Isolation and characterization of Dehalococcoides sp strain FL2, a trichloroethene (TCE)- and 1,2-dichloroethene-respiring anaerobe
Isolation and characterization of Dehalococcoides sp strain FL2, a trichloroethene (TCE)- and 1,2-dichloroethene-respiring anaerobe
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DOI：
10.1111/j.1462-2920.2005.00830.x
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发表时间：
2005-09-01
影响因子：
5.1
通讯作者：
Löffler, FE
中科院分区：
文献类型：
--
作者：
He, J;Sung, Y;Löffler, FE
从用河流沉积物建立的四氯乙烯（PCE）至乙烯脱氯微观宇宙中分离出一种严格的厌氧细菌，该微观宇宙没有事先暴露于氯化溶剂。分离程序包括添加2-溴乙烷磺酸盐以选择对抗产甲烷古菌，> 50个连续的1-2%（v/v）转移到用三氯乙烯（TCE）、乙酸盐和氢气修正的还原矿物盐培养基中，添加氨苄青霉素，以及稀释至消光原理。培养依赖性和16 S rRNA基因靶向方法表明培养物纯度。显微镜检查显示生物体的均质培养物具有独特的盘状形态。该分离物与Dehalococcoides簇的Pinellas组的成员具有> 99%的16 S rRNA基因序列相似性，并被命名为Dehalococcoides sp.菌株FL 2。菌株FL 2可以在完全合成的培养基中以TCE、cis-1，2-二氯乙烯（cis-DCE）或trans-DCE为电子受体，乙酸为碳源，氢为电子供体进行增殖。没有发现其他支持生长的氧化还原对。三氯乙烯、顺式二氯乙烷和反式二氯乙烷的脱氯速率分别为27.5、30.4和18.8 μ mol/l/d。用荧光标记的线性杂交探针进行的定量实时聚合酶链反应（PCR）证实了这些电子受体的生长，并表明菌株FL 2捕获了TCE至顺式DCE和1，2-DCE至VC脱氯步骤的能量。四氯乙烯和氯乙烯（VC）缓慢和共代谢脱氯的存在下，生长支持氯乙烯，但乙烯的形成是不完整的，即使经过长时间的培养。在室温下，菌株FL 2以2.4天的倍增时间生长，并且每摩尔释放的氯化物产生166.1 +/-10.2mg蛋白质。在过量电子受体的存在下，菌株FL 2消耗氢至0.061 +/- 0.016 nM的浓度。加入0.5 mM亚硫酸盐后，脱氯作用停止，而硫酸盐（10 mM）和硝酸盐（5 mM）没有抑制作用。
A strictly anaerobic bacterium was isolated from tetrachloroethene (PCE)-to-ethene dechlorinating microcosms established with river sediment without prior exposure to chlorinated solvents. The isolation procedure included the addition of 2-bromoethanesulfonate to select against methanogenic archaea, > 50 consecutive 1-2% (v/v) transfers to reduced mineral salts medium amended with trichloroethene (TCE), acetate, and hydrogen, the addition of ampicillin, and the dilution-to-extinction principle. Culture-dependent and 16S rRNA gene-targeted approaches suggested culture purity. Microscopic examination revealed a homogeneous culture of an organism with a distinct, disc-shaped morphology. The isolate shared > 99% 16S rRNA gene sequence similarity with members of the Pinellas group of the Dehalococcoides cluster, and was designated Dehalococcoides sp. strain FL2. Strain FL2 could be propagated with TCE, cis-1,2-dichloroethene (cis-DCE), or trans-DCE as the electron acceptors, acetate as the carbon source, and hydrogen as the electron donor in defined, completely synthetic medium. No other growth-supporting redox couples were identified. Trichloroethene, cis-DCE and trans-DCE were dechlorinated at rates of 27.5, 30.4 and 18.8 mu mol l(-1) day(-1) respectively. Quantitative real-time polymerase chain reaction (PCR) with a fluorescently labelled linear hybridization probe confirmed growth with these electron acceptors, and suggested that strain FL2 captures energy from both the TCE-to-cis-DCE and 1,2-DCE-to-VC dechlorination steps. Tetrachloroethene and vinyl chloride (VC) were slowly and cometabolically dechlorinated in the presence of a growth-supporting chloroethene, but ethene formation was incomplete, even after prolonged incubation. At room temperature, strain FL2 grew with a doubling time of 2.4 days, and yielded 166.1 +/- 10.2 mg of protein per mole of chloride released. In the presence of excess electron acceptor, strain FL2 consumed hydrogen to a concentration of 0.061 +/- 0.016 nM. Dechlorination ceased following the addition of 0.5 mM sulfite, whereas sulfate (10 mM) and nitrate (5 mM) had no inhibitory effects.