RESEARCH: Ethanol Out of Sugar Waste

Eckhard Boles, co-founder of the Swiss biofuel company Butalco GmbH (www.butalco.com) and a professor at Goethe-University in Frankfurt (www.uni-frankfurt.de), Germany, has discovered a new enzyme that teaches yeast cells to ferment xylose into ethanol. Xylose is an unused waste sugar in the cellulosic ethanol production process. The researchers have recently filed a patent application for their process, according to Butalco GmbH.In industrial fermentation processes, the yeast Saccharomyces cerevisiae is commonly used for ethanol production. Current bioethanol production technologies can use only parts of the plants, namely the storage sugars, like glucose, sucrose or starch. However, this technology is in competition with food and feed production. As such, Butalco GmbH says Boles has been searching for ways of teaching the microorganisms to convert waste sugars, xylose and arabinose, into ethanol. According to Butalco, Boles and his colleagues have succeeded in genetically modifying industrial yeast strains, thus producing ethanol from xylose in a single step. This breakthrough, combined with previous efforts by Boles and his research team in transforming arabinose into ethanol by genetically modified yeast strains, Butalco GmbH says it now has an efficient method for converting most of the plants energy into biofuel.The new research will aid in the commercialization of cellulosic ethanol, according to Boles. However, Boles says ethanol is not the best renewable fuel, and he is currently leading research efforts with Butalco GmbH to construct yeast strains to convert plant waste materials into biobutanol, which he says is a superior alternative fuel as compared to ethanol due to favorable chemical and physical properties.