| مستخلص: |
A case history is described in which a practical systems engineering approach was applied to the industrial biosynthetic production of antibiotics, with the aim to develop a better operating policy for a single fermentor. The control variables to be optimized are: the sequence of discrete additions of substrate, the initial concentration of substrate and the duration of the batch (batch time). Three different criteria were considered, namely batch profit, production rate and substrate utilization efficiency. A relatively simple (formally a chemical-kine-tic) model is shown, giving good agreement with the measured process outputs. For optimization, a simulation study and the Quasi Newton method (with simple bounds on variables) were combined. From the results obtained, the following practical recommendations are given: 1. the initial concentration of substrate should be remarkably increased, 2. a falling sequence for substrate additions should be introduced, 3. for the first two criteria, higher substrate addition rate is desirable, whereas for the third criterion substrate additions later during the batch are to be canceled, 4. batch time is generally not a critical variable; eventually it can be optimized by an univariable search. In the light of these conclusions, further research of substrate inhibition in this process is highly desirable. |
