Gellan is a microbial polysaccharide produced by Pseudomonas elodea and produces gels having similar properties to agar. The molecular structure of gellan gum is a linear chain based on repeating glucose, rhamnose and glucuronic acid units. In its native, or high acyl form, two acyl substituents - acetate and glycerate - are present. Both substituents are located on the same glucose residue, and on average, there is one glycerate per repeat and one acetate per every two repeats. In low acyl gellan gum, the acyl groups are removed completely. Deacylation provides gellan gum in this low acyl form. The acyl groups have a profound influence on gel characteristics. The high acyl form produces soft, elastic, non-brittle gels, whereas the low acyl form produces firm, non-elastic, brittle gels.