| บทคัดย่อ(English) |
A mathematical model is developed to explain the process dynamics of ethanolproduction by flocculating yeast, Saccharomyces cerevisiae M30. Molasses, the mainfeedstock for ethanol production in Thailand, is used as the substrate source for allexperiments. Firstly, the experiments are carried out by the batch fermentation in shakingflasks with the initial sugar concentration ranging from 3 to 25%w/v and incubate at 33(+,ฐ)C.Subsequently, the optimal initial sugar concentration growth and production is found to be22%w/v. At the optimal initial sugar concentration (22%w/v), the fermentation areperformed with operating temperature ranging from 30 to 42(+,ฐ)C. The mathematical model isdeveloped from Monod kinetic model. It consists of three main factors; initial substrateconcentration, substrate and ethanol concentration, and operating temperature, and countswith death rate and cell maintenance for biomass equation. Polynomial equation is used todescribe the relationship between initial substrate concentration and kinetic parameters.Then, exponential relationships between operating temperature and kinetic parameters suchas both maximum specific growth rate and production rate and maximum productionconcentrations are determined. The parameters of model are converged by using least-squaremethod. The results reveal a good agreement between the simulation and the experimentdata. The optimum conditions of ethanol batch fermentation by using molasses as substrateare at 22%w/v initial reducing sugar and 33(+,ฐ)C of operating temperature. The results can befurther used to improve the ethanol fermentation process performance. |
