Automated Synthesis of Algal Polysaccharides

Informazioni relative al progetto

ASAP

ID dell’accordo di sovvenzione: 101087063

DOI

10.3030/101087063

Data della firma CE 12 Giugno 2023

Data di avvio 1 Dicembre 2023

Data di completamento 30 Novembre 2028

Finanziato da

• European Research Council (ERC)

Costo totale

€ 1 962 685,00

Contributo UE

€ 1 962 685,00

Coordinato da

UNIVERSITAET FUER BODENKULTUR WIEN
Austria

Periodic Reporting for period 1 - ASAP (Automated Synthesis of Algal Polysaccharides)

Periodo di rendicontazione: 2023-12-01 al 2026-05-31

Sintesi del contesto e degli obiettivi generali del progetto

ASAP addresses a fundamental bottleneck in marine glycobiology: the lack of defined oligosaccharide substrates needed to decode how marine bacteria degrade algal polysaccharides and thereby regulate carbon storage in the ocean. Marine algae fix gigatonnes of CO2 annually, storing much of this carbon in structurally complex, often highly sulfated polysaccharides. Their microbial breakdown, driven by specialized carbohydrate-active enzymes (CAZymes), determines whether carbon is rapidly remineralised or sequestered for millennia in deep-sea sediments. Studying these enzymatic pathways is challenging because algal polysaccharides are large, heterogeneous, and synthetically inaccessible.

ASAP overcomes this barrier by using Automated Glycan Assembly (AGA) to produce unprecedented libraries of structurally defined marine oligosaccharides representing all major polysaccharide classes, including carrageenans, fucoidans, alginates, agarans, porphyrans, ulvans, xylans, and laminarins. The project develops new AGA methodologies for challenging 1,2-cis linkages, uronic acids, and high-density sulfation to enable the automated synthesis of complex anionic glycans.

These synthetic tools will allow systematic functional analyses of polysaccharide degradation by (i) seawater and sediment microbial communities, (ii) cultured marine bacterial strains, and (iii) purified individual CAZymes. Using fluorescently labelled oligosaccharides and high-resolution HPLC-MS, ASAP will map substrate specificities and enzymatic pathways involved in marine carbohydrate turnover.

Lavoro eseguito dall’inizio del progetto fino alla fine del periodo coperto dalla relazione e principali risultati finora ottenuti

During the first project period, we made substantial progress towards producing structurally defined oligosaccharides representing major algal polysaccharides and in establishing enzymatic tools to study their degradation. We synthesized first examples or explored synthetic strategies for β-1,3-glucan, xylan, fucoidan, carrageenan and alginate oligosaccharides using both automated glycan assembly and solution-phase approaches. To verify substrate suitability and establish reference degradation patterns, we produced and purified marine glycoside hydrolases. Fucoidanases and β-1,3- and MLX-xylanases were heterologously expressed and used to develop a digestion and analysis pipeline combining C-PAGE and HPLC-MS, which performed well on natural fucoidan extracts and synthetic xylan oligosaccharides. We thereby identified a previously unknown β-1,3-cleaving activity of the marine xylanase AlXyn26A that was obscured when only heterogeneous natural substrates were available.

Overall, the project has so far delivered well-defined algal oligosaccharides and marine hydrolases, and robust analytical workflows for monitoring polysaccharide degradation. These technical achievements provide a solid foundation for upcoming microbial and environmental degradation studies.

Progressi oltre lo stato dell’arte e potenziale impatto previsto (incluso l’impatto socioeconomico e le implicazioni sociali più ampie del progetto fino ad ora)

After the first project period the stage is set to use the synthetic oligosaccharides for investigating the polysaccharide-degrading abilities of marine bacteria and seawater samples. Continued efforts at synthesizing the algal oligosaccharides are needed to make these studies a success.