Production and characterization of new families of polyglucuronic acids from TEMPO–NaOCl oxidation of curdlan

Abstract

Curdlan from Agrobacterium sp. was oxidized using 2,2,6,6,-tetramethylpiperidine-1-oxyl radical (TEMPO)–NaBr–NaClO systems at pH 11. The effects of oxidation conditions on degrees of oxidation and polymerization of the products obtained were studied using SEC–MALLS, NMR and IR analyses. Different families of water-soluble β-(1,3)-polyglucuronic and β-(1,3)-polyglucoglucuronic acid sodium salts were quantitatively generated with a yield of 80% and without significant loss of their molecular weights. Given that β-(1,3)-polyglucuronic acids prepared from the regioselective oxidation of curdlan by the TEMPO–NaBr–NaClO systems regularly consist of the glucuronic acid repeating unit; they may open new biotechnological fields for the utilizations of water soluble forms of curdlan.