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Microbial Community Response of an Organohalide Respiring Enrichment Culture to Permanganate Oxidation.

Sutton NB, Atashgahi S, Saccenti E, Grotenhuis T, Smidt H, Rijnaarts HH - PLoS ONE (2015)

Bottom Line: In contrast, high permanganate treatment disrupted dechlorination beyond cis-dichloroethene and caused at least a 2-4 orders of magnitude reduction in the abundance of all measured OHRB and rdh genes, as compared to the biotic control.High permanganate treatments resulted in a notably divergent microbial community, with increased abundances of organisms affiliated with Campylobacterales and Oceanospirillales capable of dissimilatory Mn reduction, and decreased abundance of presumed supporters of OHRB.Overall, this detailed investigation into dose-dependent changes of microbial composition and activity due to permanganate treatment provides insight into the mechanisms of OHR stimulation or disruption upon chemical oxidation.

View Article: PubMed Central - PubMed

Affiliation: Environmental Technology, Wageningen University, Wageningen, The Netherlands.

ABSTRACT
While in situ chemical oxidation is often used to remediate tetrachloroethene (PCE) contaminated locations, very little is known about its influence on microbial composition and organohalide respiration (OHR) activity. Here, we investigate the impact of oxidation with permanganate on OHR rates, the abundance of organohalide respiring bacteria (OHRB) and reductive dehalogenase (rdh) genes using quantitative PCR, and microbial community composition through sequencing of 16S rRNA genes. A PCE degrading enrichment was repeatedly treated with low (25 μmol), medium (50 μmol), or high (100 μmol) permanganate doses, or no oxidant treatment (biotic control). Low and medium treatments led to higher OHR rates and enrichment of several OHRB and rdh genes, as compared to the biotic control. Improved degradation rates can be attributed to enrichment of (1) OHRB able to also utilize Mn oxides as a terminal electron acceptor and (2) non-dechlorinating community members of the Clostridiales and Deltaproteobacteria possibly supporting OHRB by providing essential co-factors. In contrast, high permanganate treatment disrupted dechlorination beyond cis-dichloroethene and caused at least a 2-4 orders of magnitude reduction in the abundance of all measured OHRB and rdh genes, as compared to the biotic control. High permanganate treatments resulted in a notably divergent microbial community, with increased abundances of organisms affiliated with Campylobacterales and Oceanospirillales capable of dissimilatory Mn reduction, and decreased abundance of presumed supporters of OHRB. Although OTUs classified within the OHR-supportive order Clostridiales and OHRB increased in abundance over the course of 213 days following the final 100 μmol permanganate treatment, only limited regeneration of PCE dechlorination was observed in one of three microcosms, suggesting strong chemical oxidation treatments can irreversibly disrupt OHR. Overall, this detailed investigation into dose-dependent changes of microbial composition and activity due to permanganate treatment provides insight into the mechanisms of OHR stimulation or disruption upon chemical oxidation.

No MeSH data available.


Heatmap of 10 most abundant OTUs in data set.Sample labels as in Table 2 and relative abundances are given as fraction of 1.
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pone.0134615.g005: Heatmap of 10 most abundant OTUs in data set.Sample labels as in Table 2 and relative abundances are given as fraction of 1.

Mentions: OTUs were classified into 31 bacterial phyla, with 98.3% of the OTUs belonging to 7 major phyla i.e. Bacteriodetes, Chlorobi, Chloroflexi, Firmicutes, Nitrospirae, Proteobacteria, and Spirochaetes (Fig 4). The most abundant OTUs were found to belong to the genus Acetobacterium in the class Clostridia (Firmicutes), the genus Sulfurospirillum in the class Epsilonproteobacteria, and Geobacter of the class Deltaproteobacteria (Fig 5). Clostridia were prevalent in many samples, with relative abundances up to 96% (H9; Fig 4). Overall, good correspondence was seen between duplicate microcosms, although high permanganate treatments (H3+H4, H5+H6) and longer incubation times (H8+H9) seemed to cause more divergence between the microbial community in replicate microcosms.


