JPH0290903A - Flocculant derived from microbe and flocculation method - Google Patents

Abstract

PURPOSE:To attain flocculation effect in a wide range covering inorganic to organic various emulsions and oily emulsions by preparing a flocculant mainly consisting of alcaligenes faecalis culture or its treated product. CONSTITUTION:The culture or treated one of strains which belong to alcaligenes and are able to produce a flocculant originated from microbe, as a typical example the culture of alcaligenes-lettuce B-16 strain (FERM BP 2015), is prepared. The treated culture has characteristic of a transparent or light yellow solid, an anionic polymer, and about 1000-15000cps viscosity. Ethanol is added to the culture fluid, the product is then separated, washed with water, and freeze-dried to obtain a treated culture product. Generally, flocculation is carried out by adding the culture of alcaligenes faecalis or a treated one in a prescribed amount to various kinds of emulsions.

Description

Detailed Description of the Invention 1) Industrial Application Field The present invention relates to a flocculant derived from microorganisms and a flocculation method, and is applicable to the treatment of various pollutants, the wastewater treatment field of various industries, urban sewage, and various types of agglomeration. It is expected to be used in a wide range of applications, including the treatment of fermentation liquids, treatment of oily substances, and even the recovery and use of useful substances.

2) Prior art With the progress of various industries, flocculants are widely used in various processes and the wastewater discharged from them. Flocculants are generally classified into synthetic polymer-based flocculants (eg, polyacrylamide-based, etc.), inorganic-based flocculants (eg, sulfuric acid, etc.), and biological-based flocculants. Among these, microorganism (produced) flocculants are substances produced by microorganisms that have the ability to flocculate other substances and make them easier to precipitate (sediment). From a functional standpoint, they can be classified into three types: cationic, nonionic, and anionic. The production volume of flocculants in Japan is said to be 15,000 tons for 7 years for anionic/nonionic synthetic polymer flocculants and 9,000 tons for 7 years for cationic synthetic polymer flocculants.

Conventionally, these synthetic polymer-based and inorganic flocculants have been widely used as clarification agents in the field of wastewater treatment using activated sludge methods and the like, as well as in civil engineering dredging work and the like.

In addition, flocculants are used in a very wide range of fields, from the water production field of water and middle water supplies, downstream processing fields such as the separation of fermentation liquor and cultured bacteria in the fermentation industry, to the food industry field. It is expected. As described above, the use of flocculants is deeply integrated into today's social life and is indispensable, and it is expected that their uses will become more diverse and the amount used will increase in the future. Therefore, the use of flocculants is considered to have a direct connection to the environment and even to human health. However, although the currently widely used synthetic polymer flocculants (e.g., polyacrylamide) are superior in terms of performance and economy, they are said to have safety and environmental problems. . Furthermore, when considering the application to downstream processing in bioindustry, the use of synthetic polymer flocculants is thought to be problematic.

The development of a new flocculant that eliminates or overcomes these shortcomings is desperately needed from various fields, and there are particularly high hopes for the development of a biologically derived flocculant that is biodegradable, safe, and free from the risk of secondary pollution. It was increasing.

By the way, regarding microorganism-produced flocculants, microorganism-produced flocculant N0 derived from the genus Rhodococchus, which belongs to Gram-positive bacteria.
C-1 (Japanese Patent Box No. 1,096,062) is already known and effective as a flocculant, but a microorganism-produced flocculant with a higher yield has been sought.

3) Problems to be solved by the invention Based on this background, the present inventors have developed a wide range of microorganisms, particularly microorganisms such as Durum-negative bacteria, in order to solve and overcome the problems of polymer-based flocculants, etc. A search was conducted for the produced flocculant. In other words, regarding a safe flocculant that has excellent safety and biodegradability and does not cause secondary pollution, and a flocculation method using the same,
Through various research and development efforts, we have found that bacterial cultures belonging to the genus Alkaligenes, Durham-negative bacteria, or culture-treated products, or their presence in the presence of at least one inorganic salt or natural flocculant, have an excellent flocculating effect. The present inventors have discovered that a flocculant can be obtained in high yield by having the following properties, and have completed the present invention.

