JPH064123B2 - Microorganism-derived aggregating agent and aggregating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION 1) Field of Industrial Application The present invention relates to a flocculant derived from microorganisms and a flocculation method, and is applicable to various pollutants, various industrial wastewater treatment fields, municipal wastewater, various It is expected to be used in a wide range of applications such as fermentation liquor treatment, oil turbidity treatment, and recovery and utilization of useful substances.

2) Prior art Flocculants are widely used in various processes and wastewater fields discharged from them in accordance with the progress of various industries. Flocculants are generally classified into synthetic polymer type (for example, polyacrylamide type), inorganic type flocculants (for example, sulfuric acid band), and biological type flocculants. Among them, the microorganism (production) flocculant is a substance produced by the microorganism and has a property of facilitating the precipitation (precipitation) of other substances by aggregating. Also, from the viewpoint of function, they can be classified into three categories: cationic, nonionic, and anionic. The amount of flocculants produced in Japan is 15,000 tons / year for anionic / nonionic synthetic polymer flocculants, and for cationic synthetic polymer flocculants.
It is said to be 9,000 tons / year.

Heretofore, these synthetic polymer-based and inorganic-based flocculants have been widely used as clarification treatment agents from the field of wastewater treatment using the activated sludge method or the like to civil engineering dredging work and the like. In addition, the use of coagulants over a very wide range of fields, such as waterworks, waterworks in the field of waterworks, downstream processing fields such as fermentation liquid separation in the fermentation industry and further application to the food industry field Is expected. As described above, since the use of the coagulant is deeply incorporated into today's social life and is indispensable, it is expected that the use will increase even more and more in the future. Therefore, it is considered that the use of the flocculant is directly connected to the environment and human health. However, it is said that synthetic polymer flocculants (eg, polyacrylamide) which are widely used at present are excellent in capacity and economical efficiency, but have been pointed out to have problems in safety and environment. . Furthermore, the use of synthetic polymeric flocculants is considered to be problematic when considering their application to downstream processing in bioindustry.

The development of new flocculants that overcomes and overcomes these drawbacks has been earnestly desired by various parties, and in particular, expectations are high for the development of bioflocculating flocculants that are biodegradable, safe, and free from the risk of secondary pollution. Was there.

By the way, regarding the microorganism-producing flocculant, the microorganism-producing flocculant NO derived from the genus Rhodococcus belonging to Gram-positive bacteria NO
C-1 (Japanese Patent No. 1,096,062) is already known and effective as a flocculant, but a higher yield of microbial-produced flocculant has been sought.

3) Problems to be Solved by the Invention Against this background, the present inventors have widely used microorganisms, particularly microorganisms caused by Gram-negative bacteria, in order to solve or overcome the problems of the polymer-based flocculant and the like. A search was performed for a producing flocculant. That is, a safe coagulant having excellent safety and biodegradability and having no fear of secondary pollution, and its coagulating method,
As a result of repeated research and development, the Gram-negative bacterium Alcaligenes latus strain B-16 (F
ERM BP-2015) It has an excellent flocculating effect in the presence of a culture, a culture-treated product, or an inorganic salt or at least one of natural flocculants and that a flocculant can be obtained in a high yield. Heading out, the present invention has been completed.

4) Means for Solving the Problems The strain used in the present invention belongs to the genus Alcaligenes,
Alcaligenes latus B-16
The stock has been deposited as FERM BP-2015.

The mycological properties of the strain (FERM BP-2015) used in the present invention are shown in Table 1 below. From the mycological properties shown in Table 1,
Bergey's Manual of Systematic Bacter
Physiology Volume 1), (1984) p.372, it was found to belong to the genus Alcaligenes. In the type strain (ATCC29712), there is no description in Table 1 of "deoxyribonuclease,""citricacid,""argininedehydrolase,""acrylamidase,""production of acid from sugar,""production of extracellular polymer". The other strains have the same type strain as the strain of the present application.

