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Full-Text Articles in Biotechnology

Optimal Switching Control For Microbial Fed-Batch Culture, Chongyang Liu, Zhaohua Gong, Enmin Feng, Hongchao Yin Jan 2008

Optimal Switching Control For Microbial Fed-Batch Culture, Chongyang Liu, Zhaohua Gong, Enmin Feng, Hongchao Yin

Chongyang Liu

In fed-batch culture of glycerol bio-dissimilation to 1,3-propanediol (1,3-PD), the aim of adding glycerol is to obtain as much 1,3-PD as possible. Hence, a proper feed strategy is required during the process. In this paper, we present an optimal switching control model based on our proposed controlled switching system. Some properties of the controlled switching system are obtained. Subsequently, we prove the existence of optimal control. In order to deduce the optimality conditions, we transcribe the optimal switching control model into an equivalent one with fixed switching instants and parameters. Finally, the optimality conditions of the equivalent problem are investigated …


Identification Of Intracellular Kinetic Parameters In Continuous Bioconversion Of Glycerol By Klebsiella Pneumoniae, Enmin Feng, Chongyang Liu, Zhaohua Gong, Yaqin Sun Jan 2008

Identification Of Intracellular Kinetic Parameters In Continuous Bioconversion Of Glycerol By Klebsiella Pneumoniae, Enmin Feng, Chongyang Liu, Zhaohua Gong, Yaqin Sun

Chongyang Liu

In this paper, we propose a hybrid nonlinear dynamical system to describe the concentration changes of extracellular and intracellular substances of glycerol bioconversion to 1,3- propanedol (1,3-PD) in microbial continuous cultures. It is proved that the solution to the system exists and is continuous with respect to kinetic parameters. Subsequently, a novel quantitative definition of biological robustness is investigated. We present a performance index based on experiment data of extracellular concentrations and biological robustness. Taking the proposed hybrid nonlinear dynamical system as a constraint, we establish an identification model to determine the most reasonable metabolic pathway and optimal kinetic parameters. …