4) Means for solving the problems The bacterial strain used in the present invention belongs to the genus Alcaligenes,
Any strain can be used as long as it has the ability to produce a microbial flocculant, but
The representative strain is Alcaligenes latus (Al
caligenes Iatus) B-16 strain,
FEl? It has been deposited as M BP-2015.

Below, representative strain (FERMBl)-20 used in the present invention
Table 1 shows the mycological properties of No. 15). From the mycological properties shown in Table 1, Bergey's Manual Systematic Bacteriology Volume 1 (Bergey's M
annual of Systematic Bacte
riology Volume I).

(1984) p. 372, it was found that it belongs to the genus Alcaligenes. Type strain (ATCC29
712), the deoxyribonucleases in Table 1.

citric acid.

Arginine dividerolase.

Acrylamidase.

Production of acid from sugar.

Extracellular polymer production ability.

Although there is no description of this, the type strain matches the strain of the present application in other properties.

Table 1 Mycological properties (continued) Carbon sources for such strains include monosaccharides and oligosaccharides such as fructose, glucose, and sucrose, as well as natural polymers such as hemicellulose, starch, and corn starch, and Preferably, carbon sources of oils such as the following are used. Additionally, urea.

Inorganic nitrogen sources such as ammonium chloride, ammonium nitrate, ammonium sulfate, and tryptone.

Organic nitrogen sources such as yeast extract, meat extract, peptone, and malt extract, as well as inorganic salts such as potassium phosphate, magnesium sulfate, and common salt, are used as culture medium components.

The culture may be a liquid culture. Initial pl+ of culture is 4-10
The cultivation is carried out at a temperature in the range of 15 to 40°C, and is usually carried out by aerated stirring culture. Cultivation is carried out for between 10 and 10 incubations, depending on the type of carbon source, etc., and the maximum flocculation activity period is set during this period.

The properties of the cultured product are colorless and transparent or pale yellow solid;
It is an anionic polymer, and its viscosity is approximately i, ooo
~15,000 eps. The viscosity is measured by adding 100 times as much water (20°C) and using a rotational viscometer in a state where the water is completely absorbed.

A culture having flocculation ability is obtained by culturing. Add twice the amount of ethanol to the culture solution, leave it overnight at 5°C, collect the precipitate by filtering it with No. After washing on paper for three times, water can be removed by freeze-drying, etc., and the aggregated material or cultured material can be recovered as a cultured material. However, in the present invention, there is no need to use the cultured material separated and purified in this way. , the culture itself can be used as is.

In addition, the inorganic salt used in combination to further promote the flocculation effect is desirably one that can generate cations in water, preferably one that can generate polyvalent cations of divalent or higher valences, such as chloride. Those that generate calcium ions, such as calcium, are advantageously used. As a natural flocculant used in combination, chitosan extracted from the shells of crabs and the like is used for 4R purposes.

However, the amount of the inorganic salt and natural flocculant used in combination is desirably determined depending on the type of object to be flocculated, and is generally not particularly restricted.

In the present invention, there are no particular restrictions on what is to be agglomerated. Typical examples include suspensions of kaolin, a type of clay;
Coke wastewater containing toxic substances such as phenol, and colored,
Examples include papermaking wastewater containing fine suspended matter, and organic food wastewater. Generally, it is carried out suitably for each aggregation target.

The method of the present invention generally involves adding the culture or culture treatment product of the Alcaligenes bacteria according to the present invention to various suspensions, or adding the culture of the Alcaligenes bacteria according to the present invention to various %i solutions. Add the culture or culture treatment,
This is then carried out by adding an inorganic salt or a natural flocculant to be used in combination. These implementation methods are not particularly restricted. Furthermore, pl+ of the mixed solution during aggregation may be made from neutral to slightly alkaline, but especially plL7!
] There is no need to perform adjustment.

