TY - JOUR
T1 - Reductive transformation of TNT by Escherichia coli
T2 - Pathway description
AU - Yin, Hong
AU - Wood, Thomas K.
AU - Smets, Barth F.
N1 - Funding Information:
Acknowledgements This work was supported by an Award from the National Science Foundation to B.F.S. and T.K.W. (BES-0114126). We thank Dr. Joseph Hughes (Georgia Institute of Technology) for providing the dihydroxylaminonitrotoluene standard, Dr. Kenneth M. Noll (University of Connecticut) for discussions on E. coli physiology, and Dr. Glenn Johnson and Ms. Shirley F. Nishino (Air Force Research Laboratory) for sharing details on chemical analytical techniques. The experiments comply with the current laws of the United States in which the experiments were performed.
PY - 2005/5
Y1 - 2005/5
N2 - The reductive transformation of 2,4,6-trinitrotoluene (TNT) was studied using aerobically grown Escherichia coli cultures. In the absence of an external carbon or energy source, E. coli resting cells transformed TNT to hydroxylaminodinitrotoluenes (2HADNT, 4HADNT, with 4HADNT as the dominant isomer), aminodinitrotoluenes (4ADNT, with sporadic detection of 2ADNT), 2,4-di(hydroxylamino)-6-nitrotoluene (24D(HA)6NT), 2,4-diamino-6-nitrotoluene (24DA6NT), and an additional compound which was tentatively identified as a (hydroxylamino)aminonitrotoluene isomer via gas chromatography/mass spectroscopy and spectral analysis. The resting cell assay, performed in an oxygen-free atmosphere, avoided formation of azoxy dimers and provided good mass balances. Significant preference for reduction in the para versus ortho position was detected. The formation of 24D(HA)6NT, but not ADNT, appeared inhibited by the presence of TNT. The rate and extent of TNT reduction were significantly enhanced at higher cell densities, or by supplying an exogenous reducing power source, revealing the importance of enzyme concentration and reducing power. Whether the oxygen-insensitive E. coli nitroreductases, encoded by nfsA and nfsB, directly catalyze the TNT reduction or account for the complete TNT transformation pathway, remains to be determined.
AB - The reductive transformation of 2,4,6-trinitrotoluene (TNT) was studied using aerobically grown Escherichia coli cultures. In the absence of an external carbon or energy source, E. coli resting cells transformed TNT to hydroxylaminodinitrotoluenes (2HADNT, 4HADNT, with 4HADNT as the dominant isomer), aminodinitrotoluenes (4ADNT, with sporadic detection of 2ADNT), 2,4-di(hydroxylamino)-6-nitrotoluene (24D(HA)6NT), 2,4-diamino-6-nitrotoluene (24DA6NT), and an additional compound which was tentatively identified as a (hydroxylamino)aminonitrotoluene isomer via gas chromatography/mass spectroscopy and spectral analysis. The resting cell assay, performed in an oxygen-free atmosphere, avoided formation of azoxy dimers and provided good mass balances. Significant preference for reduction in the para versus ortho position was detected. The formation of 24D(HA)6NT, but not ADNT, appeared inhibited by the presence of TNT. The rate and extent of TNT reduction were significantly enhanced at higher cell densities, or by supplying an exogenous reducing power source, revealing the importance of enzyme concentration and reducing power. Whether the oxygen-insensitive E. coli nitroreductases, encoded by nfsA and nfsB, directly catalyze the TNT reduction or account for the complete TNT transformation pathway, remains to be determined.
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U2 - 10.1007/s00253-004-1736-x
DO - 10.1007/s00253-004-1736-x
M3 - Article
C2 - 15490158
AN - SCOPUS:18244376061
SN - 0175-7598
VL - 67
SP - 397
EP - 404
JO - Applied Microbiology and Biotechnology
JF - Applied Microbiology and Biotechnology
IS - 3
ER -