Fermentation nutrient solution for culturing transgenic xanthomonas campestris and method for producing xanthan gum
By optimizing the fermentation nutrient solution formula and CRISPR/Cas technology, the yield of GMOs in genetically modified wild rapeseed was improved, the problem of insufficient xanthan gum production was solved, and performance improvement in oil field applications was achieved.
Patent Information
- Application Number
- CN202411433108.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-15
- Publication Date
- 2024-12-31
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
In the prior art, the value-added rate of transgenic wild rapeseed Xanthan sperm is not high, resulting in the restriction of xanthan gum production and affecting its promotion in oilfield applications.
Provide a fermentation nutrient solution formula, including soluble sugars, citric acid and inorganic culture solution ingredients, optimize culture conditions by adjusting pH and adding specific minerals such as ZnO, CaCO3 and HCl, and using CRISPR/Cas technology to increase strain yield .
It significantly improves the yield and quality of xanthan gum, is suitable for laboratory and industrial production, and enhances its application value in microbial oil repellent technology.
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of xanthan gum preparation, and more specifically, relates to a fermentation nutrient solution for culturing transgenic Xanthomonas campestris and a method for producing xanthan gum. Background Art
[0002] Xanthan gum (XG), also known as xanthan gum and xanthan gum, is an acidic polysaccharide. At present, it is mainly obtained by aerobic deep fermentation of Xanthomonas campestris with corn starch, sucrose and other carbohydrates as the main raw materials. The basic structure of xanthan gum is a repeating unit composed of three monosaccharides, namely glucose, mannose and glucurone, with a ratio of 2:2:1. Due to its unique structure, it has good thickening, suspension and emulsification stability, becoming a multifunctional microbial polysaccharide with huge commercial benefits and potential value, and plays an important role in the preparation of oil displacement agents in microbial oil recovery technology.
[0003] However, due to the inherent limitations of microbial oil recovery technology, coupled with the poor geological conditions and great development difficulties of most oil fields, there are still some problems to be solved in the application of microbial oil recovery technology in oil fields. For example, the production process of xanthan gum mainly uses microbial fermentation, including seed culture, strain fermentation, and fermentation liquid post-treatment. However, due to the low growth rate of transgenic wild campestris, the yield of existing strains is limited, which affects its application and promotion.
[0004] In view of this, there is an urgent need to provide a fermentation nutrient solution formula for culturing transgenic wild campestris and an optimization method for producing xanthan gum, so as to increase the yield of xanthan gum while maintaining good performance. Summary of the invention
[0005] In order to at least solve one or more of the technical problems mentioned above, the present application proposes solutions for improving the prior art in multiple aspects.
[0006] In a first aspect, the present application relates to a fermentation nutrient solution, which comprises: soluble sugars, citric acid and inorganic culture solution components; the soluble sugars include sucrose, and the inorganic culture solution components include NH4NO3, KH2PO4, MgCl2, Na2SO4, H3BO3 and FeCl3.
[0007] According to one embodiment of the present application, the content of sucrose is 30-50 g / L, the content of citric acid is 1.5-3 g / L, the content of NH4NO3 is 1-2 g / L, the content of KH2PO4 is 2-3 g / L, the content of MgCl2 is 0.3-1 g / L, the content of Na2SO4 is 50-150 mg / L, the content of H3BO3 is 2-10 mg / L, and the content of FeCl3 is 10-30 mg / L.
[0008] According to one embodiment of the present application, 4-8 mg / L ZnO, 10-30 mg / L CaCO3 and 0.1-0.16 ml / L concentrated HCl are also added to the fermentation nutrient solution, and the pH value of the fermentation nutrient solution is adjusted to 7.0 by adding sodium hydroxide.
[0009] In a second aspect, the present application relates to a fermentation nutrient solution, which includes: soluble sugars and inorganic culture solution components; the soluble sugars include glucose, and the inorganic culture solution components include (NH4)3PO4, MgSO4 and KH2PO4.
[0010] According to one embodiment of the present application, the content of glucose is 15-30 g / L, the content of (NH4)3PO4 is 1.0-3 g / L, the content of MgSO4 is 0.05-0.15 g / L, and the content of KH2PO4 is 2-3 g / L.
