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Pal Y, Mayilraj S, Krishnamurthi S. Uncovering the structure and function of specialist bacterial lineages in environments routinely exposed to explosives. Lett Appl Microbiol 2022; 75:1433-1448. [PMID: 35972393 DOI: 10.1111/lam.13810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 07/30/2022] [Accepted: 08/05/2022] [Indexed: 11/29/2022]
Abstract
Environmental contamination by hexahydro-1, 3, 5-trinitro-1, 3, 5-triazine (RDX), and Octahydro-1, 3, 5, 7-tetranitro-1, 3, 5, 7-tetrazocine (HMX), the two most widely used compounds for military operations, is a long-standing problem at the manufacturing and decommissioning plants. Since explosives contamination has previously been shown to favour the growth of specific bacterial communities, the present study attempts to identify the specialist bacterial communities and their potential functional and metabolic roles by using amplicon targeted and whole-metagenome sequencing approaches (WMS) in samples collected from two distinct explosives manufacturing sites. We hypothesize that the community structure and functional attributes of bacterial population are substantially altered by the concentration of explosives and physicochemical conditions. The results highlight the predominance of Planctomycetes in contrast to previous reports from similar habitats. The detailed phylogenetic analysis revealed the presence of OTU's related to bacterial members known for their explosives degradation. Further, the functional and metabolic analyses highlighted the abundance of putative genes and unidentified taxa possibly associated with xenobiotic biodegradation. Our findings suggest that microbial species capable of utilizing explosives as a carbon, energy, or electron source are favoured by certain selective pressures based on the prevailing physicochemical and geographical conditions.
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Affiliation(s)
- Yash Pal
- Microbial Type Culture Collection and Gene Bank (MTCC), CSIR-Institute of Microbial Technology, Sec-39A, Chandigarh, -160036
| | - Shanmugam Mayilraj
- Microbial Type Culture Collection and Gene Bank (MTCC), CSIR-Institute of Microbial Technology, Sec-39A, Chandigarh, -160036.,Director of Research, Bentoli AgriNutrition, India Pvt Ltd., 3F2, Third Floor, Front Block, Metro Tower, Building No.115, Poonamallee, High Road, Chennai, - 600 084
| | - Srinivasan Krishnamurthi
- Microbial Type Culture Collection and Gene Bank (MTCC), CSIR-Institute of Microbial Technology, Sec-39A, Chandigarh, -160036
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Luo D, Li Y, Yao H, Chapman SJ. Effects of different carbon sources on methane production and the methanogenic communities in iron rich flooded paddy soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 823:153636. [PMID: 35124061 DOI: 10.1016/j.scitotenv.2022.153636] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Revised: 01/25/2022] [Accepted: 01/29/2022] [Indexed: 06/14/2023]
Abstract
Various carbon sources as substrates and electron donors can produce methane via different metabolic pathways. In particular, the methane produced by rice cultivation has a severe impact on climate change. However, how Fe3+, the most abundant oxide in paddy soil, mediates the methanogenesis of different carbon sources is unknown. In this study, we investigated the effect of four carbon sources with different chain lengths (acetate, glucose, nonanoate, and starch) on CH4 production and associated methanogens in iron-rich paddy soil over 90 days of anaerobic incubation. We found that glucose and starch were the more preferential substrates for liberating methane compared to acetate, and the rate was also faster. Nonanoate was unable to support methane production. Methanosarcinales and Methanobacteriales were the most predominant methanogenic archaea as shown by 16S rRNA gene sequencing, though their abundance changed over time. Additionally, a significantly higher content of iron-reducing bacteria was observed in the glucose and starch treatments, and it was significantly positively correlated with the copy number of the methanogenic mcrA gene. Together, we confirmed the methanogenic capacity of different carbon sources and their related microorganisms. We also showed that iron oxides play a central role in regulating methane emissions from paddy soils and need more attention to be paid to them.
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Affiliation(s)
- Dan Luo
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, People's Republic of China; Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, Ningbo Urban Environment Observation and Research Station-NUEORS, Institute of Urban Environment, Chinese Academy of Sciences, Ningbo 315800, People's Republic of China; University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Yaying Li
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, People's Republic of China; Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, Ningbo Urban Environment Observation and Research Station-NUEORS, Institute of Urban Environment, Chinese Academy of Sciences, Ningbo 315800, People's Republic of China
| | - Huaiying Yao
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, People's Republic of China; Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, Ningbo Urban Environment Observation and Research Station-NUEORS, Institute of Urban Environment, Chinese Academy of Sciences, Ningbo 315800, People's Republic of China; Research Center for Environmental Ecology and Engineering, School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan 430073, People's Republic of China.
