Methanogen communities in a municipal landfill complex in China

Landfills are significant global sources of atmospheric methane, but little is known about the ecology and community structure of methanogens in these sites. Here, we investigated the methanogen community based on methyl coenzyme M reductase A gene amplicons in the vertical profiles of three different sites at a municipal landfill complex in China. Links between methanogen communities and refuse properties were explored using multivariate analysis. Clone library results showed that most clones (92%) were related to the hydrogenotrophic methanogens, Methanomicrobiales. Almost all of the Methanomicrobiales clones retrieved in this study are members of the genus Methanoculleus. Eight clones were affiliated with the genus Methanofollis. The remaining clones were clustered within the genus Methanosarcina. Terminal restriction fragment length polymorphism profiles showed that the landfill was predominated by 22 taxa, making up 69%-96% of the community. Of these, a single taxon comprised 36%-65% of the communities across all sites and depths. Principal components analysis separated the methanogen community into three groups, irrespective of site or depth. Redundancy analysis suggested that total phosphorus and pH play roles in structuring methanogen communities in landfills.