SA, medium viscosity, from brown algae, with a molecular weight ranging from 80,000 to 120,000 g/mol and composed of ~61% mannuronic acid
and 39% guluronic acid (M/G ratio of 1.
Alginate, the biopolymer of b-D- mannuronic acid
its C-5 epimer a-L-guluronic acid, has wide range of industrial and pharmaceutical applications (Butt et al.
Two sugars in variable portions, L-guluronic acid and D- mannuronic acid
constitute alginate which is an acidic linear polysaccharide.
These long cellulose fibers are coated with hemicelluloses which are branched polysaccharides mainly consisting of D-xylose and small amounts of L-arabinose, D-glucose, D-mannose, D-galactose, glucuronic acid, mannuronic acid
and lignin (WYMAN et al.
Chemically, alginic acid is a block copolymer of anhydro [beta]-D mannuronic acid
and anhydro [alpha]-D glucouronic acid.
Alginates are, in fact, polymers of two uronic acids--guluronic acid (G) and mannuronic acid
(M)--grouped into homopolymeric segments of guluronic (G blocks) and mannuronic acid
(M blocks), respectively, and a block of alternating residues (MG blocks).
These unidentified peaks were not N-acetyl-mannosamine, arabinose, fucose, fructose, galactosamine, galacturonic acid, [TABULAR DATA FOR TABLE III OMITTED] glucosamine, glucuronic acid, mannosamine, mannuronic acid
, rhamnose, or xylose.
The second stage appears in the range between 231 and 283[degrees]C which could be assigned to degradation of PMA chain  and may be also due to breaking of segments of mannuronic acid
and glucuronic acid of alginate .
1] are characteristic for polysaccharide structure, and they confirm the presence of guluronic and mannuronic acid
Alginate derived from brown sea algae is a random anionic linear polymer consisting of varying ratios of [beta]-L guluronic acid (G) and [alpha]-D mannuronic acid (M) units (4).
The cations ionically interact with -COO- groups of guluronic acid and mannuronic acid residues to form the cross links.