Hemicelluloses are non-cellulosic low-molecular-mass polysaccharides that are
found together with cellulose in plant tissues. Xylan is the major component of
the plant cell wall and the most abundant renewable hemicellulose (Timell,
1967). Heteropolysaccharides, based on a backbone structure of �� -1,4-linked D-xylose
residues, are collectively referred to as �� -1,4-xylans and constitute the
main polymeric compound of the hemicellulose fraction (Coughlan and
Hazlewood, 1993). �� -Xylanase (1,4-�� -D-xylan-xylanohydrolase, EC 3.2.1.8) is
capable of degrading xylans and has received considerable attention in the food,
feed and paper industries (Graham and Inborr, 1992; Maat et al., 1992; Nissen
et al., 1992; Wong and Saddler, 1993). A thermostable, cellulase-free xylanase
from the filamentous fungus Thermomyces lanuginosus was isolated by Singh et
al. (2000b). The xylanase from this fungus is not only remarkably thermostable,
but is also active over a wide pH range (Singh et al., 2000a). The yeast
Saccharomyces cerevisiae has several properties which have established it as a
host for the expression of heterologous proteins of biotechnological interest, and
several studies have been conducted on the secretion of heterologous xylanases
by S. cerevisiae (Crous et al., 1995; P��rez-Gonzalez et al., 1996; La Grange et
al., 1996).
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufs/oai:etd.uovs.ac.za:etd-09202002-113154 |
| Date | 20 September 2002 |
| Creators | Nel, Sanet |
| Contributors | Dr J Albertyn, Dr. E van Heerden, Dr. RR Bragg |
| Publisher | University of the Free State |
| Source Sets | South African National ETD Portal |
| Language | en-uk |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://lourie.uovs.ac.za//theses/available/etd-09202002-113154/restricted/ |
| Rights | restricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University Free State or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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