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| dc.contributor.author | Legese, Asmamaw | |
| dc.date.accessioned | 2021-08-16T06:12:26Z | |
| dc.date.available | 2021-08-16T06:12:26Z | |
| dc.date.issued | 2021-03 | |
| dc.identifier.uri | http://ir.bdu.edu.et/handle/123456789/12420 | |
| dc.description.abstract | Alcohol distillery processes are agro based industries that produces different types of alcohol liquors to serve communities as a drink, raw material for other industries and power alcohol. Alcohol liquors are produced in molasses fermentation stage. Before fermentation processes the required quantity of yeast propagations are taking place for fermentation processes. The cane sugar molasses fermentation by yeasts is a dilution process operated by three step procedures (media preparation for two processes, yeast propagation and molasses fermentation processes). The propagation and fermentation optimization processes using molasses were done to get the required quantity of viable yeast cells and maximum alcohol production efficiency and research developed a method to obtain better results. To do this, media was prepared first from molasses, process water and nutrients with optimized conditions. The raw materials (cane molasses and process water) characterizations were analyzed to formulate optimum process parameters. For both yeast propagation and fermentation process parameters, laboratory analysis and Design expert 7.0 software was used for proper optimization purposes. Three influential process variables initial media brix, initial media pH and cell sizes have been chosen to conduct the experiment. Viable yeast cell count of 735x106 cells per milliliter sample was obtained at the optimum condition of initial media brix of 11.75, initial media pH of 4.4 and inoculums size of 26.665 % which is very high when compared with the current factory result below 240x106 cell/ml samples. Alcohol content of 10.42alcohol % was obtained at the optimum condition of initial brix of 17, initial pH of 4.3 and inoculums size of 20% which is very high when compared with the current factory result below 7 % of alcohol (v/v).The validity, verification and effect of different levels of each parameter (initial media brix, initial media pH and cell size inoculums) on each processes responses are also studied. Finally, the yeast strain available in Metahara sugar factory ethanol plant microbial laboratory was found favorable yeasts and has to be kept properly with proper optimization to get the maximum alcohol production processes. | en_US |
| dc.language.iso | en_US | en_US |
| dc.subject | CHEMICAL AND FOOD ENIGINEERING | en_US |
| dc.title | Optimization of Yeast Propagation and Molasses Fermentation Processes Parameters to Increase Ethanol Production Efficiency: The Case of Metehara Sugar Factory | en_US |
| dc.type | Thesis | en_US |
