UTILIZATION OF WATER YAM (Dioscorea alata) AS A SOURCE OF ETHANOL

Abstract

Ethanol (C2H5OH) is a primary alcohol which can be produced by fermentation, using any of the sources of carbohydrates such as sugarcane, cassava, grains and yam tubers among others. Production of ethanol fermented from renewable sources for fuel and fuel additives are known as bioethanol. Since the need of bioethanol is increasing, the production of bioethanol must be increased using cheaper and eco friendly raw materials. This study was conducted, using cheaper and eco friendly raw materials; water yam (Dioscorea alata) as alternative sources for ethanol production. The starch that was produced from water yam was hydrolysed into fermentable sugar, using acid hydrolysis. The fermentable sugar was converted into ethanol by fermentation process at pH 4.5 using fermenting brewer's yeast (Saccharomyces calsbergensis). Starch, glucose and ethanol which were obtained were analysed for physicochemical properties. Findings revealed that the starch sample obtained gave a blue-black colouration on addition of few drops of iodine solution. This confirmed that the carbohydrate content was mainly starch. On calculation of viability, findings further showed that water yam is a good raw material for production of ethanol, therefore indigenous production of ethanol obtained from water yam is economically viable and recommended. This will save the country from lot of money spends annually on the importation of ethanol and it can also provide job opportunity for many wandering and unemployed Nigerians.