title: Quantification of toluene dioxygenase induction and kinetic modeling of TCE cometabolism by Pseudomonas putida TVA8.
abstract: As measured by the toluene-induced bioluminescent response of Pseudomonas putida TVA8 in batch experiments, toluene dioxygenase (Tod) enzyme activities are dependent on toluene concentration between 0 and 30 mg/L. To provide a measure of the Tod activity for use in Michaelis-Menten competitive-inhibition kinetics, a correlation between toluene concentration and induced Tod activity as measured by an induced bioluminescent response of P. putida TVA8 is presented as a nondimensional Tod activity parameter. A packed-bed, radial-flow bioreactor (RFB) using the bioreporter P. putida TVA8A serves as the model system for studying the effect of the enzyme activity parameter on model predictions of vapor-phase toluene oxidation and trichloroethylene (TCE) cometabolism. Mass balances were performed on a differential section of the RFB to describe the radial transport of vapor-phase toluene and TCE through a bulk gas phase and the concomitant biological reaction in a stationary biofilm phase. The finite-element Galerkin weak-statement formulation with first-order basis functions was used to find the optimum solution to the highly nonlinear, coupled equations. For this RFB system with toluene concentrations less than 1 mg/L in the bulk gas phase, the Tod activity parameter enables accurate predictions of steady-state TCE degradation rate (0.27 microg TCE/min).
authors.affiliation: Center for Environmental Biotechnology, The University of Tennessee, 676 Dabney Hall, Knoxville, Tennessee 37996-1605, USA.
authors.forename: J T
authors.initials: JT
authors.lastname: Shingleton
authors.forename: B A
authors.initials: BA
authors.lastname: Applegate
authors.forename: A J
authors.initials: AJ
authors.lastname: Baker
authors.forename: G S
authors.initials: GS
authors.lastname: Sayler
authors.forename: P R
authors.initials: PR
authors.lastname: Bienkowski
mesh_terms: D007700:Kinetics; D049449:Luminescence; D013058:Mass Spectrometry; D015233:Models, Statistical; D008962:Models, Theoretical; D010105:Oxygenases / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D016958:Pseudomonas putida / Q000201:enzymology*; D013997:Time Factors; D014241:Trichloroethylene / Q000737:chemistry / Q000378:metabolism*
chemical_list: D014241:Trichloroethylene; D010105:Oxygenases; C023172:toluene dioxygenase