Kastelein J, Logtenberg M T, Hesselink P G
TNO, Department of Industrial Biotechnology and Biosafety, Zeist, The Netherlands.
Enzyme Microb Technol. 1992 Jul;14(7):553-60. doi: 10.1016/0141-0229(92)90126-9.
A TNO bacterial aerosol challenge (TBAC) filter test rig was developed for direct assessment of the effectiveness of bioreactor off-gas filters as an alternative to routinely applied indirect wet integrity testing (IT). This TBAC test rig is based on bacterial aerosol challenging with Pseudomonas diminuta and dual monitoring by laser particle counting (LPC) and Andersen microbial sampling (AMS) of viable cells. The TBAC filter test rig is able to reproduce the various conditions encountered in fermentation processes. In experiments with several filters from one class, it was demonstrated that some filters were actually penetrated by up to 3,000 viable cells per test, despite their approval by commercially available IT test equipment. Repetitive filter use, prolonged use, and autoclaving of filters resulted in an increase in pressure drop over the filter but improved the performance of leaking/deviant filters due to building up of a filter cake (this phenomenon was identified by electron microscopy). The integrity tests used were found inadequate for accurate assessment of filter quality. Certification of filter lots by random tests of commercially available off-gas filters using sensitive direct methods such as those presented here might be advisable, as not all filters purchased were of appropriate quality.
开发了一种TNO细菌气溶胶挑战（TBAC）过滤器试验台，用于直接评估生物反应器废气过滤器的有效性，作为常规应用的间接湿完整性测试（IT）的替代方法。该TBAC试验台基于用微小假单胞菌进行细菌气溶胶挑战，并通过激光粒子计数（LPC）和活细胞的安德森微生物采样（AMS）进行双重监测。TBAC过滤器试验台能够再现发酵过程中遇到的各种条件。在对同一类别的多个过滤器进行的实验中，结果表明，尽管一些过滤器已通过商用IT测试设备的批准，但每次测试实际上仍有多达3000个活细胞穿透。过滤器的重复使用、长期使用以及过滤器的高压灭菌导致过滤器的压降增加，但由于滤饼的形成，泄漏/偏差过滤器的性能得到改善（这种现象通过电子显微镜得以识别）。发现所使用的完整性测试不足以准确评估过滤器质量。使用如本文所述的灵敏直接方法对商用废气过滤器进行随机测试来认证过滤器批次可能是可取的，因为并非所有购买的过滤器质量都合格。
