Abstract

Methane metabolism in deep subsurface petroleum reservoirs is of paramount interest in the global biogeochemical cycle of carbon. Methanogenesis in such habitats is driven mostly by methanogens in syntrophic association with bacteria. In the present study, methanogenic communities in production water samples from six wells of a high-temperature petroleum reservoir were analyzed based on both genomic 16S rDNA and metabolically active 16S rRNA. The PCR-amplified mcrA gene analysis showed that Methanosaeta (26%) and Methanomassiliicoccus (56%) were separately the dominant members in sample W2_71 and W9_18 at the DNA level. In comparison, the RNA-based analysis showed that Methanosaeta (63 ∼ 83%) followed by Methanolinea (16 ∼ 23%) were the most active methanogens, which were different from the communities of genomic DNA. While several lines of studies indicated that CO₂-reducing methanogens of the genus Methanothermobacter was the most frequently detected phylotype in deep-subsurface petroleum reservoirs. Redundancy analysis (RDA) showed the possible correlation between active methanogens (Methanosaeta) and environmental factors (CO₃^2-). The datasets indicated the importance of investigating methanogenic community by integrating DNA- and RNA-based approaches. These results provide new insight into active methanogens in high-temperature petroleum reservoirs, and promote a comprehensive understanding of methanogens as well as their potential methanogenic pathways in such environments.

抽象的

在地下碳的全球生物地球化学循环中，深层地下石油储层中的甲烷代谢至关重要。在这些生境中的产甲烷作用主要是由与细菌同养的产甲烷菌驱动的。在本研究中，基于基因组16S rDNA和代谢活性16S rRNA，分析了高温石油储层6口井采出水样品中的产甲烷菌群落。PCR扩增的mcrA基因分析表明，在DNA水平上，甲烷菌（26％）和甲烷菌（56％）分别是样品W2_71和W9_18的主要成员。相比之下，基于RNA的分析表明，甲烷菌（63〜83％）其次是甲醇（16-23％）是最活跃的产甲烷菌，与基因组DNA群落不同。虽然研究几行表明，CO ₂ -还原属的甲烷菌Methanothermobacter在深地下油气藏的最常检测到的种系型。冗余分析（RDA）显示了活性产甲烷菌（Methanosaeta）与环境因素（CO ₃ ^2-）。数据集表明了通过整合基于DNA和RNA的方法研究产甲烷菌群落的重要性。这些结果为高温石油储层中的活性产甲烷菌提供了新的见解，并促进了对产甲烷菌及其在此类环境中潜在产甲烷途径的全面了解。