AbstractThe dynamic behaviour of bioreactors was analysed by means of experimental process identification using correlation analysis with pseudo‐random binary input signals (PRBS) for excitation of the process. Agitation speed and airflow were used as input signals. The correlation with oxygen partial pressure in the liquid and oxygen and carbon dioxide concentrations in the exhaust gas were calculated. Results of the computation are: degree of a linear differential equation and coefficients of the equation, which can then be used to design adaptive controllers. The dead time of the system can be found by comparing the least squares of different models. The variation of the parameters during process time are shown for a low order adaptive controlle