JPS63126596A - Decoloring method for soluble dye by microorganism - Google Patents

Abstract

PURPOSE:To easily decolor a soluble dye by bringing the soluble dye into contact with the cultured matter or culture treated obtd. by culturing microorganisms which belong to the Rhodococcus genus and have microorganism flocculating agent NOC-1 generatability in the presence of an inorg. salt. CONSTITUTION:The soluble dye is brought into contact with the cultured matter or culture-treated matter obtd. by culturing the microorganisms (e.g., Phodococcus Erythropores KR-S-1 strain) which belong to the Rhodococcus genus and have the microorganism flocculating agent NOC-1 generatability in the presence of the inorg. salt (e.g., calcium chloride). This soluble dye is a black dye resulted by compounding of the amino acid formed in the distillation residue of, for example, alcohol fermentation and reducing saccharides. The decoloration of the soluble dye which is considered most difficult is facilitated if the above-mentioned method is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION 1) Industrial Field of Application The present invention relates to a method for decolorizing soluble pigments using microorganisms, and is applicable to the field of wastewater treatment of dyeing factory dyes and pigment manufacturing factories, treatment of various fermentation liquids, It is also expected to be used in a wide range of applications, including decolorization processes in various chemical factories and in food manufacturing.

2) Prior Art Conventionally, there have been few effective decolorization methods for decolorizing soluble dyes from aqueous systems, and a method of decolorizing them by slightly adsorbing them onto activated carbon has been used.

Although it is not bleaching itself, there is also bleaching using bleaching powder. However, the former requires a large amount of activated carbon;
Due to its high cost, it is not used except in special cases, and the latter is merely decolorized in appearance, and the main body of the soluble pigment, which is still a coloring substance, dissolves in water. There is.

On the other hand, it is impossible to decolorize and remove soluble pigments by physical methods such as centrifugation, and only a few methods of adsorption using activated carbon or ion column chromatography can be considered.Especially in the field of pollution, BOD ( There are three issues: removal of carbon sources and other substances that cause biological oxygen demand (biological oxygen demand), decolorization, and deodorization.Currently, BOD removal has almost been completed using activated sludge methods, etc.
Decolorization is almost completely impossible with the activated sludge method.

For this reason, large amounts of water are used to greatly dilute colored wastewater before being discharged, or colored wastewater and fermentation liquids are evaporated and the colored liquid is concentrated at a huge amount of energy and cost, and then shipped to ships. Methods include transporting the waste to the open ocean and dumping it in the open ocean, or burning it. In addition, methods such as dumping into the open ocean are simply attempting to dispose of the material in an invisible manner, and when considering global pollution, they are simply spreading the colored substances thinly and widely over the entire surface. There is no change in the fact that we are in trouble.

As described above, the reality is that no matter which method is adopted, there is no way to be satisfied as a decolorizing method.

3) Problems to be Solved by the Invention Based on this background, the present inventors have proposed that if it becomes possible to coagulate and precipitate soluble pigments from an aqueous system and perform solid-liquid separation, the pigment coagulates and precipitates will be collected. From the viewpoint that it is easy to dispose of by incineration and has great economic benefits, we have conducted various research and development on a safe method of decolorizing soluble dyes without the risk of secondary pollution. The present inventors discovered that NOC-1 (Patent No. 1,096,062), a microorganism-produced flocculant derived from Rhodococcoccus, which was previously developed by the present inventors, has an excellent decolorizing effect, leading to the completion of the present invention.

That is, the present invention relates to a culture obtained by culturing a microorganism belonging to the genus Rhodococchus and having the ability to produce the microbial flocculant NOC-1, or a culture product obtained by contacting a soluble pigment with a soluble pigment in the presence of an inorganic salt to decolorize the soluble pigment. It is related to the method of forcing.

4) Means for solving the problems The bacterial strain used in the present invention belongs to the genus Rhodococchus,
Any strain can be used as long as it has the ability to produce the microbial flocculant NOC-1, but a representative example is Rhodococcus erythropores (formerly Nocardia erythropores)!
The IR-5-1 strain (FERM No. P3530) has been deposited. The former name Nocardia erythropores was reorganized and reclassified as Rhodococcus erythropores by the International Committee on Nomenclature of Microorganisms in 1980.

The culture medium for the strain such as , i: contains carbon sources such as glucose and fructose, inorganic nitrogen sources such as urea and ammonium sulfate, residual nitrogen sources such as enzyme extracts, and nutrients such as inorganic salts and vitamins. used.

