How ethanol is made

2019-06-05

Ethanol is produced from biomass mostly via a fermentation process using glucose derived from sugars (sugar cane, sugar beet and molasses), starch (corn, wheat, grains) or cellulose (forest products) as raw materials. In this form, it is renewable.  Synthetic ethanol can also be produced from non-renewable sources like coal and gas.

 

In some country, ethanol is made from waste products as sugar cane, the waste from starch production, and red sorghum. This means that ethanol production does not interfere with food production at all. Innovations in ethanol continue with the development of other feedstocks, such as algae, cellulosic biomass, trees and grasses.

How Conventional Ethanol is manufactured

From a chemical viewpoint conventional ethanol is manufactured via a process where glucose is transformed by yeast into ethanol called fermentation.

 

In this process the feedstock is first converted into glucose.  In the case of sugar this is quite straightforward as the sugar is simply dissolved in water.  Starch however requires pre-processing where the starch is transformed into glucose through a process call liquefaction and saccharification.  This process through the addition of enzymes frees the glucose bound in the starch and makes it available for fermenting into alcohol.