Summarises the processes involved in the industrial production of ethanol from sugar cane.

Sugarcane ethanol is an alcohol-based fuel produced by the fermentation of sugarcane juice and molasses. Because it is a clean, affordable and low-carbon bio-fuel, sugarcane ethanol has emerged as a leading renewable fuel for the transportation sector.

At the mill, sugar cane is weighed and processed then moved to a shredder. The shredder breaks apart the cane and juice cells. Rollers are used to separate sugar juice from the fibrous material, called bagasse. The bagasse is extracted and its properties utilised to serve as a fuel for the mill boiler furnaces. The sugarcane juices are then purified before being concentrated as they boil in an evaporator.The process of making sugar cane can be summarised by the following flow chart:

To create ethanol, the sugars must first be fermented. Fermentation is a process in which glucose is converted to ethanol and carbon dioxide by the action of the enzymes in yeast. In order to do this the necessary conditions are that the sugars need to be in solution, yeast containing certain enzymes must be present, a temperature of about 37˚C must be applied and the solution must be deprived from oxygen and hence be in anaerobic conditions. The ethanol produced must then be distilled from the water it is dissolved in.

Enzymes are biological catalysts. They convert the sucrose into glucose and/or fructose. Other enzymes convert glucose or fructose into ethanol and carbon dioxide. This can be represented by the following equation:

Bubbles of carbon dioxide are slowly given off by the process, The yeast can produce ethanol contents of up to 15%. It is then up to fermentation to raise the amount of ethanol to 95%. The ethanol must be subjected to further elaborate distillation processes to make it 100% pure.