JPH08103273A - Proliferated and immobilized substance of microorganism and its production - Google Patents

Abstract

PURPOSE: To obtain the subject immobilized substance, consisting essentially of a water-soluble silicic acid compound and PVA, having the biodegradability and a stable shape, readily handleable and useful for a bioreactor, waste water treatment, etc., by transplanting a microorganism into a gel carrier containing a culture medium and water. CONSTITUTION: A 10% aqueous solution of PVA, regulated to pH1.3 and having 30-40% acetate residues and 500-2000 polymerization degree and a 20% aqueous solution of a water-soluble silicic acid compound such as potassium silicate regulated to pH11.9 are simultaneously mixed and stirred with a culture solution of a microorganism belonging to the genus Rhodobacter, Rhodopseudomonas, Rhodospirillum or Chromatium (e.g. Rhodopseudomonas capsulata), a culture medium and water and regulated so as to provide the final pH6.5-8.5. Thereby, the gelation is carried out to afford the objective proliferated and immobilized substance of the microorganism, consisting essentially of the water-soluble silicic acid compound and polyvinyl alcohol, comprising the microorganism transplanted into the interior of the gel carrier containing the culture medium and water and useful for a bioreactor, waste water treatment, purification, etc., of water systems for culturing fishes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microorganism immobilization product for use in an aquatic environment such as an aquaculture plant, a river, a paddy field and a wastewater treatment plant, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, many methods of using polyvinyl alcohol (hereinafter referred to as "PVA") as a carrier for immobilized microorganisms used in bioreactors, wastewater treatment, purification of fish culture water systems, etc. have been announced. , Is known. However, in order to stabilize the shape of the immobilized microorganisms in a gel form, a method of eliminating the hydrophilic character of PVA by intermolecular crosslinking or polymerization is used. As a typical method, a PVA-based immobilized microorganism that gels by repeating freezing and thawing has been proposed (Japanese Patent Laid-Open No. 271425/1993).

[0003]

However, since the PVA-based immobilized microorganisms have to be repeatedly frozen and thawed in order to gel, they affect the survival of the microorganisms and are not always satisfactory. Was not.
In addition, in the case of a system in which the medium is not actively added, since the microorganisms are simply transplanted, the growth of the microorganisms does not occur in the gel carrier, and the survival of the microorganisms just transplanted is further increased. It will be difficult. In addition, even if a growth-immobilized product of a microorganism to which a medium is positively added, a gel is formed by the freeze / thaw operation as described above, the growth of the microorganism is seriously threatened. The conventional PVA-based immobilized microorganisms have not been designed with a gel in consideration of survival and growth of the microorganisms.

On the other hand, the microorganism-immobilized and immobilized product used in the aquatic environment such as aquaculture farms, rivers, paddy fields, and wastewater treatment plants settles on the bottom of the water, and the microorganisms are released to leach into the aquatic environment. The formation of environmental microflora at the bottom of the water to maintain the natural environment or to change the poor environmental condition to the original natural environment,
The biota must be able to restore normal ecosystems. In addition, when it is put into an aquatic environment, the composition of the microorganism-immobilized immobilization product must be chemically stable, and the molded microorganism-immobilized immobilization product must have physical strength and can be used for a long period of time. Furthermore, it is necessary that the microorganisms immobilized in the same growth-immobilized product do not leak or the leakage is minimized.

Moreover, the microbial flora in the environment is changed,
When using microorganisms to change the ecosystem,
Unless a large amount of microorganisms are continuously supplied locally, the microorganisms adapted to the existing environment cannot survive or proliferate in the existing environment. On the other hand, if the gel carrier for immobilizing microorganisms is stable in the environment, it remains in the environment and destroys the environment. It is important that the decomposition products are not toxic and that they do not change the environment because they are decomposed by microorganisms.

[0006] Furthermore, the microorganism-immobilized and immobilized product is easy to handle and stably collapses or cracks in shape because it is put into an aquatic environment such as an aquaculture plant, a river, a paddy field, and a wastewater treatment plant for use. It should be free from any problems such as transportation, movement, movement, movement, and odor. In addition, it is necessary that it does not physically change at room temperature and room temperature, that it can be cultured after being filled in a container, that it has excellent releasability from the container, and that it does not float in water. Conventional immobilized microorganisms cannot satisfy all the above conditions.

