KINETICS OF COMETABOLIC BIODEGRADATION OF 4-CHLOROPHENOL AND PHENOL BY STENOTROPHOMONAS MALTOPHILIA KB2

The cometabolic biodegradation of 4-Chlorophenol (4-CP) by the Stenotrophomonas maltophilia KB2 strain in the presence of phenol (P) was studied. In order to determine the kinetics of biodegradation of both substrates, present alone and in cometabolic systems, a series of tests was carried out in a batch reactor changing, in a wide range, the initial concentration of both substrates. The growth of the tested strain on phenol alone was described by Haldane kinetic model (mu(m) = 0.9 1/h, K-sg = 48.97 g(g)/m(3), K-Ig = 256.12 g(g)/m(3), Y-xg = 0 : 5715). The rate of 4-CP transformation by resting cells of KB2 strain was also described by Haldane equation and the estimated parameters of the model were: k(C) = 0.229 g(c)/g(x)h, K-SC = 0.696 g(c)/m(3), K-Ic = 43.82 g(c)/m(3). Cometabolic degradation of 4-CP in the presence of phenol was investigated for a wide range of initial 4-CP and phenol concentrations (22-66 g(c)/m(3) and 67-280 g(g)/m(3) respectively). The experimental database was exploited to verify the two kinetic models: CIModel taking only the competitive inhibition into consideration and a more universal CNIModel considering both competitive and non-competitive inhibition. CNIModel approximated experimental data better than CIModel.