Substrate inhibition kinetics of phenol degradation by Pseudomonas aeruginosa and Pseudomonas fluorescence

The effect of aeration and initial substrate concentration on the biodegradation of phenol by Pseudomonas aeruginosa NCIB 950, Pseudomonas fluorescence NCIB 3756 and their mixed was investigated in batch reactor. Increasing initial concentration from 100 ppm (100 mg L^-1) to 250 and 500 ppm increased the lag phase for pure culture Pseudomonas aeruginosa to 8 and 16 h, respectively. Mixed cultures had a lag phase only at concentration of 500 mg L^-1. There was increase in biodegradation rate when there was increase in aeration rate, but statically the effect of initial concentration was more significant at 95% confidence level. Pseudomonas aeruginosa had better degradation rate. Fitting data into the integrated Haldane Model, the kinetic parameters values derived from the model (μ_max, Ki and Ks), for pure culture in 250 and 500 ppm phenol are 0.46,97,450 and 0.38 h ^-1,195 and 450 mg L^-1, respectively while for mixed culture in 250 and 500 ppm phenol 0.85, 48, 250 and 0.58 h^-1, 127 and 450 mg L^-1, respectively were obtained.