[0011] According to one embodiment of the present application, 1-5 g / L of CaCO3 is further added to the fermentation nutrient solution, and the pH value of the fermentation nutrient solution is adjusted to 7.0 by adding sodium hydroxide.
[0012] In a third aspect, the present application relates to a method for producing xanthan gum, comprising the following steps:
[0013] 1) Fermentation culture step: the transgenic wild Xanthomonas campestris is cultured in a fermentation nutrient solution, and is successively cultured on a plate, purified at level II, and inoculated at levels III and IV;
[0014] 2) Pretreatment step: pasteurize the fermentation nutrient solution containing the strain obtained in step 1), then add lysozyme and neutral protease in sequence, stir and perform enzymolysis, and then filter;
[0015] 3) Xanthan gum separation step: add NaOH to the fermentation nutrient solution containing the strain obtained in step 2) to adjust the pH value to alkaline, add CaCl2 and stir thoroughly to form a xanthan gum-calcium salt mixture; dehydrate and dry to form lumps, wash with alcohol and add HCl; then dehydrate and dry again and grind into powder; filter and collect the suspension after washing with alcohol, and centrifuge to obtain xanthan gum.
[0016] According to one embodiment of the present application, the fermentation nutrient solution in step 1) is the fermentation nutrient solution of the first aspect or the fermentation nutrient solution of the second aspect.
[0017] According to one embodiment of the present application, step 2) satisfies any one of the following conditions:
[0018] The weight percentage of lysozyme added in step 2) is 0.01% to 0.05% of the total amount;
[0019] The weight percentage of the neutral protease added in step 2) is 0.1% to 0.5% of the total amount.
[0020] According to one embodiment of the present application, the content of CaCl2 added in step 3) is 10-20 g / L. DETAILED DESCRIPTION
[0021] The following will be combined with the specific implementation methods in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.
[0022] It should be understood that the terms "include" and "comprising" used in the description and claims of the present invention indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.
[0023] It should also be understood that the terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the claims, the singular forms of "a", "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It should also be further understood that the term "and / or" used in the specification of the present invention and the claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.
[0024] As used in this specification and claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.
[0025] In the present invention, the materials or reagents used, unless otherwise specified, can be obtained from conventional commercial channels.
[0026] The present invention uses CRISPR / Cas technology to obtain high-yield Agrobacterium by implanting a recombinant plasmid from a DNA fragment of xanthan gum produced by a Xanthomonas campestris strain into Agrobacterium, and the recombinant Agrobacterium strain is named Agrobacterium-XG (that is, the "transgenic Xanthomonas campestris" referred to above). Xanthomonas campestris / Xanthomonas campestris Source: Wuhan Huizao Biotechnology Co., Ltd., Product No.: HZB140304.
[0027] As an embodiment of the present application, the present application provides a fermentation nutrient solution I for culturing transgenic campestris, which includes: soluble sugars, citric acid and inorganic culture solution components; the soluble sugars include sucrose, and the inorganic culture solution components include NH4NO3, KH2PO4, MgCl2, Na2SO4, H3BO3 and FeCl3.
[0028] Preferably, the content of sucrose is 30-50 g / L, the content of citric acid is 1.5-3 g / L, the content of NH4NO3 is 1-2 g / L, the content of KH2PO4 is 2-3 g / L, the content of MgCl2 is 0.3-1 g / L, the content of Na2SO4 is 50-150 mg / L, the content of H3BO3 is 2-10 mg / L, and the content of FeCl3 is 10-30 mg / L.
[0029] More preferably, the content of sucrose is 40 g / L, the content of citric acid is 2.1 g / L, the content of NH4NO3 is 1.144 g / L, the content of KH2PO4 is 2.866 g / L, the content of MgCl2 is 0.507 g / L, the content of Na2SO4 is 89 mg / L, the content of H3BO3 is 6 mg / L, and the content of FeCl3 is 20 mg / L.
[0030] Preferably, 4-8 mg / L ZnO, 10-30 mg / L CaCO3 and 0.1-0.16 ml / L concentrated HCl are also added to the fermentation nutrient solution, and the pH value of the fermentation nutrient solution is adjusted to 7.0 by adding sodium hydroxide.
