Transformation and Carbon Isotope Fractionation of Tetra- and Trichloroethene to Trans-Dichloroethene by Dehalococcoides sp Strain CBDB1
Transformation and Carbon Isotope Fractionation of Tetra- and Trichloroethene to Trans-Dichloroethene by Dehalococcoides sp Strain CBDB1
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DOI：
10.1021/es1023459
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发表时间：
2011-02-15
影响因子：
11.4
通讯作者：
Adrian, Lorenz
中科院分区：
文献类型：
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作者：
Marco-Urrea, Ernest;Nijenhuis, Ivonne;Adrian, Lorenz
脱盐球菌属 sp.菌株CBDB1将全氯乙烯（PCE）和三氯乙烯（TCE）还原脱氯为主要的反式1,2-二氯乙烯（反式DCE）。通过直接显微镜进行细胞计数表明，菌株 CBDB1 使用 PCE 和 TCE 作为呼吸生长的电子受体，在两种情况下每释放 mol 氯化物获得 3.9 x 10(12) 个细胞的生长产量。 PCE 和 TCE 以 3.4 (+/- 0.2):1 的平均恒定比率脱氯为反式和顺式 DCE，这与在一些含有未培养的 Dehalococcoides 类物种的产生反式 DCE 的沉积物和土壤中发现的比率一致。在 PCE 和 TCE 还原脱卤过程中观察到显着的碳同位素分馏。 TCE 的富集因子（ε C = -11.2）在先前报道的其他 Dehalococcoides 物种的 TCE 脱氯值范围内，尽管菌株 CBDB1 中不存在负责后者培养物中乙烯生成的 tceA 基因。相反，PCE 的富集因子 (ε C = -1.6) 比 Dehalococcoides sp 的富集因子低 3.8 倍。菌株 195 中负责 PCE 脱氯的 pceA 基因与菌株 195 具有高度相似性。此外，根据两个累积产物 cis-DCE (epsilon C (TCE -> cis-DCE) = -11.0) 和 trans-DCE (epsilon C (TCE -> trans-DCE) = -11.0) 的产物同位素特征计算了 TCE 脱卤的产物相关富集因子。 -15.9）。这些结果特别令人感兴趣，因为菌株 CBDB1 与最近分离的菌株 MB 一起构成了独特的 Dehalococcoides 物种，无法对除 DCE 之外的 PCE 和 TCE 进行脱氯。
Dehalococcoides sp. strain CBDB1 reductively dechlorinated perchloroethene (PCE) and trichloroethene (TCE) to predominantly trans-1,2-dichloroethene (trans-DCE). Cell counting by direct microscopy showed that strain CBDB1 used PCE and TCE as electron acceptors for respiratory growth obtaining a growth yield of 3.9 x 10(12) cells per mol of chloride released in both cases. PCE and TCE were dechlorinated to trans- and cis-DCE at an average constant ratio of 3.4 (+/- 0.2):1, which is consistent with the ratios found in several trans-DCE-producing sediments and soils containing uncultured Dehalococcoides-like species. Significant carbon isotope fractionation was observed during PCE and TCE reductive dehalogenation. The enrichment factor of TCE (epsilon C = -11.2) was within the range of previously reported values for TCE dechlorination by other Dehalococcoides species although the tceA gene responsible for ethene generation in the latter cultures was absent in strain CBDB1. On the contrary, the enrichment factor of PCE (epsilon C = -1.6) was 3.8-times lower than that obtained for Dehalococcoides sp. strain 195 although both strains shared a high similarity in the pceA gene responsible for PCE dechlorination in strain 195. In addition, the product-related enrichment factors for TCE dehalogenation were calculated based on product isotope signature of the two accumulated products cis-DCE (epsilon C (TCE -> cis-DCE) = -11.0) and trans-DCE (epsilon C (TCE -> trans-DCE) = -15.9). These results are of particular interest since strain CBDB1 constitutes, together with the recent isolated strain MB, the unique Dehalococcoides species unable to dechlorinate PCE and TCE beyond DCE.