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ORIGINAL RESEARCH article
Front. Microbiol.
Sec. Microbiological Chemistry and Geomicrobiology
Volume 15 - 2024 |
doi: 10.3389/fmicb.2024.1414379
This article is part of the Research Topic Subsurface Microbiology within Hydrocarbon Resources or Stored Gases View all 5 articles
Generation of secondary microbial methane of high-rank coals: Insights from the microbial community and carbon isotope
Provisionally accepted- 1 Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, China
- 2 Marine Core Research Institute, Kōchi University, Kochi, Kōchi, Japan
Secondary microbial methane could provide a valuable energy source if it was better understood. Although coal seam is an ideal environment for investigating secondary microbial methane, there are few studies to trace the secondary microbial methane of high-rank coals. Here, we collected coproduced water samples from coalbeds in the Qinshui Basin (China) and analyzed the microbial community structure by 16S ribosomal RNA (16S rRNA) amplicon sequencing analysis. 16S rRNA sequencing demonstrated abundant methanogens in coalbeds including 6 orders (Methanobacteriales, Methanococcales, Methanofastidiosales, Methanomassiliicoccale, Methanomicrobiales and Methanosarciniales) and 22 genera of methanogens. Superheavy DIC (δ 13 CDIC ranging from -4.2‰ to 34.8‰) and abundance of methanogenic microbes in co-produced water revealed the generation of secondary biogenic methane in high-rank coal seams in the Qingshui Basin. Hydrogenotrophic methanogenesis is the main pathway for secondary biogenic methane production. In deeply buried coal seams, biogenic methane is dominated by CO2 and H2 reduction methanogenesis, and in shallow buried coal seams, it may be produced synergistically by hydrocarbon degradation and hydrogenotrophic methanogenic microbes. The study discussed here is important for a better understanding of the generation of secondary microbial methane in high-rank coal.
Keywords: Coalbeds, microbial community, δ 13 C, Secondary microbial methane, High-rank coal
Received: 08 Apr 2024; Accepted: 12 Jul 2024.
Copyright: © 2024 Nai, Xu, Chen, Zhong, Fang, Qin and Sano. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Sheng Xu, Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, China
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Biying Chen
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