scholarly journals Microbial Communities Associated with Sustained Anaerobic Reductive Dechlorination of α-, β-, γ-, and δ-Hexachlorocyclohexane Isomers to Monochlorobenzene and Benzene

2019 ◽  
Author(s):  
Wenjing Qiao ◽  
Luz A. Puentes Jácome ◽  
Xianjin Tang ◽  
Line Lomheim ◽  
Minqing Ivy Yang ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Reductive Dechlorination ◽  
Hexachlorocyclohexane Isomers

scholarly journals Microbial Communities Associated with Sustained Anaerobic Reductive Dechlorination of α-, β-, γ-, and δ-Hexachlorocyclohexane Isomers to Monochlorobenzene and Benzene

2019 ◽  
Author(s):  
Wenjing Qiao ◽  
Luz A. Puentes Jácome ◽  
Xianjin Tang ◽  
Line Lomheim ◽  
Minqing Ivy Yang ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Amplicon Sequencing ◽  
Contaminated Sites ◽  
Molar Ratio ◽  
Rrna Gene ◽  
Absolute Abundance ◽  
Hch Isomers ◽  
Persistent Pesticide ◽  
Hexachlorocyclohexane Isomers ◽  
Archaeal Communities

AbstractIntensive historical and worldwide use of the persistent pesticide technical-grade hexachlorocyclohexane (HCH), composed of the active ingredient γ-HCH (called lindane) along with several other HCH isomers, has led to widespread contamination. We derived four anaerobic enrichment cultures from HCH-contaminated soil capable of sustainably dechlorinating each of α-, β-, γ-, and δ-HCH isomers stoichiometrically and completely to benzene and monochlorobenzene (MCB). For each isomer, the dechlorination rates increased progressively from <3 µM/day to ∼12 µM/day over two years. The molar ratio of benzene to MCB produced was a function of the substrate isomer, and ranged from β (0.77±0.15), α (0.55±0.09), γ (0.13±0.02) to δ (0.06±0.02) in accordance with pathway predictions based on prevalence of antiperiplanar geometry. Cultivation with a different HCH isomer resulted in distinct bacterial communities, but similar archaeal communities. Data from 16S rRNA gene amplicon sequencing and quantitative PCR revealed significant increases in the absolute abundance of Pelobacter and Dehalobacter, especially in the α-HCH and δ-HCH cultures. This study provides the first direct comparison of shifts in anaerobic microbial communities induced by the dechlorination of distinct HCH isomers. It also uncovers candidate microorganisms responsible for the dechlorination of α-, β-, γ-, and δ-HCH, a key step towards better understanding and monitoring of natural attenuation processes and improving bioremediation technologies for HCH-contaminated sites.

scholarly journals Effects of Sulfate Reduction on Trichloroethene Dechlorination by Dehalococcoides-Containing Microbial Communities

2017 ◽  
Vol 83 (8) ◽  
Author(s):  
Xinwei Mao ◽  
Alexandra Polasko ◽  
Lisa Alvarez-Cohen
Keyword(s):  
Microbial Communities ◽  
Sulfate Reduction ◽  
Electron Donor ◽  
Reductive Dechlorination ◽  
Sulfate Reducer ◽  
Content Type ◽  
Dehalococcoides Mccartyi ◽  
Sulfide Inhibition ◽  
Genes Encoding ◽  
High Sulfate

