Practice ArticleHybrid intelligent control of substrate feeding for industrial fed-batch chlortetracycline fermentation process

•A hybrid intelligent control method for substrate feeding is proposed.•A novel TIVSS soft sensing algorithm is proposed for substrate prediction.•The tracking performance, regulation stability and final yields are analyzed.•The proposed method enables the automatic control of substrate feeding.•Successful applications to industrial fed-batch chlortetracycline cultivation process.

The lack of accurate process models and reliable online sensors for substrate measurements poses significant challenges for controlling substrate feeding accurately, automatically and optimally in fed-batch fermentation industries. It is still a common practice to regulate the feeding rate based upon manual operations. To address this issue, a hybrid intelligent control method is proposed to enable automatic substrate feeding. The resulting control system consists of three modules: a presetting module for providing initial set-points; a predictive module for estimating substrate concentration online based on a new time interval-varying soft sensing algorithm; and a feedback compensator using expert rules. The effectiveness of the proposed approach is demonstrated through its successful applications to the industrial fed-batch chlortetracycline fermentation process.