JPS63148979A - Electrodialytic fermentation - Google Patents

Abstract

PURPOSE:To prevent deterioration of a microorganism and improve efficiency of fermentation, by the presence of polyphosphoric acid or a salt thereof in a fermentation liquor in continuing fermentation while separating a fermentation product by electrodialysis. CONSTITUTION:The anode 2 and cathode 3 are provided in an electrodialytic cell 1 and two pairs each of cation exchange membranes 4 and anion exchange membranes 4 are placed between both the electrodes 2 and 3 to divide the interior of the electrodialytic cell 1 into an anode compartment 6, concentration chamber 7, dilution chamber 8, concentration chamber 7 and cathode compartment 9. A fermentation liquor is circulated through the dilution chamber 8, cathode compartment 9 and fermenter 11 and a fermentation liquor is circulated through the concentration chamber 7 and recovery tank 12. In the process, polyphosphoric acid or a salt thereof is added to the fermentation liquor. Triphosphoric acid, particularly tetra- or higher phosphoric acid is preferred as the polyphosphoric acid. The amount of the polyphosphoric acid or salt thereof is preferably 0.02-0.2g to 1l fermentation liquor.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to electrification dialysis, in which fermentation is carried out while electricity is applied to the fermentation liquid, and the resulting product is separated from the fermentation liquid by electrodialysis using an ion exchange membrane. Regarding fermentation methods.

[Prior Art and Problems to be Solved by the Invention] In the microbial industry, as a method for improving the productivity of target substances through fermentation, an energizing fermentation method is known in which the fermentation liquid is over-electrified (Japanese Patent Publication No. 47 -15745). This method involves immersing any two of the standard electrode, cathode, and anode in the emitting solution and applying a voltage between the two electrodes, which has the advantage of increasing the amount of the target substance produced. There is. After that, we took full advantage of the advantages of this electrification fermentation method, and
In order to separate the target substance produced by fermentation from the fermentation solution, a cation exchange membrane and an anion exchange membrane are placed between the anode and the cathode, and the fermentation solution is supplied to the cathode chamber to separate the target substance produced by fermentation. Attempts have been made to separate target substances by electrodialysis. [Applied and Environmental Microbiology
nd Enrirona+@nta1miarolio
log7 Vol. 52, No. 2, pp. 314-319 1986
)]. Compared to the method of simply applying electricity to the fermentation liquid, this method allows the target substance to be separated from the fermentation liquid extremely quickly.
It also has the advantage of being easy to perform. However, when we actually try to implement the above method, we find that the excellent effects of the energized fermentation method described above can be obtained immediately after startup, but as time passes, the increase in the amount of target substance produced reaches a plateau. However, a problem has arisen in that the amount of the target substance produced cannot be increased using the above-mentioned electric fermentation method.

[Means for solving problems]

Therefore, the present inventors developed a method (
We have been conducting extensive research in order to solve the problems in the electrification dialysis fermentation method (hereinafter referred to simply as the electrification dialysis fermentation method) and to increase the amount of the target substance produced. As a result, it was found that the problems of the above-mentioned electrical dialysis fermentation method were caused by a decrease in the growth of microorganisms present in the fermentation liquid. As a result of further research on ways to prevent the decline in microbial growth,
The present inventors have discovered that excellent effects can be obtained by using polyphosphoric acid or its soil as a phosphate ion source added to fermentation broth for culturing microorganisms, and have completed the present invention.

That is, the present invention provides an electrodialysis tank in which a cation exchange membrane and an anion exchange membrane are disposed between an anode and a cathode, in which a product obtained by fermentation is separated from a fermentation solution by electrodialysis. This dialysis fermentation method is characterized by the presence of polyphosphoric acid or a salt thereof in the fermentation liquid.

As the polyphosphoric acid used in the present invention, any known polyphosphoric acid can be used without any restriction. Specific examples of polyphosphoric acids used in the present invention include chain polyphosphoric acids such as birophosphoric acid, triphosphoric acid, tetraphosphoric acid, pentaphosphoric acid, and hexaphosphoric acid; Acids, cyclic polyphosphoric acids such as hexa-metaphosphoric acid can be mentioned. In addition, as the salt of polyphosphoric acid, the above-mentioned metal salts of poly-I phosphoric acid can be used without any limitation, but in particular, alkali metal salts such as sodium salt, potassium salt, etc., or magnesium salt, calcium salt, barium salt, etc. alkaline earth metal rings are preferred. As the polyphosphoric acid or its salt used in the present invention, triphosphoric acid or tri-metaphosphoric acid or more chain or cyclic phosphoric acid is preferably a salt thereof.
Phosphorus modified or linear or cyclic poly-I phosphoric acid of 4 or more metaphosphoric acids or a salt thereof is preferable because it facilitates microbial growth and production of the target substance.

