Valuable biomolecules from nine North Atlantic red macroalgae:Amino acids, fatty acids, carotenoids, minerals and metals

In modern society, novel marine resources are scrutinized pursuing compounds of use in the medical, pharmaceutical, biotech, food or feed industry. Few of the numerous marine macroalgae are currently exploited. In this study, the contents of nutritional compounds from nine common North Atlantic red macroalgae were compared: the lipid content was low and constant among the species, whereas the fatty acid profiles indicated that these species constitute interesting sources of polyunsaturated fatty acids (PUFA). The dominating essential and non-essential amino acids were lysine and leucine, aspartic acid, glutamic acid, and arginine, respectively. The amino acid score of the nine algae varied from 44% to 92%, the most commonly first limiting amino acid being histidine. Lutein, β-carotene, and zeaxanthin were the identified carotenoids. Contents of all macro and trace minerals, with the exception of phosphorus, were higher than those described for conventional food. Low sodium/potassium ratios (0.08 - 2.54) suggested a potential for using the ash fraction for sodium salt replacement. The algae constituted rich sources of carbohydrates (40% to 71% of DM) which show their potential for a broader commercial exploitation. In some species, the concentrations of arsenic, cadmium, and lead exceeded limit values for application in food or feed. In conclusion, the nine algae represent promising potential sources of health promoting additives for human and animal diets, in whole or in a biorefinery concept

Impact of environmental conditions on biomass yield, quality, and bio-mitigation capacity of Saccharina latissima

Seaweeds are attractive as a sustainable aquaculture crop for food, feed, bioenergy and biomolecules. Further, the non-value ecosystem services of seaweed cultivation (i.e. nutrient recapture) are gaining interest as an instrument towards sustainable aquaculture and for fulfilling the aims of the EU Marine Strategy Framework Directive. Environmental factors determine the yield and quality of the cultivated seaweed biomass and, in return, the seaweed aquaculture affects the marine environment by nutrient assimilation. Consequently, site selection is critical for obtaining optimal biomass yield and quality and for successful bio-mitigation. In this study, 5 sites for cultivation of Saccharina latissima were selected within a eutrophic water body to guide site selection for future kelp cultivation activities. Results were coupled to marine monitoring data to explore the relationship between environmental conditions and cultivation success. The biomass yields fluctuated 10-fold between sites due to local variations in light and nutrient availability. Yields were generally low, i.e. up to 510 g fresh weight (FW) per meter seeded line; however, the dry matter contents of protein and high-value pigments were high (up to 17% protein and 0.1% fucoxanthin). Growth performance, biomass quality and bio-mitigation potential was restricted by low availability of light and bioavailable phosphorus, and biofouling through juvenile suspension feeders was a critical factor at all cultivation sites. At specific sites, the tissue metal contents (Pb and Hg) exceeded the limit values for feed or food. Our results emphasize the importance of careful site selection before establishing large-scale cultivation, and stress the challenges and benefits of kelp cultivation in eutrophic waters