JPS6044919B2 - Method for producing xanthan gum with excellent transparency - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing xanthan gum with excellent transparency.

Xanthan gum is used as a food or industrial raw material that takes advantage of its stable production, stable quality, and excellent physical properties.

However, the solution of xanthan gum generally has low transparency due to contamination with microorganisms or other substances, which limits its use in transparent foods or polymers for Ξ-stage recovery where clogging by insoluble substances is a problem. is in a state of In general, xanthan gum can be purified by removing bacterial cells from the culture solution by filtration or centrifugation as needed, and then drying as is, or by adding an organic solvent to insolubilize and separate the gum. It is used. If a transparent product is required, it is not impossible to clarify the culture medium by filtration or centrifugation, but filtration or centrifugation of culture liquids with high viscosity is generally difficult, and specific This method requires dilution of the culture solution with water and treatment at high temperatures, and is difficult to call a rational method in terms of cost and operational difficulty. The present inventors first discovered that the cause of the opacity of the liquid was due to the contamination of microbial cells, and at the same time confirmed that by removing this, the liquid could be made transparent. As a result of extensive research into methods for efficiently removing bacterial cells, we found that the method of solubilizing bacteria using enzymes is superior in terms of cost, ease of operation, and mass production. This discovery led to the completion of the present invention.

The enzyme used in the present invention is endo-N-acetyl muramitase, which is named lysozyme in terms of plant and animal origin, and can be easily processed by adding a small amount to a culture solution or gum solution. A clear gum solution can be obtained.

In general, some enzymes called cell wall lytic enzymes, including lysozyme, act on the cell wall isolated from microbial cells, but have a hard time acting on the cell wall of whole bacteria, so it is unclear how effective they are. There are many things that you can't understand until you actually try to make enzymes work.

In the present invention, we have found that lysozyme has the best effect, and that this enzyme alone is sufficiently effective without chemical or mechanical pretreatment of microbial cells.

Furthermore, we have also discovered that depending on the degree of transparency required for the product, it is possible to further enhance the effect by using it in combination with other enzymes called cell wall lytic enzymes.
Examples of enzymes used in combination here include N-acetylmuramyl-L-alanine amiguse and peptidase. Next, conditions for more effectively achieving transparency according to the present invention will be described below. The xanthan gum solution used may be the culture solution as it is, or may be one that has been separated and then dissolved again in water.

The concentration of gum in the solution is not particularly limited, and any concentration may be used as long as the enzyme can be stirred until it is sufficiently homogeneous after addition, but it is preferably 1% to 10%.
A concentrated solution is used. There is no particular need to pre-treat the liquid to be treated before the enzyme is applied, and the culture liquid can be used as is.
It can also be applied once the liquid has been sterilized. The amount of enzyme added is determined depending on the required transparency of the liquid, and is preferably 1pp.
It is added in a range of m to 500 ppm. The pH of the reaction is
It is carried out in the range of 4.0 to 9.0, preferably 6.0 to 9.0.
7.0. The reaction temperature is 25°C to 60°C, preferably 30°C to 50°C. Other required operating conditions include gentle stirring during the reaction so that the highly viscous liquid becomes homogeneous. As described above, the present invention enables transparentization to be achieved on an industrial scale at a much lower cost and with ease compared to the conventional methods of transparency using filtration or centrifugation. It has become possible to obtain excellent microorganism-produced gum, and at the same time, it has become fully applicable to fields that were previously not applicable due to cost or quality considerations.

Example 1 Glucose 4% Peptone 0.2% K2HPO4O. 5% MgSO4・7H200.
18f of a medium consisting of 0.02% was placed in a 30f fermenter, inoculated with Xanthomonas camhestris inoculum culture, and P.
Aerated agitation culture was carried out at 7,30°C for 4 days.

Add 25 ppm of lysozyme (manufactured by SIGMA) to this culture solution.
was added, and the reaction was carried out at 40° C. with gentle stirring, and the transmittance was measured every hour. The transmittance was measured using a spectrophotometer after diluting the reaction solution 2 times with water.
Under the conditions of 0rT1μ cell length 1cm. It is expressed as transmittance at . As shown in Table-1, the transmittance increases with time and reaches 90% after 10 hours! External Example 2 Glucose 6% Peptone 0.2% K2HPO4O. 5% MgSO4・7H200.
02% medium 18e was placed in a 30e fermenter, inoculated with Xanthomonas camhestris inoculum culture, and P.
Aerated agitation culture was carried out at 7.3O<0>C for 5 days.

The culture solution can be prepared by: 1. without separating the bacterial cells; After adding a large amount of isopropanol and separating the gum, vacuum drying.
0.72 kg of purified xanthan gum was obtained. Next, a 0.25% aqueous solution of this purified gum was prepared, and lysozyme 5
ppm was added and the reaction was carried out at 45°C for 5 hours, and the transparency was 92.
A 5% xanthan gum solution with excellent transparency was obtained. Example 3 - Glucose 6% Peptone 0.2% K2HPO
4O. A medium 180e consisting of 5% MgSO4.7H200.02% was placed in a 300e fermenter, and the pH was adjusted to 7.
Aeration and agitation culture was performed at 30° C. for 5 days.

100 ppm of lysozyme was added to this culture solution, and the temperature was increased to 45°C.
After reacting for a predetermined period of time, 1. A small amount of isopropanol was added to insolubilize the gum. This precipitate was separated and collected, and then dried to obtain a transparent gum. This gum was dissolved to 0.25%, its transmittance was measured, and the relationship between lysozyme treatment time and transmittance was shown in Table-2.
It was shown to.

Example 4 XanthOmOnus. obtained in Example 1. camp
estris culture solution was added with 25 ppm of lysozyme (manufactured by SIGMA) and reacted at 40°C with gentle stirring in 311r.
After adding N-acetylmuramyl-L-alanine amidase and endopeptidase obtained by fractionation and purification from the culture solution of busG and carrying out a 511r reaction at 40°C, the reaction solution was diluted 20 times with water. The transmittance value measured using a spectrophotometer under the same conditions as in Example 1 was 94%.

Claims (1)

[Claims] 1. A method for producing xanthan gum with excellent transparency, characterized by treating an aqueous xanthan gum solution with lysozyme.