Inulins are natural occurring polysaccharides, composed mainly of fructose units, and typically have a terminal glucose. Plant inulins contain between 20 and several thousand fructose units. Smaller compounds are called fructo-oligosaccharides, the simplest being 1-kestose, which has 2 fructose units and 1 glucose unit. Although many plants are known to produce inulins the only plant cultivated for the production of inulin is chicory. At present inulins are predominantly and increasingly used in processed foods. Inulin is a dietary fibre and it can be used to replace sugar, fat, and flour. Other (industrial) uses of inulin include High Fructose Syrups (HFS with uses in beverages) and carboxymethyl inulin (CMI, antiscalent with uses in detergents, off shore oil drilling and the paper and pulp industry).
In the transition of the chemical industry from depleting fossil raw materials to renewable feedstock, carbohydrates like fructose are expected to become of great importance. One of the most appealing examples of novel green building blocks is FDCA (furane dicarboxylic acid), a chemical building block that is commonly referred to as "the sleeping giant". All commercial and technical viable production routes for the production of FDCA and intermediate product HMF (hydroxymethyl furfural), run from or via fructose.
In the DRIVE4EU-project, inulin biosynthesis of TKS genes will be identified and used as targets in breeding for high inulin yield, based on the existing knowledge on the biosynthesis and degradation of inulin in a relative crop, chicory (knowledge from EU-FAIR and related projects from DLO). Up till now, chicory is used as the production crop for inulin. The extracted inulin from chicory taproots is only used for the food market as pre-biotic fibre and in hydrolysed form as fructose syrup. The regulation of inulin biosynthesis and the inulin profile has been studied in great detail in chicory and this information can be translated to TKS.