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3
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Shobnam N, Sun Y, Mahmood M, Löffler FE, Im J. Biologically mediated abiotic degradation (BMAD) of bisphenol A by manganese-oxidizing bacteria. JOURNAL OF HAZARDOUS MATERIALS 2021; 417:125987. [PMID: 34229371 DOI: 10.1016/j.jhazmat.2021.125987] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/28/2021] [Accepted: 04/28/2021] [Indexed: 06/13/2023]
Abstract
Bisphenol A (BPA), a chemical of environmental concern, is recalcitrant under anoxic conditions, but is susceptible to oxidative degradation by manganese(IV)-oxide (MnO2). Microbial Mn(II)-oxidation generates MnO2-bio; however, BPA degradation in cultures of Mn(II)-oxidizing bacteria has not been explored. We assessed MnO2-bio-mediated BPA degradation using three Mn(II)-oxidizing bacteria, Roseobacter sp. AzwK-3b, Erythrobacter sp. SD-21, and Pseudomonas putida GB-1. In cultures of all three strains, enhanced BPA degradation was evident in the presence of Mn(II) compared to replicate incubations without Mn(II), suggesting MnO2-bio mediated BPA degradation. Increased Mn(II) concentrations up to 100 µM resulted in more MnO2-bio formation but the highest BPA degradation rates were observed with 10 µM Mn(II). Compared to abiotic BPA degradation with 10 μM synthetic MnO2, live cultures of strain GB-1 amended with 10 μM Mn(II) consumed 9-fold more BPA at about 5-fold higher rates. Growth of strain AzwK-3b was sensitive to BPA and the organism showed increased tolerance against BPA in the presence of Mn(II), suggesting MnO2-bio alleviated the inhibition by mediating BPA degradation. The findings demonstrate that Mn(II)-oxidizing bacteria contribute to BPA degradation but organism-specific differences exist, and for biologically-mediated-abiotic-degradation (BMAD), Mn-flux, rather than the absolute amount of MnO2-bio, is the key determinant for oxidation activity.
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Affiliation(s)
- Nusrat Shobnam
- Department of Civil Engineering, Kansas State University, Manhattan, KS 66506, USA
| | - Yanchen Sun
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, TN 37996, USA; Center for Environmental Biotechnology, University of Tennessee, Knoxville, TN 37996, USA
| | - Maheen Mahmood
- Department of Civil Engineering, Kansas State University, Manhattan, KS 66506, USA
| | - Frank E Löffler
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, TN 37996, USA; Center for Environmental Biotechnology, University of Tennessee, Knoxville, TN 37996, USA; Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA; Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA; Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN 37996, USA
| | - Jeongdae Im
- Department of Civil Engineering, Kansas State University, Manhattan, KS 66506, USA.
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Dang H, Cupples AM. Diversity and abundance of the functional genes and bacteria associated with RDX degradation at a contaminated site pre- and post-biostimulation. Appl Microbiol Biotechnol 2021; 105:6463-6475. [PMID: 34357428 DOI: 10.1007/s00253-021-11457-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/30/2021] [Accepted: 07/03/2021] [Indexed: 11/28/2022]
Abstract
Bioremediation is becoming an increasingly popular approach for the remediation of sites contaminated with the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Multiple lines of evidence are often needed to assess the success of such approaches, with molecular studies frequently providing important information on the abundance of key biodegrading species. Towards this goal, the current study utilized shotgun sequencing to determine the abundance and diversity of functional genes (xenA, xenB, xplA, diaA, pnrB, nfsI) and species previously associated with RDX biodegradation in groundwater before and after biostimulation at an RDX-contaminated Navy Site. For this, DNA was extracted from four and seven groundwater wells pre- and post-biostimulation, respectively. From a set of 65 previously identified RDX degraders, 31 were found within the groundwater samples, with the most abundant species being Variovorax sp. JS1663, Pseudomonas fluorescens, Pseudomonas putida, and Stenotrophomonas maltophilia. Further, 9 RDX-degrading species significantly (p<0.05) increased in abundance following biostimulation. Both the sequencing data and qPCR indicated that xenA and xenB exhibited the highest relative abundance among the six genes. Several genes (diaA, nsfI, xenA, and pnrB) exhibited higher relative abundance values in some wells following biostimulation. The study provides a comprehensive approach for assessing biomarkers during RDX bioremediation and provides evidence that biostimulation generated a positive impact on a set of key species and genes. KEY POINTS: • A co-occurrence network indicated diverse RDX degraders. • >30 RDX-degrading species were detected. • Nine RDX-degrading species increased following biostimulation. • Sequencing and high-throughput qPCR indicated that xenA and xenB were most abundant.
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Affiliation(s)
- Hongyu Dang
- Department of Civil and Environmental Engineering, Michigan State University, A135, 1449 Engineering Research Court, East Lansing, Michigan, 48824, USA
| | - Alison M Cupples
- Department of Civil and Environmental Engineering, Michigan State University, A135, 1449 Engineering Research Court, East Lansing, Michigan, 48824, USA.
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Abstract
Aluminosilicate clay minerals are often a major component of soils and sediments and many of these clays contain structural Fe (e.g., smectites and illites). Structural Fe(III) in smectite clays is redox active and can be reduced to Fe(II) by biotic and abiotic processes. Fe(II)-bearing minerals such as magnetite and green rust can reduce Hg(II) to Hg(0); however, the ability of other environmentally relevant Fe(II) phases, such as structural Fe(II) in smectite clays, to reduce Hg(II) is largely undetermined. We conducted experiments examining the potential for reduction of Hg(II) by smectite clay minerals containing 0–25 wt% Fe. Fe(III) in the clays (SYn-1 synthetic mica-montmorillonite, SWy-2 montmorillonite, NAu-1 and NAu-2 nontronite, and a nontronite from Cheney, Washington (CWN)) was reduced to Fe(II) using the citrate-bicarbonate-dithionite method. Experiments were initiated by adding 500 µM Hg(II) to reduced clay suspensions (4 g clay L−1) buffered at pH 7.2 in 20 mM 3-morpholinopropane-1-sulfonic acid (MOPS). The potential for Hg(II) reduction in the presence of chloride (0–10 mM) and at pH 5–9 was examined in the presence of reduced NAu-1. Analysis of the samples by Hg LIII-edge X-ray absorption fine structure (XAFS) spectroscopy indicated little to no reduction of Hg(II) by SYn-1 (0% Fe), while reduction of Hg(II) to Hg(0) was observed in the presence of reduced SWy-2, NAu-1, NAu-2, and CWN (2.8–24.8% Fe). Hg(II) was reduced to Hg(0) by NAu-1 at all pH and chloride concentrations examined. These results suggest that Fe(II)-bearing smectite clays may contribute to Hg(II) reduction in suboxic/anoxic soils and sediments.
