Phenol degradation kinetics of an aerobic mixed culture

Biodegradation of 0.25–7.0 mmol l−1 phenol with a mixed bacterial consortium at a temperature of 25 ± 2 °C and a pH of 7.2 was studied in batch aerobic reactors. Substrate inhibition was calculated from experimental growth parameters using the Haldane equation. Kinetic parameters were derived by non-linear regression with a correlation factor (R2) of 0.987. The values for Haldane constants μmax, Ks and Ki were 0.3095 h−1, 0.7933 mmol l−1 and 6.887 mmol l−1, respectively. The value of Ki is one of the highest values obtained for mixed cultures degrading phenol under batch conditions. The yield factor (units A578 mmol−1 phenol) ranged from 0.10 to 0.16. The biokinetic parameters were used to predict the biodegradation profile, which agreed well with the experimental data. The results obtained from this study could be useful for an estimation of the relationship between growth rate and substrate utilization, which may be used to evaluate mass balance for a phenol containing wastewater treatment system involving mixed culture as the “biocatalysts”.