JPH034512B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing a porous porcelain structure that can be used as a bioreactor, a material, a sound absorbing material, a heat insulating material, an aeration tube, or the like.

(Prior art) There are various methods for immobilizing microorganisms, enzymes, etc., such as carrier binding method, crosslinking method, entrapping method, and composite method. It will be done.

The lattice type is a method in which the enzyme is wrapped in a gel lattice, and ceramic porous bodies are increasingly being used as a holder for the gel lattice because ceramic has advantages such as chemical resistance and microbial resistance.

(Problems to be solved by the invention) However, in the conventional technology, enzymes, bacterial cells, etc. There were problems such as spillage, product contamination, reduced yields, and increased manufacturing costs.

(Means for Solving the Problems) The present invention was made as a result of intensive studies to solve the above problems, and is a method for forming fibrous crystals of silicon nitride in porous porcelain. Based on the idea, we first manufactured porous porcelain, filled the pores with silicon powder, and then fired it in a mixed gas atmosphere of hydrogen and nitrogen to create fibrous crystals of silicon nitride in the pores. This technology succeeded in forming a 100% polyurethane, overcoming the problems of the prior art.

(Function) According to the present invention, the pores of porous porcelain contain desired active fibrous crystals (whiskers) of silicon nitride.
Since the pores are filled with fibers, the gel is firmly fixed in the pores by the fibers, and the amount of microbial enzymes etc. that flows out can be significantly reduced.

Example 1 Silicon powder (1st grade reagent 200 mesh pass)...300g Tertiary butyl alcohol...240ml Hydroxypropyl cellulose (HPS-SL manufactured by Nippon Soda)...3g More than this were put into an alumina porcelain pot mill with an internal volume of 1 (15mmφ99.9 % alumina coccule (1 kg)) Grind and mix for 72 hours. Transfer the slurry obtained in this way to a beaker and pour into it alumina porous porcelain (average pore diameter 70 μm, porosity 62%, size 50 mm).
×80mm×5mm).

The beaker is placed in a vacuum deaerator to remove the air inside the porous body, and then returned to atmospheric pressure to allow the slurry to permeate into the pores.

The product obtained in this way was heated in a mixed gas atmosphere of 60% by volume of nitrogen gas and 40% by volume of hydrogen gas.
It was fired at 1380°C for 1 hour. Baked products are the first
As shown in (micrographs) in Figures to Figure 3, the insides of the pores are filled with fine silicon nitride fibers.
(Magnification of each figure: ×200, ×500, ×2000) Therefore, the gel is firmly fixed in the pores by the fibers, and the amount of microorganisms, enzymes, etc. that leak out can be significantly reduced.

Example 2 A honeycomb was formed using spinel (MgAl ₂ O ₄ ) material, and enzyme immobilization and fermentation tests were conducted.

(1) Creation and firing of honeycomb structure Spinel (MgAl ₂ O ₄ : Iwatani Chemical) 1000g polyvinyl alcohol 100g water 500ml or more are dissolved and mixed in a kneader for 1 hour to form a paste.

This is set in a simple extrusion molding machine (manual type), extruded into a kerosene bath cooled to -15°C below freezing with dry ice, and frozen.

The dimensions of the honeycomb molded body are as shown in Figure 4: length 100mm, diameter 50φmm, pitch 3mm, wall thickness.
It is 0.5mm.

The two frozen molded bodies are placed in a freeze dryer and dried for 6 hours.

The dried product is fired in an electric furnace at a temperature of 1680°C for 2 hours.

The fired body is a porous body with a porosity of 60% and an average pore size of 30μ.

Note that the dimensions remained the same as at the time of molding.

(2) Silicon impregnation and baking treatment One of the fired products was treated using the same silicon slurry and impregnation method as in Example 1, and baked under the same conditions.

This material has a tissue structure in which silicon nitride fibers are formed in pores.

(3) Enzyme immobilization Mix 35 g of K-carrageenan and 1000 ml or more of water, heat to 80°C to dissolve, and then allow to cool.

Separately, prepare 15 ml of a sake yeast suspension and mix it with the carrageenan solution.

Two types of honeycombs are immersed in this mixed solution, vacuum degassed to remove air, and then the pressure is returned to atmospheric pressure to impregnate the pores with the solution.

On the other hand, prepare 2000 ml of 1.5% KCl solution and soak the honeycomb in this solution to gel the impregnating solution.

The yeast-immobilized gel thus obtained was soaked in 1500 ml of culture solution and cultured at 30°C for 5 days.

In this way, a honeycomb-shaped immobilized yeast gel is obtained.

(4) Alcohol fermentation test A fermentation test was carried out using a fermentation apparatus as shown in Figure 5 by adding 300 ml of a fermentation liquid containing glucose as the main ingredient.

The outline of the device is shown in Fig. 5.
is installed in the device 2. A condenser 3 is attached to the upper part of the device 2, and cooling water is caused to flow in the direction of the arrow for cooling. In addition, the device 2 is connected with a pipe so that the fermentation liquid circulates from the upper side to the lower end, and a constant temperature water tank 5 is installed in the middle.
A heat exchanger 4 and a circulation pump 6 are provided in this order. The lower part of the device 2 is also connected to an air pump 7. Further, the upward flow rate of the fermentation liquid in the device 2 is tcm/sec, and the flow rate in the pipe is 4300 ml/min.

The results of a fermentation test using this apparatus are shown in FIG.

According to this, the honeycomb structure according to the present invention can obtain a high alcohol concentration in a short period of time, whereas the untreated one shown as a comparative example has a lower alcohol production rate. In the case of the invention, no blockage was observed in the honeycomb cells, but in the case of the comparative example, it was observed that the immobilized gel had peeled off from the pores and partially blocked the honeycomb cells.

In carrying out the present invention, the material of the porous porcelain is not limited to the above-mentioned alumina, and titania, silica, zirconia, etc. may also be selected as appropriate.

Effects of the Invention According to the present invention, fibrous crystals of silicon nitride can be generated in the pores of porous porcelain by an extremely simple method, and the manufactured product can be produced in the pores of the conventional simple porous porcelain. The remarkable increase in the surface area of fibrous crystals compared to the surface area and the lattice defects of fibrous crystals provide a porous carrier with excellent adsorption and binding properties, and the carrier itself is dimensionally stable. stability, stability against bacteria, stability against PH changes and chemical attack of the solution,
It can exhibit excellent performance such as thermal stability, enabling reuse of degraded enzymes by high-temperature combustion, and long-term stability of the activity of immobilized enzymes. In addition to enzymes, it can be used to separate and purify microorganisms, biochemical substances, and immobilize microorganisms, and can also be applied to a wide range of fields such as reaction tubes, materials, sound absorbing materials, heat insulation materials, and aeration pipes. Needless to say, it is possible.

[Brief explanation of drawings]

Figures 1 to 3 are micrographs showing the shape of silicon nitride fibers. FIG. 4 is a perspective view of the dimensions of the honeycomb structure used in the test, FIG. 5 is a simplified illustration of the alcohol fermentation test apparatus, and FIG. 6 is a graph of the fermentation test results. 1... Honeycomb structure, 2... Device, 3... Condenser, 4... Heat exchanger, 5... Constant temperature water tank,
6...Circulation pump, 7...Air pump.

Claims (1)

[Claims] 1 Fill the pores of porous porcelain with silicon powder,
A method for manufacturing a porous ceramic structure, characterized by forming fibrous crystals of silicon nitride in pores by firing in a hydrogen and nitrogen mixed gas atmosphere.