We evaluated the ventilation ability of two types (plug-type and cap-type) of culture-stoppers having standard air permeability. The culture-stoppers were evaluated using the circulation direct monitoring and sampling system with CO2 concentration in the gas phase of a shake-flask culture as an index. The half-lives of CO2 in the headspace of the shake flask with the plug-type and cap-type stoppers were about 51.5 min and about 30.3 min, respectively. Based on these half-lives, we formulated a model equation to simulate the behaviour of CO2 with different culture-stoppers. After validating the model equation by shake-flask culture with Saccharomyces cerevisiae, we investigated the effect of different ventilation abilities of the culture-stoppers on the growth of Pelomonas saccharophila and Escherichia coli: the sensitivity of the culture-stopper to the ventilation ability was dependent on the microorganism species. In the case of P. saccharophila, when the plug-type culture-stopper was combined with controlled CO2 concentration (6%) in the flask, the maximum yield increased by twofold compared to that of the control. This study shows the importance of ventilation in headspace and conventional culture-stoppers during the shake-flask culture of microorganisms. The problems that may occur between the conventional shake-flask culture approach using a breathable culture-stopper and the next-generation shake-flask culture without a conventional culture-stopper were clarified from the evaluation of gas-permeable culture-stoppers. The importance of controlled gaseous phase in the headspace during shake-flask culture of the microorganisms was also elucidated. KEY POINTS: • Ventilation capacity of culture-stoppers was evaluated using the CO2 half-life concentration. • Behaviour of microorganisms varies with the type of culture-stopper. • Developed a PID system for control of CO2 in flask gas phase to enhance the shake-flask culture.

中文翻译：

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微生物摇瓶培养过程中多孔透气塞的分析和气相PID控制的发展。

我们评估了具有标准透气性的两种类型的塞子（塞式和帽式）的通风能力。使用循环直接监测和采样系统对培养瓶进行评估，以摇瓶培养物气相中的CO2浓度为指标。带有塞型和帽型塞子的摇瓶顶部空间中的CO2半衰期分别为约51.5分钟和约30.3分钟。基于这些半衰期，我们制定了一个模型方程来模拟不同培养物对CO2的影响。在通过酿酒酵母摇瓶培养验证模型方程后，我们研究了培养物塞子的不同通气能力对果蝇和大肠杆菌生长的影响：培养塞对通风能力的敏感性取决于微生物种类。在嗜糖毕赤酵母中，当塞型培养塞与烧瓶中受控的CO2浓度（6％）结合使用时，与对照相比，最大产量增加了两倍。这项研究表明，在微生物摇瓶培养过程中，顶空和传统培养瓶中通风的重要性。通过对透气性塞子的评估，明确了在使用透气式塞子的常规瓶式培养方法与不使用常规塞子的下一代瓶式培养方法之间可能出现的问题。还阐明了在摇瓶培养微生物过程中顶空中受控气相的重要性。要点：•使用CO2半衰期浓度评估了塞子的通风能力。•微生物的行为随培养物塞子的类型而变化。•开发了PID系统，用于控制烧瓶气相中的CO2，以增强摇瓶培养。