Microbial diversity of a coalbed methane reservoir in Ordos Basin, China, characterized by 454 pyrosequencing

It is generally believed that biogenic coalbed methane (CBM) were end products of biodegradation of coal by methanogenic archaea and syntrophic bacteria. However, the process of biodegradation of coal was not fully understood, and especially more information about microbial populations involved in coal biodegradation was urgently needed. In this work, the archaeal and bacterial communities of CBM reservoir associated with Ordos Basin in China were investigated using 454 pyrosequencing and DGGE, where the CBM were suggested to be produced by methylotrophic methanogenesis. Sampling water, coal and rock in the Basin, a total of 46598 sequence reads were obtained to evaluate the diversity of archaeal and bacterial communities. The genus Methanolobus was dominant archaea in all samples. Bacterial communities in coal and rock samples were similar, while distinctly separated with water sample. The most predominant types of bacteria identified in coal and rock samples included the genera Brevundimonas, Hydrogenophaga and Acinetobacter, whereas the genera Arcobacter and Azonexus dominated water sample. Our results strongly suggested that the methylotrophic methanogenesis governed the CBM formation in this area, and depicted a more accurate picture of archaeal and bacterial communities associated with CBM, enriching the network of reaction constituting coal biodegradation and providing the microbial support for renewable exploitation of CBM in this area.