Factor optimization for phenol removal using activated carbon immobilized with Pseudomonas putida.

Removal efficiency of phenol from aqueous solutions was measured using a suspended culture of Pseudomonas putida (ATCC 3180) or the activated carbon on which the microorganisms were immobilized. Experiments were performed as a function of pH (7-9), temperature (30-36 degrees C), and concentrations of glucose (0.5-0.7 g/l) and ammonium sulfate (0.5-0.7 g/l). The Box-Behnken design was applied in a second-degree quadratic, polynomial regression model to identify the significant effects and the interactions among the above four factors. Based on response curve method the conditions for maximizing phenol removal (initially 0.2 g/l) were recognized as pH 7, temperature 30 degrees C, glucose 0.6 g/l, and ammonium sulfate 0.6 g/l. The inhibition effect of carbon and nitrogen sources beyond a concentration of 0.6 g/l on phenol removal was obvious.