The culture may be liquid culture or solid culture.
IN is pu4~11. The culture is carried out at a temperature in the range of 20 to 40°C, and is usually carried out by aeration with agitation. At this time, it is desirable to keep the aeration volume to the volume of the medium at a ratio of 1 or less, and the culture is completed in about 3 days to 1 week. , to obtain a culture with flocculation ability. The supernatant from which the bacterial strain was removed by centrifugation was used for ethanol precipitation, etc. and 0.8&! The aggregated substances can be isolated by ammonium sulfur salting out, and the cultured product can be recovered. However, in the present invention, the culture itself may be used without using the purified culture product, and since the bacterial cells themselves have a flocculating ability, they can be used as they are.

In addition, the inorganic salt used here is desirably one that can generate cations in water, preferably one that can generate polyvalent cations of divalent or higher valences, such as calcium chloride, which can generate calcium ions. Those that do are used to advantage. However, the amount of these inorganic salts added is desirably determined by the type of soluble dye and is generally not particularly restricted.

In the present invention, representative soluble pigments to be decolorized include, for example, black pigments that are a complex of amino acids and reducing sugars produced in the distillation residue of alcohol fermentation, and amino acids with benzene nuclei produced in molasses. Examples include melanoidin-based pigments such as black pigments derived from natural pigments, various soluble pigments, and colored pigments derived from lignin in the manufacture of bulbs.

The method of the present invention generally comprises: a soluble dye coloring solution;
This is carried out by adding an inorganic salt and then adding the culture or culture treatment of Rhodococcus sp. according to the present invention, and then making the coloring solution from neutral to slightly alkaline. The implementation method is not particularly limited.

5) Examples Next, the present invention will be explained in more detail with reference to Examples.

In addition, as shown below, the decolorizing activity of the colored liquid according to the present invention was determined by measuring the absorbance of the colored liquid.

(Method for Measuring Decolorizing Activity by Absorbance) After the reaction, the reaction solution was allowed to stand for a certain period of time (5 minutes, 30 minutes, or 60 minutes), and the absorbance of the supernatant of the treated solution was measured using a spectroscopic optical needle. (Depending on the type of soluble dye, the measurement was determined by centrifuging (1,00gX 1 second) immediately after the reaction instead of allowing it to stand still and measuring the absorbance of the supernatant.) The wavelength is the maximum absorption wavelength of the soluble dye, etc. I decided.

(Preparation of cultured product (microorganism-produced flocculant NOC-1)) Glucose 10g 5KH-Po42g-z 1lP
500ml of a medium prepared by dissolving 5g of O4, 1Mg5O40.2g, 0.5g of urea, and 0.5g of yeast extract in distilled water and adjusting the medium pH to pH 7.5.
Transfer to a 120-liter Erlenmeyer flask and autoclave to 120
After aseptic sterilization at ℃ for 15 minutes, R.
-3-1 (FERM-P3530) was transplanted into a flask in an amount of 1 platinum loop, rotary cultured at 30°C, and cultured for 4 days to obtain a culture. Bacterial cells were removed from this culture by refrigerated centrifugation (10,000 g
．． 8 Add ammonium sulfate until saturation (or add ethanol until 60%), leave overnight at 5°C, perform ammonium sulfate salting out (or ethanol precipitation), and obtain a precipitate.

This precipitate was dissolved in distilled water and then dialyzed against distilled water using a Visking tube to remove ammonium sulfate (or ethanol) to obtain an aqueous solution containing the flocculant NOC-1. These operations were repeated several times, and the water was removed by freeze-drying or the like to obtain a flocculant NOC-1. Through these operations, 100 mg of the flocculant NOC-1 was obtained from culture solution 1.

(Example 1) A 1% aqueous inorganic salt solution (Ca" or 8j) was added to pigment wastewater 97-i.
2sj! was added and mixed, the flocculant NOC-
1 aqueous solution 1aj! (0.1mg NOC-1/ml
Add > and mix. For comparison, measurements were also conducted on pigment wastewater to which no decolorizing agent was added and pigment wastewater to which an inorganic salt (or flocculant) was added. The maximum absorption wavelength of this wastewater system is 425ruw, and the absorbance of the treated water is 425ruw.
Displayed in mm. The results are shown in Table-1.

As is clear from Table 1, in the present invention, when the flocculant NOC-1 is added in combination with an inorganic salt, the soluble dye forms flocs of a clearly visible size and coagulates and precipitates after 5 minutes. This revealed that the pigment wastewater colored by the soluble dye was decolorized.

