Mitigating release of the potent greenhouse gas N₂O from the nitrogen cycle - could enzymic regulation hold the key?

When faced with a shortage of oxygen, many bacterial species use nitrate to support respiration via the process of denitrification. This takes place extensively in nitrogen-rich soils and generates the gaseous products nitric oxide (NO), nitrous oxide (N₂O) and dinitrogen (N₂). The denitrifying bacteria protect themselves from the endogenous cytotoxic NO produced by converting it to N₂O, which can be released into the atmosphere. However, N₂O is a potent greenhouse gas and hence the activity of the enzyme that breaks down N₂O has a crucial role in restricting its atmospheric levels. Here, we review the current understanding of the process by which N₂O is produced and destroyed and discuss the potential for feeding this into new approaches for combating N₂O release.