Aerobic batch degradation of phenol using immobilized Pseudomonas putida

Alginate concentrations between 2 and 4% had little effect on the degradation rate of phenol by alginate-immobilized Pseudomonas putida. Ten-degree shifts from 25 degrees C resulted in approximately 30% slower degradation. Maximal degradation rates were favored at pH 5.5-6.0. The response of degradation rate to increased air flow in the bubble column used was almost linear and an optimal higher than 16 vol vol(-1) was indicated, although free cells appeared in the reaction medium above 12 vol vol(-1). When the initial phenol concentration was raised, degradation rate was not significantly affected until levels higher than 1200 mg ml(-1) where performance was markedly reduced. Increasing the ratio of total bead volume to medium volume gave progressively smaller increases in degradation rate. At a medium volume to total bead volume ratio of 5:1, the maximum degradation rate was 250 mg L-1 h(-1).