"If the U.S. is to have
a future hydrogen-based economy, we'll need a
way to generate abundant quantities of hydrogen
safely and economically," said Daniel (Niels)
van der Lelie, a biologist at the U.S. Department
of Energy's Brookhaven National Laboratory. Van
der Lelie will discuss the prospect of using vats
of microbes to brew up the hydrogen in a talk
at the 232nd national meeting of the American
Chemical Society in San Francisco, California,
at 3:35 p.m. Pacific Time on Tuesday, September
12, 2006, in the Telegraph Hill room of the Sheraton
Palace.
The focus on hydrogen as a future
fuel source is compelling given dwindling supplies
of oil and natural gas, as well as escalating
costs and the fact that burning fossil fuels releases
large amounts of carbon dioxide, a "greenhouse"
gas, into the atmosphere. In contrast, burning
hydrogen gas (for example, in a fuel cell) produces
no pollution, and hydrogen, a constituent of water,
is widely abundant. However, finding simple, inexpensive
ways to extract that abundant element and produce
it in a pure gaseous form - a crucial step toward
making the "hydrogen economy" a reality
- has been a technological challenge.
Vander Lelie's group reports
that experimental setups using Thermatoga neapolitana
bacteria given a simple glucose feedstock can
generate copious amounts of hydrogen gas at temperatures
between 158 and 185 degrees Fahrenheit at atmospheric
to elevated pressure. In his talk, van der Lelie
will describe the complex biochemistry of these
reactions as well as the potential to scale up
this system for continuous, farm-based, economical
hydrogen production. One significant finding was
that Thermatoga neapolitana produced hydrogen
most efficiently in a moderately low-oxygen environment.
Previously, hydrogen production by bacteria has
only been reported under anaerobic, or oxygen-free,
conditions.
"Oxygen normally kills anaerobic
microbes like Thermatoga neapolitana,"
van der Lelie said. That would be a problem for
any real-world production facilities, as eliminating
all oxygen from production lines could be very
expensive.
"Our research provides the first evidence
that bacteria can efficiently produce hydrogen
gas when oxygen is present.”
In collaboration with Paul King,
a scientist at the National Renewable Energy Laboratory,
the Brookhaven team is now elucidating the mechanisms
by which Thermatoga neapolitana can avoid
oxygen toxicity during hydrogen production. "Understanding
the oxygen tolerance of Thermatoga neapolitana
will facilitate its practical application to produce
hydrogen from agricultural resources," van
der Lelie said.
Source:
http://www.sciencenews.org
