Nitrous oxide guzzlers are intended to reduce greenhouse gas emissions

The widespread use of nitrogen fertilizers leads to the release of the greenhouse gas nitrous oxide (N2O), also known as ‘laughing gas’, from agricultural lands. According to the Norwegian University of Life Sciences (NMBU), these emissions currently account for about a third of all greenhouse gas emissions from agriculture. Until now they were believed to be inevitable.

Researchers from Norway and Austria report in the journal ‘Nature’ about a bacterium that literally ‘eats’ nitrous oxide formed in the soil. If widely used, it may be released into the atmosphere.

Nitrous oxide is 300 times more powerful than CO2
Nitrous oxide is produced by micro-organisms in the soil under certain conditions: if they do not have access to oxygen, they are forced to find other ways to get energy, for example by breathing nitrate instead of oxygen. Through a process called ‘denitrification’, the nitrate is converted into nitrous oxide, among other things. “This greenhouse gas has an effect about 300 times stronger than CO2, and agriculture is responsible for about three-quarters of N2O emissions in Europe,” explains Wilfried Winiwarter, one of the co-authors of the International Institute study for Applied Systems Analysis. (IIASA).

After a long search, scientists have now identified a special type of bacteria that can reduce nitrous oxide to harmless nitrogen gas (N2), but cannot produce nitrous oxide itself. This bacterium “simply lacks the gene to produce laughing gas, it can only eat it,” says Elisabeth Hiis of the NMBU.

The research team is now working on finding other bacteria that ‘eat’ nitrous oxide. This method could make it possible to reduce nitrogen oxide emissions from agriculture in Europe by a third.