The genome sequence of Methylococcus capsulatus a species typical of methane-breathing bacteria commonly found in soils, landfills, sediments and peat bogs includes a full and at times redundant toolkit of genes for using methane as an energy and carbon source. Such methane-consuming microbes are called methanotrophs.

The study, to be published in the October issue of PLoS Biology and posted online this week, found an unexpected flexibility in M. capsulatus metabolic pathways, hinting that the bacterium is capable of responding to changes in its environment by functioning through different chemical pathways for using methane. That finding, if confirmed by later experiments, may increase the bacterium's potential as a biotech workhorse.

Methanotrophs play an important role in the global energy cycle because they consume methane, a gas that is produced mostly by chemical processes in landfills, in the guts of ruminant livestock such as cows, and by oil and natural gas processing plants.

In recent years, environmental scientists have shown increasing interest in methanotrophs because their use of methane as a sole source of carbon and energy could possibly be harnessed to play an important role in efforts to reduce methane emissions that are generated by biological sources such as ruminants and landfills.

The PLoS Biology study found that M. capsulatus has multiple pathways for different stages in the oxidation of methane. They also found genes that suggest metabolic flexibility, including the microbe's likely ability to grow on sugars, to oxidize sulfur, and to live in reduced-oxygen environments.

"We now have a much better picture of the relationship between M. capsulatus and its environment,
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Contact: Robert Koenig
rkoenig@tigr.org
301-795-7880
The Institute for Genomic Research
20-Sep-2004