School of Resource & Civil Engineering, Northeastern University, Shenyang, People's Republic of China.
Environ Technol. 2023 Jun;44(15):2327-2340. doi: 10.1080/09593330.2022.2027028. Epub 2022 Jan 20.
The purpose of this study was to explore the stimulation mechanism of low pulsed electric field (PEF) strength treatment to promote the growth metabolism of aerobic denitrifying bacteria W207-14. The results indicated that compared with the control group, the strain W207-14 treated with PEF entered the logarithmic growth phase 5 h earlier, the growth time to reached the maximum cell optical density at 600 nm (OD600) of 1.935 ± 0.04 was only 24 h, which shortened by half. With the reduction of growth time, the metabolic rate of the strain increased significantly, in which the removal efficiency of COD, NO-N and TN was 97.67 ± 1.12%, 90.34 ± 0.73% and 90.13 ± 0.10% in 24 h, respectively. The maximum nitrate removal rate increased from 3.49 mg/L/h to 7.53 mg/L/h. A large number of cells with simultaneous cell membrane damage and high physiological activity were observed by flow cytometry (FCM) in combination with fluorescence staining analysis, which confirmed the reversible electroporation on the cell membrane of strain W207-14 treated with PEF. Transcriptomic analysis indicated that PEF activated the highly significant differential expression of membrane porin (opdB, opdC, and oprB) and cytochrome oxidoreductase related genes (ccoP, ccoN, cioA and cioB) on the cell membrane, which promoted the transport of nutrients through the cell membrane and electron transfer during aerobic respiration and provided an explanation for the possible mechanism of PEF promoting the growth metabolism of strain W207-14 at the micro level. These results lay a foundation for the practical application of PEF enhanced aerobic denitrification technology.
本研究旨在探索低脉冲电场（PEF）强度处理刺激促进好氧反硝化菌 W207-14 生长代谢的机制。结果表明，与对照组相比，PEF 处理的 W207-14 菌株提前 5 h 进入对数生长期，达到最大细胞光密度（OD600）600nm 的生长时间仅为 24 h，缩短了一半。随着生长时间的缩短，菌株的代谢率显著增加，其中 COD、NO-N 和 TN 的去除效率分别在 24 h 内达到 97.67±1.12%、90.34±0.73%和 90.13±0.10%。最大硝酸盐去除速率从 3.49mg/L/h 增加到 7.53mg/L/h。流式细胞术（FCM）结合荧光染色分析观察到大量同时发生细胞膜损伤和高生理活性的细胞，证实了 PEF 对 W207-14 菌株细胞膜的可逆电穿孔。转录组分析表明，PEF 激活了细胞膜上高度显著差异表达的膜孔蛋白（opdB、opdC 和 oprB）和细胞色素氧化还原酶相关基因（ccoP、ccoN、cioA 和 cioB），促进了营养物质通过细胞膜的运输和有氧呼吸过程中的电子传递，为 PEF 促进 W207-14 菌株生长代谢的微观机制提供了可能的解释。这些结果为 PEF 增强好氧反硝化技术的实际应用奠定了基础。
