TRR 420:  Carbon sequestration at Å resolution - CONCENTRATE

• Subject Area: Biology ; Medicine
• Term: since 2025
• Website: Homepage
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 542264307

Marine algae annually convert about five times as much carbon dioxide into structurally diverse polysaccharides or glycans as modern human society emits by burning fossil fuels. Bacteria possess thousands of enzymes to degrade these glycans, converting the captured carbon back into carbon dioxide. Yet, surprisingly, we find enormous amounts of glycans accumulating in the global oceans, suggesting there are unknown factors that stabilize glycan structures. As long as the ratio of glycan biosynthesis exceeds glycan consumption, carbon is captured and stored in the oceans, both on short-term (days) and long-term (geological) time scales. This fundamental marine process, termed carbon sequestration, regulates the amount of carbon dioxide in the atmosphere and contributes to a stabilized climate. Our previous work suggests that unknown factors prevent marine bacteria from decomposing algal glycans into carbon dioxide, which promotes carbon sequestration. To identify the unknown controls that limit microbial degradation of glycans, we propose the TRR CONCENTRATE, in which we will conduct “test tube” experiments and environmental measurements with bacteria, fungi, algae and their glycans and proteins. Our main objective is to mechanistically understand, how marine microorganisms interact and sequester carbon in the form of glycans, with a focus on relevant processes and reactions at sub-nanometer (Ångström, Å) resolution. We will concentrate on protein-based machineries that interact with glycans with key-lock specificity and enzyme active sites at a high level of resolution. We aim to discover and unravel the unknown biotic and abiotic factors that render glycans stable against degradation. We will focus on the sunlit surface ocean as the primary hotspot of algal glycan biosynthesis. Our investigated time scales of glycan stability will span from days to years to assess the contribution of different factors. The TRR 420 aims to deconstruct the complexity of glycan sequestration in the ocean and to understand and mimic the underlying processes that control the balance between degradation and sequestration. The discovery of unknown agents that protect glycans from degradation will lead to an advanced understanding of ocean functioning, potentially including key knowledge to counter increasing atmospheric carbon dioxide levels. Switching between the test tube and the sea, we will iteratively decouple the cycle of algal glycan synthesis and microbial degradation until we obtain mechanistic details of the interplay between organismic and molecular-level processes down to Ångström resolution.

• DFG Programme: CRC/Transregios

Current projects

• A01 - FUEL - Glycan energy controls carbon flow in microbiomes (Project Head Schweder, Thomas )
• A02 - FUN - Fungi impact glycan sequestration via interactions with bacteria and diatoms (Project Heads Klawonn, Ph.D., Isabell ;  Reich, Marlis )
• A03 - SELFISH - Selfish bacteria limit glycan carbon sequestration (Project Head Reintjes, Greta )
• A04 - STRESS – Stressed bacteria contribute to sequester glycan carbon (Project Head Fuchs, Bernhard )
• A05 - CRYST - Inorganic minerals protect glycans from microbial degradation (Project Heads Friedrich, Michael ;  Scheffel, André )
• A06 - HOME - Glycans protect eukaryotes against bacteria and shape the microbi-ome (Project Heads Bengtsson, Ph.D., Mia ;  Hoff, Katharina )
• A07 - PREY - Synergism, antagonism & mortality in a seasonal context (Project Heads Amann, Rudolf ;  Teeling, Hanno )
• B01 - KEY - Sulfates, esters, ethers & other chemistry control the activity of enzymes (Project Heads Bornscheuer, Uwe T. ;  Lammers, Michael )
• B02 - TRAP - Bacteria require adapted proteins to bind the right glycans (Project Head Zühlke, Marie-Katherin )
• B03 - SPACE - Quaternary structures of protein machines that utilize glycans (Project Heads Rappsilber, Juri ;  Schweder, Thomas )
• B04 - LOCK – Recalcitrant glycans share common chemical structure motifs (Project Head Harder, Tilmann )
• B05 - GLUE – Glycans cross-link and precipitate bacterial proteins in the ocean (Project Head Hehemann, Jan-Hendrik )
• B06 - SYNTH - Synthetic glycan diversity can exceed bacterial innovation (Project Head Seeberger, Peter H. )
• B07 - ACID - Basic chemistry at interfaces controls glycan degradation (Project Head Roggatz, Ph.D., Christina )
• C01 - ADMIN - Central administration and coordination (Project Head Schweder, Thomas )
• C02 - MSPROT - Proteomics and mass spectrometry platform (Project Head Becher, Dörte )
• C03 - GLYCAN ANALYTICS - Glycan analytics in complex marine communities (Project Head Hehemann, Jan-Hendrik )
• C04 - INF - Research data management and analysis strategies (Project Head Waltemath, Dagmar )
• C05 - PR - Public Relations (Project Heads Bengtsson, Ph.D., Mia ;  Roggatz, Ph.D., Christina ;  Scheffel, André )

• Applicant Institution: Universität Greifswald
• Co-Applicant Institution: Universität Bremen
• Participating University: Technische Universität Berlin
• Participating Institution: Leibniz-Institut für Ostseeforschung Warnemünde (IOW); Max-Planck-Institut für Kolloid- und Grenzflächenforschung; Wissenschaftspark Potsdam-Golm; Max-Planck-Institut für Marine Mikrobiologie
• Spokesperson: Professor Dr. Thomas Schweder