How's this for innovative: A Berkeley Lab-led team hopes to engineer a new enzyme that efficiently converts methane to liquid transportation fuel.
"There's a lot of methane available, and we want to develop a new way to harness it as an energy source for vehicles," says Christer Jansson, a biochemist in Berkeley Lab's Earth Sciences Division who heads the effort.
Methane is the main component of natural gas and biogas from wastewater treatments and landfills. Another source is "stranded natural gas," which is currently flared or vented at remote oil fields, and which represents an enormous unused energy resource.
But methane has disadvantages. It remains a gas at surface temperatures and pressure, which makes it problematic and costly to transport. Large portions of the known natural gas reserves are located in remote areas of the world. And methane is a potent greenhouse gas, with a global warming potential more than 20 times that of carbon dioxide.
Methane can be converted to liquid hydrocarbons by thermochemical processes. But these processes are both energy intensive and often non-selective.
So Jansson and colleagues are turning to biology. There are bacteria in nature that gobble up methane and convert it to chemicals that can be fashioned into fuel. These bacteria, called methanotrophs, have an enzyme that serves their needs just fine. Unfortunately, the enzyme doesn't produce chemicals with the efficiency needed to make transportation fuels.
Scientists are working to make this enzyme more efficient, but Jansson's team is taking a new approach. They're starting with a different enzyme that ordinarily takes in carbon dioxide. Its structure is relatively simple and well understood, making it an ideal platform to tinker with, which in this case means engineering the enzyme to consume methane instead of carbon dioxide and release a product that can feed into a pathway for fuel synthesis.
|Contact: Dan Krotz|
DOE/Lawrence Berkeley National Laboratory