The amount of the salt of the above-mentioned poly-IJ IJ phosphoric acid used is not particularly limited, but from the viewpoint of increasing production by fermentation, it is added to the fermentation solution from 0.007.9/d to 1.0/d.
#/dj further αo 21/ / all ~ 0.217
It is preferable to make it exist in the range of 64 degrees.

The current dialysis fermentation method of the present invention can be applied to any known fermentation as long as the product is tortoiseshell. For example, amino acid fermentation such as glutamic acid fermentation, lysine fermentation, valine fermentation, ornithine fermentation, homoserine fermentation, threonine fermentation, and inleucine fermentation; nucleic acid fermentation such as inosinic acid fermentation and guanylic acid fermentation; citric acid fermentation, hexamaric acid fermentation, Organic acid fermentation such as lactic acid fermentation, halogen fermentation, acetic acid fermentation, gluconic acid fermentation, pyruvic acid fermentation, α-tetoglutal sporadic formation, itaconic acid fermentation, malic acid fermentation;
Fatty acid fermentation; antibiotic fermentation, etc. can be mentioned.

In addition, various culture conditions such as the type of microorganism used in the fermentation of the present invention, the composition of the medium, the culture temperature, the pH of the single-shot culture solution, the degree of aeration and agitation, etc., are the same as those known in the above-mentioned various fermentations. The conditions are adopted without any restrictions.

At this time, as a medium to be used, either a synthetic medium or a natural medium can be used as long as it contains a suitable amount of a nitrogen source, inorganic substances, and other growth promoting substances in addition to the main carbon source, but when performing electrodialysis, It is desirable to use a synthetic medium as much as possible in order to prevent clogging, deterioration, etc. of the ion exchange membrane, resulting in an abnormal increase in voltage and a decrease in the current effect.

For example, commonly used carbon sources include sugars such as sucrose, galactose, 7-lactose, glucose, starch, maltose, rhamnose, xylose, and lactose; alcohols such as methanol, ethanol, n-propyl alcohol, and glycerin; n-paraffin There are chain hydrocarbons such as, and these may be used in combination. Nitrogen sources include ammonia, ammonium sulfate, ammonium,
Inorganic or organic nitrogen compounds such as ammonium nitrate, ammonium phosphorus, urea, ammonium acetate, ammonium chloride, etc. are used. Usually these include a phosphate source.

Potassium source, magnesium source, sulfur source, iron source.

In addition to these metal salts as a manganese source, growth promoting substances such as biotin and thiamine, and calcium carbonate as a pH lowering preventive agent may also be added.

In the present invention, as the microorganism used in fermentation, the culture solution of bacterial cells can be used directly as it is, but it is more preferable to use one that has been immobilized by a known method. For example, as a method of immobilization, bacteria collected from a culture solution by centrifugation or filtration are suspended in saline solution, and the bacteria Ili! Polyvinyl alcohol and polyacrylamide are added to the cloudy liquid.

Kappa carrageenan, calcium alginate, photocrosslinkable resin prepolymer, collagen, cellulose succinate, casein succinate), methyl acrylate,
Examples include a method of obtaining immobilized microbial cells by adding a carrier such as a methacrylic acid copolymer, a crosslinking agent, or an entrapping material.

In the present invention, it is a preferred embodiment that a substance that undergoes reversible redox is present in the fermentation liquid. Such substances include metal ions such as iron, manganese, copper, zinc, cobalt and lead; iron-containing complex compounds such as red blood salt and yellow blood salt; methyl viologen and benzyl viologen.

Examples include redox dyes such as 22-tral red and neutral violet. The amount of these substances to be used is not particularly limited, but considering the fermentation equipment, generally 0.11+9/dj to 10
It is preferable to use it within the range of (1)/d4.

