State Key Laboratory of Organic Geochemistry and Guangdong-Hong Kong-Maco Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Environ Sci Technol. 2024 Nov 26;58(47):20931-20941. doi: 10.1021/acs.est.3c10948. Epub 2024 Oct 29.
Combining organohalide-respiring bacteria with nanoscale zero-valent iron (nZVI) represents a promising approach for remediating chloroethene-contaminated aquifers. However, limited information is available regarding their synergistic dechlorinating ability for chloroethenes when nZVI is sulfidated (S-nZVI) under the organic electron donor-limited conditions typically found in deep aquifers. Herein, we developed a combined system utilizing a mixed culture containing () and S-nZVI particles, which achieved sustainable dechlorination with repeated rounds of spiking with 110 μM perchloroethene (PCE). The relative abundance of considerably increased from 5.2 to 91.5% after five rounds of spiking with PCE, as evidenced by 16S rRNA gene amplicon sequencing. S-nZVI corrosion generated hydrogen as an electron donor for and other volatile fatty acid (VFA)-producing bacteria. Electron balance analysis indicated that 68.1% of electrons from Fe consumed in S-nZVI were involved in dechlorination, and 6.2, 1.1, and 3.2% were stored in formate, acetate, and other VFAs, respectively. The produced acetate possibly served as a carbon source for . Metagenomic analysis revealed that , , , and were likely involved in VFA production. These findings provide valuable insights into the synergistic mechanisms of biotic and abiotic dechlorination, with important implications for sustainable remediation of electron donor-limited aquifers contaminated by chloroethenes.
利用能够代谢卤代烃的细菌与纳米零价铁（nZVI）结合，是一种修复含氯碳氢化合物污染含水层的很有前途的方法。然而，当 nZVI 在深含水层中通常存在的有机电子供体有限的条件下被硫化（S-nZVI）时，关于其与 S-nZVI 协同脱氯能力的信息有限，而这种条件下存在含氯碳氢化合物。在此，我们开发了一种利用含有 （）和 S-nZVI 颗粒的混合培养物的组合系统，该系统通过重复添加 110 μM 全氯乙烯（PCE）实现了可持续脱氯。通过 16S rRNA 基因扩增子测序证明，经过五轮 PCE 冲击后， 相对丰度从 5.2%增加到 91.5%。S-nZVI 腐蚀产生氢气作为电子供体，供 和其他产生挥发性脂肪酸（VFA）的细菌使用。电子平衡分析表明，S-nZVI 中消耗的 Fe 所携带的电子中 68.1%用于脱氯，6.2%、1.1%和 3.2%分别储存在甲酸盐、乙酸盐和其他 VFA 中。产生的乙酸盐可能为 提供碳源。宏基因组分析表明， 、 、 和 可能参与 VFA 的产生。这些发现为生物和非生物脱氯的协同机制提供了有价值的见解，对受含氯碳氢化合物污染的电子供体有限的含水层的可持续修复具有重要意义。
