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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/3323

Title: Bioethanol Production and Optimization test from Agricultural Waste: The case of wet coffee processing waste (pulp)
Authors: Ayele, Kefale
Advisors: Araya Asfaw(Dr.)
Mesfin Redi(Dr.)
Keywords: Bioethanol
Optimization test
Copyright: May-2011
Date Added: 9-Jul-2012
Publisher: Addis Ababa University
Abstract: Biofuels are alternatives to fossil fuels to ensure energy security and mitigate climate change. Currently, most biofuel is in the form of bioethanol generated from starch or sugar. Conversion of cellulosic biomass, which is both abundant and renewable, to bioethanol is a promising alternative. The objective of this work was to evaluate the feasibility of ethanol production and optimization from coffee pulp by using commercial bakery yeast, i.e., S. cereviciae. To conduct this study, fermentation was held at temperature 30 °C and pH 5, and treated using different acid concentrations and residence times. Coffee pulp was hydrolyzed by refluxing, a solid to liquid ratio of 1:10, using dilute sulfuric acid (1, 2 and 4 %) and distilled water at hydrolysis time of 1, 2, 4, 6 and 10 hours keeping boiling temperature. 90 % maximum total sugar concentration was obtained at 4 h acid free hydrolysis. Based on these hydrolysis results, fermentation process was performed. In the process, it was observed that ethanol concentration decreased with an increase in acid concentration, hydrolysis time and fermentation time. The maximum result was obtained with distilled water hydrolysis for 4 h and 24 h fermentation. Under these conditions maximum ethanol concentration production was 7.398 g/L, a satisfactory result as compared with literature data. The result indicated that being available in plentiful amounts and non-edible material, coffee pulp will be potential feedstock for bioethanol production in Ethiopia.
Description: A thesis presented to the School of Graduate Studies of the Addis Ababa University in the partial fulfillment of the requirement for the Degree of Masters of Science in Environmental Science
URI: http://hdl.handle.net/123456789/3323
Appears in:Thesis - Environmental Sciences

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