Yimam, Abubeker (PhD)Berhane, Kiros2018-07-162023-11-102018-07-162023-11-102016-06http://etd.aau.edu.et/handle/12345678/8561There is a vested interest in developing alternate sources of fuel to fossil fuel due to lowering stocks, increasing prices and the need for environmentally sustainable energy sources. One major alternative to fossil fuels is bio-ethanol (ethanol from biomass) and waste paper (used office paper) represents a significant source for bioethanol production because of its high cellulose and hemicellulose contents. This study involved ethanol production from waste paper (used office paper) and investigation of process variables (temperature and time) on the yield of bioethanol. The conversion of waste paper to ethanol can be achieved mainly by four process steps: pretreatment of waste paper to remove lignin and hemicellulose, acid hydrolysis of pretreated waste paper to convert cellulose into reducing sugar (glucose), fermentation of the sugars to ethanol using Saccharomyces cerevisiae and finally distillation of the fermented sugar into final product. A three level full factorial design with two factors (time and temperature) was applied to optimize the acid hydrolysis process and study the interaction effects of the factors. The experimental results were analyzed by using Design Expert 7 software, to investigate the effects of hydrolysis parameters on yield of ethanol. High yield of bioethanol 14.5ml/50g (0.23g/g) was obtained at the optimum parameters, temperature of 1400C and time 60 min. ANOVA (statistical analysis) showed that an ethanol yield of 14.2426ml/50ml (0.22g/g) was obtained at a temperature of 1400C and time 63.24 min. Investigation on the preliminary economic analysis of the ethanol production was performed and results from the feasibility study indicated that the proposed work was feasible with rate of return (ROR) of 26% and the payback period of 1.8 year. Keywords: Bioethanol, waste paper, fermentation, Saccharomyces cerevisiaeenBioethanol; waste paper; fermentation; Saccharomyces cerevisiaeThesis