Xanthan gum fermentations

Zhao, X., H. Zongding, A. W. Nienow, C. A. Kent, and S. Chatwin (1994). Rheological characteristics, power consumption, mass and heat transfer during xanthan gum fermentation. Chin. J. Chem. Eng., 2(4), 198-209. 

Xanthan Gum. Xanthan gum [11138-66-2] is produced by industrial fermentation of a carbohydrate under aerobic conditions by culturing the... 

Xanthan gum [11138-66-2] is an anionic heteropolysaccharide produced by several species of bacteria in the genus Aanthomonas A. campestris NRRL B-1459 produces the biopolymer with the most desirable physical properties and is used for commercial production of xanthan gum (see Gums). This strain was identified in the 1950s as part of a program to develop microbial polysaccharides derived from fermentations utilizing com sugar (333,334). The primary... 

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. 

Polar organic solvents readily precipitate exopolysaccharides from solution. The solvents commonly used are acetone, methanol, ethanol and propan-2-ol. Cation concentration of the fermentation liquor influences the amount of solvent required for efficient product recovery. In the case of propan-2-ol, increasing the cation concentration can lead to a four-fold reduction in die volume of solvent required to precipitate xanthan gum. Salts such as calcium nitrate and potassium chloride are added to fermentation broths for this purpose. 

Scleroglucan is a polysaccharide secreted by the mycelia of certain microorganisms. It is produced by aerobic fermentation of D-glucose by such microorganisms. Scleroglucan has been proposed as a better alternative to xanthan gum for drilling fluid compositions [666]. 

Most of the xanthan gum used in oil field applications is in the form of a fermentation broth containing 8% to 15% polymer. The viscosity is less dependent on the temperature in comparison with other polysaccharides. 

Most polymers used in oil field operations and resource recovery are synthetic. The man-made materials in common use are polyO-amidoethylene) ( = polyacrylamide ), poly( 1-amidoethylene-r-( sodium 1-carboxylatoethylene ) ( = partially hydrolyzed polyacrylamide ), poly(l-amidoethylene-r-( sodium 1-(2-methylprop-1N-yl-1-sulfonate)amidoethylene) (AMPS-acrylamide copolymer), and xanthan gum. Xanthan gum is a synthetic because no one finds a pool or river contaminated with Xanthomonas compestris that experiences the right sequence of solute to naturally produce the exocellular gum polymer. A fermenter is a man made object, a tree is not. 

Production. Xanthan gum is produced by the microorganism X. campestris, originally isolated from the mtabaga plant. The gum is produced commercially by culturing X. campestris purely under aerobic conditions in a medium containing commercial glucose, a suitable nitrogen source, dipotassium phosphate, and appropriate essential elements. When the fermentation is complete, the gum is recovered from the fermentation broth by precipitation with isopropyl alcohol, and dried, milled, tested, and packed. 

In 1974. the Northern Regional Research Center (Peoria. Illinoisi nf the U.S. Department of Agriculture and the Kelco Company were joint recipients of the Institute of Food Technologists award for the development and commercialization of xanthati gum See also Xanthan Gum. This gum differs hy virtue of its production by pure-culture fermentation of a carbohydrate as contrasted with refilling a naturally occurring substance. 

Mechanical agitation and gas-liquid mass transfer are very important in viscous fermentation media. Most recently, Lim and Yoo (1989) and Lee and Wang (1989) have examined mixing effects in the fermentation of Xanthan gum. Aunins-cf al. (1989) evaluated the effects of paddle geometry on power input and mass transfer in small-scale animal cell culture, 500 mL Corning spinner vessels. The results indicate that power dissipation dependency differs from literature correlations and may compromise scale-up at constant power input from these vessels. 

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. ° ... 

Xanthan gum by aerobic glucose fermentation Xathomonas campestris... 

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