J. Manning

University of Notre Dame, South Bend, IN, United States

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Publications (16)21.79 Total impact

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    ABSTRACT: The metabolism of trinitrobenzene by a Pseudomonas consortium was studied. The Pseudomonas consortium used trinitrobenzene as a sole source of nitrogen, but not as a sole source of carbon. Trinitrobenzene was metabolized within 60 h of incubation. The main intermediates produced were dinitroaniline, 1,5-dinitrobenzene, nitroaniline, 5-nitrobenzene, and ammonia. The ammonia concentration in the culture medium increased during the course of incubation. Nearly stoichiometric amounts of 1,5-dinitrobenzene and 5-nitrobenzene were produced by the consortium. During trinitrobenzene metabolism by this bacterial consortium, the trinitrobenzene was first reduced to an amino compound, dinitroaniline. This intermediate was reductively deaminated with the release of ammonia into the culture medium and production of 1,5-dinitrobenzene. By the same mechanism, 1,5-dinitrobenzene was further converted to 5-nitrobenzene, which was not metabolized further, even after 60 days of incubation. This pathway is believed to be novel in that an aerobic bacterial consortium uses the nitroaromatic compound as its nitrogen source but leaves the ring intact. The bacterial consortium studied could be used in a syntrophic culture system with other 5-nitrobenzene-degrading bacteria to remove trinitrobenzene completely from soil and water at contaminated sites.Key words: trinitrobenzene, aniline, nitrobenzene, biodegradation, transformation.
    Canadian Journal of Microbiology 02/2011; 40(9):787-790. · 1.20 Impact Factor
  • R. Boopathy, J. Manning
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    ABSTRACT: The addition of food-grade surfactants could improve the use of native soil bacteria to biodegrade explosives-contaminated soil under co-metabolic conditions by enhancing the rates of explosives' desorption from soil, thus increasing the bioavailability of explosives for microbial degradation. The objective of this study is to decrease residence time in the reactor, thereby increasing output and reducing cleanup costs. In this study, Tween 80 (monooleate) served not only as a surfactant but also as the carbon substrate for soil microorganisms. Four 2-L soil slurry reactors were operated in batch mode with soil containing 2,4,6-trinitrotoluene (TNT). Results indicated that TNT was removed in all reactors except the control (no added carbon source). The reactor enriched with surfactant and molasses performed better than reactors with either molasses or surfactant alone. The TNT and its metabolite, 4-amino-2,6-dinitrotoluene, were removed faster in the reactor with surfactant plus molasses (35 days) than in the reactor with molasses alone as carbon source (45 days). A radiolabeling study of the mass balance of TNT in the slurry reactors showed substantial mineralization of TNT to carbon dioxide.
    Water Environment Research 12/1998; 71(1):119-124. · 1.13 Impact Factor
  • Ramaraj Boopathy, John Manning
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    ABSTRACT: A laboratory study was conducted to determine whether tetryl can be biodegraded by native soil bacteria under soil-slurry conditions with molasses as cosubstrate. A 2-L laboratory reactor was set up with a 15% (weight/volume) slurry of contaminated soil in deionized water. The soil slurry was mixed continuously at 80 r/min. Molasses at 0.3% (volume/volume) was added weekly as a cosubstrate. A no-carbon control reactor was also set up without molasses addition. The concentration of tetryl in the soil was monitored periodically. The results showed 100% removal of tetryl from the soil within 3 months of operation. In the no-carbon control, no significant degradation of tetryl was observed. The gas chromatographic/mass spectrometric analysis of the aqueous phase of the soil slurry showed metabolites identified as trinitro-n-methylaniline, trinitrobenzeneamine, dinitrobenzenediamine, nitroaniline, and aniline. None of these metabolites persisted more than a week after they appeared in the reactor system. The parameters relevant to biodegradation and process control, such as pH, dissolved oxygen, bacterial counts, and metabolites produced in the reactor, are discussed.
