Abstract:
Bio- ethanol is suggested as a sustainable fuel which can be produced from renewable resources and reduce the level of greenhouse gases. Therefore, this study was focused on producing bio ethanol fuel from teff (Eragrostis tef) straws in batch fermentation using yeast (Saccharomyces cerevisiae). Fifty grams of acid pretreated and untreated teff straw were incubated with10ml of 1% of yeast under three different temperature (20℃, 30℃ and 40℃) treatments and allowed to ferment over 16 days. Yeast cell density, total reducing sugars and ethanol production was measured at 4 days interval beginning from the incubation period. The results were observed within 4 days of intervals starting from first day of fermentation period. In pretreated and untreated substrates high amount bio ethanol production were observed on 12th day fermentation with 300C temperatures, whereas after 12th day of fermentation it was declined. This may be due to decreasing of fermentable sugar or high alcohol concentration. The high amount of bio ethanol (11ml) was produced from pretreated substrates on the 12th day of fermentation with 300 C temperatures treatment. In addition, on 12th day of fermentation with 300 C temperatures relatively high amount of cell density concentrations were recorded from pre-treated (8.62mg/mol) and untreated substrates (7.40mg/mol) respectively. Results showed that all measured parameters subsequently decrease with increasing days of fermentation in both acid pre-treated and untreated substrates. Finally, it was proved that the bioethanol was produced from teff straw using Saccharomyces cerevisiae in batch fermentation and the yield was increased with acid pre-treatment and incubation under 30oC temperature. According to this research, it is recommended that teff straw can be used as a feedstock for bioethanol production and the yield can be increased with acid pre-treatment and incubation under 30oC temperature
