Effects of surface treatment and process parameters on immobilization of recombinant yeast cells by adsorption to fibrous matrices |
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Authors: | Kilonzo Peter Margaritis Argyrios Bergougnou Maurice |
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Institution: | Department of Chemical and Biochemical Engineering, University of Western Ontario, London, Ontario, Canada N6A 5B9 |
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Abstract: | The effects of surface properties of Saccharomyces cerevisiae strains 468/pGAC9 and 468 on adhesion to polyethyleneimine (PEI) and/glutaraldehyde (GA) pre-treated cotton (CT), polyester (PE), polyester + cotton (PECT), nylon (NL), polyurethane foam (PUF), and cellulose re-enforced polyurethane (CPU) fibers were investigated. Process parameters (circulation velocity, pH, ionic strength, media composition and surfactants) were also examined. 80%, 90%, and 35% of the cells were adsorbed onto unmodified CT, PUF, and PE, respectively. PEI-GA pre-treated CT and alkali treated PE yielded 25% and 60% cell adhesion, respectively. Adsorption rate (Ka) ranged from 0.06 to 0.17 for CT and 0.06-0.16 for PE at varied pH. Adhesion increased by 15% in the presence of ethanol, low pH and ionic strength, and decreased by 23% in the presence of yeast extract and glucose. Shear flow and 1% Triton X-100 detached 62% and 36% nonviable cells from PE and CT, respectively, suggesting that cell immobilization in fibrous-bed bioreactors can be controlled to optimize cell density for long-term stability. |
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Keywords: | Fibrous-matrices Adsorption Surface treatment Recombinant yeast Process parameters |
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