Polysaccharide complexes, lipopolysaccharides, and O-specific polysaccharides of Xanthomonas campestris pv campestris 8183a

Culture liquid of Xanthomonas campestris pv. campestris 8183a exponentially growing in synthetic Eikman medium was found not to contain the free xanthan-like exopolysaccharide typical for this species; instead, the isolation procedure yielded a polysaccharide-lipid complex (213.2 mg/l) and an exolipopolysaccharide (42.2 mg/l). Extraction of Lipopolysaccharide from the biomass of this bacterium by the Westphal method and its degradation produced two O-specific polysaccharides separable by ion-exchange chromatography. These polysaccharides, similar in their sugar composition, contained 62.2 and 56% rhamnose and 27 and 30% amino sugar. Analysis of the chemical composition of the isolated polysaccharide-lipid complex, exolipopolysaccharide, and lipopolysaccharide showed that lipopolysaccharide from the bacterial outer membrane and exolipopolysaccharide from the culture liquid were not identical: the isolated biopolymers markedly differed in their fatty acid pattern.