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Ariyarathna T, Ballentine M, Vlahos P, Smith RW, Cooper C, Böhlke JK, Fallis S, Groshens TJ, Tobias C. Degradation of RDX (Hexahydro-1,3,5-trinitro-1,3,5-triazine) in contrasting coastal marine habitats: Subtidal non-vegetated (sand), subtidal vegetated (silt/eel grass), and intertidal marsh. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 745:140800. [PMID: 32721618 DOI: 10.1016/j.scitotenv.2020.140800] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 06/28/2020] [Accepted: 07/05/2020] [Indexed: 06/11/2023]
Abstract
Hundreds of explosive-contaminated marine sites exist globally, many of which contain the common munitions constituent hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Quantitative information about RDX transformation in coastal ecosystems is essential for management of many of these sites. Isotopically labelled RDX containing 15N in all 3 nitro groups was used to track the fate of RDX in three coastal ecosystem types. Flow-through mesocosms representing subtidal vegetated (silt/eel grass), subtidal non-vegetated (sand) and intertidal marsh ecosystems were continuously loaded with isotopically labelled RDX for 16-17 days. Sediment, pore-water and overlying surface water were analyzed to determine the distribution of RDX, nitroso-triazine transformation products (NXs) and nitrogen containing complete mineralization products, including ammonium, nitrate+nitrite, nitrous oxide and nitrogen gas. The marsh, silt, and sand ecotypes transformed 94%, 90% and 76% of supplied RDX, respectively. Total dissolved NXs accounted for 2%-4% of the transformed 15N-RDX. The majority of RDX transformation in the water column was by mineralization to inorganic N (dissolved and evaded; 64%-78% of transformed 15N-RDX). RDX was mineralized primarily to N2O (62-74% of transformed 15N-RDX) and secondarily to N2 (1-2% of transformed 15N-RDX) which exchanged with the atmosphere. Transformation of RDX was favored in carbon-rich lower redox potential sediments of the silt and marsh mesocosms where anaerobic processes of iron and sulfate reduction were most prevalent. RDX was most persistent in the carbon-poor sand mesocosm. Partitioning of 15N derived from RDX onto sediment and suspended particulates was negligible in the overall mass balance of RDX transformation (2%-3% of transformed 15N-RDX). The fraction of 15N derived from RDX that was sorbed or assimilated in sediment was largest in the marsh mesocosm (most organic carbon), and smallest in the sand mesocosm (largest grain size and least organic carbon). Sediment redox conditions and available organic carbon stores affect the fate of RDX in different coastal marine habitats.
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Affiliation(s)
- Thivanka Ariyarathna
- University of Connecticut, Department of Marine Sciences, 1084 Shennecossett Road, Groton, CT 06340, United States of America.
| | - Mark Ballentine
- University of Connecticut, Department of Marine Sciences, 1084 Shennecossett Road, Groton, CT 06340, United States of America
| | - Penny Vlahos
- University of Connecticut, Department of Marine Sciences, 1084 Shennecossett Road, Groton, CT 06340, United States of America
| | - Richard W Smith
- University of Connecticut, Department of Marine Sciences, 1084 Shennecossett Road, Groton, CT 06340, United States of America
| | - Christopher Cooper
- University of Connecticut, Department of Marine Sciences, 1084 Shennecossett Road, Groton, CT 06340, United States of America
| | - J K Böhlke
- U.S. Geological Survey, 431 National Center, Reston, VA 20192, United States of America
| | - Stephen Fallis
- Naval Air Warfare Center Weapons Division, Chemistry Division, China Lake, CA 93555, United States of America
| | - Thomas J Groshens
- Naval Air Warfare Center Weapons Division, Chemistry Division, China Lake, CA 93555, United States of America
| | - Craig Tobias
- University of Connecticut, Department of Marine Sciences, 1084 Shennecossett Road, Groton, CT 06340, United States of America
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Niedźwiecka JB, McGee K, Finneran KT. Combined Biotic-Abiotic 2,4-Dinitroanisole Degradation in the Presence of Hexahydro-1,3,5-trinitro-1,3,5-triazine. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:10638-10645. [PMID: 32687325 DOI: 10.1021/acs.est.0c02363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The Department of Defense has developed new explosive formulations in which traditionally used cyclic nitramines such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) have been updated with the insensitive munition (IM) 2,4-dinitroanisole (DNAN). Understanding combined degradation of both compounds at explosive-contaminated sites will allow remediation approaches that simultaneously target both contaminants. DNAN reduction in the presence of RDX was evaluated in abiotic experiments using substoichiometric, stoichiometric, and superstoichiometric concentrations of ferrous iron and anthrahydroquinone disulfonate within a pH range from 7.0 to 9.0. Biological degradation was investigated in resting cell suspensions of Geobacter metallireducens strain GS-15, a model Fe(III)-reducing Bacteria. Cells were amended into anoxic tubes buffered at pH 7.0, with initial 100 μM DNAN and 40-50 μM RDX. In both abiotic and biological experiments, the DNAN was reduced through the intermediate 2-methoxy-5-nitroaniline or 4-methoxy-3-nitroaniline to 2,4-diaminoanisole. In biological experiments, the RDX was reduced to form methylenedinitramine, formaldehyde (HCHO), and ammonium (NH4+). Cells were able to reduce both DNAN and RDX most readily in the presence of extracellular electron shuttles and/or Fe(III). DNAN degradation (abiotic and biotic) was faster than degradation of RDX, suggesting that the reduction of IMs will not be inhibited by cyclic nitramines, but degradation dynamics did change in mixtures when compared to singular compounds.
