Claims
- 1. A process for the recovery and purification of xanthan gum from an aqueous fermentation broth containing dissolved xanthan gum and microbial cellular debris which comprises:
- a) adjusting the pH of the broth to an initial pH of 9 to 12.5;
- b) heating the solution from step a at a temperature of 45.degree. to 70.degree. C. for at least 30 minutes;
- c) immediately after step b), adding an alkaline protease to the solution obtained from step b) in an amount of from 10 to 500 ppm and heating the solution at a temperature of 40.degree. to 65.degree. C. and a pH of 6 to 10 for at least 30 minutes; and then,
- d) adding lysozyme to the solution obtained from step c) in an amount of 0.5 to 100 ppm and heating the solution at a temperature of 25.degree. to 60.degree. C. and a pH of 5.5 to 8.0 for at least 30 minutes;
- e) maintaining the broth obtained from step d) at a temperature of 50.degree. to 80.degree. C. for at least about 30 minutes; and then
- f) adding a hydrophilic organic non-solvent for xanthan gum to the broth obtained from step e) to precipitate the dissolved xanthan gum and recovering the precipitated xanthan gum from the broth.
- 2. A process for the recovery and purification of xanthan gum from an aqueous fermentation broth containing dissolved xanthan gum and microbial cellular debris which comprises:
- a) adjusting, if necessary, the pH of the broth to an initial pH of 9 to 12.5;
- b) heating the solution from step a) at a temperature of 45.degree. to 70.degree. C. for at least 30 minutes;
- c) immediately after step b), adding lysozyme to the solution obtained from step b) in an mount of 0.5 to 100 ppm and heating the solution at a temperature of 25.degree. to 60.degree. C. and a pH of 5.5 to 8.0 for at least 30 minutes; and then,
- d) adding an alkaline protease to the solution obtained from step c) in an amount of 10 to 500 ppm and carrying out an alkaline protease treatment at a temperature of 40.degree. to 65.degree. C. and a pH of 6 to 10 for at least 30 minutes.
- e) maintaining the broth obtained from step a) at a temperature of 50.degree. to 80.degree. C. for at least about 30 minutes; and then
- f) adding a hydrophilic organic non-solvent for xanthan gum to the broth obtained from step e) to precipitate the xanthan gum in the broth and recovering the xanthan gum therefrom.
- 3. The process of claim 1 or 2 wherein the hydrophilic organic non-solvent is isopropanol or an aqueous solution of isopropanol having an isopropanol concentration of not less than 80% by weight.
- 4. The process of claim 1 or 2 wherein in step f), the weight ratio of the broth to hydrophilic organic non-solvent ranges from 1:1.0 to 1:1.5.
- 5. The process of claim 1 or 2 wherein the heating step b) is carried out at a temperature in the range from about 50.degree. C. to 60.degree. C.
- 6. The process of claim 1 or 2 wherein the heating step b) is carried out at a pH in the range from about 9 to 12.5.
- 7. The process of claim 1 or 2 wherein step f) is carried out by forming a mixture of the broth from step e) and the non-solvent to produce a xanthan gum precipitate, feeding the mixture to a cutting device and cutting the precipitate in the mixture to produce a finely-divided xanthan gum, and separating and recovering the suspended finely-divided xanthan gum from the mixture.
- 8. The process of claim 1 or 2 wherein step c) is carried out at a temperature from about 50.degree. to 60.degree. C.
- 9. The process of claim 1 or 2 wherein step d) is carried out at a temperature from about 50.degree. to 60.degree. C.
- 10. The process of claim 2 wherein step d) is carried out at a temperature from about 50.degree. to 60.degree. C.
- 11. The process of claim 1 or 2 wherein step f) is carried out by feeding the broth from step e) and the non-solvent to a cutting device and rotary turbine to form a mixture thereof and form a precipitate of xanthan gum in the mixture, cutting the precipitate in the mixture with a shearing cutter to obtain a finely-divided fibrous xanthan gum and separating and recovering the suspended finely-divided fibrous xanthan gum from the mixture.
- 12. Xanthan gum obtained from the process of claim 1 or 2 having a nitrogen content of less than 0.5% by weight, an ash content of less than 10% by weight, and a light transmittance of greater than 80%, a yellowness index of less than 10, and a Brookfield viscosity of greater than 1,000 centipoise.
- 13. Xanthan gum obtained from the process of claim 7 having a nitrogen content of less than 0.5% by weight, an ash content of less than 10% by weight, and a light transmittance of greater than 80%, a yellowness index of less than 10, and a Brookfield viscosity of greater than 1,000 centipoise.
- 14. Xanthan gum obtained from the process of claim 11 having a nitrogen content of less than 0.5% by weight, an ash content of less than 10% by weight, and a light transmittance of greater than 80%, a yellowness index of less than 10, and a Brookfield viscosity of greater than 1,000 centipoise.
Priority Claims (2)
Number |
Date |
Country |
Kind |
6-148904 |
Jun 1994 |
JPX |
|
6-294172 |
Nov 1994 |
JPX |
|
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of application Ser. No. 08/345,076 filed Nov. 28, 1994, now U.S. Pat. No. 5,595,892 which in turn, is a continuation-in-part of application Ser. No. 07/990,758, filed Dec. 15, 1992, the contents of each of which are incorporated by reference.
Foreign Referenced Citations (2)
Number |
Date |
Country |
0549230 |
Jun 1993 |
EPX |
0545674 |
Sep 1993 |
EPX |
Non-Patent Literature Citations (2)
Entry |
Patent Abstracts of Japan, vol. 18, No. 191 (C-1186), Apr. 4, 1994, and JP A 5-345801 of Dec. 27, 1993. |
Patent Abstracts of Japan, vol. 98 (C-339) �2155! Apr. 15, 1986, and JP A 60-227692 of Dec. 12, 1985. |
Continuation in Parts (2)
|
Number |
Date |
Country |
Parent |
345076 |
Nov 1994 |
|
Parent |
990758 |
Dec 1992 |
|