Eschlbeck Elisabeth, Bauer Simon A W, Kulozik Ulrich
Chair of Food and Bioprocess Engineering, Technical University of Munich, Weihenstephaner Berg 1, Freising, DE, Germany.
ZIEL Institute for Food & Health, Weihenstephaner Berg 1, 85354, Freising, Germany.
AMB Express. 2017 Dec;7(1):157. doi: 10.1186/s13568-017-0458-2. Epub 2017 Jul 27.
Bacillus subtilis spores are often used as biological indicators (BI) to monitor decontamination processes with gaseous hydrogen peroxide. Results in practical inactivation validation tests, however, vary considerably with no available explanation so far. This study reports on the effect of cultivation pH on spore surface hydrophobicity. Surface hydrophobicity is suspected to have an impact on the decontamination of technical surfaces such as packaging material when gaseous, condensing hydrogen peroxide is applied. It is the aim of this study to examine the impact of different cultivation pH levels on surface hydrophobicity and resistance of B. subtilis spores. Submersed cultivation of B. subtilis in bioreactors at controlled conditions with different static pH levels led to contact angles ranged between 50° and 80°, which was analyzed with water on a homogeneous layer of spores on a filter sheet. Resistance of spores was also affected by the cultivation pH. The results show that the culturing conditions during BI production should be controlled to obtain BI with specified characteristics in inactivation validation tests.
枯草芽孢杆菌孢子常被用作生物指示剂（BI），以监测气态过氧化氢的去污过程。然而，实际灭活验证试验的结果差异很大，目前尚无合理的解释。本研究报告了培养pH对孢子表面疏水性的影响。当使用气态、冷凝的过氧化氢时，表面疏水性被怀疑会影响诸如包装材料等工业表面的去污效果。本研究的目的是检验不同培养pH水平对枯草芽孢杆菌孢子表面疏水性和抗性的影响。在生物反应器中，在不同静态pH水平的受控条件下对枯草芽孢杆菌进行浸没培养，导致接触角在50°至80°之间，这是通过水在滤纸上均匀的孢子层上进行分析得到的。孢子的抗性也受培养pH的影响。结果表明，在生物指示剂生产过程中，培养条件应加以控制，以便在灭活验证试验中获得具有特定特性的生物指示剂。
