This paper deals with the design of a feedback controller for the decorrelated estimation of a parameter couple appearing in an unstructured model for growth of one biomass on one limiting substrate in a fed-batch bioreactor. By optimal experimental design, feed rate strategies for decorrelated parameter estimation have been constructed las reported elsewhere). These profiles have in common a feeding phase in which the substrate concentration is kept constant at a setpoint value by a feedforward controller. On simulation level this controller can be applied as an open loop controller. However, in practice these feed rate strategies are to be implemented in closed loop. Since during experimental design on simulation level a nominal parameter set is required, an iterative approach is needed to end up with a truly optimal experiment for estimation of the unknown parameters. Such an iterative scheme is proposed and its convergence properties are discussed.