Asgard archaea are widely distributed in anaerobic environments. Previous studies revealed the potential capability of Asgard archaea to utilize various organic substrates including proteins, carbohydrates, fatty acids, amino acids and hydrocarbons, suggesting that Asgard archaea play an important role in sediment carbon cycling. Here, we describe a previously unrecognized archaeal phylum, Hermodarchaeota, affiliated with the Asgard superphylum. The genomes of these archaea were recovered from metagenomes generated from mangrove sediments, and were found to encode alkyl/benzyl-succinate synthases and their activating enzymes that are similar to those identified in alkane-degrading sulfate-reducing bacteria. Hermodarchaeota also encode enzymes potentially involved in alkyl-coenzyme A and benzoyl-coenzyme A oxidation, the Wood–Ljungdahl pathway and nitrate reduction. These results indicate that members of this phylum have the potential to strictly anaerobically degrade alkanes and aromatic compounds, coupling the reduction of nitrate. By screening Sequence Read Archive, additional genes encoding 16S rRNA and alkyl/benzyl-succinate synthases analogous to those in Hermodarchaeota were identified in metagenomic datasets from a wide range of marine and freshwater sediments. These findings suggest that Asgard archaea capable of degrading alkanes and aromatics via formation of alkyl/benzyl-substituted succinates are ubiquitous in sediments.

Asgard 古菌广泛分布于厌氧环境中。先前的研究揭示了 Asgard 古生菌利用各种有机底物（包括蛋白质、碳水化合物、脂肪酸、氨基酸和碳氢化合物）的潜在能力，表明 Asgard 古生菌在沉积物碳循环中发挥着重要作用。在这里，我们描述了一个以前未被认识的古菌门 Hermodarchaeota，它隶属于 Asgard 超门。这些古细菌的基因组是从红树林沉积物产生的宏基因组中回收的，并被发现编码烷基/苄基-琥珀酸合酶及其激活酶，这些酶与烷烃降解硫酸盐还原细菌中鉴定的那些相似。Hermodarchaeota 还编码可能参与烷基辅酶 A 和苯甲酰辅酶 A 氧化的酶，Wood-Ljungdahl 途径和硝酸盐还原。这些结果表明，该门的成员具有严格厌氧降解烷烃和芳香族化合物的潜力，与硝酸盐的还原相结合。通过筛选序列读取存档，在来自广泛海洋和淡水沉积物的宏基因组数据集中，鉴定了与 Hermodarchaeota 中类似的编码 16S rRNA 和烷基/苄基琥珀酸合酶的其他基因。这些发现表明，能够通过形成烷基/苄基取代的琥珀酸盐来降解烷烃和芳烃的 Asgard 古菌在沉积物中普遍存在。在来自各种海洋和淡水沉积物的宏基因组数据集中，鉴定了与 Hermodarchaeota 中类似的编码 16S rRNA 和烷基/苄基琥珀酸合酶的其他基因。这些发现表明，能够通过形成烷基/苄基取代的琥珀酸盐来降解烷烃和芳烃的 Asgard 古菌在沉积物中普遍存在。在来自各种海洋和淡水沉积物的宏基因组数据集中，鉴定了与 Hermodarchaeota 中类似的编码 16S rRNA 和烷基/苄基琥珀酸合酶的其他基因。这些发现表明，能够通过形成烷基/苄基取代的琥珀酸盐来降解烷烃和芳烃的 Asgard 古菌在沉积物中普遍存在。