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dam-l Algae as "green fuel"/LS

Johannesburg, South Africa. February 24 2000

         Algae may be 'green' fuel of future

         Scientists have discovered how to force algae to produce pure
hydrogen, an environmentally
         friendly fuel.



                MICROSCOPIC green algae may soon be pumping out clean and
efficient hydrogen gas to fuel
                the world's cars, power industry and keep the lights on,
scientists said on Monday.

         Several teams have abandoned high-tech ways to produce energy and
turned to nature, which long ago
         figured out how to make energy from water and sunlight.

         In this case algae, known as Chlamydomonas reinhardtii, have a
special trick that allows them to make
         hydrogen -- an enzyme called hydrogenase, which can split water
into its component parts of hydrogen
         and oxygen.

         "The microscopic plant uses the energy of the sun to produce
hydrogen," Tasios Melis, a professor of
         plant and microbial biology at the University of California
Berkeley, told a news conference.

         The algae, grown in a solution that looks like a lime-green soft
drink, are found "just about
         everywhere," Melis said.

         They need sulphur to grow and photosynthesize. But scientists
found that when they starved the algae
         of sulphur, they switched into hydrogenase mode.

         "The green algae do not die, they do not suffocate, but they use
this trick," Melis said. "The hydrogen
         process for them is simply an alternative way of breathing."

         Elias Greenbaum of the Oak Ridge National Laboratory in Tennessee
said the algae, instead of using
         light to make carbohydrates out of carbon dioxide and water, use
hydrogenase to break down energy
         stores.

         Plants normally give off oxygen as a byproduct but when they
switch to the hydrogenase cycle they
         give off hydrogen.

         "Think of it as a biological version of electrolysis
         of water," Greenbaum said, referring to the use of
         electricity to split water molecules into hydrogen
         and oxygen.

         The by-product -- pure, clean water.

         Melis's team told a meeting of the American Association for the
Advancement of Science that to get the
         algae to produce hydrogen they first grow the algae naturally,
letting them use sunlight and water to
         photosynthesize.

         "Then ... we deprive them of the sulphur," Melis said.

         It takes about 20 hours, but the algae switch into back-up mode,
which the scientists believe may be a
         relic from times when the Earth was less clement and what little
life there was had to adjust to harsh
         conditions.

         After four or five days the algae start to eat up their own
protein, so they have to be allowed to
         photosynthesize again. But there has been no limit to how many
cycles the algae can be forced through.

         "In essence they live forever," Melis said.

         He estimated that a small pond full of algae -- he would not say
how big a pond -- could produce
         enough hydrogen to operate a dozen cars for a week.

         He foresees a complex where pond after pond of the algae bubble
out hydrogen, with tarps that could
         be rolled back to give them their regular dose of vital sunlight
and sulphur.

         Perhaps they could even be fed sewage, he said, solving two
pollution problems at once.

         Melis said not to expect algae-produced natural gas any time soon.
"We are not ready to go forward
         commercially with this process," he said. "We are not happy with
the yields that we get."

         Every litre of algae growing in culture produces about three
millilitres of hydrogen gas per hour. Melis
         thinks his team can increase that tenfold.

         Greenbaum's team has developed an even more efficient method, and
they think other algae and
         perhaps bacteria also use the trick. Scientists are screening such
microbes now.

         Scientists at the National Renewable Energy Laboratory are working
to make a mutant version of the
         bacteria that can work more efficiently and under less stringent
conditions.

         Before people can expect to use the gas in their cars, the problem
of storing and using the highly
         flammable hydrogen must be solved.

         -- Reuters, February 24 2000.

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      Lori Pottinger, Director, Southern Africa Program,
        and Editor, World Rivers Review
           International Rivers Network
              1847 Berkeley Way, Berkeley, California 94703, USA
                  Tel. (510) 848 1155   Fax (510) 848 1008
                        http://www.irn.org
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