Microbial community and the type of methanogenesis associated with biogenic gas in Luling Coalfield, China

Abstract:

[Objective] The aim of this study was to study microbial community structures and type of methanogenesis associated with biogenic gas in Luling Coalfield, China. [Methods] We detected microbial distribution of the formation water by high-throughput pyrosequencing and bioinformatic analysis. Anaerobic culture was also used to verify the type of methanogenesis. [Results] The composition and stable isotopic ratios of gas samples implied a mixed biogenic and thermogenic methane. Archaeal 16S rRNA gene analysis revealed the survival of the acetoclastic, methylotrophic, and hydrogenotrophic methanogen in the produced water. Most detected bacteria could degrade aromatic and cellulose-derived compounds in coal. The activity and potential of methanogens of the related bacteria were confirmed by the obvious methane production in enrichments supplemented with acetate, formate or H₂+CO₂. [Conclusion] Acetoclastic and methylotrophic as well as hydrogenotrophic methanogenesis was responsible for the methanogenesis in Luling coalfield. These results would provide theoretical basis to improve the coal bed methane production using microbial technology and realize the sustainable exploitation of coal bed methane.

Key words:coal bed methane;acetoclastic methanogenesis;methanogens