermoproteota (TACK superphylum)^5–7. Following enrichment cultivation of Candidatus Methanodesulfokora washburnenis strain LCB3 we used measurements of metabolic activity and isotope tracer conversion to demonstrate methanol reduction to methane using hydrogen as electron donor. Analysis of the archaeon’s circular genome and transcriptome revealed unique modifications in the energy conservation pathways linked to methanogenesis, including enzyme complexes involved in hydrogen and sulfur metabolism. The cultivation and characterization of this novel group of archaea is critical for a deeper evaluation of the diversity, physiology, and biochemistry of methanogens.

古细菌介导的产甲烷作用是甲烷（一种强温室气体）的主要来源，因此对于了解地球的气候动态至关重要。最近，在隶属于多个古菌门的宏基因组组装基因组中发现了编码不同产甲烷途径的基因^1-7 。然而，所有关于产甲烷菌的实验研究目前仅限于培养的广古菌代表。在这里，我们首次展示了 Thermoproteota 门（TACK 超门）内 Korarchaeia 谱系成员的产甲烷生长^5-7 。在对Candidatus Methodesulfokora Washburnenis 菌株 LCB3 进行富集培养后，我们使用代谢活性和同位素示踪剂转化的测量来证明使用氢作为电子供体将甲醇还原为甲烷。对古细菌环状基因组和转录组的分析揭示了与产甲烷作用相关的能量守恒途径的独特修饰，包括参与氢和硫代谢的酶复合物。这一新古菌群的培养和表征对于更深入地评估产甲烷菌的多样性、生理学和生物化学至关重要。