Methanol is used as a replacement for petrol for environmentally friendly cars and buses. Ethanol Ethanol or ethyl alcohol is the most common of all alcohols. Colloquially when one uses the word alcohol, it is generally meant to be ethanol. Ethanol is made by fermentation of sugar or by hydration of ethene. Ethanol preparation from fermentation of sugar Fermentation is a process whereby an organic compound is broken into smaller molecules by enzymes such as yeast.
Ethanol is prepared by fermentation of molasses.
Molasses, a by product of sugar industry, has traces of sugar, which gets broken down into ethanol. The fermentation is initiated by yeast, which secretes two enzymes called invertase and zymase. These enzymes act as catalyst for converting sugar into ethanol. The reaction is exothermic and carbon dioxide is released in the process. Yeast is mixed in the molasses.