Local Production of Ethanol using Cassava Tuber locally Sourced in Nigeria

Cassava processing equipment at cassava processing
unit, IITA Ibadan, Nigeria. 
Ethanol, also called ethyl alcohol, can be used as fuel alcohol, drinking alcohol, and grain alcohol. The common type of ethanol is the one found in alcoholic beverages. It is also used as fuel for cars and often called alcohol or spirit.

Ethanol can be prepared in the laboratory by several methods like hydrolyzing ethyl esters with a hot alkali and reducing ethanal with nascent hydrogen.

As we are more concerned about the commercial production of ethanol, we can also prepare ethanol locally by fermentation of starch.

Cassava tuber as a case study, has in the past been an efficient source of ethanol in Nigeria, where foreign and local investors have the opportunity to invest in the production of ethanol even in large amount. Cassava, an edible starchy tuberous root, is grown in large quantities and well suited for the production of ethanol.

Cassava ethanol in Nigeria have been in existed since independence, and apart from food and pharmaceutical uses, cassava ethanol is playing a major role in renewable energy as in Ethanol or Bio-diesel Bio-fuel. Cassava produces a better quality alcohol, and the distilling technique employed ensures a high quality product, free of all type of odors and not harmful to the environment.

Nigerian biofuel plant would bring in fresh cassava, wash and peel, grate, cook in a jet cooker, ferment, distil and bottled. In addition, a steam boiler, generating set, effluent treatment plant, and electrical system are required.

The actual amount of cassava needed is dependent upon the starch content. As a guide, cassava at 25 % starch will produce 230 litres of alcohol. A typical plant will produce approximately 10,000 litres/day at 40%. Tthis plant will also produce around 2-3 m3/hr of effluent. The effluent has to be disposed off properly and is normally used as animal feed. This alcohol can be collected by batch fermentation and can process approximately 4-6 batches/day. Producing 520 litres of alcohol/ batch.

The plant will need a good supply of water and continuous electrical supply. This has greatly contributed to abundant local alcohol in Nigeria today and has significantly contributed to economy boost, serving as a source of income for rural farmers.

The cassava granules are first extracted by crushing and pressure-cooking the material; they are then treated with malt at 50 – 60 degree Celsius for an hour. Malt is partially germinated barley which contains the enzyme diastase and converts the cassava starch into maltose. Yeast is then added in adequate proportion at room temperature. Yeast contains maltase which converts maltose to glucose, and zymase which decompose glucose to ethanol and carbon (IV) oxide is evolved.

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