As a carbon source of such strains, in addition to monosaccharides and oligosaccharides such as fructose, glucose and sucrose, carbon sources of natural polymers such as hemicellulose, starch, corn starch and oils such as olive oil are preferably used. To be In addition, inorganic nitrogen sources such as urea, ammonium chloride, ammonium nitrate and ammonium sulfate,
Organic nitrogen sources such as tryptone, yeast extract, meat extract, peptone, and malt extract, as well as inorganic salts such as potassium phosphate, magnesium sulfate, and salt are used as medium constituents.

The culture may be liquid culture. Culture has an initial pH of 4-10, temperature
It is carried out at a temperature in the range of 15 to 40 ° C., and usually aeration and agitation culture. Culture depends on the type of carbon source etc.
It is carried out for 0 days, during which the period of maximum aggregation activity is set.

The properties of the cultured product are colorless and transparent or light yellow solid,
It is an anionic polymer and its viscosity is about 1,000-15,000c.
ps. To measure viscosity, add 100 times water (20 ℃),
Perform with a rotary viscometer while completely absorbing water.

By performing the culture, a culture having an aggregating ability is obtained. Double the amount of ethanol was added to the culture solution, the precipitate was left overnight at 5 ° C, filtered with No.2 paper and collected, then 70%.
After washing with ethanol three times and further with distilled water three times on paper, the aggregated substances whose water has been removed by freeze-drying or the like can be recovered as a culture-treated product. However, in the present invention, the culture itself can be used as it is without using the culture-treated product thus separated and purified.

Further, as the inorganic salt used together for further promoting the aggregation effect, those capable of forming cations in water are desirable, and those capable of forming multivalent cations having two or more valences are preferable, for example, chlorination. Those that produce calcium ions such as calcium are advantageously used. As a natural flocculant used in combination, chitosan extracted from such as crab is advantageously used.

However, the added amounts of the inorganic salt and the natural flocculant used in combination are preferably determined depending on the kind of the object to be flocculated, and are not particularly limited in general.

In the present invention, the target of aggregation is not particularly limited. As a representative example, kaolin (white clay) suspension, which is a kind of clay as an inorganic material,
Coke wastewater containing poisonous substances such as phenol, coloring,
Examples include papermaking wastewater containing fine suspensions, and organic food wastewater. Generally, it is preferably carried out for each aggregation target.

The method of the present invention is generally carried out by adding the culture of Alcaligenes retus B-16 strain of the present invention or a culture-treated product to various suspensions, or by adding Alcaligenes of the present invention to various suspensions. -It is carried out by adding a culture or a culture-treated product of Rattus B-16 strain, and then adding an inorganic salt or a natural flocculant to be used in combination. There is no particular limitation on how to implement these. Further, the pH of the mixed solution at the time of aggregation may be changed from neutral to slightly alkaline, but it is not particularly necessary to adjust the pH.

As shown below, the agglutination activity of the suspension or the like according to the present invention is determined by measuring the absorbance of the treatment liquid, the COD measurement and the S
It was determined by the S (suspending fine solids) removal rate and the like.

(B) Method of measuring agglutination activity by absorbance This activity measuring method is based on the journal of the Japanese Society of Agricultural Chemistry (Agric.Biol.C).
hem.) Vol. 50, No. 9, page 2310, based on the method of Kurane et al. That is, kaolin 5,000ppm suspension 80ml
20m to 100x diluted culture (or culture processed product) 10m
After adding l, and further adding 10 ml (1%) of calcium chloride, the pH was adjusted to 7.0 and the reaction solution was allowed to stand for 5 minutes in a 100 ml graduated cylinder, and the absorbance of the supernatant of the treatment solution was measured at a wavelength of 550 nm.
Was measured by using a spectrophotometer. After measuring each absorbance, the aggregation activity (FA) was calculated by the following formula.

The OD ₅₅₀ of Kotrol is the value of the absorbance at 0 hours of culture, that is, the medium was replaced with the above-mentioned culture, and all other conditions were the same as those described above.