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Affiliation(s)
- Jolanta B Niedźwiecka
- Environmental Engineering and Earth Sciences, Clemson University, 312 Biosystems Research Complex (BRC) Suite 312, Clemson, South Carolina 29634, United States
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia, Branišovská 1760, České Budějovice 370 05, Czech Republic
| | - Kameryn McGee
- Environmental Engineering and Earth Sciences, Clemson University, 312 Biosystems Research Complex (BRC) Suite 312, Clemson, South Carolina 29634, United States
| | - Kevin T Finneran
- Environmental Engineering and Earth Sciences, Clemson University, 312 Biosystems Research Complex (BRC) Suite 312, Clemson, South Carolina 29634, United States
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Berens MJ, Ulrich BA, Strehlau JH, Hofstetter TB, Arnold WA. Mineral identity, natural organic matter, and repeated contaminant exposures do not affect the carbon and nitrogen isotope fractionation of 2,4-dinitroanisole during abiotic reduction. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2019; 21:51-62. [PMID: 30484795 DOI: 10.1039/c8em00381e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The recent development of insensitive munitions, such as 2,4-dinitroanisole (DNAN), as components of military explosives has generated concern for potential subsurface contamination and created a need to fully characterize their transformation processes. Compound specific isotope analysis (CSIA) has proven to be a useful means of assessing transformation pathways according to characteristic stable isotope fractionation patterns. The C and N isotope fractionation of DNAN associated with abiotic and enzymatic hydrolysis was recently assessed. The extent to which DNAN isotope fractionation will be affected by other potentially competing transformation pathways known for nitroaromatic compounds (e.g., reduction) and if previous knowledge can be extrapolated to other environmental matrices remains to be understood. Here, we investigated the C and N isotope fractionation and reaction rate constants of DNAN during abiotic reduction mediated by mineral-associated Fe(ii) species as a function of mineral type, natural organic matter presence, and repeated exposures to DNAN. Though rate constants varied, N and C apparent kinetic isotope effects (AKIEs) remained consistent across all experiments (averaged values of 15N-AKIE = 1.0317 ± 0.0064 and 13C-AKIE = 1.0008 ± 0.0005) and revealed significant 15N- and minimal 13C-enrichment in agreement with previous work on nitroaromatic compounds. Moreover, the observed fractionation was clearly distinct from trends for abiotic and enzymatic hydrolysis. This study provides a strengthened basis for the use of CSIA as a robust tool for monitoring DNAN degradation in complex environmental matrices as a component of future remediation efforts.
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Affiliation(s)
- Matthew J Berens
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, 500 Pillsbury Drive SE, Minneapolis, MN 55455-0116, USA.
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Ariyarathna T, Ballentine M, Vlahos P, Smith RW, Cooper C, Böhlke JK, Fallis S, Groshens TJ, Tobias C. Tracing the cycling and fate of the munition, Hexahydro-1,3,5-trinitro-1,3,5-triazine in a simulated sandy coastal marine habitat with a stable isotopic tracer, 15N-[RDX]. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 647:369-378. [PMID: 30086489 DOI: 10.1016/j.scitotenv.2018.07.404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 07/26/2018] [Accepted: 07/29/2018] [Indexed: 05/06/2023]
Abstract
Coastal marine habitats become contaminated with the munitions constituent, Hexahydro-1,3,5-trinitro-1,3,5-trazine (RDX), via military training, weapon testing and leakage of unexploded ordnance. This study used 15N labeled RDX in simulated aquarium-scale coastal marine habitat containing seawater, sediment, and biota to track removal pathways from surface water including sorption onto particulates, degradation to nitroso-triazines and mineralization to dissolved inorganic nitrogen (DIN). The two aquaria received continuous RDX inputs to maintain a steady state concentration (0.4 mg L-1) over 21 days. Time series RDX and nitroso-triazine concentrations in dissolved (surface and porewater) and sorbed phases (sediment and suspended particulates) were analyzed. Distributions of DIN species (ammonium, nitrate + nitrite and dissolved N2) in sediments and overlying water were also measured along with geochemical variables in the aquaria. Partitioning of RDX and RDX-derived breakdown products onto surface sediment represented 13% of the total added 15N as RDX (15N-[RDX]) equivalents after 21 days. Measured nitroso-triazines in the aquaria accounted for 6-13% of total added 15N-[RDX]. 15N-labeled DIN was found both in the oxic surface water and hypoxic porewaters, showing that RDX mineralization accounted for 34% of the 15N-[RDX] added to the aquaria over 21 days. Labeled ammonium (15NH4+, found in sediment and overlying water) and nitrate + nitrite (15NOX, found in overlying water only) together represented 10% of the total added 15N-[RDX]. The production of 15N labeled N2 (15N2), accounted for the largest individual sink during the transformation of the total added 15N-[RDX] (25%). Hypoxic sediment was the most favorable zone for production of N2, most of which diffused through porous sediments into the water column and escaped to the atmosphere.
