Commercial cultivation and bioremediation potential of sugar kelp, Saccharina latissima, in Danish waters

Several seaweed species have been successfully tested for their biofilter potential for integrated multi-trophic aquaculture (IMTA). In this study, Saccharina latissima bioremediation potential was assessed over 12 months with respect to the yield, phosphorous (P), nitrogen (N) content and N removal. The experiment took place at two commercial cultivation areas; in close proximity to a blue mussel and fish farm (IMTA) and at a reference site, both situated outside Horsens fjord in Denmark. The maximum biomass yield over the first growing season was achieved in August (1.08±0.09 and 1.51±0.13 kg FW m-1) and September (0.92±0.18 and 1.49±0.16 kg FW m-1).Yield was significantly higher at the IMTA compared to the reference site in August (P<0.05). A second growing season did not improve biofiltration efficiency. The highest N and P removal was achieved in August and September. Again the IMTA location showed better N and P removal compared with the reference site in August; 5.02-7.02 g N and 0.86-1.23 g P m-1 of cultivation line (P<0.05). S. latissima shows potential for assimilation and removal of nutrients, particularly nitrogen. Seasonal variations of biofilter efficiency, conditions and potential applications should be taken into account when evaluating the best suited harvest time. For Horsens fjord, our results showed that the harvest time should take place in August-September in order to achieve maximum biofiltration efficiency (including N and P in epiphytes). However, for human consumption, it is better to harvest in May where the seaweed is free of epiphytes

Bioactive compounds in seaweed; functional food applications and legislation

Seaweed is more than the wrap that keeps rice together in sushi. Seaweed biomass is already used for a wide range of other products in food, including stabilising agents. Biorefineries with seaweed as feedstock are attracting worldwide interest and include low-volume, high value-added products and vice versa. Scientific research on bioactive compounds in seaweed usually takes place on just a few species and compounds. This paper reviews worldwide research on bioactive compounds, mainly of nine genera or species of seaweed, which are also available in European temperate Atlantic waters, i.e. Laminaria sp., Fucus sp., Ascophyllum nodosum, Chondrus crispus, Porphyra sp., Ulva sp., Sargassum sp., Gracilaria sp. and Palmaria palmata. In addition, Undaria pinnatifida is included in this review as this is globally one of the most commonly produced, investigated and available species. Fewer examples of other species abundant worldwide have also been included. This review will supply fundamental information for biorefineries in Atlantic Europe using seaweed as feedstock. Preliminary selection of one or several candidate seaweed species will be possible based on the summary tables and previous research described in this review. This applies either to the choice of high value-added bioactive products to be exploited in an available species or to the choice of seaweed species when a bioactive compound is desired. Data are presented in tables with species, effect and test organism (if present) with examples of uses to enhance comparisons. In addition, scientific experiments performed on seaweed used as animal feed are presented, and EU, US and Japanese legislation on functional foods is reviewed