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To: Crimson Ghost who wrote (40883)	2/21/2000 2:41:00 PM
From: Les H	Read Replies (4) \| Respond to of 99985

Algae may be new fuel source of future -experts WASHINGTON, Feb 21 (Reuters) - 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 need sulfur to grow and photosynthesize. But scientists found that when they starved the algae of sulfur, 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. 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 sulfur,' 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 sulfur. 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 liter (quart) of algae growing in culture produces about three milliliters of hydrogen gas per hour. Melis thinks his team can increase that 10-fold. 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.