Sugarcane vinasse was utilized as a substrate in thermophilic anaerobic degradation operated at hydraulic retention time (HRT) of 35 to 15 days, corresponding to organic loading rate (OLR) of 2.14 to 5.00 kg COD/m3.day. This study focuses on the soluble chemical oxygen demand (sCOD) reduction performance, kinetic evaluation through substrate inhibition model and model selection through the Akaike information criterion (AIC). The efficiency of sCOD reduction reached 84.7 % at OLR of 2.14 kg COD/m3.day and declined significantly to 51.4 % at OLR of 5.00 kg COD/m3.day. The Solver tool in Microsoft Office Excel was used to fit experimental data to the substrate inhibition models in the evaluation of the maximum specific substrate utilization rate (rxmax), substrate saturation constant (KS) and substrate inhibition constant (Ki). Model discrimination was performed using AIC and Tessier model was selected as the best fitted model with the highest likelihood of occurrence. Kinetic evaluation through the Tessier model gives: rxmax = 14.6745 /day, KS = 16.3218 and Ki = 16.9691.
