Chemoenzymatic synthesis and hydrogelation of amylose-grafted xanthan gums

This paper reports the chemoenzymatic synthesis of an amylose-grafted xanthan gum. An amine-functionalized maltooligosaccharide was chemically introduced to xanthan gum by condensation with its carboxylates using a condensing agent to produce a maltooligosaccharide-grafted xanthan gum. Then, a phosphorylase-catalyzed enzymatic polymerization of glucose 1-phosphate from the graft chain ends on the xanthan gum derivative was performed, giving an amylose-grafted xanthan gum. Furthermore, the product formed a gel with an ionic liquid, which was converted into a hydrogel with high water content by replacement of the ionic liquid with water. The ionically cross-linked hydrogel was also provided by soaking the primary formed hydrogel in FeCl3 aqueous solution. The mechanical properties of the resulting hydrogels were evaluated by compressive testing. (C) 2011 Elsevier B.V. All rights reserved.