Tissues and industrial co-products formed during alginate extraction from Laminaria hyperborea provide different metabolite profiles depending on harvest season

The metabolic profiles of different tissues and industrially relevant co-products of alginate extraction from Laminaria hyperborea samples harvested in different seasons were assessed using Hydrophilic Interaction Liquid Chromatography – Mass Spectrometry (HILIC-MS). Positive and negative mode MS data, predicted exact mass data and matching with database and literature searches, allowed the putative identification of 57 major metabolites. The metabolites ranged from known and abundant components (e.g., iodide, mannitol, and various betaines) to components not previously noted in this species and 11 major components which could not be identified. The levels of these components varied between tissues and co-products with some metabolites seemingly specific to certain samples. The components also varied between winter and summer harvested material, perhaps reflecting seasonality in their biosynthesis and accumulation in the tissues and co-products. The approach applied in this work could assess when components of potential specific commercial interest were maximally accumulated and help plan the most efficient exploitation of the harvested biomass. It could also be used to define variation in components in L. hyperborea from different locations or potential biotopes of this species. This initial work extends our ability to understand the phenotype of seaweeds whilst also identifying new components and new commercial opportunities.