Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The deterioration of harvested sugarcane as a result of bacterial growth causes
major losses of sucrose and a build-up of exopolysaccharides (EPS).
Polysaccharides present during production increase the massecuite viscosity, which
negatively influences evaporation and crystallisation. In this study 38 culturable EPSproducing
bacteria were isolated from milled sugarcane. Analysis of the EPS showed
the ubiquitous presence of glucose, however, 14 polysaccharides also contained
mannose, fructose or galactose. In vitro treatment using Chaetomium erraticum
dextranase to evaluate is effectiveness indicated that 37 of the EPS were hydrolysed
to some extent. There were 21 polysaccharides that were only partially digested. The
capacity of the isolates to produce EPS on different sugars indicated a correlation
between sucrose and polysaccharide formation in 37 isolates. The results indicate
there are more species involved in EPS production than previously thought as well
as the presence of non-dextran polysaccharides. / AFRIKAANSE OPSOMMING: Bakteriële groei veroorsaak ‘n afname in gehalte, sukrose en ‘n verhoging in die
hoeveelheid van eksternepolisakkeriede (EPS). Die verhoogde konsentrasie van
polysakkariede gedurende die verwerkingsprosses veroorsaak ‘n verhoging in
“massecuite” viskositeit. Hierdie verskynsel het ‘n nadelige uitwerking op die
verdamping en kristalvorming van die produk. In gemaalde skuikerriet was 38
groeibare EPS-produserende bakterieë geisoleer. Die geanaliseerde EPS van
hierdie bogenoemde bakterieë was daar in almal glukose teenwoordig. In 14 van
hulle was mannose, fruktose en galaktose ook gevind. Die in vitro effektiwieteit van
Chaetomium erraticum dekstranase op die EPS het gewys dat 37 het tot ‘n mate
gehidroliseer maar 21 was net gedeeltelik verteer. As gevolg van die bo-genoemde
resultate was daar gevind dat sukrose was ‘n noodsaaklike subtraat vir EPS
produksie in die geisoleerde bakterieë. In hierdie studie was bevestig ‘n groter
verskiedenheid EPS-produserende bakterieë gevind was en dat hulle assosiasie aan
sukierriet prossering meer kompleks is as wat vooreen gedink was.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/71627 |
| Date | 12 1900 |
| Creators | Willard, Kyle |
| Contributors | Kossmann, Jens, George, G. M., Stellenbosch University. Faculty of AgriSciences. Dept. of Genetics. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Rights | Stellenbosch University |
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