title: Bio-ethanol production from wet coffee processing waste in Ethiopia.
abstract: Large amounts of coffee residues are generated from coffee processing plants in Ethiopia. These residues are toxic and possess serious environmental problems following the direct discharge into the nearby water bodies which cause serious environmental and health problems. This study was aimed to quantify wet coffee processing waste and estimate its bio-ethanol production. The study showed that the wastes are potential environmental problems and cause water pollution due to high organic component and acidic nature. The waste was hydrolyzed by dilute H2SO4(0.2, 0.4, 0.6, 0.8 and 1 M) and distilled water. Total sugar content of the sample was determined titrimetrically and refractometry. Maximum value (90%) was obtained from hydrolysis by 0.4 M H2SO4. Ethanol production was monitored by gas chromatography. The optimum yield of ethanol (78%) was obtained from the sample hydrolyzed by 0.4 M H2SO4for 1 h at hydrolysis temperature of 100 °C and after fermentation for 24 h and initial pH of 4.5. Based on the data, it was concluded that reuse of the main coffee industry wastes is of significant importance from environmental and economical view points. In conclusion, this study has proposed to utilize the wet coffee processing waste to produce bio-ethanol which provides the alternative energy source from waste biomass and solves the environmental waste disposal as well as human health problem.
authors.affiliation: School of Chemical and Bio-Engineering, Addis Ababa Institute of Technology, Addis Ababa University, P.O. Box 385, Addis Ababa, Ethiopia.
authors.forename: Asrat Gebremariam
authors.initials: AG
authors.lastname: Woldesenbet
authors.affiliation: School of Chemical and Bio-Engineering, Addis Ababa Institute of Technology, Addis Ababa University, P.O. Box 385, Addis Ababa, Ethiopia.
authors.forename: Belay
authors.initials: B
authors.lastname: Woldeyes
authors.affiliation: Department of Chemistry, College of Natural Sciences, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia.
authors.forename: Bhagwan Singh
authors.initials: BS
authors.lastname: Chandravanshi
keywords: Bio-ethanol; Ethiopia; Fermentation; Hydrolysis; Wet coffee waste