It is an object of the present invention to ensure the survival of microorganisms in a gel carrier so that they proliferate well, and to prevent the leakage of microorganisms before proliferation while releasing the microorganisms into the aquatic environment in a controlled manner. And a growth-immobilized product of a microorganism capable of continuously supplying a large amount of the microorganism locally. In addition, the composition of the microorganism-immobilized product is chemically stable, has physical strength, and can be used for a long period of time.
In addition, the gel carrier does not remain in the environment and destroys the environment, has a degrading property, and provides a microorganism growth immobilization product having no toxicity to the degradation product. In addition, the shape is stable, it does not crumble, crack, fluidize, has no odor, is easy to carry and move, is extremely easy to handle, and can be cultured after filling into a container and can be easily removed from the container. The present invention provides a growth immobilization product of microorganisms that is excellent in that does not float in water.

[0008]

In order to achieve the above object, the present invention comprises a water-soluble silicic acid compound and PVA as main components, and a microorganism is transplanted into a gel carrier containing a medium and water. The growth and immobilization product of living microorganisms was adopted.

The microorganism immobilization product of the present invention comprises a water-soluble silicic acid compound, PVA, a medium, water and a microorganism culture solution, and when all the components are mixed, gelation begins and the microorganism grows in this gel. It is a thing.

As described above, with PVA alone, it is necessary to repeat the freeze / thaw operation in order to obtain a stable gel, but this is eliminated by using a water-soluble silicic acid compound as the main component of the gel carrier.

However, since the water-soluble silicic acid compound does not give a more elastic gel as the pH becomes lower and it hardens, it gives elasticity, solubility in water and degradability, and further gelation. PVA is also mixed as one component constituting the gel carrier because it is necessary to have the ability of the microorganisms to grow therein.

[0012] This eliminates the need for freezing and thawing, so that the microorganisms can be cultured and grown in the gel.

However, ensuring the survival of microorganisms in the gel,
To further improve the culture growth, the hydrogen ion concentration (p
Adjustment of H) is essential. Although there are some variations depending on the type of microorganism, usually, when the pH is lowered to less than 6.5, good growth of the microorganism is not ensured. This is because microorganisms, especially photosynthetic bacteria themselves become difficult to survive in this acidic region, and the water-soluble silicic acid compound does not harden uniformly with elasticity in a state of being mixed with other components, and it hardens nonuniformly. is there. On the other hand, when the pH is brought to a range over 8.5 and mixed, the water-soluble silicic acid compound does not function as a gelling agent.

As a result of further examination of the pH range in which the microorganisms immobilized in the gel carrier survive and proliferate, if the final pH is 6.5 to 8.5, 1 g of the gel carrier is in culture.
Among them, it was found that microorganisms survive on the order of 10 ⁶ or more. As a result of further examination, the final pH was 8.
It has been found that the one adjusted to 1 to 8.4 is optimum. In this region, the viable cell count is at least 10 ⁸
A 10 ⁹ the order of.

Therefore, in the case of producing a growth immobilization product of this microorganism, a water-soluble silicic acid compound, PVA, a medium, water and a culture solution of the microorganism are mixed to adjust the final pH to 6.5 to 8.5. Need to be gelled. The pH can be adjusted by using an acid such as hydrochloric acid after mixing the components, but the water-soluble silicic acid compound is treated with an alkaline component solution while taking the pH of the culture solution of the microorganism into consideration. Prepare,
The most preferable method is to prepare a PVA solution in advance as an acid component solution and secure a pH in an optimum range during mixing. This is because of the need for flexible gelling and creating a stable microbial survival environment. That is,
This is because if the pH is adjusted afterwards using an acid such as hydrochloric acid, the pH changes relatively rapidly, which is not preferable as a better environment for survival of microorganisms.

As described above, PVA imparts elasticity and the like to the water-soluble silicic acid compound that imparts hardness, and also has solubility and degradability in water, and further, the growth of microorganisms in the gel. Although it is a constituent of the gel carrier because it is necessary to provide the polymer, the degree thereof is mainly controlled by the acetate residue of PVA and the degree of polymerization, and the mixing ratio of PVA and the water-soluble silicic acid compound. The acetate residue of PVA is 30 to 40%, the degree of polymerization is 500 to 2000, and the mixing ratio of PVA and the water-soluble silicic acid compound is 1.5 to 1 in the most preferable range.

Examples of the water-soluble silicic acid compound include potassium silicate and sodium silicate as the inorganic silicic acid compound, and methyl silicate, ethyl silicate, propyl silicate as the organic silicic acid compound. Examples thereof include butyl silicate and the like.