The kaolin suspension was obtained by the method described above, but depending on the target wastewater, the wavelength of the absorbance measurement was 550 nm.
Was appropriately converted from each of the samples and measured at each most preferable wavelength.

(B) COD (Chemical Oxygen Demand) measurement of aggregation activity:
The COD was measured according to JIS standard.

(C) Aggregation activity measurement by SS (Suspended Solid): SS was carried out by measuring the weight of 1 μm glass filter residue.

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

[Example 1] <Culture of flocculant-producing bacterium and recovery of flocculant> Fructose 15 g, KH ₂ PO ₄ 8.4 g, K ₂ HPO
_{4 4.4g, MgSO 4 · 7H 2} O0.2g, salt 0.1 g, urea 0.5g, dissolved yeast extract 0.5g distilled water 1 was adjusted medium PH7.2～7.6. 50 ml of the medium was placed in a 300 ml Erlenmeyer flask and sterilized by autoclave at 120 ° C. for 15 minutes, and then Alcaligenes retus B-16 strain (FERM BP-2015) was transferred to the flask in an amount of 1 platinum loop. Rotary culture is performed at ℃. The rotation speed is
It is 180 rpm.

Using 0.1 ml of the culture at this time, the aggregation activity of the culture was measured under the combined use of calcium chloride with the above-mentioned kaolin as an index. The growth of the cells was determined by measuring the turbidity at a wavelength of 660 nm.

The results are shown in Table 2.

As is clear from Table 2, the present aggregating activity reaches its maximum in the logarithmic growth phase of the growth of the bacterium, and the activity decreases as it enters the stationary phase.

Aggregated substances were recovered from the 3rd day culture medium showing the maximum aggregation activity. That is, twice the amount of ethanol of the culture solution was added and the mixture was left overnight at 5 ° C. to obtain a precipitate. Precipitate No.
After collecting with 2 paper, wash with 70% ethanol 3 times, wash with distilled water 3 times on paper, and then remove water by freeze-drying etc. Thing). By using the above medium by these operations, about 12 g (dry weight) per culture solution
Aggregated material was obtained.

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

To 80 ml of a 5,000 ppm kaolin suspension, 10 ml of the above 10% aqueous solution of aggregating substance was added and gently mixed, 10 ml of distilled water was further added, and the mixture was gently mixed again, and then allowed to stand for 5 minutes for aggregation activity (F.
A.) was measured. For comparison, the measurement was carried out by using hot alkaline water containing no freeze-dried preparation as a control.

The results are shown in Table 3.

As shown in Table 3, in the present invention, Alcaligenes.
The kaolin suspension forms flocs after 5 minutes by adding the freeze-dried flocculent substance aqueous solution obtained by culturing the lethaces bacterium B-16 strain (FERM BP-2015), and the flocculated kaolin flocculates. It became clear that it would precipitate.

[Example 3] The coke factory wastewater contains a very large amount of fine carbide suspensions (SS) and also contains toxic phenols, etc. It is said that the wastewater does not easily agglomerate, and has a high fine SS content and a high COD (chemical oxygen demand).

To 90 ml of this coke drainage, 10 ml of a 5 times diluted culture solution obtained in Example 1 was added, and then the reaction solution containing calcium chloride added to have a concentration of 1% was allowed to stand for 5 minutes. The SS amount and COD of the clear liquid were measured. As a control, 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, the fine carbonized suspension in the coke drainage was efficiently removed by coagulation sedimentation and COD in the coke drainage.

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

10 ml of a 5-fold dilution of the culture broth obtained in Example 1 was added to 90 ml of this waste water, and then extracted from the shells of crustaceans such as crabs as a natural flocculant, which was produced through a processing step. Chitosan was added at a concentration of 150 ppm, and the coagulation effect of the combined use of this coagulant and a natural coagulant was investigated. The results are shown in Table 5.

As shown in Table 5, it was not possible to coagulate and precipitate the fine suspension only with the natural coagulant chitosan, whereas it is possible to coagulate and precipitate with the coagulant and natural coagulant combination section. Became.

