Hochschulschrift:
Dissertation, Mathematisch-Naturwissenschaftliche Fakultät der Universität Greifswald, 2020
Anmerkungen:
Literaturverzeichnis: Seite 93-109
Beschreibung:
Biochemie
In contrast to its terrestrial counterpart, the metabolic degradation of marine polysaccharides is underexplored. This work aimed to functionally characterize ulvan- and xylan-degrading enzymes from marine Bacteroidetes in order to clarify the metabolic degradation pathway. For the provision of a broad polysaccharide substrate spectrum, ulvan from several different algal sources was extracted to be used in further characterization experiments. The structural differences of these ulvans could be demonstrated by enzymatic degradation with ulvan-active enzymes. In order to clarify the synergistic catalytic effects of polysaccharide sulfatases with GHs in the degradation process of ulvan, several putative sulfatases from F. agariphila were produced recombinantly in E. coli. For that, a coexpression with an FGE encoding gene was required. It could be demonstrated that several glycoside hydrolases are inhibited, if their substrate is sulfated at the cleavage position and that a previous desulfation using one of the sulfatases enabled the further degradation. Some of the sulfatases showed an endolytic or exolytic cleavage behavior like reported for several GHs. With the combined catalytic activities, it was possible to successfully elucidate the complex ulvan degradation mechanism for the first time, which enables the use of ulvan as a biotechnological source for the production of fine chemicals and pharmaceuticals. This degradation mechanism was shown to be complemented by an ...