Uptake rate of phenol by Pseudomonas putida grown in unsteady state

Abstract

The uptake rate of phenol by washed cells of Pseudomonas putidagrown on phenol in fermenter in an un steady state, caused by the step increase of dilution rate and/or phenol concentration in the feed, was studied. The Monod-Haldane type equation was applied to fit the data and the best kinetic parameters were calculated by nonlinear least-square techniques. It was found that the minimum period of unsteady state required for induction of the phenol metabolic pathway was approximately 30 min. The values of kinetic parameters in an unsteady state varied according to each parameter. The values of u(m) first monotonically increased to reach their highest value after about 120 min and then monotonically decreased to equal the u(m) in new steady state after about five residence times. No regularity in changing of K(s) and K(i), in unsteady state was observed. However, the greatest change in the values of K(i), was 45% while the change in values of K(s) was as much as two times compared to K(i) and K(s) in steady state prior to disturbance.