Department of Civil Engineering, Yeungnam University, Gyeongsan, 38541, Republic of Korea.
Environ Sci Pollut Res Int. 2022 May;29(23):34500-34514. doi: 10.1007/s11356-022-18611-6. Epub 2022 Jan 17.
The present study reports for the first time, a novel disinfection method that combines ultrasonication with a natural biocide terpinolene to inhibit tough and opportunistic antimicrobial-resistant (AMR) microorganisms isolated from hospital wastewater treatment plant (HWWTP). The enhancement of the disinfection process was evaluated for the effect of ultrasonication power, operating temperature, and inoculum size. A hybrid methodology combining terpinolene with traditional physico-chemical method of acoustic cavitation delivered efficient disinfection of the secondary effluent of field scale HWWTP, amended with a higher inoculum size of multi-drug-resistant coliform bacteria Enterobactor sp., Citrobacter freundii, and Klebsiella pneumonia. A bacterial load of 6.4 log CFU/mL was completely eliminated in 25 min. The present study also reports that due to the hybrid process, a very small concentration of 0.312 mM (0.25 × Minimum Inhibitory Concentration or MBC) of terpinolene was enough to completely disinfect the multi-drug-resistant coliforms. The leakage of intracellular nucleic acids during the disinfection process suggested disruption of cell membrane as the primary mechanism of disinfection followed by disruption of cellular metabolic function measured by respiratory chain dehydrogenase activity. Moreover, this study is the first to prove that terpinolene remained stable even after the cavitation process, thus revealing possibilities of recycling of the natural compound for wastewater disinfection. The results of the present research suggest that using terpinolene as a bio-additive can efficiently eliminate hazardous multi-drug-resistant bacteria and drastically reduce operational time and cost thus rendering it suitable to replace conventional wastewater disinfection.
本研究首次报道了一种将超声波与天然杀菌剂松油烯相结合的新型消毒方法，以抑制从医院污水处理厂（HWWTP）分离出的坚韧和机会性抗微生物药物耐药（AMR）微生物。评估了超声功率、操作温度和接种物大小对消毒过程的增强效果。结合松油烯和传统的声空化物理化学方法的混合方法对现场规模 HWWTP 的二级出水进行了有效的消毒，该方法中添加了更高接种量的多药耐药大肠埃希氏菌 Enterobactor sp.、弗氏柠檬酸杆菌和肺炎克雷伯菌。6.4 log CFU/mL 的细菌负荷在 25 分钟内完全消除。本研究还报告称，由于混合过程，只需非常低的 0.312 mM（0.25×最小抑菌浓度或 MBC）浓度的松油烯即可完全消毒多药耐药大肠埃希氏菌。消毒过程中细胞内核酸的泄漏表明细胞膜的破坏是消毒的主要机制，随后是细胞代谢功能的破坏，这可以通过呼吸链脱氢酶活性来衡量。此外，这项研究首次证明松油烯即使在空化过程后仍保持稳定，从而为用于废水消毒的天然化合物的回收利用提供了可能性。本研究的结果表明，使用松油烯作为生物添加剂可以有效地消除危险的多药耐药细菌，并大大缩短操作时间和成本，因此适合替代传统的废水消毒。
