Current Events » in reply to Re: but the leftists still whine
Researchers have found a metabolic switch in algae that allows the primitive plants to produce hydrogen gas - a discovery that could ultimately result in a vast source of cheap, pollution-free fuel. Hydrogen, which can be used as a clean-burning fuel in cars and power plants, is virtually limitless in availability, because it is part of the water molecule. It is a candidate to become the world's primary fuel in coming decades. But until now, it was obtainable in quantity only through relatively expensive extraction procedures involving the electrolysis of water or processing natural gas. The breakthrough, by scientists at the University of California at Berkeley and the U.S. Department of Energy, would make possible the commercial production of hydrogen gas by photosynthesis in tanks, ponds or the open ocean. “I guess it's the equivalent of striking oil,” said Tasios Melis, a microbial biology professor at UC Berkeley. “It was enormously exciting. It was unbelievable.” Melis made the discovery with UC Berkeley researcher Liping Zhang and with Michael Seibert, Maria Ghiardi and Marc Forestier of the National Renewable Energy Laboratory, a Department of Energy project in Golden, Colo. The team's findings appear in this month's issue of Plant Physiology, a science journal. Seibert said it has been known for decades that algae give off small amounts of hydrogen. The problem from a commercial perspective, he said, was hydrogenase - an enzyme that produces hydrogen, but does so only in the absence of oxygen. All green photosynthetic plants - including algae - consume carbon dioxide in the presence of light to build tissue, respiring oxygen as a waste product. “But because hydrogenase shuts down in the presence of oxygen, it doesn't function during photosynthesis,” he said. “It basically only works during darkness, when photosynthesis isn't occurring.” Because plant functions are at low ebb during darkness, Seibert said,the amount of hydrogen produced is minimal. But the team was able to solve the problem, said Seibert, by imposing a “nutrient stress” to the algae. “First we grow out the algae, `fatten' it under normal photosynthetic conditions,” he said. “Then we withhold sulfur.” Sulfur is critical for the completion of normal photosynthesis, Seibert said. In the absence of the element, the algae ceased emitting oxygen and stopped storing energy as carbohydrates, protein and fats. Instead, the algal cells began using “an alternative metabolic pathway” to exploit stored energy reserves anaerobically - in the absence of oxygen. The hydrogenase was activated, splitting large amounts of hydrogen gas from water and releasing it as a byproduct.
