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Title: Transformation of 2,4,6-trinitrotoluene (TNT) by actinomycetes isolated from TNT-contaminated and uncontaminated environments

Abstract

Biotransformation of TNT has been reported under both aerobic and anaerobic conditions. Actinomycetes are important decomposers in composts. This study examines the tolerance of acitomycete cultures, isolated from both TNT-contaminated and uncontaminated environments for different concentrations to TNT, determined how selected isolates transform TNT, and examined whether such TNT transformations were constitutive or induced by exposure to TNT. 33 refs., 1 figs., 1 tab.

Authors:
; ; ;  [1]
  1. Univ. of Idaho, Moscow, ID (United States)
Publication Date:
OSTI Identifier:
433565
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied and Environmental Microbiology; Journal Volume: 62; Journal Issue: 3; Other Information: PBD: Mar 1996
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 55 BIOLOGY AND MEDICINE, BASIC STUDIES; TNT; BIODEGRADATION; ACTINOMYCES; BIOLOGICAL PATHWAYS

Citation Formats

Pasti-Grigsby, M.B., Lewis, T.A., Crawford, D.L., and Crawford, R.L. Transformation of 2,4,6-trinitrotoluene (TNT) by actinomycetes isolated from TNT-contaminated and uncontaminated environments. United States: N. p., 1996. Web.
Pasti-Grigsby, M.B., Lewis, T.A., Crawford, D.L., & Crawford, R.L. Transformation of 2,4,6-trinitrotoluene (TNT) by actinomycetes isolated from TNT-contaminated and uncontaminated environments. United States.
Pasti-Grigsby, M.B., Lewis, T.A., Crawford, D.L., and Crawford, R.L. 1996. "Transformation of 2,4,6-trinitrotoluene (TNT) by actinomycetes isolated from TNT-contaminated and uncontaminated environments". United States. doi:.
@article{osti_433565,
title = {Transformation of 2,4,6-trinitrotoluene (TNT) by actinomycetes isolated from TNT-contaminated and uncontaminated environments},
author = {Pasti-Grigsby, M.B. and Lewis, T.A. and Crawford, D.L. and Crawford, R.L.},
abstractNote = {Biotransformation of TNT has been reported under both aerobic and anaerobic conditions. Actinomycetes are important decomposers in composts. This study examines the tolerance of acitomycete cultures, isolated from both TNT-contaminated and uncontaminated environments for different concentrations to TNT, determined how selected isolates transform TNT, and examined whether such TNT transformations were constitutive or induced by exposure to TNT. 33 refs., 1 figs., 1 tab.},
doi = {},
journal = {Applied and Environmental Microbiology},
number = 3,
volume = 62,
place = {United States},
year = 1996,
month = 3
}
  • The US Army is obligated to restore land previously contaminated with the explosive 2,4,6-trinitrotoluene (TNT). One remediation method that is being tried is composting. In this method, the soil to be treated is mixed with a readily decomposable source of organic carbon, which is usually a mixture of readily available organic material. Samples of composted soil were extracted with solvent, then hydrolyzed with acid or base. The concentrations of extractable, unbound 2,4,6-trinitrotoluene and its mono- and diamino metabolites fell rapidly after the first days of composting. Hydrolysis of the extracted residues released significant quantities of intact metabolites. The objectives ofmore » this work were to differentiate between bound and unbound explosives and their transformation products in composted soil, to investigate the time course of metabolite evolution and binding, and to evaluate various hydrolysis methods.« less
  • The response of potential nitrification activity (PNA), nitrogen-fixation activity (NFA), and dehydrogenase activity (DHA) in soil to 2,4,6-trinitrotoluene (TNT) was assessed. Two garden soils of contrasting texture were spiked with TNT. Soil microbial activities and TNT residues were analyzed 1 week later. The estimated IC50 ranged from 39 to 533 mg/kg of the acetonitrile-extractable (AE) TNT, depending on indicators and soils. The lowest LOEC (lowest-observed-effect concentration) was 1 mg AE TNT/kg. Field soil was collected from three known contaminated sites in an abandoned TNT manufacturing facility. Microbial toxicity significantly correlated to TNT levels in these soils. The LOEC and NOECmore » (no-observed-effect concentration) values were site and indicator specific, with the lowest LOEC being 1 mg AE TNT/kg and the lowest NOEC being 0.4 mg AE TNT/kg. The IC50 of the pooled field samples was 51 mg AE TNT/kg for PNA or 157 mg AE TNT/kg for DHA. These results indicate that microbial responses were consistent and comparable between the laboratory and the field and that TNT could significantly inhibit soil microbial activities at very low levels. Both AE TNT and deionized water-extractable (DW) TNT concentrations correlated well with microbial toxicity, but AE TNT provided a better evaluation of TNT bioavailability than did DW TNT.« less
  • 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 removedmore » 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 than in the reactor with molasses alone as carbon source. A radiolabeling study of the mass balance of TNT in the slurry reactors showed substantial mineralization of TNT to carbon dioxide.« less
  • 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 [{sup 14}C]TNT was mineralized, 27% was converted to biomass, and 8% was adsorbed onto the soil. The rest of the [{sup 14}C]TNT was accounted for as metabolites, includingmore » 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.« less
  • During the two World Wars, large amounts of TNT were released into the environment. Until today, high concentrations of TNT can be found in the soil of former ammunition plants. To obtain basic data for a novel treatment process for highly contaminated soils, the homogeneous aqueous hydrolysis of TNT in the pH range from 10 to 12 and the alkaline treatment of two contaminated soils at pH 11 and pH 12 were investigated. The experimental data were described for their respective pH values using a pseudo-first-order model. In the homogeneous experiments, 95--97% of the TNT was hydrolyzed. During alkaline hydrolysis,more » up to two nitrogroups per TNT molecule were released, indicating the irreversible destruction of TNT. Except for the formation of small traces of amino dinitrotoluenes and trinitrobenzenes, no nitroaromatic benzenes or toluenes were detected during GC analysis. For the less contaminated soil, ELBP2, with an initial TNT concentration of 116 mg/kg, a destruction of 99% was achieved. The highly contaminated soil, HTNT2 (16.1 g of TNT/kg), showed a hydrolyzation level of 90-94%. The results show that the alkaline treatment of highly contaminated soils may prove to be effective as an alternative treatment technology.« less