Microbial Methanogenesis in Coal-Bed Systems

Microbial methanogenesis in coal-bed systems represents a convergence of geology, microbiology and energy science, whereby subsurface microbial consortia convert coal-derived organic matter into methane. This process depends on complex microbial networks, including fermentative bacteria that depolymerise coal polymers into simple substrates and methanogenic archaea that produce methane via hydrogenotrophic or acetoclastic pathways. Environmental factors such as coal rank, pore structure, trace element availability and the geochemical milieu shape community composition, metabolic rates and gas yields. Advances in genomic and isotopic analyses have elucidated functional roles of key taxa and revealed that biofilms form on coal surfaces, facilitating substrate exchange. Manipulations such as biostimulation and bioaugmentation have been explored to enhance in situ conversion rates, offering a potential route to low-carbon gas production. Global interest centres on harnessing microbial conversion for unconventional gas recovery, mitigating greenhouse emissions and exploring carbon-neutral or negative energy options within existing infrastructure.

Research from Nature Portfolio

Recent investigations have demonstrated that supplementing coal seams with plant-derived carbohydrates can bypass the intrinsic limitations of coal bioavailability, enabling indigenous microbes to generate low-carbon renewable natural gas without reliance on coal solubilisation. Concurrent studies have quantified the nano-pore structural evolution of coal during microbial treatment, revealing that bio-conversion can increase accessible micropore volume and enhance methane adsorption capacity by opening previously closed pore networks. These insights underscore the interplay between microbial metabolism and physical reservoir properties. Complementary genomic and phenotypic analyses of facultative anaerobes from subsurface coal seals have highlighted diverse ecological strategies among early-colonising bacteria, which recycle biomass and funnel nutrients into methanogenic pathways, thereby sustaining long-term community function and stabilising methane production.

Microbial Methanogenesis in Coal-Bed Systems publication trend

The graph below shows the total number of articles in microbial methanogenesis in coal-bed systems across all publications each year (not limited to Nature Index journals).

Technical terms

Microbial methanogenesis: Biological production of methane by specialised archaea from simple substrates.

Hydrogenotrophic methanogenesis: Methane synthesis using hydrogen and carbon dioxide as substrates.

Acetoclastic methanogenesis: Methane production from acetate cleavage by methanogenic archaea.

Biostimulation: Enhancement of indigenous microbial activity via nutrient or substrate amendment.

Poromechanics: Study of mechanical and fluid interactions within porous geological materials.

Coalbed methane: Natural gas stored in coal seams, often adsorbed on internal surfaces.

References

1. Low carbon renewable natural gas production from coalbeds and implications for carbon capture and storage. Nature Communications (2017).
2. Changes in pore structure of coal caused by coal-to-gas bioconversion. Scientific Reports (2017).
3. Genomic and phenotypic insights point to diverse ecological strategies by facultative anaerobes obtained from subsurface coal seams. Scientific Reports (2019).
4. Understanding poromechanical response of a biogenic coalbed methane reservoir. International Journal of Coal Science & Technology (2024).
5. Bioconversion of coal to methane by microbial communities from soil and from an opencast mine in the Xilingol grassland of northeast China. Biotechnology for Biofuels and Bioproducts (2019).
6. Long-term succession in a coal seam microbiome during in situ biostimulation of coalbed-methane generation. The ISME Journal: Multidisciplinary Journal of Microbial Ecology (2018).