GeoChip-based analysis of functional microbial communities during the reoxidation of a bioreduced uranium-contaminated aquifer

ABSTRACT Microbial community composition associated with benzene oxidation under in situ Fe(III)-reducing conditions in a petroleum-contaminated aquifer located in Bemidji, Minn., was investigated. Community structure associated with benzene degradation was compared to sediment communities that did not anaerobically oxidize benzene which were obtained from two adjacent Fe(III)-reducing sites and from methanogenic and uncontaminated zones. Denaturing gradient gel electrophoresis of 16S rDNA sequences amplified with bacterial orGeobacteraceae-specific primers indicated significant differences in the composition of the microbial communities at the different sites. Most notable was a selective enrichment of microorganisms in the Geobacter cluster seen in the benzene-degrading sediments. This finding was in accordance with phospholipid fatty acid analysis and most-probable-number–PCR enumeration, which indicated that members of the familyGeobacteraceae were more numerous in these sediments. A benzene-oxidizing Fe(III)-reducing enrichment culture was established from benzene-degrading sediments and contained an organism closely related to the uncultivated Geobacter spp. This genus contains the only known organisms that can oxidize aromatic compounds with the reduction of Fe(III). Sequences closely related to the Fe(III) reducer Geothrix fermentans and the aerobe Variovorax paradoxus were also amplified from the benzene-degrading enrichment and were present in the benzene-degrading sediments. However, neither G. fermentans nor V. paradoxusis known to oxidize aromatic compounds with the reduction of Fe(III), and there was no apparent enrichment of these organisms in the benzene-degrading sediments. These results suggest thatGeobacter spp. play an important role in the anaerobic oxidation of benzene in the Bemidji aquifer and that molecular community analysis may be a powerful tool for predicting a site’s capacity for anaerobic benzene degradation.

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Microbial communities along biogeochemical gradients in a hydrocarbon-contaminated aquifer

Environmental Microbiology ◽

10.1111/1462-2920.12168 ◽

2013 ◽

Vol 15 (9) ◽

pp. 2603-2615 ◽

Cited By ~ 51

Author(s):

Karolin Tischer ◽

Sabine Kleinsteuber ◽

Kathleen M. Schleinitz ◽

Ingo Fetzer ◽

Oliver Spott ◽

...

Keyword(s):

Microbial Communities ◽

Contaminated Aquifer

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Vertical stratification of microbial communities and isotope geochemistry tie groundwater denitrification to sampling location within a nitrate-contaminated aquifer

The Science of The Total Environment ◽

10.1016/j.scitotenv.2022.153092 ◽

2022 ◽

pp. 153092

Author(s):

Anirban Chakraborty ◽

Martin Suchy ◽

Casey R.J. Hubert ◽

M. Cathryn Ryan

Keyword(s):

Microbial Communities ◽

Isotope Geochemistry ◽

Vertical Stratification ◽

Sampling Location ◽

Contaminated Aquifer

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Biotic and Abiotic Biostimulation for the Reduction of Hexavalent Chromium in Contaminated Aquifers

Water ◽

10.3390/w14010089 ◽

2022 ◽

Vol 14 (1) ◽

pp. 89

Author(s):

Andriani Galani ◽

Daniel Mamais ◽

Constantinos Noutsopoulos ◽

Petra Anastopoulou ◽

Alexia Varouxaki

Keyword(s):

Microbial Communities ◽

Hexavalent Chromium ◽

Soil Column ◽

Carbon Sources ◽

Anaerobic Respiration ◽

Electron Donors ◽

Natural Soil ◽

Contaminated Aquifer ◽

Reducing Bacteria

Hexavalent chromium is a carcinogenic heavy metal that needs to be removed effectively from polluted aquifers in order to protect public health and the environment. This work aims to evaluate the reduction of Cr(VI) to Cr(III) in a contaminated aquifer through the stimulation of indigenous microbial communities with the addition of reductive agents. Soil-column experiments were conducted in the absence of oxygen and at hexavalent chromium (Cr(VI)) groundwater concentrations in the 1000–2000 μg/L range. Two carbon sources (molasses and EVO) and one iron electron donor (FeSO4·7H2O) were used as ways to stimulate the metabolism and proliferation of Cr(VI) reducing bacteria in-situ. The obtained results indicate that microbial anaerobic respiration and electron transfer can be fundamental to alleviate polluted groundwater from hazardous Cr(VI). The addition of organic electron donors increased significantly Cr(VI) reduction rates in comparison to natural soil attenuation rates. Furthermore, a combination of organic carbon and iron electron donors led to a longer life span of the remediation process and thus increased total Cr(VI) removal. This is the first study to investigate biotic and abiotic Cr(VI) removal by conducting experiments with natural soil and by applying biostimulation to modify the natural existing microbial communities.

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

Biochemical Society Transactions ◽

10.1042/bst20190172 ◽

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.

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