Molecular analysis of enrichment cultures of marine methane oxidising bacteria

Methane oxidising bacteria (methanotrophs) are an important group of bacteria in the global cycling of methane and may act as a sink for methane in freshwater, soil and marine environments. Their ecology is fairly well documented in terrestrial and freshwater environments but marine methanotrophs have been less-well characterised, partly due to the difficulties in the isolation, cultivation and identification of these organisms. Molecular ecological techniques are being developed to aid the characterisation and enumeration of marine methane oxidising bacteria and to assess their role in the turn-over of methane in the marine environment. 16S ribosomal RNA gene probes have been developed to detect and identify marine methanotrophs. The use of these probes, coupled with fluorescence microscopy techniques, to aid enrichment, cultivation and subsequent characterisation of marine methanotrophs is described. The use of the polymerase chain reaction to amplify methane monooxygenase genes from enrichments of marine methanotrophs is also described.