Use this URL to cite or link to this record in EThOS:
Title: Factors influencing the performance of immobilized cells
Author: Edwards, P.
Awarding Body: University of Wales Swansea
Current Institution: Swansea University
Date of Award: 1998
Availability of Full Text:
Access from EThOS:
The objective of this project is to investigate the potential of a novel porous silicone rubber matrix material to immobilize the brewing yeast, Saccharomyces cerevisiae, NCYC 1026, so that the resulting man-made immobilized yeast cell particles, with thin disc geometry, (10mm diameter by 1 mm thick), can be used at high immbolized cell biomass loadings in brewing vessels. A simple engineering modification of a conventional non-mechanically mixed brewing vessel was developed, the Closed Loop Swirl Bioreactor, (CLSB) to induce mixing of the liquid phase in the vessel, so as to suspend the immobilized yeast discs and reduce the liquid phase mass transfer limitations, thereby existing equipment to be used for immobilized yeast brewing. The kinetic state of the immobilized yeast cells was measured independently of the immobilized cell batch bioreactors, using a mathematical model for free call liquid phase batch culture and a set of time course data from a single batch experiment. Mathematical models have been developed for the design of commercial immobilized cell batch bioreactors and the testing of the performance of experimental bioreactors. Due to the complexity of time based batch culture rate processes, and the additional complication of the solid phase mass transfer limited immobilized biomass hold-up, the rate mass balances were integrated numerically. Dimensionless plots of the time based design performance response of the batch bioreactor model were used to determine the key importance of the interacting factors of colonization of, and leakage from, the solid phase matrix to batch bioreactor operation. The immobilizing matrix was found to enhance and stabilize yeast cell kinetics by protecting the cells from changes in the external liquid phase culture environment. The porous silicone rubber is therefore a durable and biocompatible immobilizing matrix with particular reference to brewing. The conclusion and observations made in this research have direct relevance to the industrial application and development of immobilized cell batch bioreactors. Recommendations for future research have been made.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available