Xanthomonas campestris, polysaccharide

Several anionic carbohydrate polymers (e.g., carboxymethyl cellulose, xanthomonas campestris polysaccharide, cellulose sulfate ester, etc.) do not adsorb from fresh water solutions, but their adsorption in saline solutions plays an... 

Synonyms cas 11138-66-2 corn sugar gum xanthomonas campestris polysaccharide gum Xylenol... 

Figure 7.11 Restriction map of Xanthomonas campestris xanthan gene cluster. Adapted from R W Vanderslice at at. Genetic engineering of polysaccharide structure In Xanthomonas campestris. In Biomedical and Biotechnological Advances In Industrial Polysaccharides, 1989, Gordon and Breach N Y.

Xanthan Gum. Xanthan gum is produced by the bacterium Xanthomonas campestris. Commercial productions started in 1964. Xanthans are water-soluble polysaccharide polymers with the following repeating units [502], as given in Table 17-5 and Figure 17-6. 

Xanthan (Figure 11) is a commercially important polysaccharide produced by the bacterium Xanthomonas campestris.187 188 The xanthan backbone consists of a P(l-4)-linked D-glucopyranose chain with a trisaccharide side chain attached at C3 to alternate glucose residues. These side chains consist of an acetylated mannose residue, a glucuronic acid residue, and a pyruvate ketal linked to a terminal mannose residue. The acetate and pyruvate content depend on the fermentation and isolation conditions used by the supplier. 

Holzwarth, G., Conformation of the extracellular polysaccharide of Xanthomonas campestris, Biochemistry, 15, 4333, 1976). 

Norton, I. T., Goodall, D. M., Morris, E. R., and Rees, D. A. Kinetic evidence for intramolecular conformational ordering of the extracellular polysaccharide (xanthan) from Xanthomonas campestris,. Chem. Soc. Chem. Comm., 545,1980. 

The oil price rises in the 1970s stimulated interest in Enhanced Oil Recovery (EOR), and fairly rapidly the biopolymer xanthan, the extracellular polysaccharide from the bacterium Xanthomonas campestris. an organism which normally resides on cabbage leaves, was identified as a leading contender as a viscosifier for polymer enhanced water flooding. 

It has been discovered that galactomannans interact with a number of bacterial polysaccharides.168 The most studied has been the interaction with the exo-polysaccharide from Xanthomonas campestris. Mixtures of this non-gelling polysaccharide with locust-bean gum form firm, rubbery gels at total-polysaccharide concentrations181 211 greater than 0.5%. The gels are firmest at a Xanthomonas polysaccharide locust-bean gum ratio of 1 3. 

Xanthomonas campestris causes leaf blight in cabbage, and, generally, Xanthomonas species are plant pathogens. In this invasion of the plant, the viscous, extracellular polysaccharides may bind strongly to the cell-wall polysaccharides of the vascular system, and... 

Xanthan is the extracellular (exocellular) polysaccharide produced by Xanthomonas campestris. As with other microbial polysaccharides, the characteristics (polymer structure, molecular weight, solution properties) of xanthan preparations are constant and reproducible when a particular strain of the organism is grown under specified conditions, as is done commercially. The characteristics vary, however, with variations in the strain of the organism, the sources of nitrogen and carbon, degree of medium oxygenation, temperature, pH, and concentrations of various mineral elements. 

Xanthan Gum. As a result of a project to transform agriculturally derived products into industrially useful products by microbial action, the Northern Regional Research Laboratories of the USDA showed that the bacterium Xanthomonas campestris produces a polysaccharide with industrially useful properties (77). Extensive research was carried out on this interesting polysaccharide in several industrial laboratories during the early 1960s, culminating in commercial production in 1964. 

Xanthan is an extracellular polysaccharide produced by Xanthomonas campestris and related species. The structure of xanthan was determined chemically42,43 as a /3-(l - 4)-linked D-glucan to which are attached trisaccharide side-chains on each second D-glucosyl residue, as depicted in 1Z. 

In the biosynthesis of the capsular polysaccharide from Xanthomonas campestris, the modification was shown265 to occur at the level of a polyprenyl pentasaccharide diphosphate intermediate prior to polymerization of the repeating units, and enolpyruvate phosphate was a precursor of the pyruvic acid residues. A similar observation was made during a study of the biosynthesis of Rhizobium meliloti exopolysaccharide.266... 

Xanthan Gum occurs as a cream colored powder. It is a high-molecular-weight polysaccharide gum produced by a pure-culture fermentation of a carbohydrate with Xanthomonas campestris, purified by recovery with isopropyl alcohol, dried, and milled. It contains D-glucose and D-mannose as the dominant hexose units, along with D-glucuronic acid and pyruvic acid, and it is prepared as the sodium, potassium, or calcium salt. It is readily soluble in hot or cold water, but it is insoluble in alcohol. Its solutions are neutral. 

Xanthan gum Thickener exhibits synergy with locust bean gum Polysaccharide Aerobic fermentation of Xanthomonas campestris... 

Xanthan gum is a polysaccharide produced by a pure-culture aerobic fermentation of a carbohydrate with Xanthomonas campestris. The polysaccharide is then purified by recovery with propan-2-ol, dried, and milled. ° ... 

J. J. Zhang and F. Kong, Synthesis of an xylosylated rhamnose pentasaccharide, the repeating unit of the O-chain polysaccharide of the lipopolysaccharide of Xanthomonas campestris pv. begoniae GSPB 525, Carbohydr. Res., 337 (2002) 391-396. 

Sloneker, J. H. and Jeanes, A. R., "Exocellular Bacterial Polysaccharides from Xanthomonas campestris NRRL B-1459. 

Microbial polysaccharides from Xanthomonas campestris, notably xanthan gum for use in food industry, have been studied. Other polysaccharides like dextrans, pullulans, scleroglucan were isolated from several microbial sources. Incorporation of xanthan gum in traditional Indian fermented foods like Idli and Dosa has been investigated in elaborate details. Other products with supplementation of xanthan gum which have been investigated include orange and lemon squash, commercial tomato soup, yogurt preparations with or without CMC. Immunological methods for detection of xanthan gum in... 

---