Barry D. Bruce, professor of biochemistry, cellular and molecular biology,
at the University of Tennessee, Knoxville,
is turning the term "power plant" on its head. The biochemist and a team of
researchers have developed a system that taps into photosynthetic processes to
produce efficient and inexpensive energy.
Bruce collaborated with researchers from the Massachusetts Institute of
Technology (MIT) and Ecole Polytechnique Federale in Switzerland to develop a process
that improves the efficiency of generating electric power using molecular
structures extracted from plants. The biosolar breakthrough has the potential
to make "green" electricity dramatically cheaper and easier.
"This system is a preferred method of sustainable energy because it is clean
and it is potentially very efficient," said Bruce, who was named one of "Ten
Revolutionaries that May Change the World" by Forbes magazine in 2007 for his
early work, which first demonstated biosolar electricity generation. "As
opposed to conventional photovoltaic solar power systems, we are using
renewable biological materials rather than toxic chemicals to generate energy.
Likewise, our system will require less time, land, water and input of fossil
fuels to produce energy than most biofuels."
Their findings are published in Nature:
Scientific Reports.
To produce the energy, the scientists harnessed the power of a key component
of photosynthesis known as photosystem-I (PSI) from blue-green algae. This
complex was then bioengineered to specifically interact with a semi-conductor
so that, when illuminated, the process of photosynthesis produced electricity.
Because of the engineered properties, the system self-assembles and is much
easier to re-create than his earlier work. In fact, the approach is simple
enough that it can be replicated in most laboratories—allowing others around
the world to work toward further optimization.
"Because the system is so cheap and simple, my hope is that this system will
develop with additional improvements to lead to a green, sustainable energy
source," said Bruce, noting that today's fossil fuels were once, millions of
years ago, energy-rich plant matter whose growth also was supported by the sun
via the process of photosynthesis.
This green solar cell is a marriage of non-biological and biological
materials. It consists of small tubes made of zinc oxide—this is the
non-biological material. These tiny tubes are bioengineered to attract PSI
particles and quickly become coated with them—that's the biological part. Done
correctly, the two materials intimately intermingle on the metal oxide
interface, which when illuminated by sunlight, excites PSI to produce an
electron which "jumps" into the zinc oxide semiconductor, producing an electric
current.
The mechanism is orders of magnitude more efficient than Bruce's earlier
work for producing bio-electricity thanks to the interfacing of PSI with the
large surface provided by the nanostructured conductive zinc oxide; however it
still needs to improve manifold to become useful. Still, the researchers are
optimistic and expect rapid progress.
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