Anaerobic microorganisms are critical in regulating ethane in geothermal environments, where selenate and selenite are common contaminants. Although coupling ethane oxidation with selenate reduction has been demonstrated as feasible, such processes remain poorly explored in geothermal environments. This study addressed this gap by successfully enriching thermophilic anaerobic cultures capable of coupling ethane oxidation with selenate/selenite reduction, achieving selenate and selenite removal rate of 2.7 mg Se/L/d and 2.1 mg Se/L/d, respectively. Metagenomic analysis revealed a novel genus ‘Candidatus Ethanivorans selenatireducens’, which accounted for 16.0 % and 32.6 % of microbial communities in selenate- and selenite-dependent systems, respectively. This microorganism encoded pathways for anaerobic ethane oxidation via fumarate addition and genes required for the sequential reduction of selenate to elemental selenium. These findings unveiled a novel microbial mechanism linking ethane oxidation and selenate reduction in geothermal systems, providing new insights into the biogeochemical interaction between carbon and selenium in thermophilic environments.

中文翻译：

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嗜热厌氧乙烷氧化偶联硒酸盐和亚硒酸盐还原


厌氧微生物对于在地热环境中调节乙烷至关重要，其中硒酸盐和亚硒酸盐是常见的污染物。尽管乙烷氧化与硒酸盐还原耦合已被证明是可行的，但此类过程在地热环境中仍然缺乏探索。本研究通过成功富集能够将乙烷氧化与硒酸盐/亚硒酸盐还原耦合的嗜热厌氧培养物来解决这一差距，分别实现了 2.7 mg Se/L/d 和 2.1 mg Se/L/d 的硒酸盐和亚硒酸盐去除率。宏基因组分析揭示了一个新的属 'Candidatus Ethanivorans selenatireducens'，在硒酸盐和亚硒酸盐依赖系统中分别占微生物群落的 16.0% 和 32.6%。这种微生物编码通过富马酸盐添加厌氧乙烷氧化的途径以及将硒酸盐连续还原为元素硒所需的基因。这些发现揭示了地热系统中乙烷氧化和硒酸盐还原之间的一种新的微生物机制，为嗜热环境中碳和硒之间的生物地球化学相互作用提供了新的见解。