Isomalto/malto-polysaccharides from starch: Reaction pathways and new characterization strategies

The 4,6-α-glucanotransferase (GTFB) enzyme is able to convert starch into isomalto/malto-polysaccharides (IMMPs). Although the proof of principle has been demonstrated that IMMPs can be produced from several starches, the influence of the structural properties of the starch substrate and the role of additionally present sugars during IMMP synthesis has remained unknown. Until now, since this has been the core topic of the research presented in this thesis. In chapter 2 we analyse the influence of the structural properties of starch-based substrates on the final IMMP structure. In chapter 3 we present and demonstrate an enzymatic fingerprinting method specially developed for the analysis of isomalto/malto-polysaccharides. In chapter 4 we investigate the reaction dynamics of the GTFB enzyme by following GTFB modification on two linear substrates with varying chain length distributions. In chapter 5 we demonstrate how the presence of mono- and di-saccharides change the outcome of GTFB modification and demonstrate that we are able to direct the modification of IMMPs. In chapter 6 we discuss potential applications and the future perspectives of isomalto/malto-polysaccharides and the GTFB enzyme.