[0031] More preferably, 6 mg / L of ZnO, 20 mg / L of CaCO3 and 0.13 ml / L of concentrated HCl are further added to the fermentation nutrient solution, and the pH value of the fermentation nutrient solution is adjusted to 7.0 by adding sodium hydroxide.
[0032] The fermentation nutrient solution I is an ideal laboratory formula for the fermentation nutrient solution for culturing transgenic Xanthomonas campestris.
[0033] As an embodiment of the present application, the present application also provides a fermentation nutrient solution II for culturing transgenic campestris, which includes: soluble sugars and inorganic culture solution components; the soluble sugars include glucose, and the inorganic culture solution components include (NH4)3PO4, MgSO4 and KH2PO4.
[0034] Preferably, the content of glucose is 15-30 g / L, the content of (NH4)3PO4 is 1.0-3 g / L, the content of MgSO4 is 0.05-0.15 g / L, and the content of KH2PO4 is 2-3 g / L.
[0035] More preferably, the content of glucose is 25 g / L, the content of (NH4)3PO4 is 1.5 g / L, the content of MgSO4 is 0.1 g / L, and the content of KH2PO4 is 2.5 g / L.
[0036] Preferably, 1-5 g / L of CaCO3 is also added to the fermentation nutrient solution, and the pH value of the fermentation nutrient solution is adjusted to 7.0 by adding sodium hydroxide.
[0037] More preferably, 3 g / L of CaCO3 is further added to the fermentation nutrient solution, and the pH value of the fermentation nutrient solution is adjusted to 7.0 by adding sodium hydroxide.
[0038] The fermentation nutrient solution II is an industrial-grade formula of the fermentation nutrient solution for culturing transgenic Xanthomonas campestris.
[0039] As an embodiment of the present application, the present application relates to a method for producing xanthan gum, which comprises the following steps:
[0040] 1) Fermentation culture step: The transgenic wild Xanthomonas campestris is cultured in a fermentation nutrient solution, and is successively cultured on a plate, purified at level II, and inoculated at levels III and IV.
[0041] Preferably, the III and IV level inoculation cultures are inoculated at a ratio of 5-10% and cultured at 32° C. and 200 rpm / min for 48-72 hours.
[0042] 2) Pretreatment step: pasteurize the fermentation nutrient solution containing the strain obtained in step 1), then add lysozyme and neutral protease in sequence, stir and perform enzymolysis, and then filter.
[0043] Preferably, the pasteurization is carried out at 78° C. and pH>10 for 40 minutes.
[0044] Preferably, 0.01% to 0.05% lysozyme is first added to the fermentation broth, and the broth is fully stirred and decomposed for 2 hours at 53° C. and a pH value of 5.5.
[0045] Preferably, 0.1% to 0.5% of neutral protease is added at 40° C. and pH 7.2, and the mixture is stirred and enzymolyzed for 4 hours.
[0046] Preferably, double-layer nylon gauze is used for filtering.
[0047] 3) Xanthan gum separation step: add NaOH to the fermentation nutrient solution containing the strain obtained in step 2) to adjust the pH value to alkaline, add CaCl2 and stir thoroughly to form a xanthan gum-calcium salt mixture; dehydrate and dry to form lumps, wash with alcohol and add HCl; then dehydrate and dry again and grind into powder; filter and collect the suspension after washing with alcohol, and centrifuge to obtain xanthan gum.
[0048] Preferably, step 3) comprises at least one of the following specific steps:
[0049] a. The fermentation nutrient solution containing the strain obtained in step 2) was adjusted to pH 11.5 by adding NaOH;
[0050] b. Add 2% or 15g / L CaCl2 and stir thoroughly for 1 hour to form a xanthan gum-calcium salt mixture;
[0051] c. Centrifugal dehydration and drying to form blocks;
[0052] d. Add 500g / L (the actual amount is 2-3 times the fermentation nutrient solution) of industrial ethanol, adjust the pH value to 1.5-2.0 with HCl, and stir thoroughly for 30 minutes;
[0053] e. Dehydrating, drying and grinding the lumps into powder;
[0054] f. Add 300g / L of industrial ethanol, adjust the pH to 7.0 with NaOH, and stir thoroughly for 30 minutes;
[0055] g. Filter and collect the yellow suspension to remove the precipitate;
[0056] h. Centrifuge to obtain xanthan gum precipitate; then dry and crush to obtain the finished product.
