This study aimed to elucidate some kinetic aspects involved during the degradation of waste scrap tyre by a Bacillus sp. previously isolated. After a 5-day cultivation, 2.03 +/- 0.22% and 0.005 +/- 0.001% of weight loss were observed for tyre sample and control group, respectively. The potential organic compounds leached out from tyre, identified by GC-MS, mainly consisted of n-alkanes and some alkylated phenols. A mixture of tetradecane, nonadecane, and 2,4-di-tert-butylphenol (60 mg l(-1) total concentration) supported the isolate growth during the 5-day cultivation. The n-alkanes were removed more effectively (tetradecane, 64.93% and nonadecane, 47.92%) than the alkylated phenol (3.03%), contributing to the tyre degradation by Bacillus sp. observed. The optimal conditions were determined as 6.70 mg l(-1) dissolved oxygen concentration, pH 7, 10% (v/v) inoculum size, 30 degrees C, and 120 mm(2) tyre surface area. The highest maximum specific growth rate (mu(max)) (0.06 OD unit d(-1) for S and SI) and the shortest lag phases (0.28 d for S and 0.17 d for SI) were obtained under the optimized conditions for the Bacillus sp. incubation. The electron micrographs showed the isolate ability to colonize the waste tyre surface.