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Affiliation(s)
- Thivanka Ariyarathna
- University of Connecticut, Department of Marine Sciences, 1084 Shennecossett Road, Groton, CT 06340, United States of America.
| | - Mark Ballentine
- University of Connecticut, Department of Marine Sciences, 1084 Shennecossett Road, Groton, CT 06340, United States of America
| | - Penny Vlahos
- University of Connecticut, Department of Marine Sciences, 1084 Shennecossett Road, Groton, CT 06340, United States of America
| | - Richard W Smith
- University of Connecticut, Department of Marine Sciences, 1084 Shennecossett Road, Groton, CT 06340, United States of America
| | - Christopher Cooper
- University of Connecticut, Department of Marine Sciences, 1084 Shennecossett Road, Groton, CT 06340, United States of America
| | - J K Böhlke
- U.S. Geological Survey, 431 National Center, Reston, VA 20192, United States of America
| | - Stephen Fallis
- Naval Air Warfare Center Weapons Division, Chemistry Division, China Lake, CA 93555, United States of America
| | - Thomas J Groshens
- Naval Air Warfare Center Weapons Division, Chemistry Division, China Lake, CA 93555, United States of America
| | - Craig Tobias
- University of Connecticut, Department of Marine Sciences, 1084 Shennecossett Road, Groton, CT 06340, United States of America
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Strehlau JH, Berens MJ, Arnold WA. Mineralogy and buffer identity effects on RDX kinetics and intermediates during reaction with natural and synthetic magnetite. CHEMOSPHERE 2018; 213:602-609. [PMID: 30292004 DOI: 10.1016/j.chemosphere.2018.09.139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 09/17/2018] [Accepted: 09/22/2018] [Indexed: 06/08/2023]
Abstract
Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is known to undergo reduction mediated by ferrous iron in the presence of minerals, including magnetite. Idealized laboratory conditions may not provide representative reaction kinetics or pathways compared to field conditions. The effects of magnetite mineral morphology, the aquifer material matrix, the presence of aqueous Fe(II), and the buffer identity on RDX reduction kinetics and intermediate formation are investigated in this work. Reactions in bicarbonate buffer were substantially slower than those performed in 3-(N-morpholino)propanesulfonic acid (MOPS) buffer, and the presence of quartz and clays in magnetite-containing aquifer material resulted in slower reaction kinetics and production of additional iron oxide phases. Buffer identity also changed the rate controlling step and reaction product distribution. Conditions as close to those expected in field systems are necessary to evaluate the reaction rates and pathways of RDX in reduced groundwater systems.
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Affiliation(s)
- Jennifer H Strehlau
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Matthew J Berens
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, Minneapolis, MN, USA
| | - William A Arnold
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, Minneapolis, MN, USA.
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Kwon MJ, O'Loughlin EJ, Ham B, Hwang Y, Shim M, Lee S. Application of an in-situ soil sampler for assessing subsurface biogeochemical dynamics in a diesel-contaminated coastal site during soil flushing operations. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2018; 206:938-948. [PMID: 29220820 DOI: 10.1016/j.jenvman.2017.11.053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 11/17/2017] [Accepted: 11/20/2017] [Indexed: 06/07/2023]
Abstract
Subsurface biogeochemistry and contaminant dynamics during the remediation of diesel-contamination by in-situ soil flushing were investigated at a site located in a coastal region. An in-situ sampler containing diesel-contaminated soils separated into two size fractions (<0.063- and <2-mm) was utilized in two monitoring wells: DH1 (located close to the injection and extraction wells for in-situ soil flushing) and DH2 (located beyond sheet piles placed to block the transport of leaked diesel). Total petroleum hydrocarbon (TPH) concentrations and biogeochemical properties were monitored both in soil and groundwater for six months. A shift occurred in the groundwater type from Ca-HCO3 to Na-Cl due to seawater intrusion during intense pumping, while the concentrations of Ni, Cu, Co, V, Cr, and Se increased substantially following surfactant (TWEEN 80) injection. The in-situ sampler with fine particles was more sensitive to variations in conditions during the remedial soil flushing process. In both wells, soil TPH concentrations in the <0.063-mm fraction were much higher than those in the <2-mm fraction. Increases in soil TPH in DH1 were consistent with the expected outcomes following well pumping and surfactant injection used to enhance TPH extraction. However, the number of diesel-degrading microorganisms decreased after surfactant injection. 16S-rRNA gene-based analysis also showed that the community composition and diversity depended on both particle size and diesel contamination. The multidisciplinary approach to the contaminated site assessments showed that soil flushing with surfactant enhanced diesel extraction, but negatively impacted in-situ diesel biodegradation as well as groundwater quality. The results also suggest that the in-situ sampler can be an effective monitoring tool for subsurface biogeochemistry as well as contaminant dynamics.
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Affiliation(s)
- Man Jae Kwon
- Dept. Earth and Environmental Sciences, Korea University, Seoul, Republic of Korea; Green School, Korea University, Seoul, Republic of Korea.
| | | | - Baknoon Ham
- Green School, Korea University, Seoul, Republic of Korea
| | - Yunho Hwang
- Korea Institute of Science and Technology, Gangneung, Republic of Korea
| | - Moojoon Shim
- Korea Institute of Science and Technology, Gangneung, Republic of Korea
| | - Soonjae Lee
- Dept. Earth and Environmental Sciences, Korea University, Seoul, Republic of Korea.
