多氯乙烯(Chlorinated ethenes, CEs)在台灣本土污染場址佔據數量之冠，尤其於富含硫酸鹽的地下水中，嚴重阻礙了整治進程。由硫酸還原菌產生的硫化氫(H2S)會影響 Dehalococcoides 的脫氯反應效率，使含氯有機物降解不完全，進而導致生物復育失敗。為了探究硫酸還原和脫氯之間的相互作用，本研究旨在利用亞鐵化合物來克服硫化氫的毒性，從而生成硫化亞鐵(FeS)。由於其高還原潛能， FeS 被廣泛應用於化學整治領域。首先，透過添加氯化亞鐵(FeCl2)，能夠有效移除硫酸還原菌產生的硫化氫，進而促進對多氯乙烯的完全降解。其次，藉由添加與硫酸鹽濃度相等比例的 FeCl2 ，有效將硫化氫移除至僅剩 3.1% 並促進生物性 FeS 的形成。相比過量濃度 FeCl2 的添加， FeS 的晶體顆粒大小有效降低多達 10 倍，減緩了對現地整治中造成的堵塞問題。透過轉錄體分析證實，添加 FeCl2 不僅有效地消除了硫化氫的抑制作用，增強了有機鹵素呼吸相關酵素的活性，甚至上調了參與電子傳遞的關鍵基因表現，從而提高了脫氯效率和硫酸還原菌的活性。最後，利用臺灣本土原生脫氯菌群應證於硫酸鹽及 CEs 共存環境下，脫鹵球菌的增長趨勢與 FeS 的形成呈現正相關。由多樣性分析進一步證實了 FeS 的生成有助於恢復菌群結構，甚至增加了菌群的多樣性。本研究彰顯了在硫酸鹽和多氯乙烯共存環境下共培養系統對於生成生物性硫化亞鐵的潛力，同時移除了硫酸還原產物硫化氫對脫氯反應的抑制，並結合化學及生物整治工法以提升多氯乙烯的降解效率。;Chlorinated ethenes (CEs) constitute a predominant contaminant in Taiwan′s native polluted sites, particularly in groundwater inundated with sulfate salts that substantially impede remediation efforts. Hydrogen sulfide (H2S) produced by sulfate-reducing bacteria (SRB) impairs the dechlorination efficiency of Dehalococcoides, resulting in incomplete chloride degradation and thereby leading to the failure of bioremediation. In order to elucidate interactions between sulfate reduction and dechlorination, this study aims to utilize ferrous compounds to overcome H2S toxicity by synthesizing ferrous sulfide (FeS), which is commonly utilized in chemical remediation due to its high reduction potential. Initially, the addition of ferrous chloride (FeCl2) effectively removed H2S production from SRB and enhanced the degradation of trichloroethylene to ethene. Optimal efficiency in biogenic FeS generation was achieved by adding FeCl2 in equal ratio to sulfate concentration. This approach effectively reduced H2S and crystal particle sizes by up to 10 times compared to excessive FeCl2 dosages, mitigating clogging issues during in situ remediation. Transcriptomic analysis revealed that the addition of FeCl2 eliminated hydrogen sulfide inhibition, enhanced dehalogenase activity, and upregulated key electron transport genes, increasing dechlorination efficiency and sulfate-reducing bacteria activity. Finally, utilizing Taiwan′s indigenous dechlorinating consortium CW5 in a simulated sulfate and CEs co-contaminated environment, the growth trend of Dehalococcoides showed a positive correlation with the FeS formation. Biodiversity analysis confirmed that FeS formation facilitated microbial community structure restoration and increased diversity. This study validates the potential of the co-culture system in generating biogenic FeS under sulfate and CEs co-contamination, removing sulfate-reducing products and improving CEs remediation through integrated chemical and biological remediations.
