TY - JOUR
T1 - Reductive transformation of TNT by Escherichia coli resting cells
T2 - Kinetic analysis
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 BFS and TKW (BES-0114126). We thank Yingge Qu for helping us with Excel VBA macro programming and Cairn Ely for editorial assistance. The experiments comply with current U.S. laws covering the conditions in which they were performed.
PY - 2005/12
Y1 - 2005/12
N2 - Microbial 2,4,6-trinitrotoluene (TNT) biotransformation via sequential nitro-reduction appears a ubiquitous process, but the kinetics of these transformations have been poorly understood or described. TNT transformation by Escherichia coli was monitored and a kinetic model for reductive TNT depletion was developed and experimentally calibrated in this report. Using resting cells of aerobically pregrown E. coli, TNT was quickly reduced to hydroxylaminodinitrotoluenes. The standard Michaelis-Menten model was modified to include three additional parameters: product toxicity (Tc), substrate inhibition (Ki), and intracellular reducing power (RH) limitation. Experimentally measured product toxicity (5.2 μmol TNT/mg cellular protein) closely matched the best-fit model value (2.84 μmol TNT/mg cellular protein). Parameter identifiability and reliability (km, Ks, Tc, and Ki) was evaluated and confirmed through sensitivity analyses and via Monte Carlo simulations. The resulting kinetic model adequately described TNT reduction kinetics by E. coli resting cells in the absence or presence of reducing power limitation.
AB - Microbial 2,4,6-trinitrotoluene (TNT) biotransformation via sequential nitro-reduction appears a ubiquitous process, but the kinetics of these transformations have been poorly understood or described. TNT transformation by Escherichia coli was monitored and a kinetic model for reductive TNT depletion was developed and experimentally calibrated in this report. Using resting cells of aerobically pregrown E. coli, TNT was quickly reduced to hydroxylaminodinitrotoluenes. The standard Michaelis-Menten model was modified to include three additional parameters: product toxicity (Tc), substrate inhibition (Ki), and intracellular reducing power (RH) limitation. Experimentally measured product toxicity (5.2 μmol TNT/mg cellular protein) closely matched the best-fit model value (2.84 μmol TNT/mg cellular protein). Parameter identifiability and reliability (km, Ks, Tc, and Ki) was evaluated and confirmed through sensitivity analyses and via Monte Carlo simulations. The resulting kinetic model adequately described TNT reduction kinetics by E. coli resting cells in the absence or presence of reducing power limitation.
UR - http://www.scopus.com/inward/record.url?scp=29544452545&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=29544452545&partnerID=8YFLogxK
U2 - 10.1007/s00253-005-1988-0
DO - 10.1007/s00253-005-1988-0
M3 - Article
C2 - 15838672
AN - SCOPUS:29544452545
SN - 0175-7598
VL - 69
SP - 326
EP - 334
JO - Applied Microbiology and Biotechnology
JF - Applied Microbiology and Biotechnology
IS - 3
ER -