Rapid microbial methanogenesis during CO2 storage in hydrocarbon reservoirs

Journal article

Hydrogen may be the most important electron donor available in the subsurface. Here we analyse the diversity, abundance and expression of hydrogenases in 5 proteomes, 25 metagenomes, and 265 amplicon datasets of groundwaters with diverse geochemistry. A total of 1545 new [NiFe]-hydrogenase gene sequences were recovered, which considerably increased the number of sequences (1999) in a widely used database. [NiFe]-hydrogenases were highly abundant, as abundant as the DNA-directed RNA polymerase. The abundance of hydrogenase genes increased with depth from 0 to 129 m. Hydrogenases were present in 481 out of 1245 metagenome-assembled genomes. The relative abundance of microbes with hydrogenases accounted for similar to 50% of the entire community. Hydrogenases were actively expressed, making up as much as 5.9% of methanogen proteomes. Most of the newly discovered diversity of hydrogenases was in "Group 3b", which has been associated with sulfur metabolism. "Group 3d", facilitating the interconversion of electrons between hydrogen and NAD, was the most abundant and mainly observed in methanotrophs and chemoautotrophs. "Group 3a", associated with methanogenesis, was the most abundant in proteomes. Two newly discovered groups of [NiFe]-hydrogenases, observed in Methanobacteriaceae and Anaerolineaceae, further expanded diversity. Our results highlight the vast diversity, abundance and expression of hydrogenases in groundwaters, suggesting a high potential for hydrogen oxidation in subsurface habitats

Authors: Tyne, RL; Barry, PH; Lawson, M; Byrne, DJ; Warr, O

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Nature Research
• Journal: Nature
• Volume: 600
• Issue: 7890
• Pages: 670-674
• Publication date: 2021-12-22
• DOI: 10.1038/s41586-021-04153-3
• EISSN: 1476-4687
• ISSN: 0028-0836
• Language: English
• Keywords: Ecology; Total organic carbon; Enhanced oil recovery; Chemistry; Environmental science; Isotopes of carbon; Geology; Carbon dioxide; Biology; Petroleum engineering; Environmental chemistry; Carbon sequestration; Methane; Methanogenesis; Hydrocarbon