Control of a continuous fermentation process

Abstract This paper presents the application to a real fermentation pilot plant of an original control technique called L/A control. Such a control takes into account implicitly the positivity of process variables and may be designed from classical linear methods. The underpinning idea is to release the positivity constraints through logarithmic and exponential transformations. Here simple algorithms are proposed and tested in simulation and then applied to a continuous bioreactor in order to control the substrate concentration. The performances are analysed, showing the advantage of this approach, which combines simplicity and good performance in the bioprocess control domain.