Depolymerization of sodium alginate under hydrothermal conditions

The depolymerization of sodium alginate with hydrothermal treatment (180–240 °C) was studied to understand the selectivity of monosaccharide generation. Alginate depolymerized to oligosaccharides, monosaccharides and decomposition products that included lactic acid and glycolic acid. Alginate depolymerization under hydrothermal conditions occurred in a manner that initially released mannuronic acid (M) and then was followed by the release of guluronic acid (G). Monosaccharides were generated through the hydrolysis of the glycosidic bonds between the unit monomer with different selectivities among M–M, M–G and G–G units rather than random sites within alginate. Hydrothermal treatments shows promise as a method to modify the structure of alginate polymers.