Preparation
The polysaccharide is prepared by inoculating a sterile aqueous solution of carbohydrate(s), a source of nitrogen, dipotassium phosphate, and some trace elements. The medium is well-aerated and stirred, and the polymer is produced extracellularly into the medium. The final concentration of xanthan produced will vary greatly depending on the method of production, strain of bacteria, and random variation. After fermentation that can vary in time from one to four days, the polymer is precipitated from the medium by the addition of isopropyl alcohol, and the precipitate is dried and milled to give a powder that is readily soluble in water or brine.
In the United States, the manufacture of one kilogram of cheese creates nine kg of the byproduct whey, for which the USDA sought to find more uses. Whey is composed mostly of water and lactose, so researchers developed a strain of X. campestris that would grow on lactose rather than glucose. The newly developed lactose-using bacteria produced 30 g/L of xanthan gum for every 40 g/L of whey powder. Whey-derived xanthan gum is commonly used in many commercial products, such as shampoos and salad dressings.
Read more about this topic: Xanthan Gum
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