[0057] The fermentation nutrient solution formula provided in this application mainly includes fermentation nutrient solution I as a laboratory formula and fermentation nutrient solution II as an industrial-grade formula. Among them, the fermentation nutrient solution I as a laboratory formula has more ingredients, but it has a huge improvement in the proliferation and production of transgenic wild campestris. Among them, the fermentation nutrient solution II as an industrial-grade formula has simpler ingredients, and the proliferation and yield are slightly lower than those of the fermentation nutrient solution I, but it is suitable for mass production of biopolymers and has more practical value in cost control and process operation. Specific embodiments
[0059] Example 1
[0060] The strain Agrobacterium-XG was cultured in TY liquid culture medium using the fermentation nutrient solution I formula recorded in the instruction manual. When the cultured bacteria reached OD600=0.6, the proliferation time was 2.4 days. When the yield was stable, the xanthan gum concentration in the bacterial solution and the 0.5% H2O zero shear viscosity were measured.
[0061] TY liquid culture medium (COOLABER SCIENCE&TECHNOLOGY Co., LTD, catalog number PM0762).
[0062] Example 2
[0063] The strain Agrobacterium-XG was cultured in TY liquid culture medium using the fermentation nutrient solution I formula recorded in the instruction manual. When the cultured bacteria reached OD600=0.6, the proliferation time was 2.8 days. When the yield was stable, the xanthan gum concentration in the bacterial solution and the 0.5% H2O zero shear viscosity were measured.
[0064] Example 3
[0065] The strain Agrobacterium-XG was cultured in TY liquid culture medium using the fermentation nutrient solution I formula recorded in the instruction manual. When the cultured bacteria reached OD600=0.6, the proliferation time was 3.7 days. When the yield was stable, the xanthan gum concentration in the bacterial solution and the 0.5% H2O zero shear viscosity were measured.
[0066] Example 4
[0067] The strain Agrobacterium-XG was cultured in TY liquid culture medium using the fermentation nutrient solution I formula recorded in the instruction manual. When the cultured bacteria reached OD600=0.6, the proliferation time was 4.6 days. When the yield was stable, the xanthan gum concentration in the bacterial solution and the 0.5% H2O zero shear viscosity were measured.
[0068] Example 5
[0069] The strain Agrobacterium-XG was cultured in TY liquid culture medium using the fermentation nutrient solution I formula recorded in the instruction manual. When the cultured bacteria reached OD600=0.6, the proliferation time was 5.3 days. When the yield was stable, the xanthan gum concentration in the bacterial solution and the 0.5% H2O zero shear viscosity were measured.
[0070] Example 6
[0071] The strain Agrobacterium-XG was cultured in TY liquid culture medium using the fermentation nutrient solution I formula recorded in the instruction manual. When the cultured bacteria reached OD600=0.6, the proliferation time was 7.2 days. When the yield was stable, the xanthan gum concentration in the bacterial solution and the 0.5% H2O zero shear viscosity were measured.
[0072] Example 7
[0073] The strain Agrobacterium-XG was cultured in TY liquid culture medium using the fermentation nutrient solution II formula recorded in the instruction manual. When the cultured bacteria reached OD600=0.6, the proliferation time was 4.8 days. When the yield was stable, the xanthan gum concentration in the bacterial solution and the 0.5% H2O zero shear viscosity were measured.
[0074] Example 8
[0075] The strain Agrobacterium-XG was cultured in TY liquid culture medium using the fermentation nutrient solution II formula recorded in the instruction manual. When the cultured bacteria reached OD600=0.6, the proliferation time was 5.2 days. When the yield was stable, the xanthan gum concentration in the bacterial solution and the 0.5% H2O zero shear viscosity were measured.
