Finger Millet as a Sustainable Feedstock for Bioethanol Production

Abstract

The current trend in volatile oil prices, global warming and environmental pollution, has encouraged major consumers worldwide to sharply increase their use of “green” fuels. Bioethanol is usually obtained from the conversion of carbon-based feedstock. Bioethanol from biomass sources is the principal fuel used as a fossil fuels’ substitute for road transport vehicles. Bioethanol is predominantly produced by the sugar fermentation process, although it can also be generated by the chemical process of reacting ethylene with steam. Finger millet (Eleusine coracana) is also known as Ragi (India), Kodo (Nepal), Uburo (Rwanda), Kurakkan (Srilanka), Bulo (Uganda), Kambale (Zambia) and Tamba (Nigeria) and can be used as an efficient source for bioethanol production. Despite all its importance, however, finger millet is still grossly undervalued both scientifically and internationally. This review observes current progress in bioethanol production from E. coracana feedstock and the effectiveness of various technological approaches for that. The main aspects of ethanol production from finger millet seeds have been considered. Seeds, which are already used for brewing, are the most obvious variant of feedstock for ethanol production from this crop. The conversion of finger millet straw and agricultural waste into bioethanol has also been reviewed. Practical results of development and testing the tentative technology of sweet sorghum and finger millet combined processing into bioethanol are described. The concept of the tentative technology of bioethanol production from carbohydrate raw material of the first and second generations is suggested.