Microbial Community Response of an Organohalide Respiring Enrichment Culture to Permanganate Oxidation.

Sutton NB, Atashgahi S, Saccenti E, Grotenhuis T, Smidt H, Rijnaarts HH - PLoS ONE (2015)

Heatmap of 10 most abundant OTUs in data set.Sample labels as in Table 2 and relative abundances are given as fraction of 1.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526698&req=5

pone.0134615.g005: Heatmap of 10 most abundant OTUs in data set.Sample labels as in Table 2 and relative abundances are given as fraction of 1.
Mentions: OTUs were classified into 31 bacterial phyla, with 98.3% of the OTUs belonging to 7 major phyla i.e. Bacteriodetes, Chlorobi, Chloroflexi, Firmicutes, Nitrospirae, Proteobacteria, and Spirochaetes (Fig 4). The most abundant OTUs were found to belong to the genus Acetobacterium in the class Clostridia (Firmicutes), the genus Sulfurospirillum in the class Epsilonproteobacteria, and Geobacter of the class Deltaproteobacteria (Fig 5). Clostridia were prevalent in many samples, with relative abundances up to 96% (H9; Fig 4). Overall, good correspondence was seen between duplicate microcosms, although high permanganate treatments (H3+H4, H5+H6) and longer incubation times (H8+H9) seemed to cause more divergence between the microbial community in replicate microcosms.

Bottom Line: In contrast, high permanganate treatment disrupted dechlorination beyond cis-dichloroethene and caused at least a 2-4 orders of magnitude reduction in the abundance of all measured OHRB and rdh genes, as compared to the biotic control.High permanganate treatments resulted in a notably divergent microbial community, with increased abundances of organisms affiliated with Campylobacterales and Oceanospirillales capable of dissimilatory Mn reduction, and decreased abundance of presumed supporters of OHRB.Overall, this detailed investigation into dose-dependent changes of microbial composition and activity due to permanganate treatment provides insight into the mechanisms of OHR stimulation or disruption upon chemical oxidation.

View Article: PubMed Central - PubMed

Affiliation: Environmental Technology, Wageningen University, Wageningen, The Netherlands.

ABSTRACT
While in situ chemical oxidation is often used to remediate tetrachloroethene (PCE) contaminated locations, very little is known about its influence on microbial composition and organohalide respiration (OHR) activity. Here, we investigate the impact of oxidation with permanganate on OHR rates, the abundance of organohalide respiring bacteria (OHRB) and reductive dehalogenase (rdh) genes using quantitative PCR, and microbial community composition through sequencing of 16S rRNA genes. A PCE degrading enrichment was repeatedly treated with low (25 μmol), medium (50 μmol), or high (100 μmol) permanganate doses, or no oxidant treatment (biotic control). Low and medium treatments led to higher OHR rates and enrichment of several OHRB and rdh genes, as compared to the biotic control. Improved degradation rates can be attributed to enrichment of (1) OHRB able to also utilize Mn oxides as a terminal electron acceptor and (2) non-dechlorinating community members of the Clostridiales and Deltaproteobacteria possibly supporting OHRB by providing essential co-factors. In contrast, high permanganate treatment disrupted dechlorination beyond cis-dichloroethene and caused at least a 2-4 orders of magnitude reduction in the abundance of all measured OHRB and rdh genes, as compared to the biotic control. High permanganate treatments resulted in a notably divergent microbial community, with increased abundances of organisms affiliated with Campylobacterales and Oceanospirillales capable of dissimilatory Mn reduction, and decreased abundance of presumed supporters of OHRB. Although OTUs classified within the OHR-supportive order Clostridiales and OHRB increased in abundance over the course of 213 days following the final 100 μmol permanganate treatment, only limited regeneration of PCE dechlorination was observed in one of three microcosms, suggesting strong chemical oxidation treatments can irreversibly disrupt OHR. Overall, this detailed investigation into dose-dependent changes of microbial composition and activity due to permanganate treatment provides insight into the mechanisms of OHR stimulation or disruption upon chemical oxidation.

No MeSH data available.