Winogradsky Institute of Microbiology, Research Centre of Biotechnology, Russian Academy of Sciences, Moscow, Russia.
Department of Biotechnology, Delft University of Biotechnology, Delft, The Netherlands.
Environ Microbiol. 2022 Nov;24(11):5217-5229. doi: 10.1111/1462-2920.16108. Epub 2022 Jul 18.
Methanonatronarchaeia represents a deep-branching phylogenetic lineage of extremely halo(alkali)philic and moderately thermophilic methyl-reducing methanogens belonging to the phylum Halobacteriota. It includes two genera, the alkaliphilic Methanonatronarchaeum and the neutrophilic Ca. Methanohalarchaeum. The former is represented by multiple closely related pure culture isolates from hypersaline soda lakes, while the knowledge about the latter is limited to a few mixed cultures with anaerobic haloarchaea. To get more insight into the distribution and ecophysiology of this enigmatic group of extremophilic methanogens, potential activity tests and enrichment cultivation with different substrates and at different conditions were performed with anaerobic sediment slurries from various hypersaline lakes in Russia. Methanonatronarchaeum proliferated exclusively in hypersaline soda lake samples mostly at elevated temperature, while at mesophilic conditions it coexisted with the extremely salt-tolerant methylotroph Methanosalsum natronophilum. Methanonatronarchaeum was also able to serve as a methylotrophic or hydrogenotrophic partner in several thermophilic enrichment cultures with fermentative bacteria. Ca. Methanohalarchaeum did not proliferate at mesophilic conditions and at thermophilic conditions it competed with extremely halophilic and moderately thermophilic methylotroph Methanohalobium, which it outcompeted at a combination of elevated temperature and methyl-reducing conditions. Overall, the results demonstrated that Methanonatronarchaeia are specialized extremophiles specifically proliferating in conditions of elevated temperature coupled with extreme salinity and simultaneous availability of a wide range of C -methylated compounds and H /formate.
甲醇营养甲烷古菌代表了一个深分枝的进化谱系，该谱系中的极度嗜盐（碱）和中嗜热的甲基还原产甲烷菌属于盐杆菌门。它包括两个属，即嗜碱的甲醇营养甲烷古菌和嗜中性的 Ca. 甲烷盐古菌。前者由来自高盐苏打湖的多个密切相关的纯培养物代表，而后者的知识仅限于少数与厌氧盐杆菌混合培养物。为了更深入地了解这种神秘的极端嗜甲烷古菌的分布和生态生理学，对来自俄罗斯各种高盐湖泊的厌氧沉积物悬浮液进行了不同底物和不同条件下的潜在活性测试和富集培养。甲醇营养甲烷古菌仅在高盐苏打湖样品中大量繁殖，温度升高时会大量繁殖，而在中温条件下，它与极其耐盐的甲基营养菌 Methanosalsum natronophilum 共存。甲醇营养甲烷古菌还能够在与发酵细菌的几种高温富集培养物中作为甲基营养型或氢营养型伙伴。Ca. 甲烷盐古菌在中温条件下不会繁殖，在高温条件下，它与极其嗜盐和中嗜热的甲基营养菌 Methanohalobium 竞争，在高温和甲基还原条件下，它会胜过后者。总的来说，结果表明，甲醇营养甲烷古菌是专门的极端微生物，仅在高温条件下，同时存在广泛的 C-甲基化合物和 H/甲酸盐，并且具有极高的盐度，才会大量繁殖。
