Department of Biological Science and Technology, Yonsei University, Wonju 26493, Republic of Korea.
J Microbiol Biotechnol. 2021 Oct 28;31(10):1430-1437. doi: 10.4014/jmb.2107.07017.
is an opportunistic pathogenic bacterium found in powdered infant formula and is fatal to neonates. Antibiotic resistance has emerged owing to overuse of antibiotics. Therefore, demand for high-yield bacteriophages as an alternative to antibiotics has increased. Accordingly, we developed a modified mass-production method for bacteriophages by introducing a two-stage self-cycling (TSSC) process, which yielded high-concentration bacteriophage solutions by replenishing the nutritional medium at the beginning of each process, without additional challenge. pH of the culture medium was monitored in real-time during growth and bacteriophage CS01 propagation, and the changes in various parameters were assessed. The pH of the culture medium dropped to 5.8 when the host bacteria reached the early log phase (OD = 0.3). After challenge, it decreased to 4.65 and then recovered to 4.94; therefore, we set the optimum pH to challenge the phage at 5.8 and that to harvest the phage at 4.94. We then compared phage production during the TSSC process in jar-type bioreactors and the batch culture process in shaker flasks. In the same volume of LB medium, the concentration of the phage titer solution obtained with the TSSC process was 24 times higher than that obtained with the batch culture process. Moreover, we stably obtained high concentrations of bacteriophage solutions for three cycles with the TSSC process. Overall, this modified TSSC process could simplify large-scale production of bacteriophage CS01 and reduce the unit cost of phage titer solution. These results could contribute to curing infants infected with antibiotic-resistant .
是一种机会致病菌，存在于配方奶粉中，对新生儿是致命的。由于抗生素的过度使用，出现了抗生素耐药性。因此，对抗生素替代品——高产量噬菌体的需求增加了。因此，我们通过引入两段式自我循环（TSSC）工艺，开发了一种改良的噬菌体大规模生产方法，在每个工艺开始时补充营养培养基，而无需额外的挑战，从而产生高浓度的噬菌体溶液。在噬菌体 CS01 的生长和繁殖过程中，实时监测培养基的 pH 值，并评估各种参数的变化。当宿主细菌进入早期对数期（OD = 0.3）时，培养基的 pH 值下降到 5.8。挑战后，它下降到 4.65，然后恢复到 4.94；因此，我们将最佳 pH 值设定为 5.8 以挑战噬菌体，将收获噬菌体的 pH 值设定为 4.94。然后，我们比较了 TSSC 工艺在罐式生物反应器和摇瓶分批培养工艺中的噬菌体生产情况。在相同体积的 LB 培养基中，TSSC 工艺获得的噬菌体效价溶液的浓度比分批培养工艺高 24 倍。此外，我们使用 TSSC 工艺稳定地获得了三个循环的高浓度噬菌体溶液。总的来说，这种改良的 TSSC 工艺可以简化噬菌体 CS01 的大规模生产，并降低噬菌体效价溶液的单位成本。这些结果可能有助于治愈感染抗生素耐药性的婴儿。
