Techniques for Producing Monodispersed Biocatalyst Beads for Use in Columnar Bioreactorsa

Abstract

The use of columnar bioreactors such as fixed or fluidized beds requires that the biocatalyst (e.g., microorganism) be immobilized into or onto solid support materials that will not be swept out of the bioreactor at the high flow rates frequently used in these systems. At the same time, the pathlength to and through the biocatalyst must be relatively short to reduce the effects of mass transport of substrates and products; thus, small particles or thin films of the biocatalyst should be used. In the case of fluidized-bed systems, the resulting particles must also be sufficiently small and dense to ensure fluidization without washout. If active microorganisms are used, immobilization can be carried out by interaction of the cell with a particulate surface or by encapsulation or entrapment of the organisms into a solid matrix such as a hydrocolloidal gel. The latter approach is of particular interest for systems where a well-defined microbial population is to be maintained, especially if system asepsis cannot be ensured. 9 refs., 2 figs., 2 tabs.