Methanogenic microbial community of the Eastern Paris Basin: Potential for energy production from organic-rich shales

•Methanogens can be isolated from all 5 facies of the Paper Shale Formation (Lower Jurassic, Paris Basin)•Shallow, thermally immature organic-rich shales represent considerable resources in the Paris Basin (France)•Loose relations between methanogens and lithology may be explained by water circulation at the margin of the Paris Basin.•This study extends the range of putative rock formation with potential for in situ microbial methanogenesis

Shallow, thermally immature organic-rich shales represent considerable resources in the Paris Basin (France). We investigated the presence of methanogenic consortia (i.e., syntrophic bacteria and methanogens) in the Lower Toarcian Paper Shales formation, to link geochemical and lithological properties of the rocks to the spatial distribution of microbial communities. The presence of methanogenic microbial populations, demonstrated via their growth in enrichment cultures, occurs throughout most of the rock layers, and may be explained by the transport of organics and microorganisms within the formation. The enriched consortia were able to utilize the organic matter of the rock as sole carbon source in microcosm, indicating a strong potential of these microbial communities for methanogenesis in situ.