The electrodialysis tank used in the current dialysis fermentation method of the present invention can be any electrodialysis tank used in normal electrodialysis without any limitations. An example of an electrodialysis tank used in the present invention is shown in FIG. 1. In the figure, l is an electrodialysis tank in which cation exchange membranes 4 and anion exchange membranes M5 are alternately arranged between an anode 2 and a cathode 3. This electrodialysis tank 1 includes two pairs of cation exchange #4 and anion exchange #5.
It is divided into 5 rooms by. These 5 houses are positive [i
In order from the chamber where chamber 2 is present, the anode chamber 6. Concentration chamber7. Dilution chamber8. ll1li7 and cathode chamber 9. Although FIG. 1 shows an example in which two pairs of cation exchange membranes and anion exchange membranes are used, the number of these ion exchange membranes may be one pair, or three or more pairs.

Any known cation exchange membrane and anion exchange membrane can be used without any restriction. In this case, medium components 9 necessary for the growth of bacteria present in the fermentation liquid, such as magnesium, manganese, and iron.

It is preferable that the fermentation product has excellent selective permeability to various salts such as potassium and sodium. Also, ultraviolet rays, γ-rays, and alcohol.

It is desirable to use a material that can be sterilized using a surfactant, a chlorine-based disinfectant, heating, etc., and that can also be washed. In the present invention, a preferred cation exchange membrane has a sulfonic acid group, and an anion exchange membrane has a quaternary ammonium ring group 1 containing Ti. Furthermore, as the anion exchange membrane, one having an average pore diameter of 100λ or less is preferably employed in the present invention.

Next, as the anode 2, platinum, black ship, copper, etc. are preferably used, and as the cathode 3, platinum, iron, stainless steel, etc. are preferably used. The anolyte and catholyte can be used or obtained from known ones, but generally a sulfuric acid aqueous solution is used as the anolyte and a water i'r sodium oxide aqueous solution is used as the catholyte. Furthermore, as will be described later, the fermentation liquid can also be passed through the cathode chamber without using the catholyte. Between the anode 2 and the cathode 3, a direct current m[
10 are connected.

The fermentation liquid cultured in the fermenter] 1 is led to a dilution chamber 8 and a shade chamber 9, and the products produced by fermentation pass through an anion exchange membrane 5 and move to a concentration chamber 7. On the other hand, the fermentation liquid is collected into the fermenter 11. The fermentation product transferred to the concentration chamber 7 is collected in the recovery tank 12 together with the concentrated liquid that is being circulated to the concentration chamber 7. In FIG. 1, a fermentation tank 11 and an electrodialysis tank 1 are provided independently, and fermentation and electrodialysis are performed in separate tanks. And/or fermentation can also be carried out in the cathode chamber 9.

Although FIG. 1 shows an electrolytic deposition tank in which the fermentation solution is introduced into both the dilution chamber and the cathode chamber, the fermentation solution may be introduced into either one.

Next, FIG. 2 shows an example of an electrodialysis tank suitably used for carrying out electrification dialysis fermentation continuously for a long period of time. In this electrodialysis tank, a PH controller 13 measures the PH'ik of the fermented liquid in the fermenter 11 and controls the direct current 110 between the anode and cathode on/off or current according to the measured value.
is included. As a result, electrodialysis is started or the current density is increased when the concentration of the target substance produced by fermentation exceeds the concentration that causes bacterial growth or inhibits injection, and is out of the optimum pH range for fermentation. Control such as separating the target substance from the fermentation liquid is possible.

The electrodialysis cell as described above is generally operated at a voltage of 0.1 to 35 ports and a current density of 1.6 to 10 ampere/aj. By adopting such conditions, stable operation for usually 3 to 30 days is possible. Further, when the above-mentioned immobilized microbial cells and the electrodialysis tank capable of PH control shown in FIG. 2 are used, continuous operation for 3 to 8 months is also possible.

[Effect] By adopting the current dialysis fermentation method of the present invention, it becomes possible to perform stable fermentation over a long period of time,
Be able to increase the production of the desired fermentation product. That is, as is clear from Example 1 and Comparative Example 1, which will be described later, polyphosphoric acid (Wako paper ta > tt [Example added to], the amount of bacterial cells after 72 hours of culture was 0.4 at absorbance at 660 nm,
The total production amount of L-lactic acid by fermentation reached &0.9 per 18 of the medium used. On the other hand, in Comparative Example 1, in which potassium dihydrogen phosphate, which has been conventionally used in culture medium as a phosphate ion source, was used, and other conditions were the same as in Example 1, energization fermentation was carried out. is suppressed to 0.2, and the production amount of 1, L-8 Shun is only 20 I/a.

