The characteristics of microbial growth and kinetics of DBP biodegradation was studied in a continuous culture system using DBP as a sole source of carbon. The results showed that, at high substrate concentration, the microbial growth was inhibited by DBP, and can be described by the Haldane model. Kinetic parameters based on Haldane substrate inhibition were evaluated. The values were mu(m) = 0.38 h-1, Ki = 86 mg/l, Ks = 28 mg/l. The DBP concentration to avoid substrate inhibition was inferred theoretically and determined to be 49 mg/L.