Gasoline From Thin Air?

Aug. 8, 2010— -- An enzyme found in the roots of soybeans could be the key to cars that run on air.

Vanadium nitrogenase, an enzyme that normally produces ammonia from nitrogen gas, can also convert carbon monoxide (CO), a common industrial byproduct, into propane, the blue-flamed gas found on stoves across America.

While scientists caution the research is still at an early stage, they say that this study could eventually lead to new, environmentally friendly ways to produce fuel -- and eventually gasoline -- from thin air.

"This organism is a very common soil bacteria that is very well understood and has been studied for a long time," said Markus Ribbe, a scientist at the University of California, Irvine, and a co-author of the new paper that appears in the journal Science.

"But while we were studying it, we realized that the enzyme has some unusual behavior," he added.

The organism that the researchers studied was Azotobacter vinelandii, an economically important bacteria. A. vinelandii is usually found in the soil around the roots of nitrogen-fixing plants like soybeans.

Farmers like plants that contain A. vinelandii because the bacteria use a suite of enzymes to turn unusable atmospheric nitrogen into vital ammonia and other chemicals. Other plants can then take up those chemicals and use them to grow.

Ribbe and his co-authors isolated one particular enzyme, vanadium nitrogenase, to convert nitrogen into ammonia. Then the California scientists removed the nitrogen and oxygen the enzyme is used to and filled the remaining space with CO.

Without oxygen and nitrogen, the enzyme began to to turn the CO into short chains of carbon two and three atoms long. A three-carbon chain is more commonly referred to as propane, the blue-flamed gas used in kitchens across America.

Scientifically, the new function of vanadium nitrogenase is a "profound discovery," said Jonas Peters, a scientist at Cal Tech who said he nearly leapt from his chair when the results were announced at a recent conference.