How You Can Make Bioethanol from Starch and Cellulose with the Aid of Yeast

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Draft Essay You can make ethanol from plant sugars like cellulose and starch. The ethanol production process takes polysaccharides, or complex sugars, from the plant, breaks them into single sugars and converts them into ethanol. Starch and cellulose are large carbohydrate molecules. Starch is an odourless, tasteless white substance which is found in plant tissue and obtained from cereals and potatoes. It is a polysaccharide that functions as a carbohydrate store and is an important part of the human diet used as an energy source. It is a polymer of glucose sugar which means it is composed of many glucose molecules linked in a chain. Plants store the starch instead of simple sugars. Cellulose is an insoluble substance which is the main part of plant cell walls and vegetable fibres such as cotton. It is also a polysaccharide consisting of chains of glucose monomers. Its main use is to produce paper but is also used as a food additive like starch. Because starch is a polymer of glucose and it cannot be directly fermented to ethanol. Bioethanol is a type of fuel produced from plants such as sugar cane or corn. It is produced by the fermentation of sugars with yeast and is concentrated by distillation to be used as fuel. The fermentation of starch involves the starch being converted into a sugar so it needs to be broken down to simpler glucose molecules through hydrolysis. Starch is converted enzymatically to glucose by an enzyme called amylase. The enzyme is a biological catalyst which speeds up the rate of the reaction. The resulting dextrose from the starch is then fermented into ethanol with the aid of yeast which produces carbon dioxide. Yeast is a microorganism that produces ethanol. These microorganisms are capable of converting sugars into alcohol by a biological process called fermentation. In hydrolysis the starch is ground and mixed with water to produce a

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