Biodegradation of phenol by a mixed microbial culture, isolated from a sewage treatment plant, was investigated in batch shake flasks. A minimum concentration of 100 and a maximum of 800 mg l(-1) of phenol in the media were adapted in the degradation study. The phenol degradation rate varied largely and was less than 10 mg l(-1) h(-1) at both extremes of the initial concentrations in the media. The degradation rate was maximum 15.7 mg l(-1) h(-1) at 400 mg l(-1) phenol. The culture followed substrate inhibition kinetics and the specific growth rate were fitted to Haldane and Han-Levenspiel models. Between the two models the Han-Levenspiel was found to be a better fit with a root mean square error of 0.0211. The biokinetics constants estimated using these models showed good potential of the mixed microbial culture in phenol degradation. (c) 2006 Elsevier Ltd. All rights reserved.