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.

Bioactive compounds in seaweed: functional food applications and legislation

Flora of Turkey and the East Aegean Islands.

/pdf/processes-of-carbonate-precipitation-in-modern-microbial-176vfhaypi.pdf

Processes of carbonate precipitation in modern microbial mats

Marine structures such as platforms, jetties and ship hulls are subject to diverse and severe biofouling. Methods for inhibiting both organic and inorganic growth on wetted substrates are varied but most antifouling systems take the form of protective coatings. Biofouling can negatively affect the hydrodynamics of a hull by increasing the required propulsive power and the fuel consumption. This paper reviews the development of antifouling coatings for the prevention of marine biological fouling. As a result of the 2001 International Maritime Organization (IMO) ban on tributyltin (TBT), replacement antifouling coatings have to be environmentally acceptable as well as maintain a long life. Tin-free self-polishing copolymer (SPC) and foul release technologies are current applications but many alternatives have been suggested. Modern approaches to environmentally effective antifouling systems and their performance are highlighted.

/pdf/modern-approaches-to-marine-antifouling-coatings-3xqzjm2275.pdf

Modern approaches to marine antifouling coatings

Sulfated polysaccharides and their lower molecular weight oligosaccharide derivatives from marine macroalgae have been shown to possess a variety of biological activities. The present paper will review the recent progress in research on the structural chemistry and the bioactivities of these marine algal biomaterials. In particular, it will provide an update on the structural chemistry of the major sulfated polysaccharides synthesized by seaweeds including the galactans (e.g., agarans and carrageenans), ulvans, and fucans. It will then review the recent findings on the anticoagulant/antithrombotic, antiviral, immuno-inflammatory, antilipidemic and antioxidant activities of sulfated polysaccharides and their potential for therapeutic application.

Chemical Structures and Bioactivities of Sulfated Polysaccharides from Marine Algae

https://www.univ-brest.fr/digitalAssets/6/6122_Antioxidant_and_antitumoural_activities_of_some_Phaeophyta_from_Brittany_coasts.pdf

Antioxidant and antitumoural activities of some Phaeophyta from Brittany coasts

We report here on a survey of phenolic contents in all seaweeds forming belts on a sheltered rocky shore in Brittany (France). Eight species of brown algae (7 Fucales and 1 Laminariales) were investigated over a 14-month period. Levels of phenolic compounds in members of the Fucales were generally above 2% DW and exceeded those found in the Laminariales by a factor of ten. The highest contents were found in species growing at midtide level, with a decrease above and below this shore level. There was a seasonal pattern, with a summer maximum for the Fucales and winter maximum for a member of the Laminariales.

Interspecific and temporal variation in phlorotannin levels in an assemblage of brown algae

This study deals with two range-extending brown algae from Tahitian coral reefs, Sargassum mangarevense and Turbinaria ornata; their alginate properties, mannitol and phenolic contents, antioxidant and antimicrobial activities were determined. Turbinaria ornata showed the richest alginate content with the highest extraction yield (19.2 ± 1.3% dw). Their alginates also exhibited the highest viscosity (50 ± 18 mPa.s), but the M:G ratios (mannuronic acid to glucuronic acid) of alginates (1.25–1.42) were similar in both species. Alginate yield displayed spatial variations, but no significant seasonal changes. The highest mannitol content was found in S. mangarevense (12.2 ± 2.1% dw) during the austral winter. With respect to other tropical Fucales, both algae exhibited also a high phenolic content (2.45–2.85% dw) with significant spatio-temporal variations. Furthermore, high antioxidant activity and activity against Staphylococcus aureus were also detected in extracts. According to these preliminary results, these two range-extending algae are of key interest in numerous industrial areas.

Alginate, mannitol, phenolic compounds and biological activities of two range-extending brown algae, Sargassum mangarevense and Turbinaria ornata (Phaeophyta: Fucales), from Tahiti (French Polynesia)

This study focuses on the intra-thallus variation in phlorotannin content and antioxidant activity in temperate brown seaweeds. Two species of Fucales (Ascophyllum nodosum and Sargassum muticum) and two species of Laminariales (Laminaria digitata and L. hyperborea) were collected from the shoreline of Brittany (France). Both Fucales contained high phenolic levels along their thallus (ca. 5% DW in A. nodosum and 6% DW in S. muticum). No significant differences were found between vegetative and reproductive parts of A. nodosum. In contrast, intrathallus and inter-specific variations were observed in phenolic contents of the two species of Laminariales studied. In L. digitata, phenolic content was about 0.2% DW, with a maximum in the holdfast, whereas in L. hyperborea, it averaged about 2.6% DW, with the highest value measured in the basal part of the old blade. In both species, phlorotannin contents were lower in the meristematic region. Intra-thallus variations of the antioxidant activity measured by the DPPH (2,2-diphenyl-1-picrylhydrazyl) method were also detected. Antioxidant activity was correlated to the phenol contents of the different parts of thalli in three species. In L. digitata, no activity was found because of low phenol levels. The observed variations in both the antioxidant activity and the phenol content could result from qualitative features of the phenolic pool.

Intra-thallus phlorotannin content and antioxidant activity in Phaeophyceae of temperate waters

Spatial and seasonal variation in density, reproductive status, length and phenolic content of the invasive brown macroalga Sargassum muticum (Yendo) Fensholt along the coast of Western Brittany (France)

Eric Deslandes

Papers

Antioxidant and antitumoural activities of some Phaeophyta from Brittany coasts

Interspecific and temporal variation in phlorotannin levels in an assemblage of brown algae

Alginate, mannitol, phenolic compounds and biological activities of two range-extending brown algae, Sargassum mangarevense and Turbinaria ornata (Phaeophyta: Fucales), from Tahiti (French Polynesia)

Intra-thallus phlorotannin content and antioxidant activity in Phaeophyceae of temperate waters

Spatial and seasonal variation in density, reproductive status, length and phenolic content of the invasive brown macroalga Sargassum muticum (Yendo) Fensholt along the coast of Western Brittany (France)