An international team led by the University of Barcelona has unveiled the mechanism by which a type of enzyme called alginate lyase (AL) can degrade alginates present in seaweed, according to a study published in Nature Communications. The authors believe the resultant products can be used as drug carriers, additives, and thickeners.
Tonnes of brown algae are used to extract different compounds every year, including alginates, a high-density polymer composed of sugars with many potential biotechnological applications.
Alginates are very common in seaweed and have multiple potential uses, but their practical use is limited due to their complex chemical composition. Understanding the mechanism of action of a type of enzymes that specifically breaks the chemical bonds in alginate will help overcome these limitations. “The results lay the groundwork for manipulating these enzymes and designing variants with better catalytic properties and higher efficiency on a large scale. By using industrial techniques and bioprocesses, it will be possible to optimize the production of ‘tailored alginates’ in sufficient quantities to meet society’s needs”, the researchers explain. These findings will also allow for a “better use of natural resources and boost the green economy by using enzymes as key tools in the production of these alginates.”
The study used a computational analysis of the mechanism of action for these enzymes, using 3D structures of the AL enzyme to assess how they interact with different alginate variants. Based on this structure and using the resources of the MareNostrum 5 supercomputer at the Barcelona Supercomputing Center — Centro Nacional de Supercomputación (BSC-CNS), the authors conducted several simulations, using quantum and molecular mechanics to describe the chemical reactions involving the degradation of alginates.
These simulations confirmed that the polymer breaks at the centre, not at one end. They have also found that this is a highly negatively charged species. “This finding suggests that we may be able to control at what point the polymer breaks down by mutations of certain amino acids in the enzyme’s active centre”, the researchers explained.
The team also confirmed that the enzymes belong to family 7 of lyases, the most abundant known to date. This allows researchers to extrapolate the mechanism described to other enzymes with high biotechnological potential. These results also facilitate the identification of key amino acids that can be targeted to improve the efficiency of these enzymes, a very promising line of research on which the UB team is already working.
Rivas-Fernández, J.P., Vuillemin, M., Pilgaard, B. et al. Unraveling the molecular mechanism of polysaccharide lyases for efficient alginate degradation. Nat Commun 16, 2670 (2025). https://doi.org/10.1038/s41467-025-56754-5