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What biological processes are involved in changing starch into bioethanol?

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´╗┐What is starch? Starch is an odorless tasteless white substance occurring widely in plant tissue and obtained chiefly from cereals and potatoes. Starch molecules are made up of long chains of glucose molecules. How is it treated to be used by yeast, to make bio ethanol? Ethanol has been used by humans for thousands of years, in part because it is easy to make. The process is shown in here in its simplest form: Wheat or corn kernels are ground in a hammermill to expose the starch. The ground grain is mixed with water, cooked briefly and enzymes ( for starch the enzyme used is amylase which has an optimum of Ph 6-7) ...read more.


breaks one of the chains within the cellulose crystal structure. Then, an exoglucanase (another enzyme) attaches to one of the loose ends, pulls the cellulose chain out of the crystal structure, and works its way down the chain, breaking off units of cellobiose (two glucose units joined together). Finally, a beta-glucosidase (enzyme that acts upon bonds linking two glucose or glucose-substituted molecules) splits the cellobiose into two glucose molecules, which can then be fermented into ethanol. What biological processes are involved in changing starch into bioethanol? How is Ethanol Made The modern ethanol production plants employ dry mill method, that involves use of yeast to convert sugar into ethanol. ...read more.


begins. This fermenting mash is allowed to pass through several fermenters until is it completely fermented and leaves the final tank. The entire fermentation process usually takes about 40 to 50 hours. Distillation: The fermented mash is now referred to as beer. The beer is pumped to the continuous flow, multi-column distillation system where the alcohol is separated from the solids and water with the help of heat. In the final distillation column, the alcohol at the top of the final column leaves behind a highly concentrated ethanol. Dehydration: At this stage, the alcohol in the top of the last column is then passed through a dehydration system where the left over water is removed. The alcohol product now called anhydrous ethanol (pure, without water) 1)http://e85.whipnet.net/ethanol.faq/make.ethanol.html 2.)http://www.i-sis.org.uk/ECBNESEB.php 3.)http://www.buzzle.com/articles/how-is-ethanol-made.html 4.) http://www.hort.purdue.edu/newcrop/ncnu02/v5-017.html ...read more.

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