a b s t r a c t a r t i c l e i n f oIt is generally believed that biogenic coal bed methane (CBM) is an end product of coal biodegradation by methanogenic archaea and syntrophic bacteria. In this work, the archaeal and bacterial communities of CBM reservoir associated with Ordos Basin in China were investigated using 454 pyrosequencing. Sampling produced water, coal and rock in the reservoir, a total of 46,598 sequence reads were obtained. All archaea were methanogens with the genus Methanolobus predominating. The genus consisted of 81.18% of pyrosequencing reads in water sample and > 99% in coal and rock samples. Although the phylum Proteobacteria was the main component of all samples, bacterial communities in coal and rock samples were similar at the genus level, which were distinctly separated with water sample. The results strongly suggested that methylotrophic methanogenesis governed the biogenic CBM formation. The separation of microbial communities between water and coal, rock samples should be considered when investigating the process of coal biodegradation and the generation of new biogenic CBM.

The Zoige wetland of the Tibetan Plateau is a high-altitude tundra wetland and one of the biggest methane emission centers in China. In this study, methanotrophs with respect to community structure, abundance, and activity were investigated in peat soils collected in the vicinity of different marshland plants that dominate different regions of the wetland, including Polygonum amphibium, Carex muliensis, and Eleocharis valleculosa (EV). 16S rRNA gene and particulate methane monooxygenase gene (pmoA) clone library sequence data indicated the presence of methanotrophs with two genera, Methylobacter and Methylocystis. Methylococcus, like pmoA gene sequences, were also retrieved and showed low similarity to those from Methylococcus spp. and thus indicates the existence of novel methanotrophs in the Zoige wetland. Quantitative polymerase chain reaction (qPCR) assays were used to measure the abundance of methantrophs and detected 10(7) to 10(8) of total pmoA gene copies per gram dry weight of soil in the three marshes. Group-specific qPCR and reverse transcriptase qPCR results found that the Methylobacter genus dominates the wetland, and Methylocystis methanotrophs were less abundant, although this group of methanotrophs was estimated to be more active according to mRNA/DNA ratio. Furthermore, EV marsh demonstrated the highest methanotrophs abundance and activity among the three marshes investigated. Our study suggests that both type I and type II methanotrophs contribute to the methane oxidation in the Zoige wetland.

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An improved microfluidic streak plate technique relying on droplet microfluidics can advance the exploration of deep-sea rare microbes.