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August 20, 2008

Japanese Sake Brewer makes Cellulose Ethanol Breakthrough

Major Japanese sake manufacturer Gekkeikan announced on March 28, 2008, that it has developed a new technology for producing bioethanol, which is attracting keen interest as a replacement for fossil fuels. Using "super yeast" -- sake yeast genetically modified with koji mold genes -- the innovative technology can directly produce ethanol from inedible plant materials such as paddy straw and chaff.

Plant cellulose, a raw material for bioethanol, has a chemically stable, robust structure. The new technology pretreats plants to weaken their rigid structure and make them ready for fermentation using a "subcritical water treatment." The pretreatment process uses water at high temperature and pressure in a subcritical state, and therefore, it is safer and has less environmental impacts than existing methods that use chemical agents.

Super yeast that produces alcohol is created by integrating koji mold genes that produce cellulolytic enzymes into sake yeast so that the enzymes are densely displayed on the surfaces of the yeast cells, much like the hands of a multi-armed deity. Since super yeast has the functions of koji mold, it achieves one-step production of ethanol from pretreated cellulose.

FURTHER READING
Cellulosic ethanol at wikipedia

According to U.S. Department of Energy studies conducted by the Argonne Laboratories of the University of Chicago, one of the benefits of cellulosic ethanol is that it reduces greenhouse gas emissions (GHG) by 85% over reformulated gasoline. Switchgrass and Miscanthus are the major biomass materials being studied today, due to high levels of cellulose. Cellulose, however, is contained in nearly every natural, free-growing plant, tree, and bush, in meadows, forests, and fields all over the world without agricultural effort or cost needed to make it grow.

The U.S. could potentially produce 1.3 billion dry tons of cellulosic biomass per year, which has the energy content of four billion barrels of crude oil. This translates to 65% of American oil consumption
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