Research advances understanding of how hydrogen fuel is made

Oct 05, 2005
Research advances understanding of how hydrogen fuel is made

Oxygen may be necessary for life, but it sure gets in the way of making hydrogen fuel cheaply and abundantly from a family of enzymes present in many microorganisms. Blocking oxygen’s path to an enzyme’s production machinery could lead to a renewable energy source that would generate only water as its waste product.

Image: Schematic diagram of hydrogen-oxygen reaction taking place in hydrogenase CpI. (Graphic courtesy of Jordi Cohen)

Researchers at the Beckman Institute for Advanced Science and Technology at the University of Illinois at Urbana-Champaign have opened a window by way of computer simulation that lets them see how and where hydrogen and oxygen travel to reach and exit an enzyme’s catalyst site – the H cluster – where the hydrogen is converted into energy.

The Illinois scientists and three colleagues from the National Renewable Energy Laboratory in Golden, Colo., detailed their findings in the September issue of the journal Structure. What they found could help solve a long-standing economics problem. Because oxygen permanently binds to hydrogen in the H cluster, the production of hydrogen gas is halted. As a result, the supply is short-lived.

Numerous microorganisms have enzymes known as hydrogenases that simply use sunlight and water to generate hydrogen-based energy.

“Understanding how oxygen reaches the active site will provide insight into how hydrogenase’s oxygen tolerance can be increased through protein engineering, and, in turn, make hydrogenase an economical source of hydrogen fuel,” said Klaus Schulten, Swanlund Professor of Physics at Illinois and leader of the Beckman’s Theoretical Biophysics Group.

Using computer modeling developed in Schulten’s lab – Nanoscale Molecular Dynamics (NAMD) and Visual Molecular Dynamics (VMD) – physics doctoral student Jordi Cohen created an all-atom simulation model based on the crystal structure of hydrogenase CpI from Clostridium pasteurianum.

This model allowed Cohen to visualize and track how oxygen and hydrogen travel to the hydrogenase’s catalytic site, where the gases bind, and what routes the molecules take as they exit. Using a new computing concept, he was able to describe gas diffusion through the protein and predict accurately the diffusion paths typically taken.

“What we discovered was surprising,” Schulten said. “Both hydrogen and oxygen diffuse through the protein rather quickly, yet, there are clear differences.”

Oxygen requires a bit more space compared with the lighter and smaller hydrogen, staying close to few well localized fluctuating channels. The hydrogen gas traveled more freely. Because the protein is more porous to hydrogen than to oxygen, the hydrogen diffused through the oxygen pathways but also through entirely new pathways closed to oxygen, the researchers discovered.

The researchers concluded that it could be possible to close the oxygen pathways of hydrogenase through genetic modification of the protein and, thereby, increase the tolerance of hydrogenases to oxygen without disrupting the release of hydrogen gas.

Co-authors with Schulten and Cohen were Kwiseon Kim, Paul King and Michael Seibert, all of the National Renewable Energy Laboratory. The National Institutes of Health, National Science Foundation and the U.S. Department of Energy funded the research.

NAMD is a parallel molecular dynamics code designed for high-performance simulation of large biomolecular systems. VMD is a molecular visualization program for displaying, animating and analyzing large biomolecular systems using 3-D graphics.

Source: University of Illinois at Urbana-Champaign

Explore further: New research signals big future for quantum radar

add to favorites email to friend print save as pdf

Related Stories

Huge spring tides draw crowds to French Atlantic coast

2 hours ago

France kicked off nearly a month of exceptionally large spring tides Saturday, as tourists flocked to coastal areas to witness spectacularly high water levels ahead of the so-called "tide of the century" ...

Water in Oregon pipeline is tapped for electricity

4 hours ago

Lucid Energy has developed a renewable energy system that makes use of water moving through pipelines. The company's LucidPipe Power System converts pressure in water pipelines into electricity. They have ...

Arctic oil drillers face tighter US rules to stop spills

6 hours ago

Royal Dutch Shell Plc and any oil drilling company that prospects in the Arctic Ocean must boost safety practices to prevent spills in the frigid and often hostile waters or mitigate the impact, U.S. regulators proposed Friday.

Recommended for you

New research signals big future for quantum radar

6 hours ago

A prototype quantum radar that has the potential to detect objects which are invisible to conventional systems has been developed by an international research team led by a quantum information scientist at the University ...

Top-precision optical atomic clock starts ticking

9 hours ago

A state-of-the-art optical atomic clock, collaboratively developed by scientists from the University of Warsaw, Jagiellonian University, and Nicolaus Copernicus University, is now "ticking away" at the National ...

The building blocks of the future defy logic

13 hours ago

Wake up in the morning and stretch; your midsection narrows. Pull on a piece of plastic at separate ends; it becomes thinner. So does a rubber band. One might assume that when a force is applied along an ...

Physicists find a new form of quantum friction

17 hours ago

Physicists at Yale University have observed a new form of quantum friction that could serve as a basis for robust information storage in quantum computers in the future. The researchers are building upon ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.