Wikipedia Article About Xanthan on Wikipedia Xanthan gum (or xanthum gum) is a natural gum polysaccharide used as a food additive and rheology modifier. It is produced by a biotechnological process involving fermentation of glucose or sucrose by the Xanthomonas campestris bacterium. It was discovered by an extensive research effort by the United States Department of Agriculture, which involved the screening of a large number of biopolymers for their potential uses.