    Water Environment Research 06/1998; 70(5):1049-1055. · 1.13 Impact Factor
  • R. Boopathy, J. Manning, C. F. Kulpa
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    ABSTRACT: A laboratory study was conducted to study the feasibility of removing explosives in contaminated soil under anaerobic conditions. Anaerobic enrichment cultures were prepared from soil samples under various electron-accepting conditions, namely, sulfate-reducing, methanogenic, and nitrate-reducing conditions. The sulfate-reducing condition was very effective in removing all of the explosive compounds from the soil. The sulfate-reducing consortium removed 100% of 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitrobenzene (TNB) within 10–15 days of incubation and removed 75 to 95% of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetraazocine (HMX), within 21 days of incubation. The consortium used explosive compounds as the nitrogen source, however, it did not use these compounds as the sole carbon source. The various metabolites obtained from TNT metabolism were 4-amino-2,6-dinitrotoluene (4-A-2,6-DNT), 2,4-diamino-6-nitrotoluene (2,4-d-6-NT), and 2-methyl pentanoic acid. This sulfate-reducing consortium was further studied for its usefulness in removing TNT at the contaminated site. The results showed that the consortium can remove TNT under 5% and 10% soil slurry conditions. This laboratory study demonstrated that under anaerobic conditions, sulfate-reducing bacteria can be useful in the bioremediation of contaminated soil with TNT and other explosives.
    International Biodeterioration & Biodegradation 01/1998; 41(1):67-74. · 2.06 Impact Factor
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    ABSTRACT: In recent years, research on microbial degradation of explosives and nitroaromatic compounds has increased. Most studies of the microbial metabolism of nitroaromatic compounds have used aerobic microorganisms. Ecological observations suggest that sulfatereducing and methanogenic bacteria might metabolize nitroaromatic compounds under anaerobic conditions if appropriate electron donors and electron acceptors are present in the environment, but this ability had not been demonstrated until recently. Few review papers exist, and those deal mainly with aerobic bacterial degradation of explosives; none deals with anaerobic bacteria. In this paper, we review the anaerobic metabolic processes in the degradation of explosives and nitroaromatic compounds under sulfate-reducing and methanogenic conditions.
    Bioresource Technology 01/1998; · 5.04 Impact Factor
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    ABSTRACT: The successful operation of an aerobic/anoxic laboratory-scale soil slurry reactor showed that soil contaminated with 2,4,6-trinitrotoluene (TNT) and hexahydro-l,3,5-trinitro-l,3,5-triazine (RDX) could be treated in batches or semicontinuously. Batch treatment resulted in the transformation of TNT. Semicontinuous treatment resulted in complete degradation of TNT. In addition to removing TNT, the slurry reactor also removed contaminants such as trinitrobenzene, 2,4-dinitrotoluene, RDX, and octahydro-l,3,5,7-tetranitro-l,3,5,7-tetraazocine (HMX). Radiolabeled TNT incubated with reactor biomass showed that 23% of [14C]TNT was mineralized, 27% was converted to biomass, and 8% was adsorbed onto the soil. The rest of the [14C]TNT was accounted for as metabolites, including a ring cleavage product identified as 2,3-butanediol. Increasing the frequency of soil addition from once to two or three times weekly did not affect the TNT removal rates. The soil slurry reactor also maintained the bacterial population fairly well, needing only 0.3% molasses as a cosubstrate.
    Water Environment Research 12/1997; 70(1):80-86. · 1.13 Impact Factor
  • E P Davis, R Boopathy, J Manning
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    ABSTRACT: An aerobic Gram-negative bacterium identified as Pseudomonas vesicularis was isolated from soil contaminated with 2,4, 6-trinitrotoluene (TNT) and 1,3,5-trinitrobenzene (TNB). This bacterium used TNB as the sole source of nitrogen. The TNB was metabolized within 80 h of incubation. The major metabolites produced were dinitroaniline,dinitrobenzene (DNB), nitroaniline, nitrobenzene (NB), and ammonia. The concentrations of DNB and NB produced in the culture medium were nearly stoichiometric. The ammonia concentration in the culture medium increased during the course of incubation. The end product of TNB metabolism was NB,which did not undergo further degradation even after long incubation time. This bacterium could be used in a syntrophic culture system with other NB-degrading bacteria to remove TNB completely from soil and water at contaminated sites.