[0076] Example 9
[0077] The strain Agrobacterium-XG was cultured in TY liquid culture medium using the fermentation nutrient solution II formula recorded in the instruction manual. When the cultured bacteria reached OD600=0.6, the proliferation time was 5.9 days. When the yield was stable, the xanthan gum concentration in the bacterial solution and the 0.5% H2O zero shear viscosity were measured.
[0078] Example 10
[0079] The strain Agrobacterium-XG was cultured in TY liquid culture medium using the fermentation nutrient solution II formula recorded in the instruction manual. When the cultured bacteria reached OD600=0.6, the proliferation time was 6.7 days. When the yield was stable, the xanthan gum concentration in the bacterial solution and the 0.5% H2O zero shear viscosity were measured.
[0080] Embodiment 11
[0081] The strain Agrobacterium-XG was cultured in TY liquid culture medium using the fermentation nutrient solution II formula recorded in the instruction manual. When the cultured bacteria reached OD600=0.6, the proliferation time was 7.5 days. When the yield was stable, the xanthan gum concentration in the bacterial solution and the 0.5% H2O zero shear viscosity were measured.
[0082] Example 12
[0083] The strain Agrobacterium-XG was cultured in TY liquid culture medium using the fermentation nutrient solution II formula recorded in the instruction manual. When the cultured bacteria reached OD600=0.6, the proliferation time was 9.6 days. When the yield was stable, the xanthan gum concentration in the bacterial solution and the 0.5% H2O zero shear viscosity were measured.
[0084] The fermentation broths of Examples 1 to 12 were sampled and the concentration of xanthan gum and the shear viscosity of the produced xanthan gum were determined.
[0085] Table 1 shows the concentration of xanthan gum in Examples 1-6 and the shear viscosity measurement results of the produced xanthan gum.
[0086] Table 1
[0087] Proliferation time Xanthan gum concentration <![CDATA[Zero-shear viscosity of 0.5% H2O]]> Example 1 2.4d 28.9g / L 121.6Pa·s Example 2 2.8d 26.3g / L 114.2Pa·s Example 3 3.7d 22.6g / L 97.5Pa·s Example 4 4.6d 18.9g / L 81.2Pa·s Example 5 5.3d 15.6g / L 74.3Pa·s Example 6 7.2d 12.1g / L 65.4Pa·s
[0088] As can be seen from Table 1, the xanthan gum concentration of the embodiment 1-6 cultivated by the laboratory formula of the fermentation nutrient solution I was measured, and the xanthan gum concentration was 28.9g / L when the proliferation time was 2.4 days. When the proliferation time was 2.8 days, the xanthan gum concentration was 26.3g / L. When the proliferation time was 3.7 days, the xanthan gum concentration was 22.6g / L. When the proliferation time was 4.6 days, the xanthan gum concentration was 18.9g / L. When the proliferation time was 5.3 days, the xanthan gum concentration was 15.6g / L. When the proliferation time was 7.2 days, the xanthan gum concentration was 12.1g / L.
[0089] Table 2 shows the concentration of xanthan gum in Examples 7-12 and the shear viscosity measurement results of the produced xanthan gum.
[0090] Table 2
[0091] Proliferation time Xanthan gum concentration <![CDATA[Zero-shear viscosity of 0.5% H2O]]> Example 7 4.8d 24.6g / L 104.2Pa·s Example 8 5.2d 19.2g / L 84.6Pa·s Example 9 5.9d 16.8g / L 78.1Pa·s Example 10 6.7d 13.6g / L 67.2Pa·s Embodiment 11 7.5d 10.5g / L 55.4Pa·s Example 12 9.6d 8.6g / L 50.1Pa·s
[0092] As can be seen from Table 2, the xanthan gum concentration of Examples 7-12 cultivated by the industrial-grade formula of fermentation nutrient solution II was measured. When the proliferation time was 4.8 days, the xanthan gum concentration was 24.6g / L. When the proliferation time was 5.2 days, the xanthan gum concentration was 19.2g / L. When the proliferation time was 5.9 days, the xanthan gum concentration was 16.8g / L. When the proliferation time was 6.7 days, the xanthan gum concentration was 13.6g / L. When the proliferation time was 7.5 days, the xanthan gum concentration was 10.5g / L. When the proliferation time was 9.6 days, the xanthan gum concentration was 8.6g / L.
