Cellooligosaccharides are the reaction intermediates produced during the
hydrolysis of cellulose to glucose. Hence, they have the same chemical structure as
cellulose, just shorter chain lengths. Cellooligosaccharides up to DP eight are
soluble in water. The soluble cellooligosaccharides can be used "as is" in the food
industry as non-digestible oligosaccharides and in the laboratory as representative
substrates for cellulolytic enzymes. The soluble cellooligosaccharides may also be
chemically modified for use in the laboratory, in this case serving as affinity ligands,
reporter groups, or model substrates.
A number of methods are available for the separation of
cellooligosaccharides differing only with respect to DP. This type of separation is
relevant to both laboratory and industrial applications. A new approach to the chromatographic separation of cellooligosacchandes is presented in this thesis. It is
shown that cellulose stationary phases, in conjunction with ethanol-water mobile
phases, may be used for cellooligosaccharide fractionation. The system appears to
behave as an affinity/partition system, with retention times increasing as the DP of
the cellooligosaccharides increase. The feasibility of using such a chromatographic
system for the "clean-up" of cellooligosaccharide mixtures is demonstrated.
The relative merit of different chromatographic approaches putatively used for the
fractionation of cellooligosaccharides was determined. Affinity-, adsorption-, ion-mediated-
and molecular exclusion-approaches were tested. Adsorption
chromatography, using a charcoal-celite stationary phase, was the most generally
applicable method for the preparation of near gram quantities of pure
cellooligosaccharides. Cellulose-based affinity/partition chromatography was found
to be the least time consuming and most economical method for the preparation of
cellotetraose and cellopentaose.
Studies using chemically modified cellooligosaccharides are typically limited
to derivatives whose aglycone group is conjugated to the reducing end of the sugar.
This is because the chemistry involved in modifying the reducing end is typically
much easier than that involved in selectively modifying other sites on the
oligosaccharides. A portion of the studies presented herein was aimed at exploring
approaches for the modification of the non-reducing end of cellooligosaccharides.
Methyl 6-O-p-nitrobenzoyl-β-D-glucoside was synthesized by reacting methyl 4,6-O-p-nitrobenzylidine-β-Dglucoside with N-bromosuccinimide. This method has
potential as a general method for the modification of the reducing terminus of
oligosaccharides, including, cellooligosaccharides. / Graduation date: 2003
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27274 |
| Date | 05 September 2002 |
| Creators | Akpinar, Ozlem |
| Contributors | Penner, Michael H. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
Page generated in 0.0019 seconds