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.