Selective enrichment yields robust ethene-producing dechlorinating cultures from microcosms stalled at cis-dichloroethene.
Selective enrichment yields robust ethene-producing dechlorinating cultures from microcosms stalled at cis-dichloroethene.
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DOI：
10.1371/journal.pone.0100654
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Krajmalnik-Brown R
中科院分区：
文献类型：
--
作者：
Delgado AG;Kang DW;Nelson KG;Fajardo-Williams D;Miceli JF 3rd;Done HY;Popat SC;Krajmalnik-Brown R
dehalococoides mccartyi菌株具有通过中间体顺式二氯乙烯（cis-DCE）和氯乙烯（VC）将过氯乙烯（PCE）和三氯乙烯（TCE）转化为无毒乙烯的独特能力，在生物修复中具有特别重要的意义。尽管Dehalococcoides在环境中分布广泛，但生物刺激有时不能促进除顺式dce以外的脱氯。在我们的研究中，尽管在土壤/沉积物接种物中检测到含有还原脱卤酶基因tceA、vcrA和bvcA的麦卡蒂脱卤球（dehalococides mccartyi），但在花园土壤和红树林沉积物中建立的微生物群落也处于顺式- dce状态。即使经过多次生物刺激事件和长时间的培养，还原脱氯作用也不会超过顺式dce。然而，从停滞在顺式dce的微生物转移到乙烯，随后的富集培养含有多达109个dehalococides mccartyi细胞mL - 1。在土壤/沉积物群落中占主导地位的变形菌纲在富集后无法检测到，并且在转移后产甲烷活性急剧下降。我们假设，在顺式dce停滞的微生物环境中，Dehalococcoides的生物刺激受到了其他微生物的阻碍，这些微生物丰度高于Dehalococcoides，并且利用来自土壤/沉积物的终端电子受体，因此与Dehalococcoides竞争H2。为了支持这一假设，我们发现，花园土壤和红树林沉积物微生物在各自的培养物中含有高丰度的Dehalococcoides，它们能够在一次生物刺激事件中竞争H2进行还原性脱氯，并产生乙烯，没有明显的停滞。总的来说，我们的结果提供了另一种解释，以巩固关于麦卡蒂dehalococoides mccartyi的普遍存在和偶尔在cis-DCE脱氯停滞的相互矛盾的观察结果；因此，为更好地评估不同环境的生物潜力和理解微生物相互作用控制生物修复带来了新的视角。
Dehalococcoides mccartyi strains are of particular importance for bioremediation due to their unique capability of transforming perchloroethene (PCE) and trichloroethene (TCE) to non-toxic ethene, through the intermediates cis-dichloroethene (cis-DCE) and vinyl chloride (VC). Despite the widespread environmental distribution of Dehalococcoides, biostimulation sometimes fails to promote dechlorination beyond cis-DCE. In our study, microcosms established with garden soil and mangrove sediment also stalled at cis-DCE, albeit Dehalococcoides mccartyi containing the reductive dehalogenase genes tceA, vcrA and bvcA were detected in the soil/sediment inocula. Reductive dechlorination was not promoted beyond cis-DCE, even after multiple biostimulation events with fermentable substrates and a lengthy incubation. However, transfers from microcosms stalled at cis-DCE yielded dechlorination to ethene with subsequent enrichment cultures containing up to 109 Dehalococcoides mccartyi cells mL−1. Proteobacterial classes which dominated the soil/sediment communities became undetectable in the enrichments, and methanogenic activity drastically decreased after the transfers. We hypothesized that biostimulation of Dehalococcoides in the cis-DCE-stalled microcosms was impeded by other microbes present at higher abundances than Dehalococcoides and utilizing terminal electron acceptors from the soil/sediment, hence, outcompeting Dehalococcoides for H2. In support of this hypothesis, we show that garden soil and mangrove sediment microcosms bioaugmented with their respective cultures containing Dehalococcoides in high abundance were able to compete for H2 for reductive dechlorination from one biostimulation event and produced ethene with no obvious stall. Overall, our results provide an alternate explanation to consolidate conflicting observations on the ubiquity of Dehalococcoides mccartyi and occasional stalling of dechlorination at cis-DCE; thus, bringing a new perspective to better assess biological potential of different environments and to understand microbial interactions governing bioremediation.
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影响因子：
14.9
作者：
Cole JR;Wang Q;Cardenas E;Fish J;Chai B;Farris RJ;Kulam-Syed-Mohideen AS;McGarrell DM;Marsh T;Garrity GM;Tiedje JM
通讯作者：
Tiedje JM
影响因子：
5.1
作者：
He, J;Sung, Y;Löffler, FE
通讯作者：
Löffler, FE
影响因子：
64.8
作者：
Adrian, L;Szewzyk, U;Görisch, H
通讯作者：
Görisch, H
影响因子：
4.4
作者：
DISTEFANO, TD;GOSSETT, JM;ZINDER, SH
通讯作者：
ZINDER, SH
影响因子：
4.4
作者：
Aulenta, Federico;Beccari, Mario;Tandoi, Valter
通讯作者：
Tandoi, Valter