Investigation of ethanol productivity of cassava crop as a sustainable source of biofuel in tropical countries

Abstract

The ethanol productivity of cassava crop was investigated in a laboratory experiment by correlating volumes and masses of ethanol produced to the masses of samples used. Cassava tubers (variety TMS 30555) were peeled, cut and washed. 5, 15, 25 and 35 kg samples of the tubers were weighed in three replicates, soaked in water for a period of a day, after which each sample was dried, crushed and the mash mixed with 500 ml of N-hexane (C₆H₁₄). This crushed mash was then allowed to ferment for a period of 8 days and afterwards pressed on a 0.6 mm aperture size and sieved to yield the alcohol contained in it. The alcohol was heated at 79°C for 10 h at intervals of 2 h followed by an h cooling. Ethanol yield was at average volumes of 0.31, 0.96, 1.61 and 2.21 litres, respectively, for the selected masses of cassava samples. Quantitative relationships were obtained to relate the masses of cassava used to the masses and volumes of ethanol produced. These were used to relate known production values of cassava from tropical countries to ethanol that can be potentially produced. The ethanol had boiling point of 78.5°C and relative density of 0.791. The dried mash was found to contain 61.8 calories of food energy per 100 g. This study found that a total of 6.77 million tonnes or 1338.77 million gallons of ethanol are available from total cassava production from tropical countries. The production and use of ethanol from cassava crop is recommended in the cassava-growing tropical countries of the world.

Keywords: Cassava, ethanol, fermentation

African Journal of Biotechnology Vol. 9(35), pp. 5643-5650, 30 August, 2010