The decoupling and synthesis problem for bioreactor models are investigated. A non-standard canonical form that describes the output dynamics is introduced. The new canonical form is performed by a system of non-linear differential equations exhibiting state-input and input-input interactions. A decoupling strategy permits to reach regulation objectives in spite of coupled input variables between the influent concentrations of the various species in the reactor and the dilution. Stability is proved and a systematic design of decoupled controllers is derived for systems without unstable internal dynamics.

Keywords: Modeling, multivariable control, coupled control variables, bioreactor.