The values of Example 1 are based on the conventional energization fermentation method, which uses potassium dihydrogen phosphate and 10% calcium carbonate as a pH adjuster, and is not electrification dialysis fermentation using ion exchange vibration. This value is the same as that obtained in Comparative Example 2.

As described above, according to the current dialysis fermentation method of the present invention, potassium dihydrogen phosphate or sodium phosphate, dipotassium hydrogen phosphate or sodium phosphate, or a combination thereof, which has been added to a normal medium as a phosphate ion source, can be used. Compared to conventional methods, the amount of bacterial cells after culturing for a certain period of time and the amount of the target substance produced by fermentation are large, and the excellent effects of energized fermentation can be obtained. Moreover, the present invention allows the target substance to be quickly and easily separated from the fermentation liquid while generating ##STR17##, thereby eliminating the feedback inhibition of fermentation caused by the target substance, and preventing changes in pH and viscosity of the fermentation liquid. It is possible to prevent the fermentation production ability of the bacterial cells from decreasing.

Furthermore, calcium soil, which is commonly used as a pH adjuster, promotes the infiltration of 7-age, which inhibits the growth of bacterial cells, but according to the present invention, the target substance produced by fermentation is There is no need to use such a PHII4 regulator as it can be immediately separated from the fermentation broth. Therefore, according to the present invention, it is possible to prevent bacterial cells from being contaminated by 7Age. Furthermore, since polyphosphoric acid has the effect of suppressing the infiltration of phages into the body, it is possible to prevent 7age contamination from this point as well.

As a result of these, the present invention has an excellent effect of making it possible to continuously and stably generate a signal for a long period of time.

〔Example〕

Example 1 and Comparative Example 1.2 Lactobacillus delpurz 1.2 IF03534, which is an L-lactic acid producing bacterium, was used as a seed strain. glucose 1
−o 1 /d1. yN IJ Peptone 5.01/d
Dispense 10− of a liquid medium (PH 7,0) consisting of yeast
High-pressure steam sterilization was performed at 21° C. for 15 minutes. Dan i to this
A 1" tl platinum loop was inoculated and static culture was carried out at 45°C for 24 hours. This culture solution 10- was inoculated with 100- of similarly sterilized glucose 1.OJ!/dj, polypeptone 1.0.9
/#, ll mother engineered cow α51/d1. sodium acetate J
, OJI/dt was inoculated into a liquid medium (PH 6, 8), and a seed mother was prepared by statically culturing at 45° C. for 15 hours.

The medium for main culture is glucose 10. Oj' /
dl, yeast x't
Rehefton α8 i /dJ, 4lin II α02
117d1. Magnesium sulfate 7 water α0517dl
Using 0.0117 dl of common salt, the pH was set to 7.2.

When carrying out electrification dialysis fermentation using the electrodialysis tank shown in Figure 2, the above medium 5.
After dispensing QQLt and sterilizing it, place it in the room? After cooling with ilt, the seed mother 50- was inoculated and cultured at 45° C. with gentle stirring.

In order to carry out electrification dialysis fermentation, a PH electrode for fermentation (Atovanchik FX-180) was attached to the fermenter in advance.
T) connected to a DC power supply (Takasago Seisakusho MPO35-2)
DII). Furthermore, a DC power supply was connected to each electrode of the electrodialysis tank, so that when the pH of the fermentation liquid fell below a specified value, current automatically flowed to the electrodialysis tank, allowing electrodialysis to occur. . Anion exchange membrane (Neocepta A CH-45T manufactured by Tokuyama Soda) and cation exchange membrane (Neocepta CH-45T manufactured by Tokuyama Soda ■)
45T), copper is used for the anode, platinum is used for the cathode, and 0.1NH2So is placed in the anode chamber as the electrolyte.
, 0.1N NaOH was used in the cathode chamber, and deionized water was circulated in the concentrated Jl chamber and recovery tank using a microtube pump (manufactured by Tokyo Rika Corporation, MP-3).

