Includes bibliographical references. / A high filtration resistance has been found to hinder the dewatering of the antagonistic biocontrol yeast Crytococcus albidus. Throught literature a hypothesis was developed that the extracellular polysaccharide produced by C. albidus is the major cause of hindrance to the filtration process. Microscopic analysis of C. albidus cultures illustrated cell-bound extracellular capsule. Viscosity measurements and visual observations of precipitation of the polysaccharide with ethanol were evidence extracellular polysaccharide suspended in the surrounding media. In this study, alteration of the composition of the growth medium and various pre-filtration treatments of the yeast harvest were investigated to improve filterability. The treatments included washing the yeast to remove suspended macromolecules, exposing the yeast suspension to a high shear environment to reduce the quantity of cell-bound polysaccharide, and varying suspension temperature. Us of Saccharomyces cerevisiae (Baker's yeast) and diatomaceous earth (DAE) as filter aids were investigated as a means of further improving filterability.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uct/oai:localhost:11427/12792 |
| Date | January 2005 |
| Creators | Pickering, Mark |
| Contributors | Harrison, STL |
| Publisher | University of Cape Town, Faculty of Engineering and the Built Environment, Centre for Bioprocess Engineering Research |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Master Thesis, Masters, MSc |
| Format | application/pdf |
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