Modeling 1,2-dichloroethane biodegradation by Klebsiella oxytoca va 8391 immobilized on granulated activated carbon

A mathematical model of the biodegradation of xenobiotics by microbial cells attached to particles of granulated activated carbon was developed. The model allowed the quantitative evaluation of different characteristics of the biofilm behavior: retarded microbial growth, increased concentration of immobilized cells compared to suspended cultures, potential cell detachment from the solid support and consequent independent growth of free cells. The applicability of the model was demonstrated for our own experimental data for 1,2- dichloroethane (DCA) biodegradation by Klebsiella oxytoca VA 8391 cells attached to granulated activated carbon. Two types of reactors, recirculated batch and continuous flow bioreactor, were studied. It was shown that in all investigated cases, the major contribution to DCA biodegradation was provided by the immobilized cells. Furthermore, immobilized cells were found to tolerate much higher substrate concentration and dilution rates in continuous culture than the free cells.