Growth kinetics of Pseudomonas putida in cometabolism of phenol and 4-chlorophenol in the presence of a conventional carbon source.
Growth kinetics of Pseudomonas putida (ATCC 49451) in cometabolism of phenol and 4-chlorophenol (4-cp) in the presence of sodium glutamate (SG) were studied. In the ternary substrate mixture, phenol and SG are growth substrates while 4-cp is a nongrowth substrate. Cell growth on phenol was found to follow Andrews kinetics and cells displayed substrate inhibition pattern on sodium glutamate in the range of 0-4 g L(-1) as well. A cell growth model for the ternary substrate system was established based on a simplified cell growth mechanism and subsequently modified by experimental results. Model analysis over a wide range of substrate concentrations shows that the inhibition of SG is much larger than phenol at low phenol concentrations (</=200 mg L(-1)) while phenol exerts dominant inhibition on cell growth at higher phenol concentrations (>/=600 mg L(-1)). The nongrowth substrate, 4-cp, inhibits cell growth mainly through inactivation of cells (cell decay) and competitive inhibition to cell growth on phenol. In the absence of SG, 4-cp retards cell growth severely and cells cannot grow at 250 mg L(-1) 4-cp. Addition of sodium glutamate, however, greatly attenuates the toxicity of 4-cp and supports cell growth at 4-cp concentration higher than 250 mg L(-1). By using the proposed cell growth model, we were able to optimize the amount of SG needed to enhance cell growth rate and validate model predictions against experimental data.
Wang
S J
SJ
Department of Chemical and Environmental Engineering, The National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260.
Loh
K C
KC
D001709:Biotechnology / Q000379:methods; D002244:Carbon / Q000378:metabolism; D002733:Chlorophenols / Q000378:metabolism; D007700:Kinetics; D008954:Models, Biological; D008962:Models, Theoretical; D019800:Phenol / Q000378:metabolism; D016958:Pseudomonas putida / Q000254:growth & development* / Q000378:metabolism
D002733:Chlorophenols; D019800:Phenol; C029107:4-chlorophenol; D002244:Carbon