As shown below, the aggregation activity of the suspension according to the present invention can be determined by measuring the absorbance of the treatment liquid, measuring the COD, and measuring the S
It was determined based on the S (suspended fine solids) removal rate.

(a) Aggregation activity measurement method using absorbance The water activity A+++ standard method is the Japanese Agricultural Chemistry Society Journal
ic, Biol, Chem,) Volume 50, No. 9, 231
This was carried out based on the method of Kurane et al. described on page 0.

That is, a culture (or culture treated product) diluted 20 to 100 times in 80 ml of kaolin 5,000 ppm suspension.
Add 10ml of calcium chloride, and add 10ml of calcium chloride (1
%), adjust the pH to 7.0, and add 100 ml
The reaction solution was allowed to stand for 5 minutes in a graduated cylinder, and the absorbance of the supernatant of the treated solution was measured at a wavelength of 550 nm using a spectrophotometer. After measuring each absorbance, the aggregation activity (F, A,) was calculated using the following formula.

Note that the control OLD, 55o is the absorbance value at 0 hours of culture, that is, the culture medium was replaced with the above-mentioned culture, and all other methods were the same as above.

The kaolin suspension was determined using the method described above, but depending on the target wastewater, the wavelength for absorbance measurement may be changed to 550.
The wavelength was appropriately converted from nm and measured at each most preferred wavelength.

(2) Measurement of aggregation activity by 'C0D (chemical oxygen demand): COD was measured according to JIS standards.

(c) S S (Suspended 5 solid:
Measurement of flocculation activity using finely suspended solids: SS was performed by measuring the weight of the gelatin filtration residue of 1-.

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

[Example I <Culture of flocculant-producing bacteria and recovery of flocculant> 15 g of fructose, 48.4 g of KH2PO, 44.4 g of 2HPO
g, M g SQ ・7 H200, 2g 1 salt 0
．． 1g, urea 0.5g, yeast extract 0.5g, distilled water 1
The medium was adjusted to pH 7.2-7.6. Transfer medium 501111 to a 300ml Erlenmeyer flask,
After sterilization in an autoclave at 120°C for 115 minutes, Alcaligenes latus strain B-16 (PER
M BP-2015) was transplanted into a flask in an amount of 1 platinum loop, and cultured with rotary rotation at 30°C. Note that the rotation speed is 180 rpm.

Using 0.1 ml of the culture at this time, the aggregation activity of the culture was measured using the above-mentioned kaolin as an index in combination with calcium chloride. In addition, the growth rate of bacterial cells is at a wavelength of 660n.
It was determined by measuring the turbidity at m.

The results are shown in Table 2.

Table 2 As is clear from Table 2, this agglutination activity is at its maximum during the logarithmic growth phase of bacterial growth, and the activity decreases as the bacteria enter the stationary phase.

Agglutinated substances were collected from the 30th culture solution showing the maximum aggregation activity. That is, ethanol in an amount twice that of the culture solution was added, and the mixture was left at 5°C overnight to obtain a precipitate. Precipitate N
o, 2nd door paper? Filter and collect, then 70%
After washing three times with ethanol and three times with distilled water on paper, the water was removed by freeze-drying or the like to obtain an aggregated material (cultured material). By using the above-mentioned medium through these operations, approximately 1
2 g (dry tube) of aggregated material was obtained.

[Example 2] The freeze-dried sample (flocculant) obtained in Example 1 was completely dissolved in a hot alkaline solution to prepare a 10% aqueous solution of flocculant.

5. Add the above 1 to 80ml of kaolin suspension of 5,000ppm.
Add 10ml of 0% flocculant aqueous solution and mix gently.
Furthermore, 10 ml of distilled water was added, and the mixture was gently mixed again, and then left to stand for 5 minutes, and the flocculation activity (F, A,) was measured. In addition,
For comparison, measurements were made using a sample to which hot alkaline water to which no freeze-dried sample was added was used as a control.

