Analysis of the influence of flame sterilization included in sampling operations on shake-flask cultures of microorganisms
Analysis of the influence of flame sterilization included in sampling operations on shake-flask cultures of microorganisms
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DOI：
10.1038/s41598-020-66810-3
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发表时间：
2020-06
影响因子：
4.6
通讯作者：
Masato Takahashi;Takafumi Honzawa;R. Tominaga;H. Aoyagi
中科院分区：
文献类型：
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作者：
Masato Takahashi;Takafumi Honzawa;R. Tominaga;H. Aoyagi
微生物摇瓶培养在取样过程中涉及火焰灭菌，这会产生高浓度二氧化碳的燃烧气体。气态终点还没有被深入分析。我们的目的是研究火焰灭菌对烧瓶顶空和摇瓶培养的影响。在本研究中，使用循环直接监测和采样系统的经验发现，在5-20 s的火焰灭菌过程中，顶空co2浓度增加了0.5-2.0%。利用计算流体力学理论证实了这种co2聚集；局部利率为9%。为了评估在不受其他采样因素干扰的情况下co2积累的影响，在不采样的情况下，通过向顶空无菌供应99.8%的co2来重现火焰灭菌形成的烧瓶气相。我们开发了一种可以在不中断摇晃、移动到干净的工作台、打开培养塞和火焰灭菌的情况下进行采样的装置。结果表明，不同的co2曝气条件下，大肠杆菌、嗜糖单胞菌、巴氏醋酸杆菌和酿酒酵母的生长行为不同。这些结果有望有助于改善微生物细胞培养系统。
Shake-flask cultures of microorganisms involve flame sterilization during sampling, which produces combustion gas with high CO2concentrations. The gaseous destination has not been deeply analyzed. Our aim was to investigate the effect of flame sterilization on the headspace of the flask and on the shake-flask culture. In this study, the headspace CO2concentration was found to increase during flame sterilization ~0.5–2.0% over 5–20 s empirically using the Circulation Direct Monitoring and Sampling System. This CO2accumulation was confirmed theoretically using Computational Fluid Dynamics; it was 9% topically. To evaluate the influence of CO2accumulation without interference from other sampling factors, the flask gas phase formed by flame sterilization was reproduced by aseptically supplying 99.8% CO2into the headspace, without sampling. We developed a unit that can be sampledin situwithout interruption of shaking, movement to a clean bench, opening of the culture-plug, and flame sterilization. We observed that the growth behaviour ofEscherichia coli,Pelomonas saccharophila,Acetobacter pasteurianus, andSaccharomyces cerevisiaewas different depending on the CO2aeration conditions. These results are expected to contribute to improving microbial cell culture systems.