JPS6062996A - Preparation of xanthan gum - Google Patents

Abstract

PURPOSE:To obtain xanthan gum having high solution viscosity, improved salt resistance, heat resistance, and acid resistance, by desalting a culture solution containing xanthan gum until it has a specific concentration of inorganic salt, drying it directly. CONSTITUTION:A bacterium belonging to the genus Xanthomonas is cultivated ina nutritive medium consisting of carbon, nitrogen, and an inorganic salt to give a culture solution containing xanthan gum. The prepared culture solution is desalted until the concentration of inorganic salt becomes <=5wt%, preferably <=2wt% based on xanthan gum. The desalted culture solution is directly dried. Desalting bu ultrafilter is the fittest as desalting process used. Namely, since xanthan gum has high molecular weight of about 2,000,000, the inorganic salt is a low-molecular-weight substance, so the desired desalting can be easily attained by the ultrafilter having 10,000-500,000 fraction molecular weight.

Description

[Detailed description of the invention] The present invention has high solution viscosity and salt resistance.

Heat resistance and acid resistance are 1? It is characterized by having the gelatin properties of regular xanthan gum and being extremely inexpensive to produce. This invention relates to a method for producing xanthan gum.

In recent years, xanthan gum has been increasingly used as a prize or commercial material due to its production stability due to tank culture and unique solution properties. However, since xanthan gum is more expensive than other natural gums, its uses are currently quite limited, although it has excellent crystallization properties. In other words, the method for purifying xanthan gum requires t
L5, heat sterilized and centrifuged the bacterial cells by Flft or (l
A typical method is to remove the gum by filtration, add alcohol such as isopropanol to make the gum* settle, separate and collect it, and dry it to make a product. Here, what increases the cost of producing xanthan gum pods is the cost of the alcohol used to precipitate the xanthan gum and the cost of the steam necessary for its distillation recovery. , Methods to reduce conventional alcohol costs and alcohol recovery costs and 17 are shown below.

■Method has been studied and devised.

■Method using Jfil as a precipitant other than alcohol. (e.g. S, P+Rogovin et al., J3ioeng, H
ioLechnoJ, 5. 91 +19 (38) ■ Direct spray drying or drum drying of the culture solution. (e.g. S, 13. Ogovin et al., f3io
enr<.

Uiolechnol, L 161+ 1965)
■A method of concentrating the culture solution and reducing the alcohol content.

However, each of the above methods has many problems when implemented, and cannot be called a solution.

For example, after adding a quaternary ammonium salt to form a complex with xanthan gum and separating the gum from the culture n.

There is a method in which purified xanthan gum is obtained by washing this precipitated gum with alcohol to dissolve and remove the quaternary ammonium salt. However, with this method.

Distillation recovery of the quaternary ammonium salt and alcohol is required, and sufficient cost reduction is not expected. The xanthan gum obtained by this method is:

Because the 44th class ammonium salt remains, 1.
He also sees flaws that Fukou can't do. Method (2) is an extremely easy method and has the advantage of producing a low-cost product, but the physical properties of the solution, such as one color and odor, are extremely inferior to xanthan gum obtained by iM's usual alcohol purification method. be. ■As a way to reduce alcohol use.

This method is easy to think of, but since the culture solution is highly viscous, concentration at a high 1β degree is time-consuming, and it also takes a long time if the alcohol used for washing the precipitated gum is also used. The present inventors obtained high-quality xanthan gum by direct drying of the culture solution, which is considered to be the most industrially and advantageous manufacturing method.4↓ With the aim of
It was found that this had a great effect on the physical properties [7. When directly drying the culture solution.

They discovered that high-quality xanthan gum could be obtained by removing inorganic salts in advance, and completed the invention. In the culture solution containing xanthan gum,
The salts added at the beginning are d (N11! salts formed by acids and alkalis added for adjustment, so it becomes gummy, -r.

Approximately 7 to 25% of inorganic salts are present.

The product obtained by directly drying it as it is is 1 (7 products) Not only does the xanthan gum purity become low, but the viscosity per xanthan gum concentration is also extremely low, and the degree of coloration and odor are also strong. In the present invention, the same culture solution is desalted in advance until the content of inorganic salts in the gum is less than 5%, preferably less than 2%, and then directly dried. As a result, all the products 'e' are improved, and it is possible to obtain a product which exhibits almost the same quality as the xanthan gum obtained by the rice alcohol purification method.

Furthermore, one of the features of the present invention is that the product is not easy to understand. The second advantage is that with the alcohol purification method,
All equipment is required to be explosion-proof and also requires fire extinguishing equipment, etc. However, the manufacturing method of the present invention does not use alcohol at all, and the process is extremely simple, resulting in a significant reduction in initial equipment costs. This can be reduced to

The third advantage is 1. When used for food applications, in conventional alcohol purification methods, residual alcohol, especially residual isopropyl alcohol, in the 4q product becomes a problem.9. It is said that reducing the amount of residual solvent is technically quite difficult, but according to the production method of the present invention, no alcohol is used, so such problems with residual solvent do not occur at all. The fourth advantage is that the environment is improved because there is no T+ +, which is a great advantage in terms of industrialization.

The present invention will be briefly explained below.

The xanthan gum culture solution used in the present invention can be obtained by culturing Xanthomonas #11V4 in a normal nutrient medium, even if the culture method is batch culture.

