ABSTRACT
Alginate (or algin) is a group of naturally occurring polysaccharides, which was first described by the British chemist ECC Stanford in 1881 while searching for useful products from a seaweed called Kelp. Alginate is found in plants as salts of different metals, primarily sodium and calcium, in the intercellular regions and cell walls. Its biological functions in seaweeds are of structural and ion exchange type. The source of alginate extraction mainly relies on various species of brown seaweeds such as Ascophyllum, Laminaria, Lessonia, Macrocystis, Ecklonia, Nereocystis, Undaria, Sargassum, Turbinaria, and Durvillea. The main polysaccharide found in the studied brown seaweeds (Phaeophyceae) was alginate, a linear copolymer of mannuronic (M) and guluronic (G) acids. Different types of alginic acid present different proportions and/or different alternating patterns of guluronic (G) and mannuronic (M) units. The major species of brown algae commercially utilized for alginate extraction and the chemical structure of alginate have been presented.
