Xanthomonas campestris

From a commercial point of view, xanthan gum is the most important microbial exopolysaccharide currently being manufactured. Therefore, we shall consider the fermentation of this product by Xanthomonas campestris in some detail. 

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.

Fig. 35.—Circular Dichroism of the Xanthan from Xanthomonas campestris at Various Temperatures. (Redrawn from Ref. 81.)...

Studies focused on the determination of SAR have revealed that the different enantiomeric form of catechins apparently affects their antibacterial activity. Bais et al. [101] found that (-i-)-catechin inhibited soil-borne bacteria of the species Xanthomonas campestris, R fluorescens, and Erwinia caro-... 

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. 

R. P. Lcite, G. U. Miinsavage, U. Bonas, and R. E. Stall, Detection and identification of phytopathogenic Xanthomonas species by amplification of DNA-.sequences related to the HRP genes of Xanthomonas-campestris pv. vesicatoria. Appl. Environ. Microbiol. 60 1077 (1994),... 

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. 

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... 

This gum was the first microbial gum to be used in the food industry. It is produced by the aerobic fermentation of Xanthomonas campestris. A specially selected culture is grown on a carbohydrate-containing nutrient medium with a nitrogen source and other essential elements. The pH, temperature and aeration are controlled carefully. The product is then sterilised and the gum is precipitated with propan-2-ol. Next, the precipitate is washed, then pressed to remove residual alcohol, followed by drying and grinding to the required size. 

Action pattern A was observed with extracellular, endopectate lyase of Bacillus polymyxa,4,240 with extra- and intra-cellular lyase of Erwinia carotovora,241 with extracellular enzyme of Xanthomonas campestris,23S and with lyase produced by Bacteroides ruminicola242 isolated from the rumen fluid of sheep.243... 

Martinez C, Montillet J-L, Bresson E, Agnel J-P, Dai GH, Daniel J-F, Geiger J-P, Nicole M (1998) Apoplastic peroxidase generates superoxide anions in cells of cotton cotyledons undergoing the hypersensitive reaction to Xanthomonas campestris pv. malvacearum race 18. Mol Plant Microbe Interact 11 1038-1047... 

Anhydro-l-deoxy-L- glycero-fl-D-gulo- octulopyranose 2% NPGS 208 Xanthomonas campestris 343... 

Lactose can also be used as a substrate for Xanthomonas campestris in the production of xanthan gum (Figure 2.28) which has several food and industrial applications. 

In both the experimental study and the field surveys, foliar diseases were not important on irrigated tomatoes (mostly by furrow irrigation) in the semi-arid climate of California. Only occasionally, diseases such as bacterial spot Xanthomonas campestris) occurred when it rained early in the season (Clark etal. 1998). Virus symptoms were also seldom observed. There were no differences in foliar disease incidence and severity between organic and conventional farming systems. Root diseases were quite common and sometimes severe in conventional tomato fields, but were absent or only slight in low-input and organic fields. 

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. 

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