Baker's yeast mutant can boost ethanol output -MIT
07 Dec 2006 20:16:30 GMT Source: Reuters
By Timothy Gardner NEW YORK, Dec 7 (Reuters) - Scientists have engineered baker's yeast to produce ethanol faster and more efficiently, according to a Massachusetts Institute of Technology research paper published on Thursday. The U.S. government is urging greater use of ethanol as a way to stretch domestic motor fuel supplies and make the country less dependent on foreign oil. U.S. demand for ethanol has also jumped as the oil industry uses it to replace gasoline additive MTBE, a suspected carcinogen banned in several states. The MIT scientists made "super" baker's yeast, by adding a gene already found in the microbe, to speed up ethanol production by about 50 percent. That could allow ethanol plants either to make more of the fuel in less time, or make more of the fuel in the same time, said Dr. Hal Alper, one of authors of the paper, published on Thursday in the international weekly science journal, "Science." The mutated yeast could help move U.S. ethanol production beyond its current centralized location in the Midwest to areas across the country. That's because it can more efficiently ferment either corn starch, currently the main source of ethanol made in the United States, or the sugars in woody bits of plants, which are sometimes wasted. The latter, along with switchgrass, poplar, and other sources, collectively known as biomass, can yield a new type of the fuel called cellulosic ethanol. Alper said the yeast could boost supply of ethanol in coming years. "One of the major alternatives to corn ethanol is looking at cellulosic ethanol. The benefit is that biomass is everywhere," he said. Currently there are no commercial U.S. plants making cellulosic ethanol, though research plants have been built in other countries. Cellulosic currently costs up to three times as much as conventional ethanol, but backers say costs will come down as production rises. The MIT scientists engineered the baker's yeast to survive high levels of ethanol and sugars found in the processing of the fuel that kill other fermenting microbes. "The end result is that you have yeast cells that are able to survive and grow in the presence of a toxic chemical," said Alper. The yeast can survive high levels of glucose and there's no reason why it won't survive in high levels of xylose, the other main sugar found in cellulosic ethanol, he said. The research was funded by the DuPont-MIT alliance, a collaboration between the DuPont Co. <DD.N> and the university, the National Institutes of Health, and the U.S. Department of Energy, and others. Ethanol producers are scrambling to build new ethanol plants on high demand. Current U.S. ethanol production is roughly 5.121 billion gallons per year (gpy), according to the Renewable Fuels Association, roughly 1.2 billion gpy below demand. [ID:nN27543610].
