Methane mopping bacteria could help environment
Researchers at the University of East Anglia (UEA) say bacteria could help protect the environment by ‘mopping up’ methane.
Methane is a potent greenhouse gas which is released from both natural sources and human activities. New insight from the UEA team shows how the bacteria (methanotrophs) are able to use large quantities of copper for methane oxidation. It is hoped that the findings could help develop biotechnological applications that exploit methane and protect the environment.
The research team identified a new family of copper storage proteins called Csp1 that are present in a range of bacteria including methanotrophs. They found that these proteins store metal in a way that has not been seen previously. The research reveals how Csp1 proteins can bind large quantities of copper and proposes that they accumulate copper for methane oxidation.
Co-author Prof. Colin Murrell, from UEA’s School of Environmental Sciences, said: “Methane is a potent greenhouse gas which is released from natural sources such as wetlands, as well as from human activities including waste management, the oil and gas industries, rice production and livestock farming. Globally, it is estimated that more than half of methane emissions are man-made.
“Methane emissions are rising and, molecule-for-molecule, the effect of methane on global warming is more than 20 times greater than carbon dioxide over a 100 year timeframe. Methanotrophs are the primary biological mechanism for mitigating the release of methane to the atmosphere by consuming it as a carbon and energy source.
“These microbes also have great potential in utilising methane, a readily renewable carbon source, for the production of bulk and fine chemicals.
“To oxidise methane, methanotrophs use an enzyme called methane monooxygenase whose essential cofactor is copper.
“We have known that copper is an essential element for biological methane oxidation for over thirty years and this new information will really help us to formulate new strategies for exploiting these bacteria both in the laboratory and in the environment. Understanding how methanotrophs handle copper is of great importance for all potential applications of these organisms,” he added.
Lead author, Prof. Chris Dennison from Newcastle University said: “Methane is such a useful and plentiful commodity but we need more cost effective methods to unlock its potential – using bacteria could be the best option.
“As copper is essential for the oxidation of methane, all potential applications based on this reactivity require an understanding of how methanotrophs acquire and store copper. This new family of proteins adds a new layer to our understanding of this complex process.”
‘A four-helix bundle stores copper for methane oxidation’ was published in the journal Nature.
• PHOTOGRAPH SHOWS: Professor Colin Murrell of the University of East Anglia. Picture courtesy of Holdsworth Associates.