ABSTRACT
Biotechnology is not simply the sum of microbiology, genetics, biochemistry, engineering, etc.; no, it is the integration of these disciplines, and this involves quite a bit more than just simple addition. Integration and application are the keywords which can be found in most definitions of biotechnology (Fig. 1.1). Especially when designing bioreactors, integration of biological and engineering principles is essential. The bioreactor should be designed such that specific biological and technological demands of a process are met. Naturally, quality and price of the product are decisive for commercial realization. The aim of bioreactor design can thus be defined as "minimization of the costs of the pertinent product while retaining the desired quality, and this within the biological and technological constraints." This does not mean a priori that minimizing the costs of the bioreactor also means minimizing the costs of the integral process. This depends largely on the cost-determining part(s) of the process. If running the bioreactor is cost determining, then maximization of the overall volumetric productivity of
the bioreactor is, in general, the rational approach. If, on the other hand, the downstream processing is cost determining, then maximization of the product concentration in the bioreactor is, in general, the rational thing to do. However, here again integration is the keyword. Bioreactor design should be an integral part of the overall process design.
