In the course of the project, Dendryphiella arenaria, Pseudoalteromonas atlantica, Saccharophagus degradans, Pseudoalteromonas carrageenovora and other bacteria from the brown algae Fucus vesiculosus were isolated and analysed for the production of fucoidanases and fucosidases. Fucosidases are enzymes that specifically cleave the bonds between sulphated polysaccharides consisting mainly of the monomer fucose. The production of an active fucoidanase could not be successfully completed, whereupon the investigations will be continued at the genetic level in the follow-up project.

In addition to the enzymatic hydrolysis of fucoidans, the degradation of the molecular weight was investigated using ultrasound. The molecular weights of the fucoidans could thus be significantly reduced. A loss of sulphate groups, e.g. during acidic hydrolysis of the polysaccharides, could not be detected. The anticoagulant effect of the fucoidans from the brown algae Laminaria digitata was not influenced by ultrasonic degradation. In antivirality tests, the degraded fucoidans from Laminaria digitata outperformed the fucoidans of lower molecular weight isolated from Fucus vesiculosus in terms of efficacy, whereby the latter showed no significant loss of activity due to ultrasonic degradation (IC50 of 6 µg ml^-1 only fell to 10 µg ml^-1 with increasing degradation).

Furthermore, studies were carried out on the production of poly- and oligosaccharides in order to be able to produce fucoidans with a defined molecular weight at a later stage. For this purpose, immobilisation methods for glycosidases and separation techniques for polysaccharides were investigated. Finally, the possible use of enzymes immobilised on Sepabeads® for the continuous production of poly- and oligosaccharides in a reactor system with integrated tangential flow filtration was successfully carried out using the dextran/dextranase model system.