    Current Microbiology 04/1997; 34(3):192-7. · 1.52 Impact Factor
  • R Boopathy, J Manning, C F Kulpa
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    ABSTRACT: In earlier studies (Boopathy et al. 1994a, 1994b), soil bacteria present in a TNT-contaminated site removed 2,4,6-trinitrotoluene (TNT). In this study the optimum conditions for the most efficient removal of TNT is discussed. The results suggest that the soil bacterial consortium has an optimal pH range of 6-7. Maximum growth was observed at pH 7. However, the TNT removal rate was higher at pH 6. Studies of the effects of temperature showed that the bacterial consortium had maximum metabolic activity at 20 to 22 degrees C (ambient temperature). At a higher temperature (37 degrees C) the TNT removal rate dropped significantly. The consortium could not use TNT as a nitrogen source but required the addition of ammonium. Optimal growth occurred with 0.25 g/L of ammonium chloride. Growing cells removed TNT significantly faster rates than resting cells or cell-free extract. The operation of soil slurry reactors with the optimal conditions suggested that TNT can be removed effectively from the contaminated sites. These environmental conditions established as optimal can be used to improve the efficiency of large-scale soil slurry reactors for the treatment of soil contaminated with TNT.
    Archives of Environmental Contamination and Toxicology 02/1997; 32(1):94-8. · 2.01 Impact Factor
  • C.F. Kulpa, R. Boopathy, J. Manning
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    ABSTRACT: Most studies on the microbial metabolism of nitroaromatic compounds have used pure cultures of aerobic microorganisms. In many cases, attempts to degrade nitroaromatics under aerobic conditions by pure cultures result in no mineralization and only superficial modifications of the structure. However, mixed culture systems properly operated result in the transformation of 2,4,6-trinitrotoluene (TNT) and in some cases mineralization of TNT occurs. In this paper, the mixed culture system is described with emphasis on intermediates and the characteristics of the aerobic microbial process including the necessity for a co-substrate. The possibility of removing TNT under aerobic/anoxic conditions is described in detail. Another option for the biodegradation of TNT and nitroaromatics is under anaerobic, sulfate reducing conditions. In this instance, the nitroaromatic compounds undergo a series of reductions with the formation of amino compounds. TNT under sulfate reducing conditions is reduced to triaminotoluene presumably by the enzyme nitrite reductase, which is commonly found in many Desulfovibrio spp. The removal of nitro groups from TNT is achieved by a series of reductive reactions with the formation of ammonia and toluene by Desulfovibrio sp. (B strain). These metabolic processes could be applied to other nitroaromatic compounds like nitrobenzene, nitrobenzoic acids, nitrophenols, and aniline. The data supporting the anaerobic transformation of TNT under different growth condition are reviewed in this report.
    12/1996
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    ABSTRACT: A sulfate-reducing bacterium isolated from a creek sediment and capable of metabolizing TNT (2,4,6-trinitrotoluene) using sulfate and nitrate as electron acceptors was tentatively characterized as Desulfovibrio desulfuricans strain A. The isolate was unable to use TNT as the sole source of carbon. TNT degradation was accomplished by a co-metabolic process using pyruvate as the main substrate. Two different metabolic steps were employed by this isolate under different electron-accepting conditions. Under sulfate-reducing conditions, TNT was reduced to 4-amino-2,6-dinitrotoluene, 2-amino-4,6-dinitrotoluene and 2,4-diamino-6-nitrotoluene. In contrast, under nitrate-reducing conditions, these amino compounds were not produced, instead, butyric acid was identified as the major metabolite of TNT metabolism. This organism also used a wide variety of other carbon sources, including ethanol, lactate, succinate, formate and malate. The isolate contained the electron-carrier desulfoviridin and used sulfate, nitrate, and thiosulfate as electron acceptors. The isolate had an optimal temperature of 25°C and an optimal pH of 6.8 and used ammonium chloride, nitrate and glutamate as nitrogen sources. The characteristic features of the sulfate-reducing bacterium closely resembled those of Desulfovibrio desulfuricans.
