ABSTRACT
Bioreactor design is an integral part of biotechnology. 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, 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. In the following sections of this chapter the bioreactor will be defined with respect to reactor concepts and types and to tools in bioreactor design. In the bioreactor the actual conversion is accomplished by the biocatalyst. In this chapter biocatalyst means
either an enzyme, an enzyme complex, a cell organelle or a non-viable whole cell. Furthermore, a biocatalyst can be free or immobilized, which has far-reaching consequences with respect to mass transfer. Integration of mass transfer and biokinetics is essential in the description (microkinetics) of immobilized biocatalysts. The source of biocatalysts can be of either microbial, plant of animal origin.