At the same time, when the absorbance of the same colored wastewater was measured at a wavelength of 600 nm, a large decrease in the absorbance was observed in the combined use section, and as a result, the blue dye could also be removed by aggregation and precipitation.

[Example 5] As a representative example of organic wastewater, the coagulant-precipitation effect of the present coagulant on food factory wastewater was examined. This food factory wastewater is a wastewater containing a large amount of fine plant fiber suspension as the main component.

To 80 ml of this food factory wastewater, 10 ml of the 10-fold dilution of the culture solution obtained in Example 1 was added, and then calcium chloride solution was added to a final concentration of 1% or chitosan solution to a final concentration of 100 ppm for 5 minutes. The solution was allowed to stand and the SS content and COD of the reaction-treated solution (supernatant solution) were measured.

As a control, a 10-fold diluted medium in which the production strain was not inoculated was used as a control.

The results are shown in Table 6.

As shown in Table 6, in a system to which a culture solution of the present flocculant-producing bacterium has been added, by using a cation (calcium chloride) or a natural flocculant chitosan together, fine organic matter in food wastewater, which is organic wastewater, can be obtained. It was confirmed that the suspension (SS) efficiently aggregated and precipitated.

In addition, COD in the wastewater is about
It became clear that a little less than a third can be eliminated.

[Example 6] Since NOC-1 produced by Rhodococcus erythraceus was not very effective against oily emulsions, the present flocculant was applied to not only solid suspensions but also oily emulsions. A study was made as to whether or not the effect of aggregation was exhibited.

The oil suspension emulsion was prepared as follows. First, pure water 1
To the above, 2.5 g of palm oil acid (trade name; Kao LUNACL-50) was added, and a homogenizer (Janke & Kunkelgmbh, T
A coconut oil emulsion was prepared by homogenizing with a urrax D 7813 type) at 10,000 rpm for 10 minutes.

To 90 ml of this adjusted emulsion, 10 ml of a 5-fold dilution of the culture broth obtained in Example 1 and then chitosan were added to a final concentration of 100 ppm, and the mixture was gently stirred by inversion with a 100 ml graduated cylinder for 5 minutes. The coagulation effect on the oil suspension emulsion was examined by measuring the COD of the treatment liquid after standing for 5 minutes. Since the oily emulsion has a lower specific gravity than water, the aggregation layer floats on the surface. The treatment liquid is located in the lower layer unlike Examples 1 to 5.

The results are shown in Table 7. As shown in Table 7, the combined use of the flocculant-producing fungal culture solution and chitosan effectively floats the emulsion on the surface. In the wastewater treatment containing oils and the like, the oil content is generally floated under pressure before being subjected to the activated sludge treatment, and it is said that the cost of electricity for that is considerable. It is also possible to use the present coagulant instead of such pressure floating.

6) Effects of the Invention As is clear from the above, by applying the flocculant and the flocculation method of the present invention, it is possible to effectively flocculate over a wide range of objects such as various suspensions from inorganic to organic and oil emulsions. It turned out to be possible.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI technical display location // (C12P 1/04 C12R 1:05) 7804-4B (72) Inventor Yasuhiro Nobata Yokkaichi, Mie Prefecture City 6-6-9 Examiner, Central Research Institute, Hakuto Kagaku Co., Ltd. Yoshihide Kawakami (56) Reference JP-A-49-004685 (JP, A) JP-A-51-086189 (JP, A) JP-A-60 -071009 (JP, A) JP 63-126596 (JP, A) JP 59-024649 (JP, B2)

Claims (4)

[Claims] 1. Alcaligenes lata
tus) B-16 strain (FERM BP-2015) A coagulant mainly composed of a culture or a treated product thereof. 2. At least one of an inorganic salt or a natural flocculant.
The flocculant according to claim 1, further comprising one or more species. 3. A method of aggregating by bringing the aggregating agent according to claim 1 into contact with a substance to be treated. 4. A method of decolorizing a flocculating agent according to claim 1 by bringing it into contact with a substance to be treated.