The National Science Foundation was scheduled to announce a breakthrough Thursday afternoon by two Utah State University researchers, a discovery about the structure of an enzyme that eventually could lead to cheap production of hydrogen fuel.
Hydrogen is the most abundant element in nature, the H of H2O, much of the content of our vast oceans and organic compounds. It is nearly a perfect fuel because its byproduct when burned is simply water. It can be used in ordinary car engines, with a little retrofitting for the heavy, protective tanks of hydrogen fuel.But hydrogen always was too expensive to separate from other elements, like the oxygen in water, to be affordable. Scientists have known for years how to break it down with electricity, but that was more costly than pumping hydrocarbons like oil from the ground.
Still, nature itself breaks up hydrogen compounds without resorting to massive jolts of electricity, in an enzyme secreted by certain bacteria.
The discovery by Lance Seefeldt and John Peters, both of USU, Logan, may unlock the way the enzyme works. If the technique can be brought into mass production, the world's energy picture may brighten fantastically.
Their finding will be announced in Friday's issue of the journal Science, published in Washington, D.C., by the American Association for the Advancement of Science.
Under funding by the National Science Foundation, Peters and Seefeldt made a detailed description of the enzyme, a particular kind of hydrogenase known as "Cpl." It is found in the soil microorganism called Clostridium pasteurianum.
As the NSF's Greg Lester wrote, "The workings of an iron-laden bacterial enzyme could one day provide researchers with an inexpensive and stable catalyst to create hydrogen."
Seefeldt, an associate professor of chemistry and biochemistry, told the Deseret News the enzyme occurs in soil bacteria living under anaerobic conditions, "environments that don't have any oxygen." This could include mud at the bottom of ponds, or soil where not much air penetrates.
The bacteria have an enzyme called hydrogenase that speeds reactions involving hydrogen, so that the bacteria can use sugar and other material as energy sources. The bacteria can't use oxygen for the reactions, as humans do, so they have to dump the electrons elsewhere. The electrons attach themselves to protons that are common in the water.
Kamal Shukla, NSF program manager, wrote, "The . . . hydrogenase is basically a means to get rid of unwanted electrons." The bacteria use the hydrogenase to convert protons and electrons into hydrogen as a waste product.
Hydrogen is made up of two protons and two electrons.
Seefeldt said the enzyme "takes water and converts it to hydrogen gas. And of course you recognize the significance of hydrogen gas -- it's going to be the energy of the future."
Hydrogenase shows that bacteria can create hydrogen from water, he said. Scientists have tried to understand the process for about 50 years and have managed to purify the enzyme to study it.
But they never really got a good picture of how the enzyme did the job -- until now.
"We were able to isolate this hydrogenase from this bacteria so it was the only protein in this little beaker," he said. Purification like that had been done before, but Peters and Seefeldt "managed to get this protein to crystallize."
Once it was in a solid form, which he compared to rock candy, they were able to use X-ray diffraction analysis to "reconstruct a three-dimensional image of this molecule."
The molecule itself was too tiny to image directly, but the technology of X-ray diffraction allowed them to discover the exact arrangement of the atoms in the molecule, in effect taking it apart so they could understand how it works.
They believe they were able to pinpoint "the active site, where hydrogen is being produced," showing how water is converted to hydrogen. This site turned out to be the place where the enzyme has iron atoms.
"Looking at the arrangement of the irons, there's actually six irons at the active site along with sulfur, and along with some carbon monoxide," Seefeldt said. "The enzyme's taking advantage of the unique properties of the carbon monoxide."
The researchers now can make informed predictions of how the enzyme takes in water and converts it to hydrogen.
"It doesn't solve everything, obviously," he added. But the discovery really is a big leap in understanding how the enzyme works, and that might let scientists design better catalysts to convert water into hydrogen.
Mother Nature has taken thousands of years of evolution to let the bacteria unlock hydrogen, he said. "It's really nice to get up to speed and see what she's figured out, and we can really go from there."
If the scientists can take this discovery and move it into a large-scale technology, "it would immediately, I would predict, move gasoline right out of the market."
In an NSF release, Peters noted that hydrogen is renewable and clean-burning. "The biological production of hydrogen, then, represents a tremendous reserve of energy that we may tap through our understanding of the mechanisms that have evolved in nature."
By knowing the complex structure of the hydrogenase, "protein engineers can work on methods to increase the stability of the enzyme," according to Peters. "Once in industrial use, such an efficient source of clean energy is likely to be both economically and environmentally significant."