title: The snowball effect in fed-batch bioreactions.
abstract: The bioreactor will play an important role in future biological manufacturing. For economic profit, important profiles of the feed rate in fed-batch cultures have been discussed. Unfortunately, the optimal feed rate is less robust. In these studies there exists the snowball effect in a substrate-inhibited bioprocess, in which substrate is accumulated due to uncertain parameters in the model or feed-rate error. The snowball effect also exists in multi-substrate-limited processes. In further studies, the interaction between the substrates has been higher in essential substrates than in growth-enhancing substrates. In a typical fed-batch bioreactor, the amount of the product can be reduced to 1% or less when the snowball effect arises. A new control structure, i.e., an off-line optimized feedforward controller added to a gain-scheduling PI(2)D feedback controller, is proposed to eliminate the troublesome snowball effect. The proposed control strategy recovers the yield up to 95%. Moreover, the robustness of the proposed control structure is demonstrated by simulation.
authors.affiliation: Department of Bioindustry Technology, Da Yeh University, 112 Shan Jiau Rd, Da Tsuen, Changhua 515, Taiwan, ROC. cdm@mail.dyu.edu.tw
authors.forename: Der-Ming
authors.initials: DM
authors.lastname: Chang
mesh_terms: D000465:Algorithms; D001419:Bacteria / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000379:methods*; D002455:Cell Division / Q000502:physiology*; D003198:Computer Simulation; D005246:Feedback; D007218:Industrial Microbiology; D008954:Models, Biological; D015999:Multivariate Analysis; D017711:Nonlinear Dynamics