An Integrated L‐Lysine Fermentation Model with Agitation Speed as the Manipulated variable

Abstract

AbstractThe L‐lysine fermentation process by Brevibacteria lactofermentum was investigated for improvement of process performance by manipulating cellular environmental conditions through computer monitoring and control. The main factor under consideration was dissolved oxygen concentration (DOC) in the broth. An integrated process model with agitation speed as the manipulated variable was developed for the model‐based controller using combined kinetic study and material balances. The selection of rate equations, which properly describe the specific process, was studied and the influence of different dissolved oxygen (DO) conditions to model parameters was discussed. A first order with time delay model was used to describe the oxygen transferred from gas to liquid phase. The dynamic behaviour of time constant, system gain, yields and maintenance coefficient were considered and closely correlated to the broth concentrations. The Nelder and Mead optimisation method was used for identification of all model parameters.