Aerobic respirometric experiments were conducted at a temperature of 40 °C to determine biokinetic parameters describing growth and decay of aerobic biomass acclimatized in a membrane-coupled bioreactor (MBR). The kinetic parameters were determined with the volatile fatty acids (VFA) acetic acid and propionic acid as substrates as well as the soluble fraction of a high strength rendering wastewater as substrate. The oxygen uptake rate (OUR) and cumulative oxygen uptake (OU) recorded during the experiments were fitted to Monod kinetic model to obtain true yield ( Y t), intrinsic maximum substrate removal ( k), half-saturation constant ( K s) and endogenous decay coefficient ( k d). K s were determined to be 181, 271 and 806 mg COD l −1 and k as 1.89, 1.08 and 0.85 mg COD mg VSS −1 h −1 for acetate, propionate and rendering wastewater, respectively. The continuous-flow MBR was operated under two HRT conditions, 10 and 5 d, attaining high BOD removal efficiencies of 99% and 87%, respectively. The observed yield in the MBR was 0.03 g VSS g −1 COD.