本研究利用控制論模式(cybernetic model)模擬Pichia stipitis菌種在葡萄糖和木糖混合溶液下發酵。為了符合批次發酵實驗數據，控制論模式的成長速率形式是使用contois取代原本monod形式。然後使用批次發酵所得的參數來模擬連續式發酵，其結果發現單成分葡萄糖或木糖基質在低稀釋濃度下成長酵素和低成長酵素會互相競爭而有穩定震盪現象，
　　本論文亦利用基因演算法(Genetic Algorithm)當作程序搜尋最佳化的工具。在饋料批次程序搜尋不同基質濃度比例和不同體積比例的最佳操作條件使酒精生產速率達到最大值。結果發現75%木糖和25%葡萄糖混合比例溶液的酒精生產速率最大。

In this research, the cybernetic model is used to simulate the Pichia stipitis fermentation processfor the mixture of glucose and xylose. In order to fit batch experiment data, the growth rate expression of cybernetic model of costois form is used instead of Monod form. The experimental data from batch fermentation process is used to obtain the model parameter. This model is then used to simulate continuous fermentation processes. The result shows the competition between growth enzyme and low-maintenance enzyme will exhibit some stable oscillations in low dilution rate of glucose/xylose substrate.
The optimization tool used in this research is Genetic Algorithm.This optimization method is used to maximize the ethanol productivity and to find the optimal operation conditions for different substrate conceration ratio and different volume ratio in fed-batch operation. The result shows a mixture with 75% xylose and 25% glucose can obtain maximum ethanol productivity.

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