This second article by Absolute Futures will explain the commercial production of ethanol. Ethanol is a product of fermentation. Fermentation is a sequence of reactions which release energy from organic molecules in the absence of oxygen. In this application of fermentation, energy is obtained when sugar is changed to ethanol and carbon dioxide.
Changing corn to ethanol by fermentation takes many steps. Starch in corn must be broken down into simple sugars before fermentation can occur. In earlier times, this was done by chewing the corn. This allowed the salivary enzymes to naturally break down the start. Today, this is achieved by cooking the corn and adding the enzymes alpha amylase and gluco amylase.
Once a simple sugar is obtained, yeast is added. Yeast is a single-celled fungi which feeds on the sugar and causes the fermentation. As the fungi feeds on the sugar, it produces alcohol (ethanol) and carbon dioxide. In fermentation, the ethanol retains much of the energy that was originally in the sugar, and explains why ethanol is an excellent fuel.
Most ethanol production in the United States is made in 50 production facilities in 20...