It is also applicable to continuous culture.

Next, as for the desalting method used in the present invention, -C, after thorough investigation, it was found that the desalting method using an ultrafiltration membrane is suitable for Ii). In other words, while xanthan gum has a large molecular sound of approximately 2 million yen, Jet: Machine Salt is a low-molecular substance, so it can easily achieve the desired desalination using an ultrafiltration membrane with a molecular weight cut-off of 10,000 to 500,000. can be organized.

Furthermore, according to ultrafiltration methods.

Since colored substances in the culture solution can also be removed at the same time, there is also the advantage of obtaining yellowtail products with low blueness.

The ultrafiltration membrane module to be used must be selected taking into consideration the high viscosity of these membranes, but basically flat membrane, tubular, spiral, and hollow fiber are all suitable. However, when the gum density becomes relatively high, the viscosity increases rapidly and a relatively high pressure is required for one batch, so it is preferable to use a flat membrane or a tubular membrane.

Next, how to dry the desalted culture solution.

Vacuum drying, drum drying, spray drying, hot air drying, chestnuts, etc.
Any method that can dry effectively can be used in any suitable month.

As described above, in the present invention, a xanthan gum culture solution obtained by any cultivation method is decyclized and decolorized by a method using an ultrafiltration membrane or the like.

The special feature was to dry this directly. This is a method for producing xanthan gum.1 The present invention greatly improves the reliability of xanthan gum products obtained by directly drying a conventional culture solution, and produces xanthan gum with the same product composition as the xanthan gum produced by the alcohol purification method. It has now become possible to manufacture products using very easy and industrially advantageous means.The following will explain the invention with examples, but the present invention is not limited to these examples. .

Example 1 ffiv course 4%, Hef) 70.4 s,
K, I-IPo, 0°5%, Mg80.・711.
18 t of a medium consisting of o.
8551 Yume strain) was inoculated, and the pH was adjusted to 7.3.
Aeration and agitation culture was performed at 0°C for 24 days. The concentration of inorganic salt in the culture solution was 10% relative to xanthan gum. This culture fA5/, 1l) IAI”LOPMIO diameter 150 m,
Desalting was carried out using an ultraBS filtration device equipped with a flat membrane type (manufactured by Amlcon) ultrafiltration membrane until the inorganic salt concentration was 1% based on the gum rC. Next, this gum concentration is about 2
．． The desalted culture solution in Section 5 was spray-dried using a spray dryer equipped with a high-viscosity Ml nozzle, and 180 f of Kinone Tan gum product powder was spray-dried. Direct spray drying was used as a control. and others.

The xanthan gum product obtained by complete vacuum drying was used as a control (c) and the quality ratio of the xanthan gum product obtained by the method of the present invention was +9. '+ 3 Or-p, I
n.

As shown in Table 1, the quality of the product obtained by the method of the present invention was significantly lower than that of the product obtained by directly drying the conventional culture solution. The products obtained by alcohol purification and Fi? ! Same quality M
Example 2 Gelcol 2%, peptone 0.2%, K2HP 0.0
A medium consisting of 5% 2MgSO4.71 (,00,1%) was used.

1 (dilution rate 0.l Ohr using 10tg fermenter)
The culture solution (concentration of inorganic salts is about 10 parts xanthan gum) was continuously cultured using a Qi-Blur type ultrafiltration membrane L (FM (Abcor, 9 parts). 50 tons of culture solution (gum concentration approximately 5%) that has been desalinated to the point where the amount of inorganic salt is 0.5% of the gum quality is placed in a drum (with a crystallinity of 1'2).
It was dried using a drum dryer adjusted to 0°C to obtain a xanthan gum product of 2.5Kf. Using xanthan gum culture obtained by continuous culture, Example IK
in the manner described.

Control (4) (However, dry frt drum dry!V
Control 0 and control 0 were prepared.

Figure 1 shows and compares the relationship between the solution concentration and apparent viscosity of xanthan gum prepared by each preparation method.
8 Or. using a type viscometer. Measurements were made under the conditions of .mu.+n 25"C. The product obtained by the method of the present invention had a viscosity almost the same as that obtained by the alcohol purification method, and the conventional culture solution was modified.

[Brief explanation of drawings]

FIG. 1 shows the viscosity characteristics of xanthan gum solutions obtained by the method of the present invention and a method other than the present invention in Example 20. Patent issued, 1.108 Co., Ltd. 4f Otsu no Oka a・, person wealth Δ1 rhinoceros + p mountain', B/1 j thousand tit l:! 1 song - 11 sea +

Claims (1)

[Claims] (1) Eikai medium consisting of 1% carbon and nitrogen salts. A culture solution containing xanthan gum obtained by culturing Kichi7 Tomonas beak iIN. Desalt until the concentration of inorganic salts is less than 5% of the xanthan gum, and then dry the desalted culture solution as it is. A method for producing xanthan gum with + and lr characteristics. (2)・I! 11. 1. A method for producing xanthan gum according to claim 1, characterized in that desalination is carried out until the concentration of minerals becomes less than 2 times the concentration of xanthan gum. (8) The method for producing xanthan gum according to claimant, box yA1, characterized in that the desalting method is an ultrafiltration method using an ultrafiltration membrane.