Table 1 (Example, (翁゛5) Alcohol fermentation involves using yeast as a raw material (medium nutrient source) to carry out alcohol fermentation.The residue obtained by distilling alcohol is called alcoholic yeast liquid. A strong soluble pigment called melanoidin pigment is formed from waste molasses during fermentation, distillation, etc.This melanoidin pigment is a soluble dark brown pigment, and can be processed using most processing methods. It is famous as a colored pigment that cannot be removed by decolorization from water.Currently, alcoholic yeast liquid containing this melanoidin pigment is tmlilned, which requires a huge amount of energy and cost.
It is disposed of by dumping into the open ocean.

Using this alcoholic yeast solution, we attempted to apply a decolorization method to the soluble pigment melanodin, which is considered to be the most difficult to treat.

After adjusting the alcoholic yeast solution to pH 8, just to be sure,
The precipitated portion is removed by centrifugation (10,000 g x 10 minutes) to obtain only the soluble portion. This alcoholic yeast solution containing soluble melanoidin pigment 90+*j! For,
10% calcium chloride solution 51aIl and flocculant N○c-i
Mix 5 mg of an aqueous solution (0.1 mg NOC-1/-t), adjust the reaction system to pH 8, and leave it for 1 hour.

After standing for 1 hour, the absorbance of the supernatant was measured at a wavelength of 550n.
In addition, the volume (%) of the precipitate was determined and used as the decolorizing activity.

The results are shown in Table-2.

As a result, when this decolorization method was applied to an alcoholic yeast solution containing melanoidin pigment, which is considered to be the most difficult to treat, it was found that it could be effectively decolorized.

Table 2 (Example 3) Valve waste liquid is different in composition from alcoholic yeast liquid, and it is said that the soluble pigments are dominated by lignin-based substances extracted during the process of making paper from wood. .

There are two types of valve wastewater: wastewater called black liquor and bleached alkaline wastewater. Because of its color, it is one of the types of wastewater that we try our best not to release outside of factories, and it is said to be one of the most difficult types of wastewater to decolorize and remove colored substances. An attempt was made to apply this decolorization method.

For 90 mg of these two types of valve waste liquid, add 10% calcium chloride-5 l aqueous solution of collector NOC-1
(The pH of the reaction solution after adding 0.1 mg NOC-1/mA was 5 to 7.8.) After being left for 1 hour, the absorbance of the supernatant was measured at a wavelength of 415 nm and s.

Further, in order to promote flocculation and coagulation and precipitation of soluble pigments, kaolin (a type of clay) was added as a suspended substance to a final concentration of 500 ppm. The results are shown in Table-3.

As shown in Table 3, by this decolorization method, the black liquor, which is the two types of valve waste liquids, faded, and the brown color of the bleached alkaline wastewater also became lighter, indicating that it was decolorized. Furthermore, in the system in which suspended matter was added, the formation of flocs became larger, the rate of coagulation and sedimentation was significantly improved, and the decolorization efficiency of the treated solution (supernatant) was promoted.

Table 3 (Example 4) Molasses is the remaining liquid after refining sugar from sugarcane broth. This waste dump still contains a considerable amount of sugar and minerals, so
It is frequently used as an inexpensive medium source for microbial culture in the fermentation industry, and is the basis for economically supporting the current fermentation industry.

However, it is safe to say that waste molasses is a dark black color that cannot be decolorized using normal methods, and has become a weak point for the fermentation industry.

Using waste molasses as a culture source, we tried to apply it to waste molasses wastewater after culturing yeast. 1 for 95m+ 1 of waste molasses wastewater
0% calcium chloride? Add 2.5 mjl of flE and 2.5 mjl of culture solution containing the flocculant NOC-1, and reduce the P of the reaction system.
H was adjusted to 8. Although micro flocs are clearly formed, since sedimentation takes time, centrifugation (1, oOQg
x 1 sec) to promote sedimentation. The absorbance of the supernatant was measured at 55 on-, and the volume (%) of the precipitate was determined. The results are shown in Table 4.

As shown in Table 4, in the present invention, when the culture solution was added in the presence of inorganic salts, the soluble pigments derived from the waste liquid formed flocs, and the blackish brown color of the waste liquid faded and was decolorized.

Table 4 4. Effects of the Invention As is clear from the experiments shown above, it has been found that the method of the present invention can easily decolorize soluble dyes, which are said to be the most difficult.

Claims (1)

[Claims] The feature is that a microorganism belonging to the genus Rhodococcus and having the ability to produce the microbial flocculant NOC-1 is brought into contact with a soluble pigment in the presence of an inorganic salt and a culture or culture-treated product obtained by culturing the microorganism to decolorize the soluble pigment. A method for decolorizing soluble pigments using microorganisms.