A mixed microbial culture isolated from wastewater of a refinery was tested for its potential in degrading phenol during its growth phase. Phenol was used as the sole carbon source, and its degradation was studied in batch mode. The mixed culture was able to completely degrade various concentrations of phenol (100-1,000 mg L -1). Phenol at low concentrations (100-200 mg L -1) had no inhibitory effect on the growth; however, for phenol concentration exceeding 200 mg L -1, the organism showed an initial lag phase of 48 h. A maximum observed specific growth rate of 0.39 h -1 was obtained at 200 mg L -1 concentration of phenol in the growth medium. The specific growth rate was fitted to the kinetic models of Haldane, Han Levenspeil, Aiba, Yano, and Edward models. The kinetic constants obtained from the Haldane model were μ max=3.47 h -1, K S=984.32 mg L -1, K I=463.56 mg L -1. Scanning electron and high-resolution microscopic images showed that Streptococci sp. was the predominant species. © Copyright 2012, Mary Ann Liebert, Inc.