Title : Sargassum Biorefineries: From waste to products
Abstract:
In recent years, Sargassum spp. is the new normal on the Caribbean, in the last decade massive blooms of macroalgae arrived, causing alarm among inhabitants, scientist, government and entrepreneurs. Environmental concerns are related to its decomposition which generates leachates and noxious gases which may cause health issues and could compromise water quality on several zones. In 2019, estimations of this macroalgae in ocean were about 20 million tons; affected countries have not appropriate infrastructure for the management of this amount of biomass. This situation motivated local governments and other stakeholders to explore different ways of exploitation. To define the best processes, it is necessary to include the composition of the material; in this study we developed an exhaustive characterization that indicate the presence of polyphenolic compounds which exhibit similarities with terrestrial lignin. Moreover, different carbohydrates were identified that have the potential to be used to produce bioproducts, like alginates and fucoids, also the residual of this biomass could generate clean energy. However, the presence of heavy metals in Sargassum spp. limits these possible applications, thus a traceable process should be implemented to track the mobility of metals.
In order to achieve a sustainable exploitation of Sargassum spp biomass, we propose a traceable scheme based on an alkaline process that allow the extraction of alginate from Sargasso. where the metal content per kg of alginate in comparison with the initial Sargasso achieves the reduction of all metals on a ratio of 75 to 95%. On the other hand, the waste of this extraction-process was analyzed to define another application, the results indicated that this waste-maintained carbohydrate of interest (glucose, xylose and fucose) and an optimal carbon nitrogen ratio for anaerobic digestion. In summary, this indicates that Sargassum spp could be used as a raw material for biorefineries on vulnerable zones, contributing with the mitigation of negative impacts and transforming the Sargassum crisis into an opportunity for sustainable processes.
Audience Takeaway:
- Composition of Sargassum biomass and potential applications
- Conversion of biomass in order to offer alternatives to mitigate the Sargasso problematic
- Traceability of metals in processes for obtaining bioproducts