[0093] As described above, according to the experimental data of Examples 1-6 cultured with fermentation nutrient solution I which is a laboratory formula, it can be seen that fermentation nutrient solution I greatly increased the yield of xanthan gum; and according to the experimental data of Examples 7-12 cultured with fermentation nutrient solution II which is an industrial-grade formula, it can be seen that although their proliferation and yield are slightly lower than those using fermentation nutrient solution I, they are still maintained at a relatively high level.
[0094] Although multiple embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Those skilled in the art may conceive of many changes, modifications, and alternatives without departing from the thought and spirit of the present invention. It should be understood that in the process of practicing the present invention, various alternatives to the embodiments of the present invention described herein may be adopted. The appended claims are intended to define the scope of protection of the present invention, and therefore cover equivalents or alternatives within the scope of these claims.
Claims
1. A fermentation nutrient solution, comprising: Soluble sugars, citric acid and inorganic culture fluid components; The soluble sugar Including sucrose, the inorganic culture solution components include NH4NO3, KH2PO4, MgCl2, Na2SO4, H3BO3 and FeCl3.
2. The fermentation nutrient solution according to claim 1, characterized in that: The content of sucrose is 30-50g / L, the content of citric acid is 1.5-3g / L, the content of NH4NO3 is 1-2g / L, the content of KH2PO4 is 2-3g / L, the content of MgCl2 is 0.3-1g / L, the content of Na2SO4 is 50-150mg / L, the content of H3BO3 is 2-10mg / L, and the content of FeCl3 is 10-30mg / L.
3. The fermentation nutrient solution according to claim 1 or 2, characterized in that: 4-8 mg / L ZnO, 10-30 mg / L CaCO3 and 0.1-0.16 ml / L concentrated HCl are also added to the fermentation nutrient solution, and the pH value of the fermentation nutrient solution is adjusted to 7.0 by adding sodium hydroxide.
4. A fermentation nutrient solution comprising: Soluble sugars and inorganic culture solution components; the soluble sugars include glucose, and the inorganic culture solution components include (NH4)3PO4, MgSO4 and KH2PO4.
5. The fermentation nutrient solution according to claim 4, characterized in that: The content of glucose is 15-30 g / L, the content of (NH4)3PO4 is 1.0-3 g / L, the content of MgSO4 is 0.05-0.15 g / L, and the content of KH2PO4 is 2-3 g / L.
6. The fermentation nutrient solution according to claim 4 or 5, characterized in that: 1-5 g / L of CaCO3 is also added to the fermentation nutrient solution, and the pH value of the fermentation nutrient solution is adjusted to 7.0 by adding sodium hydroxide.
7. A method for producing xanthan gum, comprising the following steps: 1) Fermentation culture step: the transgenic wild Xanthomonas campestris is cultured in a fermentation nutrient solution, and is successively cultured on a plate, purified at level II, and inoculated at levels III and IV; 2) Pretreatment step: pasteurize the fermentation nutrient solution containing the strain obtained in step 1), then add lysozyme and neutral protease in sequence, stir and perform enzymolysis, and then filter; 3) Xanthan gum separation step: add NaOH to the fermentation nutrient solution obtained in step 2) to adjust the pH value to alkaline, add CaCl2 and stir thoroughly to form a xanthan gum-calcium salt mixture; dehydrate and dry to form lumps, wash with alcohol and add HCl; then dehydrate and dry again and grind into powder; filter and collect the suspension after washing with alcohol, and centrifuge to obtain xanthan gum.
8. The production method according to claim 7, characterized in that: The fermentation nutrient solution in step 1) is the fermentation nutrient solution of any one of claims 1 to 3 or the fermentation nutrient solution of any one of claims 4 to 6.
9. The production method according to claim 7 or 8, characterized in that: Step 2) Meet any of the following conditions: The weight percentage of lysozyme added in step 2) is 0.01% to 0.05% of the total amount; The weight percentage of the neutral protease added in step 2) is 0.1% to 0.5% of the total amount.
10. The production method according to claim 7 or 8, characterized in that: The content of CaCl2 added in step 3) is 10-20g / L.