The results are shown in Table 3.

As shown in Table 3, in the present invention area, Alcaligenes
Letus bacterium B-16 strain (FERN Bl)-201
Kaolin! It was revealed that the V suspension formed flocs after 5 minutes, and the suspended kaolin coagulated and precipitated.

[Example 3] Coke factory wastewater contains fine suspensions of carbides (SS)
This wastewater contains a very large amount of phenol, which is toxic, and is said to be extremely difficult to coagulate in normal sedimentation treatment. It is said that the wastewater has a high oxygen demand (oxygen demand).

To 90 ml of this coke wastewater, 10 ml of a 5-fold dilution of the culture solution obtained in Example 1 was added, and then the reaction solution to which calcium chloride was added to a concentration of 1% was allowed to stand for 5 minutes. The SS content and COD of the clear liquid were measured. In addition, as a control group, a medium was used in the same manner instead of the culture solution. The results are shown in Table 4.

As shown in Table 4, it was confirmed that by this coagulation method, fine carbonized suspensions in coke wastewater were efficiently coagulated and precipitated, and COD in coke wastewater was also removed.

[Example 4] This flocculant solution was applied to paper processing factory wastewater, which was colored wastewater containing dye and contained a large amount of organic fine suspensions. This organic fine suspension is starch fine particles used in the coated paper manufacturing process, and the dye is a blue dye for printing.

To 90 ml of this wastewater, 10 ml of a 5-fold dilution of the culture solution obtained in Example 1 was added, and then a natural flocculant was extracted from the shells of crustaceans such as crabs and processed. Chitosan was added at a concentration of 150 ppm, and the flocculating effect of the combined use of this flocculant and a natural flocculant was investigated. The results are shown in Table 5.

As shown in Table 5, it was not possible to coagulate and precipitate fine suspensions using the natural flocculant chitosan alone.
Coagulation and sedimentation became possible when this flocculant was used in combination with a natural flocculant.

At the same time, when the absorbance of the colored wastewater was measured at a wavelength of 600 r+m, a significant decrease in absorbance was observed in the combined use area, and as a result, the blue dye was also able to be removed by coagulation and precipitation.

[Example 5] The coagulation-sedimentation effect of this flocculant on food factory wastewater as a representative example of organic wastewater was investigated. This food factory wastewater contains a large amount of fine vegetable fiber suspension as its main component.

To 80 ml of this food factory wastewater, add 10 ml of the YO-fold diluted culture solution obtained in Example 1, then add calcium chloride solution to a final concentration of 1% or chitosan solution to a final concentration of 1100 pp, for 5 minutes. The reaction mixture was allowed to stand still, and the 88-minute and COD values of the reaction treated liquid (supernatant liquid) were measured.

In addition, as a control, a 10-fold diluted medium without inoculating production bacteria was used as a control.

The results are shown in Table 6.

As shown in Table 6, in a system containing a culture solution produced by this flocculant-producing bacterium, by using cations (calcium chloride) or chitosan, a natural flocculant, it is possible to reduce the amount of Tll in food wastewater, which is organic wastewater. - ] - Organism suspension (
It was confirmed that SS) coagulated and precipitated efficiently.

Furthermore, it was also revealed that approximately 1/3 of the COD in wastewater could be removed in the cation-combined treatment area.

Claims (1)

[Scope of Claims] 1. A flocculant whose main component is a culture of bacteria of the genus Alkaligenes or a processed product thereof. 2. At least one of an inorganic salt or a natural suspended matter flocculant
The flocculant according to claim 1, further comprising at least one species. 3. Bacteria of the genus Alcaligenes are Alcaligenes, Latus (
Alkaligenes latus) B-16 strain (FE
The flocculant according to claim 1 or 2, which is RMBP-2015). 4. A method of bringing the flocculant according to any one of claims 1 to 3 into contact with a substance to be treated to flocculate it. 5. A method of decolorizing the flocculant according to any one of claims 1 to 3 by bringing it into contact with a substance to be treated.