    Bioresource Technology 01/1996; 56(2):273-278. · 5.04 Impact Factor
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    ABSTRACT: Two 0.5-L semicontinuous soil slurry reactors were operated for seven months to evaluate the performance of the slurry reactor system in bioremediating soil contaminated with munitions compounds. Nitrogen and carbon were supplemented. The soil slurry was mixed continuously and aerated 10 min/day. Ten percent of the contaminated soil was replaced every week. The 2,4,6-trinitrotoluene (TNT) concentration in soil began to drop after 15 days of treatment, falling to less than 0.5 mg/kg from 7800 mg/kg. Total plate counts in both reactors indicated that the bacterial population was maintained, with an average plate count of about 10{sup 8} CFU/mL. The soil slurry was slightly acidic. In addition to TNT, the slurry reactor also removed the other munitions compounds trinitrobenzene (TNB), 2,4-dinitrotoluene (2,4-DNT), RDX, and HMX. Radiolabeling studies on the reactor biomass showed that 23% of [{sup C}14]TNT was mineralized, while 27% was used as biomass and 8% was adsorbed on to the soil. The rest of the [{sup 14}C]TNT was accounted for as TNT metabolites. Increasing the frequency of soil replacement from once to two or three times weekly did not affect the TNT removal rates. However, the slurry system showed signs of stress, with highly acidic conditions and low oxygen uptake rates.
    04/1994
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    ABSTRACT: An aerobic bacterial consortium was shown to degrade 2,4,6-trinitrotoluene (TNT). At an initial concentration of 100 ppm, 100% of the TNT was transformed to intermediates in 108 h. Radiolabeling studies indicated that 8% of [14C]TNT was used as biomass and 3.1% of [14C]TNT was mineralized. The first intermediates observed were 4-amino-2,6-dinitrotoluene and its isomer 2-amino-4,6-dinitrotoluene. Prolonged incubation revealed signs of ring cleavage. Succinate or another substrate—e.g., malic acid, acetate, citrate, molasses, sucrose, or glucose—must be added to the culture medium for the degradation of TNT. The bacterial consortium was composed of variousPseudomonas spp. The results suggest that the degradation of TNT is accomplished by co-metabolism and that succinate serves as the carbon and energy source for the growth of the consortium. The results also suggest that this soil bacterial consortium may be useful for the decontamination of environmental sites contaminated with TNT.
    Current Microbiology 01/1994; 28(3):131-137. · 1.52 Impact Factor
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    ABSTRACT: Previous studies on the biotransformation of 2,4,6-trinitrotoluene (TNT) have shown that many aerobic bacterial consortia can transform TNT by co-metabolism. In this study various co-substrates have been used with the main objective of finding an inexpensive carbon source for large-scale biotreatment of TNT. Succinate, citrate, malic acid, acetate, glucose, sucrose, and molasses were used as carbon sources for an aerobic bacterial consortium transforming TNT. The results indicated that, among the various carbon sources studied, the cultures that received molasses at a concentration of 0·3% transformed 100 ppm of TNT within 12 h of incubation at ambient temperature, whereas the cultures with other carbon sources took more than 100 h to transform 100 ppm of TNT. The major intermediates identified were 4-amino-2,6-dinitrotoluene and its isomer, 2-amino-4,6-dinitrotoluene. Studies with [14C]TNT provided no significant evidence that TNT was mineralized to CO2. The bacterial consortium was composed of various microorganisms, primarily Gram-negative rods. Molasses is an inexpensive carbon source that can be used in large-scale application for the biotreatment of TNT-contaminated soil and water.
    Bioresource Technology.
  • R. Boopathy, J. Manning, C. F. Kulpa
  • R. Boopathy, J. Manning
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    ABSTRACT: The degradation of several munitions compounds was studied. The compounds included 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetraazocine, 2,4,6-trinitrobenzene (TNB), and 2,4-dinitrotoluene. All of the compounds studied were degraded by the sulfate reducing bacterial (SRB) enrichment culture. The SRB culture did not use the munitions compounds as their sole source of carbon. However, all the munitions compounds tested served as the sole source of nitrogen for the SRB culture. Degradation of munitions compounds was achieved by a co-metabolic process. The SRB culture used a variety of carbon sources including pyruvate, ethanol, formate, lactate, and Hâ-COâ. The SRB culture was an incomplete oxidizer, unable to carry out the terminal oxidation of organic substrates to COâ as the sole product, and it did not use acetate or methanol as a carbon source. In addition to serving as nitrogen sources, the munitions compounds also served as electron acceptors in the absence of sulfate. A soil slurry experiment with 5% and 10% munitions compounds-contaminated soil showed that the contaminant TNT was metabolized by the SRB culture in the presence of pyruvate as electron donor. This culture may be useful in decontaminating munitions compounds-contaminated soil and water under anaerobic conditions.