Synthesis and properties of a mutant type of xanthan

Abstract

A mutant of Xanthomas campestris produces good yields of an exopolysaccharide. This material differs from the wild‐type xanthan from the parent bacteria, in its very low content of acetate and pyruvate and in its molar ratio of D‐glucose:D‐mannose of 2:1. Analysis of the products from xanthan lyase indicates that most of the side‐chains are disaccharides rather than the normal trisaccharides. The polymer has lower viscosity than normal xanthan. The consistency index was 20 mPa.s compared with 78 mPa.s for the product of the parent strain under standard conditions. The polysaccharide could be further modified by prolonged treatment with β‐glucuronidase, which removed some of the terminal β‐D‐glucuronosyl residues. This enzyme‐modified product had much higher viscosity than that from the mutant.