Energy / Climate Change

August 17, 2008


Japanese Sake Brewer Produces Bioethanol from Nonfood Plant Materials

Keywords: Government Manufacturing industry Reduce / Reuse / Recycle Renewable Energy University / Research institute 

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. The combination of clean and easy pretreatment and simple and efficient ethanol production enables a small-scale operation to produce bioethanol onsite where the plant materials are produced.

The Gekkeikan Research Institute conducted the research jointly with researchers from the universities of Tohoku, Kobe, and Kyoto, as part of an Innovative Technology Development Research Project established by the Japan Science and Technology Agency (JST). The institute has already confirmed that paddy straw and chaff can be used to produce ethanol, and it will continue researching how to boost alcohol yield for commercial use.

Posted: 2008/08/17 11:49:07 AM