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12
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Lee JY, Rahman A, Behrens J, Brennan C, Ham B, Kim HS, Nho CW, Yun ST, Azam H, Kwon MJ. Nutrient removal from hydroponic wastewater by a microbial consortium and a culture of Paracercomonas saepenatans. N Biotechnol 2017; 41:15-24. [PMID: 29174513 DOI: 10.1016/j.nbt.2017.11.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 11/20/2017] [Accepted: 11/20/2017] [Indexed: 11/16/2022]
Abstract
The potential of microbial processes for removal of major nutrients (e.g., N, P) and inorganic cations (e.g., Ca2+, Mg2+, and Fe2+) from hydroponic systems was investigated. Microbial consortium- and axenic culture-based experiments were conducted in a waste nutrient solution (WNS). A microbial consortium grown in the WNS and selected microalgae species of Paracercomonas saepenatans were inoculated in two different synthetic media (Bold's Basal Medium (BBM) and synthetic WNS) in batch systems, and the microbial growth characteristics and the rate and extent of nutrient removal were determined for each system. No toxicity or growth inhibition was observed during microbial growth in either media. Both the waste-nutrient-grown microbial consortium and Paracercomonas saepenatans can be grown effectively in BBM and WNS, and both remove most ions from both media (e.g.,>99% removal of NO3- and 41-100% removal of PO43-) within 16days. Significant nutrient removal was observed during the growth phase of the microbial communities (4-10days period), indicating major nutrient utilization for microbial growth as well as chemical mineral precipitation. Furthermore, MINEQL+4.6 modeling showed higher PO43- removal in WNS during microbial growth (compared to BBM) due to precipitation of phosphate minerals (e.g., hydroxyapatite, vivianite). The dominant microbial species in both systems were also identified. DNA sequencing showed that Vorticella (58%) and Scenedesmus (33%) in WNS and Scenedesmus (89%) in BBM were the predominant species. This study demonstrates the potential application of microbial consortium (predominantly algae and protozoan)-based treatment techniques for hydroponic systems.
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Affiliation(s)
- Ju Yeon Lee
- Korea Institute of Science and Technology, Gangneung, Republic of Korea; Graduate School of Energy and Environment, Korea University, Seoul, Republic of Korea
| | - Arifur Rahman
- Civil and Environmental Engineering, The George Washington University, DC, USA
| | - Juliana Behrens
- Civil and Environmental Engineering, Manhattan College, NY, USA
| | - Conor Brennan
- Civil and Environmental Engineering, Manhattan College, NY, USA
| | - Baknoon Ham
- Korea Institute of Science and Technology, Gangneung, Republic of Korea; Graduate School of Energy and Environment, Korea University, Seoul, Republic of Korea
| | - Hyung Seok Kim
- Korea Institute of Science and Technology, Gangneung, Republic of Korea
| | - Chu Won Nho
- Korea Institute of Science and Technology, Gangneung, Republic of Korea
| | - Seong-Taek Yun
- Graduate School of Energy and Environment, Korea University, Seoul, Republic of Korea; Department of Earth and Environmental Sciences, Korea University, Seoul, Republic of Korea
| | - Hossain Azam
- Civil and Environmental Engineering, Manhattan College, NY, USA
| | - Man Jae Kwon
- Graduate School of Energy and Environment, Korea University, Seoul, Republic of Korea; Department of Earth and Environmental Sciences, Korea University, Seoul, Republic of Korea.
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13
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Cho KC, Fuller ME, Hatzinger PB, Chu KH. Identification of groundwater microorganisms capable of assimilating RDX-derived nitrogen during in-situ bioremediation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 569-570:1098-1106. [PMID: 27387802 DOI: 10.1016/j.scitotenv.2016.06.175] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 06/20/2016] [Accepted: 06/21/2016] [Indexed: 06/06/2023]
Abstract
Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), a nitroamine explosive, is commonly detected in groundwater at military testing and training sites. The objective of this study was to characterize the microbial community capable of using nitrogen derived from the RDX or RDX intermediates during in situ bioremediation. Active groundwater microorganisms capable of utilizing nitro-, ring- or fully-labeled (15)N-RDX as a nitrogen source were identified using stable isotope probing (SIP) in groundwater microcosms prepared from two wells in an aquifer previously amended with cheese whey to promote RDX biodegradation. A total of fifteen 16S rRNA gene sequences, clustered in Clostridia, β-Proteobacteria, and Spirochaetes, were derived from the (15)N-labeled DNA fractions, suggesting the presence of metabolically active bacteria capable of using RDX and/or RDX intermediates as a nitrogen source. None of the derived sequences matched RDX-degrading cultures commonly studied in the laboratory, but some of these genera have previously been linked to RDX degradation in site groundwater via (13)C-SIP. When additional cheese whey was added to the groundwater samples, 28 sequences grouped into Bacteroidia, Bacilli, and α-, β-, and γ-Proteobacteria were identified. The data suggest that numerous bacteria are capable of incorporating N from ring- and nitro-groups in RDX during anaerobic bioremediation, and that some genera may be involved in both C and N incorporation from RDX.
