Automated Synthesis of Algal Polysaccharides

Información del proyecto

ASAP

Identificador del acuerdo de subvención: 101087063

DOI

10.3030/101087063

Fecha de la firma de la CE 12 Junio 2023

Fecha de inicio 1 Diciembre 2023

Fecha de finalización 30 Noviembre 2028

Financiado con arreglo a

• European Research Council (ERC)

Coste total

€ 1 962 685,00

Aportación de la UE

€ 1 962 685,00

Coordinado por

UNIVERSITAET FUER BODENKULTUR WIEN
Austria

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

Período documentado: 2023-12-01 hasta 2026-05-31

Resumen del contexto y de los objetivos generales del proyecto

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.

Trabajo realizado desde el comienzo del proyecto hasta el final del período abarcado por el informe y los principales resultados hasta la fecha

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.

Avances que van más allá del estado de la técnica e impacto potencial esperado (incluida la repercusión socioeconómica y las implicaciones sociales más amplias del proyecto hasta la fecha)

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.