This microorganism-immobilized product is introduced into the aquatic environment such as aquaculture farms, rivers, paddy fields and wastewater treatment plants,
The dissolution of the gel carrier and the growth of the microorganisms proceed at the same time, and the microorganisms are gradually released from the gel surface into the aquatic environment,
It is used to maintain the natural environment by reforming the environmental microflora at the bottom of the water, change the poor environmental condition to the original natural environment, and restore the biota to a normal ecosystem.

Therefore, the microorganism used in the present invention is not particularly limited as long as it can be optimally used in this method of use. Usually, photosynthetic bacteria are used, and microorganisms belonging to one or more of the genera Rhodobacter, Rhodopseudomonas, Rhodosubilium, and Chromatium can be used. Although the red sulfur bacterium and the red non-sulfur bacterium can be used alone, it is preferable to use the red sulfur bacterium and the red non-sulfur bacterium as a symbiotic bacterium in order to successfully adapt to the natural environment. Further, microorganisms composed of a plurality of genera adsorbed on sludge and / or humus can also be used as long as they are symbiotic with photosynthetic bacteria.

[0020]

The present invention comprises a water-soluble silicic acid compound and PVA as main components, and is a growth and immobilization product of a microorganism in which the microorganism is transplanted in a gel carrier containing a medium and water. Unlike the system-immobilized microorganisms, the growth of the microorganisms is performed well by ensuring the survival of the microorganisms in the gel carrier,
Moreover, it is possible to release the microorganisms into the aquatic environment in a sustained release manner while preventing the leakage of the microorganisms before the proliferation. In addition, even if the microorganisms are installed in a predetermined aquatic environment such as an aquaculture plant, since they repeatedly grow well, it is possible to continuously supply a large amount of microorganisms at the installation location, and Even in an environment in which the applied microorganisms occupy a large number, the effect of the microorganisms is effectively exhibited.

The microorganism-immobilized product of the present invention has a chemically stable composition and physical strength, and can be used for a long period of time. Moreover, water-soluble silicates and PV
Since A and A are used as main gel carrier constituents, they have degradative properties without remaining in the environment and destroying the environment, and the degradation products are not toxic.

Further, the shape is stable, it does not crumble, crack, fluidize, has no odor, is easy to carry and move, is extremely easy to handle, and if it is filled in a container, it is cultured there. In addition, the elasticity of PVA provides excellent peelability from the container. Further, since it does not float in water, it can be easily settled on the bottom of the water and installed.

[0023]

Example: 2 liters of a 10% -PVA aqueous solution having a pH of 1.3, an acetate residue of about 30% and a degree of polymerization of about 1000, and a 20% potassium silicate aqueous solution having a pH of 11.9. 0.53 liters, the following medium and 4.14 liters of water, and 0.7 liters of a culture solution of Rhodopseudomonas capsulata having a pH of 8.5 were mixed and stirred at the same time, and the ungelled solution having a final pH of 8.3 was deeply mixed. 5c
and a transparent plastic container having a diameter of 10 cm and a diameter of 10 cm.

The medium used was 5 g of sodium propionate, 1 g of ammonium chloride, 0.8 g of potassium phosphate, 0.2 g of magnesium chloride, 0.1 g of sodium chloride, 0.05 g of calcium chloride, 0.5 g of sodium hydrogen carbonate, and 0 yeast extract. 0.2 g, 1000 ml of water, pH 7.5.

Shortly thereafter, the ungelled solution gelled,
A gel-like growth and immobilization product of the microorganism was obtained. After culturing under illumination for 5 days, a growth-immobilized product of a microorganism that grew bright red in the medium in the gel was obtained. When the viable cell count was measured, it was on the order of 10 ⁸ .

This was put into the aquaculture pond of aqua shrimp farm for aquaculture. The condition of the bottom of the culture solution was dived and observed, and the mud on the bottom was sampled. Hydrogen sulfide in the surface mud of the bottom of water was no longer detected. Since the gas adsorbed in the mud has disappeared, the specific gravity has increased, and the mud has become shallow and stable,
The environment for seabed fish and shellfish has been improved.

By the way, if an attempt is made to produce a growth-immobilized product of the above-mentioned microorganism whose pH is adjusted to 6.5 or less, it is impossible to mix the components because the gelation rate is high. Further, if the mixing is continued, the gel collapses and fluidizes. Further, when a growth-immobilized product of the above-described microorganisms having a pH adjusted to 8.6 was produced, the gel strength was weak, and the product became gunky and easily collapsed when taken out from the container.

