Double inhibition model for degradation of phenol by Pseudomonas putida Q5.

A semiempirical model, based on the presence of an inhibitory intermediate metabolite excreted to the broth, was developed to better predict the dynamic responses to shock loadings of Pseudomonas putida Q5 degrading phenol. Compared to the Haldane equation, the new model exhibited better prediction capabilities for a broad range of inlet concentration and dilution rate step changes. The experiments were performed at 10 degrees and 25 degrees C and ranged from stable responses to washouts. The time delays observed experimentally were successfully predicted with the dual-inhibition model and a very good agreement with the observed phenol profile also was found in a pulse experiment. A possible intermediate metabolite was detected by HPLC analyses based on the high correlation shown with the predicted inhibitory intermediate metabolite in the model. Copyright 1998 John Wiley & Sons, Inc.