Methane source discovered in the underbrush

Some six years ago scientific textbooks had to be updated because of the surprising discovery made by the research group led by Frank Keppler that plants produce methane in an oxygen-rich environment.

At that time this was unthinkable, since it was commonly accepted that biogenic methane could only be formed during the decomposition of organic material under strictly anoxic conditions. His group has now made another fascinating new observation: fungi produce methane.

Methane is 25 times more effective as a greenhouse gas when compared with carbon dioxide. Most of this gas is produced by bacteria in rice fields, landfills or cattle farming.

Following the study by Keppler and his colleagues in 2006, which reported that plants also produce methane, his research team has continued to focus on methane sources. Now Katharina Lenhart, a member of Keppler's research group at the Max Planck Institute for Chemistry, has made another interesting discovery. She discovered that fungi, which decompose dead organic matter, also emit methane.

In her study, the biologist examined eight different Basidiomycetes fungi. Under laboratory conditions she observed methane production and verified her finding using isotopic labelled substrates.

During her experiments she varied the culture media on which the fungi grew and found that the underlying substrate has an impact on the amount of methane formed. Various molecular, biological and analytical methods, in collaborative work with the University of Giessen and the Helmholtz Centre for Environmental Research in Magdeburg, showed that no methanogenic microorganisms (called archaea) – which produce methane in their energy metabolism – were involved.