The WIR!-Plant³ MarZucker consortium set out to transform Baltic Sea macroalgae into valuable, sulfated sugars that could be used in food, cosmetics and pharmaceuticals. Part 4 of the project, carried out by Enzymicals AG, focused on the pilot‑scale production of marine algal polysaccharides (MAPs) from the green alga Ulva spec. and the red alga Monostroma, and on their enzymatic conversion into marine algal oligosaccharides (MAOs) and monosaccharides. The work built on enzymes that had been engineered by the Bornscheuer and Schweder groups at the University of Greifswald; these enzymes were tested for industrial suitability and adapted to the pilot process.

The pilot process began with the isolation of MAPs from dried macroalgal biomass. Several extraction routes were compared, including aqueous extraction at controlled temperature and pH, followed by clarification. Tangential flow filtration was employed to concentrate the crude extracts, and precipitation with tert‑butanol was used to recover the polysaccharides. The resulting Ulvan and rhamnan sulfate extracts were characterised by size‑exclusion chromatography and sulphate analysis, confirming the expected high sulphate content and the presence of characteristic uronic acid residues. The extraction yields were sufficient to support downstream enzymatic hydrolysis, and the process proved scalable to the pilot‑scale batch size of several kilograms of biomass.

Enzyme production was carried out in recombinant *E. coli* strains, and the purified enzymes were tested on the Ulvan and rhamnan sulfate extracts. The Ulvan‑specific lyases and rhamnan‑sulfate‑degrading enzymes produced oligosaccharides with a degree of polymerisation between 2 and 6, as determined by HPLC‑MS. The enzymatic conversion was performed at 30 °C, pH 7.0, with a substrate loading of 10 % (w/v). Under these conditions, the reaction reached completion within 24 h, yielding a mixture of oligosaccharides that retained the original sulphate groups. The process was further optimised by adjusting enzyme loading and reaction time, resulting in a 15 % increase in oligosaccharide yield compared with the initial trials.

The pilot study also evaluated the feasibility of using Monostroma as a substitute for the red alga Furcellaria, which had proven difficult to cultivate. The Monostroma extracts displayed a similar polysaccharide profile to Ulvan, and the same enzymatic protocol produced comparable oligosaccharide yields, demonstrating the flexibility of the process. In addition, material samples were supplied to consortium partners for testing in drug‑delivery formulations, where the oligosaccharides showed promising mucoadhesive properties.

Collaboration within the consortium was tightly focused on the development of the extraction and enzymatic steps. Enzymicals AG led the pilot‑scale work and coordinated the integration of the enzyme production from the university partners. The Bornscheuer and Schweder groups supplied the engineered enzymes and provided technical guidance on reaction optimisation. Other consortium members contributed by evaluating the bioactivity of the produced oligosaccharides and by exploring potential pharmaceutical applications. The project was funded by the German Federal Ministry of Education and Research (BMBF) under grant number 03WIR2205D. The pilot phase concluded on 31 May 2023, and the final report was published on 15 November 2023. The results establish a scalable platform for converting Baltic macroalgae into high‑value, sulfated sugars, laying the groundwork for future industrial exploitation and further research into marine‑derived bioactives.