On the other hand, the final pH is 6.5, 7.0, 7.
If the above-mentioned microorganism growth and immobilization product adjusted to 8, 7.9, 8.0, and 8.5, respectively, is solidified, it does not weakly crack upon impact, elasticity is secured, and strength is high. It did not collapse when taken out of the container. Further, it was found that the viable cell count of the microorganisms in culture survived 10 ⁶ or more in 1 g of the gel carrier. Also, the pH
The growth and immobilization products of microorganisms adjusted to 8.1, 8.2, 8.3 and 8.4 all have a viable cell count of at least 10 ⁸ -1.
The order was ⁰⁹ orders, which proved to be the optimum environment.
Also, in this pH region, the shape and shape are particularly stable,
It does not crumble, crack, fluidize, or has an odor, is easy to carry and move, and is extremely easy to handle.
If you fill the container further, you can culture it there,
Moreover, it was found that PVA has elasticity and is excellent in peelability from the container.

When the pH range usable for the purpose of the present invention was measured, it was pH 6.5-8.5.

[0030]

Industrial Applicability According to the present invention, a microorganism is transplanted in a gel carrier containing a water-soluble silicic acid compound and polyvinyl alcohol as main components and containing a medium and water. The final pH is preferably 6.5. To 8.5, more preferably 8.1 to 8.4, the growth and immobilization product of the microorganism is adjusted, so that the survival of the microorganism is ensured in the gel carrier and the growth is performed well, and the microorganism is released. It can be leached into the aquatic environment and can continuously supply a large amount of microorganisms locally. In addition, the composition of the microbial growth and immobilization product is chemically stable, has physical strength, can be used for a long period of time, and has a decomposition property without the gel carrier remaining in the environment and destroying the environment. The degradation product is not toxic.

Further, the shape is stable, it does not crumble, crack, fluidize, or has an odor, is easy to carry and move, is extremely easy to handle, and can be cultivated after being filled in a container. It has excellent peelability and does not float in water.

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area // (C12N 11/04 C12R 1:01)

Claims (13)

[Claims] 1. A growth and immobilization product of a microorganism in which a microorganism is transplanted in a gel carrier containing a water-soluble silicic acid compound and polyvinyl alcohol as main components and containing a medium and water. 2. The growth-immobilized product of the microorganism according to claim 1, wherein the final pH is adjusted to 6.5 to 8.5. 3. The growth-immobilized product of the microorganism according to claim 1, wherein the final pH is adjusted to 8.1 to 8.4. 4. The microorganism immobilization product according to claim 1, 2 or 3, wherein the polyvinyl alcohol has an acetate residue of 30 to 40% and a degree of polymerization of 500 to 2000. 5. The microorganism immobilization product according to claim 4, wherein the mixing ratio of polyvinyl alcohol and the water-soluble silicic acid compound is 1.5: 1. 6. The microorganism according to claim 1, which is a photosynthetic bacterium.
A growth-immobilized product of the microorganism according to 2, 3, 4 or 5. 7. The growth-immobilized product of a microorganism according to claim 6, wherein the microorganism is a purple sulfur bacterium and / or a purple non-sulfur bacterium. 8. The microorganism according to claim 6, which is a microorganism belonging to one or more of the genus Rhodobacter, the genus Rhodopseudomonas, the genus Rhodosvirilium, and the genus Chromatium.
A growth-immobilized product of the described microorganism. 9. The growth-immobilized product of a microorganism according to claim ^{6, wherein the} number of viable microorganisms in culture is 10 ⁶ or more in 1 g of the gel carrier. 10. The growth-immobilized product of a microorganism according to claim ⁹ , wherein the viable cell count of the microorganism is 10 ⁶ to 10 ⁹ . 11. The microorganism immobilization product according to claim 6, 7, 8 or 10, wherein the microorganism comprises a plurality of genera adsorbed on sludge and / or humus. 12. The microorganism immobilization product according to any one of claims 1 to 11 is introduced into an aquatic environment such as an aquaculture farm, a river, a paddy field, a wastewater treatment plant, and the like, to simultaneously dissolve the gel carrier and grow the microorganism. , A method of using a growth-immobilized product of microorganisms, which releases the microorganisms to the aquatic environment in a controlled manner. 13. An alkaline component solution of a water-soluble silicic acid compound, an acid component solution of polyvinyl alcohol, a culture medium, water and a culture solution of a microorganism are mixed and stirred to give a final pH of 6.5 to 8.5.
A method for producing a growth-immobilized product of a microorganism, which is adjusted to a gel and is gelled.