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Affiliation(s)
- Kun-Ching Cho
- Zachry Department of Civil Engineering, Texas A&M University, College Station, TX 77843-3136, USA
| | | | | | - Kung-Hui Chu
- Zachry Department of Civil Engineering, Texas A&M University, College Station, TX 77843-3136, USA.
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14
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Cupples AM. Contaminant-Degrading Microorganisms Identified Using Stable Isotope Probing. Chem Eng Technol 2016. [DOI: 10.1002/ceat.201500479] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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15
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Cho KC, Lee DG, Fuller ME, Hatzinger PB, Condee CW, Chu KH. Application of (13)C and (15)N stable isotope probing to characterize RDX degrading microbial communities under different electron-accepting conditions. JOURNAL OF HAZARDOUS MATERIALS 2015; 297:42-51. [PMID: 25935409 DOI: 10.1016/j.jhazmat.2015.04.059] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 02/26/2015] [Accepted: 04/20/2015] [Indexed: 06/04/2023]
Abstract
This study identified microorganisms capable of using the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) or its metabolites as carbon and/or nitrogen sources under different electron-accepting conditions using (13)C and (15)N stable isotope probing (SIP). Mesocosms were constructed using groundwater and aquifer solids from an RDX-contaminated aquifer. The mesocosms received succinate as a carbon source and one of four electron acceptors (nitrate, manganese(IV), iron(III), or sulfate) or no additional electron acceptor (to stimulate methanogenesis). When RDX degradation was observed, subsamples from each mesocosm were removed and amended with (13)C3- or ring-(15)N3-, nitro-(15)N3-, or fully-labeled (15)N6-RDX, followed by additional incubation and isolation of labeled nucleic acids. A total of fifteen 16S rRNA sequences, clustering in α- and γ-Proteobacteria, Clostridia, and Actinobacteria, were detected in the (13)C-DNA fractions. A total of twenty seven sequences were derived from different (15)N-DNA fractions, with the sequences clustered in α- and γ-Proteobacteria, and Clostridia. Interestingly, sequences identified as Desulfosporosinus sp. (in the Clostridia) were not only observed to incorporate the labeled (13)C or (15)N from labeled RDX, but also were detected under each of the different electron-accepting conditions. The data suggest that (13)C- and (15)N-SIP can be used to characterize microbial communities involved in RDX biodegradation, and that the dominant pathway of RDX biodegradation may differ under different electron-accepting conditions.
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Affiliation(s)
- Kun-Ching Cho
- Zachry Department of Civil Engineering, Texas A&M University, College Station, TX 77843-3136, USA
| | - Do Gyun Lee
- Zachry Department of Civil Engineering, Texas A&M University, College Station, TX 77843-3136, USA
| | | | | | | | - Kung-Hui Chu
- Zachry Department of Civil Engineering, Texas A&M University, College Station, TX 77843-3136, USA.
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16
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Jayamani I, Cupples AM. Stable isotope probing reveals the importance of Comamonas and Pseudomonadaceae in RDX degradation in samples from a Navy detonation site. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:10340-10350. [PMID: 25721530 DOI: 10.1007/s11356-015-4256-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 02/18/2015] [Indexed: 06/04/2023]
Abstract
This study investigated the microorganisms involved in hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) degradation from a detonation area at a Navy base. Using Illumina sequencing, microbial communities were compared between the initial sample, samples following RDX degradation, and controls not amended with RDX to determine which phylotypes increased in abundance following RDX degradation. The effect of glucose on these communities was also examined. In addition, stable isotope probing (SIP) using labeled ((13)C3, (15)N3-ring) RDX was performed. Illumina sequencing revealed that several phylotypes were more abundant following RDX degradation compared to the initial soil and the no-RDX controls. For the glucose-amended samples, this trend was strong for an unclassified Pseudomonadaceae phylotype and for Comamonas. Without glucose, Acinetobacter exhibited the greatest increase following RDX degradation compared to the initial soil and no-RDX controls. Rhodococcus, a known RDX degrader, also increased in abundance following RDX degradation. For the SIP study, unclassified Pseudomonadaceae was the most abundant phylotype in the heavy fractions in both the presence and absence of glucose. In the glucose-amended heavy fractions, the 16S ribosomal RNA (rRNA) genes of Comamonas and Anaeromxyobacter were also present. Without glucose, the heavy fractions also contained the 16S rRNA genes of Azohydromonas and Rhodococcus. However, all four phylotypes were present at a much lower level compared to unclassified Pseudomonadaceae. Overall, these data indicate that unclassified Pseudomonadaceae was primarily responsible for label uptake in both treatments. This study indicates, for the first time, the importance of Comamonas for RDX removal.
