Microorganisms · Published 2026-08-05 · DOI 10.3390/microorganisms14081717
Xuan Liu, Yu Chen, Zheng Ji, Yeyue Zhang, Yini Zhang, Yuru Wang, Minrui Li
<i>Shigella flexneri</i> (<i>S. flexneri</i>), as a common foodborne and waterborne pathogen, poses a serious health threat, with its biofilm formation significantly increasing disinfection difficulty. Ferrous-activated peroxydisulfate (Fe<sup>2+</sup>/PDS) is effective for pollutant removal but limited by unstable Fe<sup>2+</sup>. To address this issue, the present study developed an epigallocatechin gallate (EGCG)-enhanced Fe<sup>2+</sup>/PDS system for inactivating <i>S. flexneri</i> biofilms. The biofilm biomass and viability were assessed via crystal violet staining and CLSM. The results showed that comparable biomass reduction and inactivation was achieved with the EGCG-enhanced system at much lower iron loading. Mechanistic analysis revealed that compared with the original system, the EGCG-enhanced system maintained a higher effective Fe<sup>2+</sup> concentration, likely contributing to a more stable Fe<sup>2+</sup>/Fe<sup>3+</sup>redox cycle. High-valent Fe species and multiple reactive oxygen species were also observed in the enhanced system which might contribute to the biomass reduction and inactivation. Compared with the Fe<sup>2+</sup>/PDS system, the EGCG-enhanced system developed in this work achieved a broader pH adaptability and stronger anti-interference capability in tap water, and exhibited lower biological toxicity. These findings provide new perspectives for green disinfection technologies and agricultural waste utilization.
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Liu, X., Chen, Y., Ji, Z., et al. (2026). EGCG-Enhanced Ferrous-Activated Peroxydisulfate Processes for Shigella flexneri Biofilm Inactivation: Efficacy, Underlying Mechanisms, and Practical Implications. Microorganisms. https://doi.org/10.3390/microorganisms14081717