Concentrated xanthan gum solutions

A process for clarifying and concentrating raw Xanthomonas heteropolysaccharide fermentation broth which comprises (1) heating the fermentation broth at a temperature between about 60.degree.-150.degree. C. for a period of time between about 0.3-3 hours;

• (2) filtering the broth to remove substantially all of the insoluble fermentation solids and provide a clarified solution containing between about 0.1-3 weight percent of xanthan gum;
• and (3) subjecting the clarified xanthan gum solution to ultrafiltration to yield a clarified and concentrated xanthan gum solution which contains between about 8-15 weight percent of xanthan gum, and which exhibits a solution viscosity between about 10,000-20,000 centipoises.

A process for clarifying and concentrating Xanthomonas hydrophilic colloid fermentation broth which comprises (1) adjusting the volume of the fermentation broth to provide a broth which contains between about 0.1-1 weight percent of xanthan gum;

• (2) heating the broth at a temperature between about 70.degree.-110.degree. C. for a period of time between about 0.5-2 hours;
• (3) filtering the broth to remove substantially all of the insoluble fermentation solids and provide a clarified solution of xanthan gum;
• and (4) subjecting the clarified xanthan gum solution to ultrafiltration to yield a clarified and concentrated xanthan gum solution which contains between about 8-15 weight percent of xanthan gum, and which exhibits a solution viscosity between about 10,000-20,000 centipoises.

A xanthan gum solution containing between about 8-15 weight percent of xanthan gum, which solution exhibits a viscosity between about 10,000-20,000 centipoises, and is characterized by the following viscosity/concentration profile:

• ______________________________________ Weight % Viscosity, centipoises ______________________________________ 15 10,000-20,000 12 9000-17,000 10 7000-15,000 8 6000-10,000 6 5000-8000 4 3500- 6000 2 2000-3000 1 1300-1800 0.8 1000-1400 0.6 800-1100 0.4 600-740 0.2 370-430 0.1 280-180 0.05 50-200 ______________________________________

A process for recovering high purity xanthan gum solids from raw Xanthomonas heteropolysaccharide fermentation broth which comprises (1) filtering the broth to remove substantially all of the insoluble fermentation solids and provide a clarified solution containing between about 0.1-3 weight percent of xanthan gum;

• (2) subjecting the clarified xanthan gum solution to ultrafiltration to yield a clarified and concentrated xanthan gum solution which contains between about 8-15 weight percent of xanthan gum, and which exhibits a solution viscosity between about 10,000-20,000 centipoises;
• (3) diluting the clarified and concentrated xanthan gum solution with a water-soluble solvent medium to precipitate xanthan gum solids from the said solution;
• and (4) separating and recovering the precipitated xanthan gum solids.