ABSTRACT In order to elucidate interactions between sulfate reduction and dechlorination, we systematically evaluated the effects of different concentrations of sulfate and sulfide on reductive dechlorination by isolates, constructed consortia, and enrichments containing Dehalococcoides sp. Sulfate (up to 5 mM) did not inhibit the growth or metabolism of pure cultures of the dechlorinator Dehalococcoides mccartyi 195, the sulfate reducer Desulfovibrio vulgaris Hildenborough, or the syntroph Syntrophomonas wolfei. In contrast, sulfide at 5 mM exhibited inhibitory effects on growth of the sulfate reducer and the syntroph, as well as on both dechlorination and growth rates of D. mccartyi. Transcriptomic analysis of D. mccartyi 195 revealed that genes encoding ATP synthase, biosynthesis, and Hym hydrogenase were downregulated during sulfide inhibition, whereas genes encoding metal-containing enzymes involved in energy metabolism were upregulated even though the activity of those enzymes (hydrogenases) was inhibited. When the electron acceptor (trichloroethene) was limiting and an electron donor (lactate) was provided in excess to cocultures and enrichments, high sulfate concentrations (5 mM) inhibited reductive dechlorination due to the toxicity of generated sulfide. The initial cell ratio of sulfate reducers to D. mccartyi (1:3, 1:1, or 3:1) did not affect the dechlorination performance in the presence of sulfate (2 and 5 mM). In contrast, under electron donor limitation, dechlorination was not affected by sulfate amendments due to low sulfide production, demonstrating that D. mccartyi can function effectively in anaerobic microbial communities containing moderate sulfate concentrations (5 mM), likely due to its ability to outcompete other hydrogen-consuming bacteria and archaea. IMPORTANCE Sulfate is common in subsurface environments and has been reported as a cocontaminant with chlorinated solvents at various concentrations. Inconsistent results for the effects of sulfate inhibition on the performance of dechlorination enrichment cultures have been reported in the literature. These inconsistent findings make it difficult to understand potential mechanisms of sulfate inhibition and complicate the interpretation of bioremediation field data. In order to elucidate interactions between sulfate reduction and reductive dechlorination, this study systematically evaluated the effects of different concentrations of sulfate and sulfide on reductive dechlorination by isolates, constructed consortia, and enrichments containing Dehalococcoides sp. This study provides a more fundamental understanding of the competition mechanisms between reductive dechlorination by Dehalococcoides mccartyi and sulfate reduction during the bioremediation process. It also provides insights on the significance of sulfate concentrations on reductive dechlorination under electron donor/acceptor-limiting conditions during in situ bioremediation applications. For example, at a trichloroethene-contaminated site with a high sulfate concentration, proper slow-releasing electron donors can be selected to generate an electron donor-limiting environment that favors reductive dechlorination and minimizes the sulfide inhibition effect.

Reductive Dechlorination of α-, β-, γ-, and δ-Hexachlorocyclohexane Isomers with Hydroxocobalamin, in Soil Slurry Systems

2010 ◽  
Vol 44 (18) ◽  
pp. 7063-7069 ◽  
Author(s):  
B. Rodríguez-Garrido ◽  
T. A. Lú-Chau ◽  
G. Feijoo ◽  
F. Macías ◽  
M.C. Monterrroso
Keyword(s):  
Reductive Dechlorination ◽  
Soil Slurry ◽  
Hexachlorocyclohexane Isomers

A peek in the micro-sized world: a review of design principles, engineering tools, and applications of engineered microbial community

2020 ◽  
Vol 48 (2) ◽  
pp. 399-409
Author(s):  
Baizhen Gao ◽  
Rushant Sabnis ◽  
Tommaso Costantini ◽  
Robert Jinkerson ◽  
Qing Sun
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Environmental Remediation ◽  
Real Life ◽  
Design Principles ◽  
Microbial Interactions ◽  
Potential Applications ◽  
New Gene ◽  
Global Biogeochemical Cycles ◽  
Synthetic Microbial Communities

Microbial communities drive diverse processes that impact nearly everything on this planet, from global biogeochemical cycles to human health. Harnessing the power of these microorganisms could provide solutions to many of the challenges that face society. However, naturally occurring microbial communities are not optimized for anthropogenic use. An emerging area of research is focusing on engineering synthetic microbial communities to carry out predefined functions. Microbial community engineers are applying design principles like top-down and bottom-up approaches to create synthetic microbial communities having a myriad of real-life applications in health care, disease prevention, and environmental remediation. Multiple genetic engineering tools and delivery approaches can be used to ‘knock-in' new gene functions into microbial communities. A systematic study of the microbial interactions, community assembling principles, and engineering tools are necessary for us to understand the microbial community and to better utilize them. Continued analysis and effort are required to further the current and potential applications of synthetic microbial communities.

T-RFLP – a representative tool to study pulmonary microbial communities

Pneumologie ◽  
2009 ◽  
Vol 63 (S 01) ◽  
Author(s):  
T Zakharkina ◽  
C Herr ◽  
A Yildirim ◽  
M Friedrich ◽  
R Bals
Keyword(s):  
Microbial Communities

Screening bioactive secondary metabolites from Costa Rican enviromental microbial communities

Planta Medica ◽  
2015 ◽  
Vol 81 (11) ◽  
Author(s):  
JJ Araya ◽  
M Chavarría ◽  
A Pinto-Tomás ◽  
C Murillo ◽  
L Uribe ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Microbial Communities ◽  
Costa Rican ◽  
Bioactive Secondary Metabolites

Enhanced CO2 concentrations change the structure of Antarctic marine microbial communities

2016 ◽  
Vol 552 ◽  
pp. 93-113 ◽  
Author(s):  
AT Davidson ◽  
J McKinlay ◽  
K Westwood ◽  
PG Thomson ◽  
R van den Enden ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Co2 Concentrations ◽  
Antarctic Marine ◽  
Marine Microbial Communities
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