Growth kinetics of Pseudomonas putida in cometabolism of phenol and 4-chlorophenol in the presence of a conventional carbon source
✍ Scribed by Si-Jing Wang; Kai-Chee Loh
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 199 KB
- Volume
- 68
- Category
- Article
- ISSN
- 0006-3592
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✦ Synopsis
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 (ഛ200 mg L -1 ) while phenol exerts dominant inhibition on cell growth at higher phenol concentrations (ജ600 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.