Archive for March 8th, 2008
Cellulosic Ethanol Economics
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Shown below is a table from the Chief Economist, USDA, March 2007. It’s the best snapshot you’ll find of the current state of cellulosic ethanol production.
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Commercial cellulose-ethanol plant is on its way
Vinod Khosla, a co-founder of Sun Microsystems and a venture capitalist who bet big and early on Google and Amazon, is now betting on Celunol Corp. Celunol is developing a 55-million gallon ethanol production facility
in Jennings, Louisiana. That’s 55 times bigger than the Canadian demonstration plant—this is a full-blown commercial plant.
In 1995 Celunol bought rights and patents from the University of Florida to commercialize their cellusose technology and has since acquired and developed more cellulose technology.
The sugar in cellulosic biomass is locked up in cellulose, which contains normal C6 sugar, and hemicellulose, which contains Xylose (C5) sugar. Since normal yeast can’t ferment Xylose, Celunol has acquired genetically engineered E. coli bacteria which can turn almost all of it into ethanol.
The diagram explained. First the hemicellulose in the biomass is broken into Xylose sugar (gray bar). Then the Xylose is separated from the remaining cellulose (blue bar). The Xylose is fermented with E. coli (top yellow), and the cellulose is broken down into normal glucose (red) which is fermented the normal way (bottom yellow). Finally all the ethanol is distilled (the water and lignin byproducts removed). The lignin is burned in the the still’s boilers.
