Nami, Faranak

Plantecellevæggen udgør næsten 50% af plantens samlede biomasse, hvilket gør den til et af de primære mål inden for bioteknologisk forskning. I denne anledning kan overgangen til et bæredygtigt bioenergi forsyning primært etableres på plantecellevægge. For at opnå en bæredygtig udvikling er det vigtigt at optimere planteproduktionen og anvendelsen af denne. De tilstedeværende polysaccharider i plantecellevæggen varierer afhængig af plantens specie og ændrer sig gennem plantens udviklingsstadie. Dette gør adresseringen af de enkelte komponenter i planten til en stor udfordring. Omdannelse af lignocelluloseholdig biomasse er nu til dags stadig udfordrende, hvor den enzymatiske hydrolyse er det begrænsende trin. Derfor kan karakteriseringen af de involverede enzymer hjælpe procesoptimeringen. Til dette kan strukturelt veldefinerede oligosaccharider opnået ved kemisk syntese bruges som model for de mere komplekse polysaccharider i studiet af deres egenskaber såsom polysaccharid biosyntese, nedbrydning og protein-kulhydrat interaktioner. Til dette formål kan ikke-naturlige substratanaloger, der binder irreversibelt til enzymet, bruges. Thio-oligosaccharider repræsenterer den største gruppe af de ikke-naturlige inhibitorer for glykanaser. I denne afhandling beskrives kemisk syntese af nogle thio-glukaner. Thio-bindingsdannelsen via en klassisk eller ikke-klassisk metode bliver studeret. To strategier, der enten gør brug af en lineær eller konvergent strategi, er blevet anvendt i syntesen mod to målmolekyler. Desuden er aktiviteten af et glykosyltransferase, der forlænger pektin polysaccharidet, studeret og delvist karakteriseret.Plant cell walls represent almost 50% of the biomass found in plants and therefore constitute one of the main targets for biotechnological research. For this reason, the transition to a sustainable bio-resource for future energy can primarily be founded on plant cell walls. Thus, in order to achieve a sustainable development, it is necessary to optimize plant production and its utilization. The polysaccharides present in the plant cell wall vary depending on the plant species and change during the developmental stage of the plant. As a result, this makes it very challenging to address the function of each individual component. The conversion of lignocellulosic biomass still remains a big challenge nowadays with the enzymatic hydrolysis being the limiting step. Indeed, characterization of the enzymes involved in this process can help the optimization development. For this reason, structurally well-defined oligosaccharides made via chemical synthesis can be used as models for the more complex polysaccharides in the investigation of properties such as polysaccharide biosynthesis, degradation and protein-carbohydrate interactions. For this purpose, non-natural substrate analogues forming irreversible binding to the enzyme can be employed. Thio-oligosaccharides represent the largest class of specific non-natural inhibitors for glycanases. In this thesis the chemical synthesis of some thio-glucans is presented. The formation of thio-linkages using a classical and non-classical method is investigated. Two strategies, relying on either a linear or a convergent strategy, have been employed in the synthesis towards two target molecules. Furthermore, the activity of a glycosyltransferase responsible for the elongation of a pectic polysaccharide has been investigated and partially characterized

Online Research Database In Technology

Synthesis of S-linked cello-oligosaccharides

http://orbit.dtu.dk/ws/files/127490255/Synthesis_of_S_linked.pdf

Synthesis of S-linked cello-oligosaccharides

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Online Research Database In Technology