Application

14 million tons of wet seaweed are produced each year throughout the world. The main exploitation of this biomass is for the food industry (75%). This trend is different in France where 75% of the annual production, reaching 90 000 tons (including imports), is mainly used for the food processing industry and chemistry (cosmetics). 

Food 

75% of the seaweed world production is directly consumed as food. Asian countries, who have been consuming this resource since centuries, are still today the main consumers and producers. China is the biggest producer of seaweed in the world with more than 5 million tons of wet seaweed per year (Saccharina or Laminaria japonica, Undaria pinnatifida). Japan produces an average of 600 000 tons of seaweed per year, mainly focused on Porphyra species (used for making Sushis).

Seaweed production and exploitation in France is limited (0.5% of the world production) and only 1% of this production is used for direct consummation of fresh or dried seaweed. 13 species are today authorized for general consummation. 

1. Ascophyllum nodosum
2. Chondrus crispus
3. Fucus vesiculosus et serratus
4. Gracilaria verrucosa
5. Himanthalia elongata
6. Lithothamne
7. Laminaria digitata
8. Saccharina latissima et japonica
9. Undaria pinnatifida
10. Palmaria palmata
11. Porphyra sp.
12. Ulva sp.
13. Enteromorpha sp.

French health regulations impose bacterial and heavy metal content controls before commercialisation. Only France and Belgium obey to such regulations in the European Union. 

Colloids 

Seaweeds are used as resource for hydro-colloids. Extraction of these molecules from seaweed has found multiple industrial applications: food-processing, cosmetics, pharmaceutics…Brown algae and particularly Laminaria species are rich in alginate, red algae present high contents of carrageenan (Chondrus crispus) and agar (Gelidium and Gracilaria). Alginate, carrageenan and agar hydrocolloids are known for their gelling, stabilising and thickening properties and are commercialised as additives under E400 and E407 for many cosmetic and food products. 
An average of 1 million tons of wet algae is used per year for extracting these three compounds. In France, 75% of the seaweed production is used for hydrocolloid extraction and commercialisation. Two companies located in Brittany (CARGILL and DUPONT) provide 20% of hydrocolloids on the world market. 

Active ingredients 

The use of seaweed extracts in cosmetic products is a French specialty recognized internationally. Besides the structural and physical role of hydrocolloids, the extract is also known to expose active properties. Oligo-alginates have proved properties such as osmo-protection or protection against pollution, acne and age. Fucoïdans are used for their anti-aging and hair-caring properties.

Fertilization and phyto-stimulants 

Adding seaweed to farming soil increases water retention and enriches the soil by bringing minerals and trace elements during its degradation. Phytostimulants extracted from seaweed improve nutrition, growth and the development of plants. The market of these compounds is progressing due to the expansion of organic farming.

Animal food 

Seaweed can be added to cattle food as it is done in Norway. However, drying and grinding processes of the seaweed are energy consuming and are hence indexed on the price of petrol. This latter makes the use of seaweed in animal food not profitable.