ISSN:
0006-3592
Keywords:
numerical modeling
;
uncertainty
;
statistics
;
cometabolism
;
trichloroethylene
;
methanotroph
;
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
The rates of methane utilization and trichloroethylene (TCE) cometabolism by a methanotrophic mixed culture were characterized in batch and pseudo-steady-state studies. Procedures for determination of the rate coefficients and their uncertainties by fitting a numerical model to experimental data are described. The model consisted of a system of differential equations for the rates of Monod kinetics, cell growth on methane and inactivation due to TCE transformation product toxicity, gas/liquid mass transfer of methane and TCE, and the rate of passive losses of TCE. The maximum specific rate of methane utilization (kCH4) was determined by fitting the numerical model to batch experimental data, with the initial concentration of active methane-oxidizing cells (X0a) also used as a model fitting parameter. The best estimate of kCH4 was 2.2 g CH4/g cells-d with excess copper available, with a single-parameter 95% confidence interval of 2.0-2.4 mg/mg-d. The joint 95% confidence region for kCH4 and X0a is presented graphically. The half-velocity coefficient (KS,CH4) was 0.07 mg CH4/L with excess copper available and 0.47 mg CH4/L under copper limitation, with 95% confidence intervals of 0.02-0.11 and 0.35-0.59 mg/L, respectively. Unique values of the TCE rate coefficients kTCE and KS,TCE could not be determined because they were found to be highly correlated in the model fitting analysis. However, the ratio kTCE/KS,TCE and the TCE transformation capacity (TC) were well defined, with values of 0.35 L/mg-day and 0.21 g TCE/g active cells, respectively, for cells transforming TCE in the absence of methane or supplemental formate. The single-parameter 95% confidence intervals for kTCE/KS,TCE and TC were 0.27-0.43 L/mg-d and 0.18-0.24 g TCE/g active cells, respectively. The joint 95% confidence regions for kTCE/KS,TCE and TC are presented graphically. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 53: 320-331, 1997.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
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