Mathematical model for evaluation of mass transfer limitations in phenol biodegradation by immobilized Pseudomonas putida

A mathematical model is proposed to analyze the mass transfer limitations i n phenol biodegradation using Pseudomonas putida immobilized in calcium alg inate. The model takes into account internal and external mass transfer lim itations, substrate inhibition kinetics and the dependence of the effective diffusivity of phenol in alginate gel on cell concentration. The model is validated with the experimental data from batch fermentation. The effect of various operating conditions such as initial phenol concentration, initial cell loading, alginate gel loading on the biodegradation of phenol is expe rimentally demonstrated. Phenol degradation time is found to decrease initi ally and reach stationary value with increase in cell loading as well as ge l loading. The model predicts these trends reasonably well and shows the pr esence of external mass transfer limitations. A new concept of effectivenes s factor is introduced to analyze the overall performance of batch fermenta tion. (C) 2001 Elsevier Science B.V. All rights reserved.