稀释速率对高浓度酒精连续发酵过程振荡行为的影响

在一搅拌罐和三段管式反应器组成的组合反应器系统中，使用葡萄糖浓度为280g/L，添加5g/L酵母膏和3g/L蛋白胨的底物，在总稀释速率分别为0.032h^-1，0.024h^-1，0.017h^-1，0.012h^-1和0.006h^-1的条件下，考察了稀释速率对高浓度酒精发酵系统振荡行为的影响。结果表明，振荡行为在特定的稀释速率条件下呈现，进而基于数学上的分岔理论，分析了振荡行为发生的可能性及对应的稀释速率范围，并与实验结果进行了比较，在此基础上，讨论了振荡行为对酒精发酵过程的影响。

Effects of Dilution Rates on the Oscillatory Behaviors of a Very High Gravity Continuous Ethanol Fermentation System

Continuous ethanol fermentation using very high gravity medium containing 280 g/L glucose, 5 g/L yeast extract and 3 g/L peptone was run at the dilute rates of 0.006 h~ -1, 0.012 h~ -1, 0.017 h~ -1, 0.024 h~ -1 and 0.032h~ -1 (based on the total working volume) in a combined bioreactor system composed of a stirred tank and three-stage tubular bioreactors in series. Oscillations marked by big fluctuations of residual glucose, ethanol and biomass were observed at the dilution rate of 0.012 h~ -1. The Hopf Bifurcation theory was used to analyze and predict the occurring of these oscillations and the dilution rates that incited oscillations. Theoretical analysis revealed that oscillations can occur at designated specific growth rates and was validated by experimental results. The benefits of oscillations for the fermentation system were also discussed by comparing the fermentation results with those without oscillations.