The objective of this work is to improve the understanding of continuous bioreactor performance. Firstly, the consequences of immobilised cell loading, or crowding, of the biomass hold-up: in the free cell liquid phase, in the Calcium Alginate gel entrapment matrix, and by partition within a dialysis membrane tube on the functioning of the yeast <I>Saccharomyces cerevisiae</I> NCYC 1026 have been investigated. Secondly, an evaluation has been made of the operational performance of experimental anaerobic, aseptic continuous bioreaction systems containing <I>Saccharomyces cerevisiae</I> NCYC 1026 as liquid phase free cells and as both a naturally and man-made immobilised cell solid phase matrix, in terms of mass transfer limitations of the packed, or crowded cells and the contribution of each biomass hold-up to the design performance models of the bioreactor. The kinetic state of the free cell biomass hold-up was measured independently of the continuous bioreaction system, such that, these data, along with on-line substrate, biomass and dilution rate data, were available for analysis of the continuous experimental bioreaction systems, using mathematical models developed in this work. Mathematical modelling of continuous free cell bioreaction systems, with the additional complication of a solid phase immobilised biomass hold-up, revealed a dual root solution to the limiting substrate mass balance, a consequence of the free cell small floc hold-up term, neither of which could be discounted. Attempts to remove the free cell liquid phase biomass hold-up from the experimental bioreaction system proved to be unsuccessful. The immobilised cell hold-up activity was identified as a key modelling parameter, which could not be effectively estimated, nor measured, by current measurement techniques.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:639240 |
| Date | January 1995 |
| Creators | Thwaites, E. M. |
| Publisher | Swansea University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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