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Affiliation(s)
- Indumathy Jayamani
- A135 Research Engineering Complex, Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI, 48824, USA
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17
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Smith RW, Tobias C, Vlahos P, Cooper C, Ballentine M, Ariyarathna T, Fallis S, Groshens TJ. Mineralization of RDX-derived nitrogen to N2 via denitrification in coastal marine sediments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:2180-7. [PMID: 25594316 DOI: 10.1021/es505074v] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a common constituent of military explosives. Despite RDX contamination at numerous U.S. military facilities and its mobility to aquatic systems, the fate of RDX in marine systems remains largely unknown. Here, we provide RDX mineralization pathways and rates in seawater and sediments, highlighting for the first time the importance of the denitrification pathway in determining the fate of RDX-derived N. (15)N nitro group labeled RDX ((15)N-[RDX], 50 atom %) was spiked into a mesocosm simulating shallow marine conditions of coastal Long Island Sound, and the (15)N enrichment of N2 (δ(15)N2) was monitored via gas bench isotope ratio mass spectrometry (GB-IRMS) for 21 days. The (15)N tracer data were used to model RDX mineralization within the context of the broader coastal marine N cycle using a multicompartment time-stepping model. Estimates of RDX mineralization rates based on the production and gas transfer of (15)N2O and (15)N2 ranged from 0.8 to 10.3 μmol d(-1). After 22 days, 11% of the added RDX had undergone mineralization, and 29% of the total removed RDX-N was identified as N2. These results demonstrate the important consideration of sediment microbial communities in management strategies addressing cleanup of contaminated coastal sites by military explosives.
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Affiliation(s)
- Richard W Smith
- University of Connecticut , Department of Marine Sciences 1080 Shennocossett Road, Groton, Connecticut 06340, United States
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18
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Livermore JA, Jin YO, Arnseth RW, Lepuil M, Mattes TE. Microbial community dynamics during acetate biostimulation of RDX-contaminated groundwater. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:7672-7678. [PMID: 23781876 DOI: 10.1021/es4012788] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Biostimulation of groundwater microbial communities (e.g., with carbon sources) is a common approach to achieving in situ bioremediation of organic pollutants (e.g., explosives). We monitored a field-scale approach to remediate the explosive RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) in an aquifer near the Iowa Army Ammunition Plant in Middletown, IA. The purpose of the study was to gain insight into the effect of biostimulation on the microbial community. Biostimulation with acetate led to the onset of RDX reduction at the site, which was most apparent in monitoring well MW309. Based on previous laboratory experiments, we hypothesized that RDX degradation and metabolite production would correspond to enrichment of one or more Fe(III)-reducing bacterial species. Community DNA from MW309 was analyzed with 454 pyrosequencing and terminal restriction fragment length polymorphism. Production of RDX metabolites corresponded to a microbial community shift from primarily Fe(III)-reducing Betaproteobacteria to a community dominated by Fe(III)-reducing Deltaproteobacteria (Geobacteraceae in particular) and Bacteroidetes taxa. This data provides a firsthand field-scale microbial ecology context to in situ RDX bioremediation using modern sequencing techniques that will inform future biostimulation applications.
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Affiliation(s)
- Joshua A Livermore
- Department of Civil and Environmental Engineering, 4105 Seamans Center, University of Iowa , Iowa City, Iowa 52242, USA
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19
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Cho KC, Lee DG, Roh H, Fuller ME, Hatzinger PB, Chu KH. Application of (13)C-stable isotope probing to identify RDX-degrading microorganisms in groundwater. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2013; 178:350-360. [PMID: 23603473 DOI: 10.1016/j.envpol.2013.03.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 03/13/2013] [Accepted: 03/19/2013] [Indexed: 06/02/2023]
Abstract
We employed stable isotope probing (SIP) with (13)C-labeled hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to identify active microorganisms responsible for RDX biodegradation in groundwater microcosms. Sixteen different 16S rRNA gene sequences were derived from microcosms receiving (13)C-labeled RDX, suggesting the presence of microorganisms able to incorporate carbon from RDX or its breakdown products. The clones, residing in Bacteroidia, Clostridia, α-, β- and δ-Proteobacteria, and Spirochaetes, were different from previously described RDX degraders. A parallel set of microcosms was amended with cheese whey and RDX to evaluate the influence of this co-substrate on the RDX-degrading microbial community. Cheese whey stimulated RDX biotransformation, altered the types of RDX-degrading bacteria, and decreased microbial community diversity. Results of this study suggest that RDX-degrading microorganisms in groundwater are more phylogenetically diverse than what has been inferred from studies with RDX-degrading isolates.
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Affiliation(s)
- Kun-Ching Cho
- Zachry Department of Civil Engineering, 3136 TAMU, 205G WERC, Texas A&M University, College Station, TX 77843-3136, USA
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20
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Mu R, Shi H, Yuan Y, Karnjanapiboonwong A, Burken JG, Ma Y. Fast Separation and Quantification Method for Nitroguanidine and 2,4-Dinitroanisole by Ultrafast Liquid Chromatography–Tandem Mass Spectrometry. Anal Chem 2012; 84:3427-32. [DOI: 10.1021/ac300306p] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ruipu Mu
- Department of Chemistry and
Environmental Research Center, Missouri University of Science and Technology, Rolla, Missouri 65409, United
States
| | - Honglan Shi
- Department of Chemistry and
Environmental Research Center, Missouri University of Science and Technology, Rolla, Missouri 65409, United
States
| | - Yuan Yuan
- Department of Civil,
Environmental
and Architectural Engineering and Environmental Research Center, Missouri University of Science and Technology, Rolla,
Missouri 65409, United States
| | - Adcharee Karnjanapiboonwong
- Department of Civil,
Environmental
and Architectural Engineering and Environmental Research Center, Missouri University of Science and Technology, Rolla,
Missouri 65409, United States
| | - Joel G. Burken
- Department of Civil,
Environmental
and Architectural Engineering and Environmental Research Center, Missouri University of Science and Technology, Rolla,
Missouri 65409, United States
| | - Yinfa Ma
- Department of Chemistry and
Environmental Research Center, Missouri University of Science and Technology, Rolla, Missouri 65409, United
States
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