Detection of methanogens and methanotrophs in natural environments

The role of methane as a greenhouse gas and the contribution of bacteria to the production (methanogenesis) and destruction (methane oxidation) of methane is described. Using experimental approaches based on DNA sequences identifying either methanogen-specific or methanotroph-specific gene sequences methods were developed to broaden the detection and identification of methane metabolizing bacteria in natural environments. These methods were focused on blanket bog peat but are suitable for other environments. In addition to group specific 16S rRNA DNA sequences, specific functional gene probes based on methane coenzyme reductase sequences for methanogens and methane monooxygenase sequences for methanotrophs, were developed. These sequences were used in PCR-based protocols to detect and amplify specific gene sequences from the total DNA isolated from transverse sections of blanket bog peat. This permitted the analysis of the vertical distribution of methanogen and methanotroph populations, discrimination between different sub-sets of these populations, and the identification of novel organisms not previously detected by culture-based methods.