Environmental Engineering and Earth Sciences, Clemson University, 168 Rich Laboratory, Anderson, South Carolina 29625, United States.
Environ Sci Technol. 2011 Sep 1;45(17):7422-30. doi: 10.1021/es201501a. Epub 2011 Aug 1.
The effects of Fe(III) reduction on TCE, cis-DCE, and VC dechlorination were studied in both contaminated aquifer material and enrichment cultures. The results from sediment batch experiments demonstrated that Fe(III) reduction did not inhibit complete dechlorination. TCE was reduced concurrently with Fe(III) in the first 40 days of the incubations. While all incubations (plus and minus Fe(III)) generated approximately the same mass of ethene within the experimental time frame, Fe(III) speciation (ferrihydrite versus Fe(III)-NTA) had an impact on daughter product distribution and dechlorination kinetics. 16S rRNA gene clone library sequencing identified Dehalococcoides and Geobacteraceae as dominant populations, which included G. lovleyi like organisms. Quantitative PCR targeting 16S rRNA genes and Reductive Dehalogenase genes (tceA, bvcA, vcrA) indicated that Dehalococcoides and Geobacteraceae were enriched concurrently in the TCE-degrading, Fe(III)-reducing sediments. Enrichment cultures demonstrated that soluble Fe(III) had a greater impact on cis-DCE and VC reduction than solid-phase Fe(III). Geobacteraceae and Dehalococcoides were also coenriched in the liquid cultures, and the Dehalococcoides abundance in the presence of Fe(III) was not significantly different from those in the cultures without Fe(III). Hydrogen reached steady-state concentrations most amenable to complete dechlorination very quickly when Fe(III) was present in the culture, suggesting that Fe(III) reduction may actually help dechlorination. This was contrasted to hydrogen levels in nitrate-amended enrichments, in which hydrogen concentration was too low for any chlororespiration.
在受污染的含水层物质和富集培养物中研究了 Fe(III)还原对 TCE、顺式-DCE 和 VC 脱氯的影响。沉积物批处理实验的结果表明，Fe(III)还原不会抑制完全脱氯。在孵育的头 40 天内，TCE 与 Fe(III)同时被还原。虽然所有的孵育（加 Fe(III)和不加 Fe(III)）在实验时间范围内产生了大致相同量的乙烯，但 Fe(III)形态（水铁矿与 Fe(III)-NTA）对副产物分布和脱氯动力学有影响。16S rRNA 基因克隆文库测序鉴定出 Dehalococcoides 和 Geobacteraceae 为优势种群，其中包括 G. lovleyi 样生物。针对 16S rRNA 基因和还原脱卤酶基因（tceA、bvcA、vcrA）的定量 PCR 表明，在 TCE 降解、Fe(III)还原沉积物中，Dehalococcoides 和 Geobacteraceae 同时得到了富集。富集培养表明，可溶性 Fe(III)对 cis-DCE 和 VC 还原的影响大于固相 Fe(III)。Geobacteraceae 和 Dehalococcoides 也在液体培养物中共同富集，并且在有 Fe(III)存在时 Dehalococcoides 的丰度与没有 Fe(III)的培养物没有显著差异。当 Fe(III)存在于培养物中时，氢达到最有利于完全脱氯的稳定浓度非常快，这表明 Fe(III)还原实际上可能有助于脱氯。这与添加硝酸盐的富集物中的氢水平形成对比，其中氢浓度太低，无法进行任何氯化呼吸。
