Eating methane

A methane-consuming micro-organism that lives in geothermal areas in Rotorua in the Bay of Plenty in New Zealand has attracted international attention for its ability to live in extremely acidic conditions.

Discovered by researchers at GNS Science, the bacterium could one day be used to reduce methane gas emissions from landfills. It could also help to cut methane emissions from geothermal power stations.

The microorganism was discovered in soil at Tikitere geothermal field, also known as Hell’s Gate, near Rotorua.

Climate researchers are expected to follow the discovery closely as the bacterium offers the potential to reduce the amount of methane entering the atmosphere. Methane is a far more potent greenhouse gas than carbon dioxide.

The bacterium is part of a group known as methanotrophs, but this one is able to live in hotter and much more acidic conditions than its relatives. Methanotrophs use methane as their only source of energy. They live mostly in soils and are especially common in environments where methane is produced.

Microbiologist at GNS Science, Matthew Stott, said it was a particularly exciting discovery as it had international significance. 'We knew methane was being produced geothermally at Hell’s Gate and we were puzzled as to why it wasn’t reaching the surface,' Dr Stott said. 'What we have found is an extremely tough methane-consuming organism that is new to science. It grows happily under extremely acidic conditions in the lab.'

Globally, acidic environments such as marshes and peat bogs generate significant quantities of methane. Scientists have always suspected that a proportion of this methane was being consumed by bacteria living in these environments. 'Our discovery has demonstrated that methane-consuming organisms do live in highly acidic environments. Without them, the amount of methane entering the atmosphere would be much greater,' he added.

'Ultimately, it may be possible to implant this organism, or a similar one, in landfills and cut methane emissions into the atmosphere.'

Fellow microbiologist at GNS Science, Peter Dunfield, who isolated the bacterium, has tentatively named it Methylokorus infernorum, which is a Latin description of its methane food source, the ‘hellish’ location of its discovery, and also a description of a structure within its cell that resembles a Koru - a stylised fern leaf pattern used in Maori carving.

GNS Science worked with colleagues at the University of Hawaii to sequence the genome of the bacterium. They found its genetic makeup was different to all known methanotrophic organisms.

The discovery stems from a collaboration between GNS Science and the owner and operator of Hell’s Gate, Tikitere Trust. The agreement between the two organisations includes the sharing of any benefits that might accrue from scientific discoveries.