earticle

영어

In this study, we utilized a unique strategy for the fed-batch fermentation process using ethanol-tolerant Saccharomyces cerevisiae to achieve a high-level of ethanol production that could be practically applied to industrial ethanol production. During this study, the aeration rate was controlled at 0.0, 0.13, 0.33, and 0.8 vvm to determine the optimal aeration conditions for the production of ethanol. Additionally, nonsterile glucose power was fed during fed-batch ethanol fermentation, and the amount of corn-steep liquor (CSL) in the medium was optimized. When aeration was conducted, the ethanol production and productivity were superior to those when the aeration was not conducted. Specifically, the maximum ethanol production reached approximately 160 g/L ethanol when the reaction was aerated at 0.13 vvm. Ethanol productivity during the early phase of the process increased, then decreased gradually during the later phase. Despite this finding, when aeration was conducted, the overall ethanol yield was not superior to that obtained when aeration was not conducted. In addition, ethanol consumption was observed at aeration rates of 0.3 and 0.8 vvm which resulted in a remarkable decrease in ethanol productivity and yield. However, the use of a much more inexpensive C-source may enable the process to be directed toward improvement of the overall ethanol production and productivity in a process that is aerated at 0.13 vvm. Furthermore, if a repeated fed-batch process in which the withdrawal and fill is conducted prior to 36 hr can be employed, aeration at a rate of 0.33 and/or 0.8 vvm may improve the overall ethanol productivity. Finally, the overall ethanol productivities in this study varied throughout the fed-batch ethanol fermentation, which indicates that the optimal operational strategy for achieving improved ethanol productivity may be set-up according to various aeration rates.