In situ field experiment shows the potential of methanogenic archaea for biomethane production from underground gas storage in natural rock environment

Abstract

Biological methanation occurs naturally in the specific rock environment of some underground gas reservoirs. To use the natural potential of hydrogenotrophic methanogenic archaea in the underground gas reservoirs environment in the future for any type of energy conversion, better knowledge of these systems is required. Most studies investigating the potential for biological methane production from hydrogen and carbon dioxide have been conducted in laboratory-scale systems, making it impossible to evaluate the process under realistic environmental conditions. A unique field experiment of biomethanation in an underground gas reservoir confirmed the feasibility of these facilities for targeted production of biologically produced methane. The experiment followed data previously obtained from long-term experiments carried out in the laboratory, including 300 days lasting operation of reactor and cultivation experiments, which led to repeated isolation of Methanothermobacter sp. This species was the dominant methanogen, which raised from 1% to 43% of all microbial population after 22 days of field experiment, while the complete conversion of hydrogen took place. In addition, the study is supported by metagenomic analysis to gain deep insight into the microbiome of the underground gas reservoir.