In electrification dialysis fermentation, the pH of the fermentation liquid is adjusted approximately 7 hours after the start of main culture.
When the temperature decreased to 4.7, the fermentation liquid was circulated to the dilution chamber using a microtube pump and started. The total production amount of L-8 powder in the fermentation liquid and the recovery tank was converted per 1 a of the medium used, and the amount of bacterial cells in the fermentation liquid was shown in j13FiJ.

The amount of L-lactic acid in the fermentation liquid and in the recovery tank was determined by the Barker-Summerlan method. The amount of bacterial cells is the culture solution I
After dilution with N-sulfuric acid, its 660 n! 11
The absorbance was measured using a spectrophotometer (Kamishimazu UV-240).
Measured using

As Comparative Example 1, instead of tetraphosphate in the main culture medium,
Electrodialysis fermentation was carried out in the same manner as in Example 1 above, except that 0.21/a of potassium dihydrogen phosphate was used.

Further, as Comparative Example 2, 0217 dl of potassium dihydrogen phosphorus was used in place of 4 phosphorus in the main culture medium, and 10.0 dl of calcium carbonate was dry-heat sterilized at 160° C. for 90 minutes as a pH adjuster. P/(except for adding #,
Culture was carried out in the same manner as in Example 1 and Comparative Example 1, but
As in Example 1 and Comparative Example 1, conventional electrification fermentation was performed without conducting electrification dialysis fermentation using an ion exchange membrane.

Comparison of these @1. The production amount and total amount of L-Kishun in Comparative Example 2 are also shown in FIG.

In Example 1, in which tetraphosphorus was used as the phosphate ion, the Sonotaiyori after 72 hours of culture was 0.4 (OD660nm).
The total production amount of L-lactic acid was aO & per 1 a of the medium used. On the other hand, in Comparative Example 1, which was used in a potassium dihydrogen phosphate medium, the growth of bacterial cells was 0.
．． 2, and L-milk #l gills were also suppressed to 2.
It was as low as 0.01/dl.

Similarly, in Comparative Example 2 in which potassium dihydrogen phosphate was used as the phosphate ion, L-lactic acid was produced to the same extent as in Example 1, and bacterial cell growth was also observed. However, in this case,
Calcium carbonate and L added to neutralize L-lactic acid
- Since calcium lactate is produced between lactic acid, the viscosity of the fermentation liquid increases as its concentration increases, and the fermentation had to be stopped after 72 hours. In this regard, in Example 1, the L-lactic acid concentration in the fermentation liquid was reduced to 0 by electrodialysis.
．． Since it was controlled to 5F/dj or less (PHa, 5 or more) and no neutralizing agent was required, stable # generation was possible even after 72 hours had passed.

Example 2 The bacterial cells from the seed culture solution used in Example 1 were centrifuged and washed with water. The washing itself was suspended in physiological saline, sodium alginate was added to this one-body suspension for 2 s, the slurry was heated to 30°C, and the slurry was poured into a 0.1 molar calcium chloride solution using a syringe. The mixture was dropped onto the plate and solidified to obtain spherical immobilized bacterial cells. Using these immobilized bacterial cells, sometimes
When energization dialysis fermentation was carried out in the same manner as in Example 1 except for replacing some of the culture medium, it was possible to operate continuously for about 8 months. L-lactic acid is produced by conventional electric fermentation.
I/dl, whereas according to the present invention, a production amount 60 times that amount was obtained.

Example 3 After high-pressure sterilization with koji juice and cooling, add 4 ethanol to this.
．． 097di, inoculated with one platinum loop of acetic acid (Acetobacter aceti IF03281), and incubated at 30°C for 3 to 30 minutes.
Static culture was performed for 5 days. Next, glucose O, 1F/
dj.

Glycerin 0.1.9/l/! j, ammonium sulfate 0
．． 117d1. 41 fi ri: /110.06 y
/dj, RW v f * sim'y 7 water 40. o
1#/dj1mealjJI O,0117d1. #fJi
kx'F7.0.051/dl Kara naru Makaban M (
P H7,0) Ip=tne11.51/di,
x pnor & OF/dj was added, and the above-mentioned culture solution was inoculated at 10%, and acclimatized by static culture at 30° C. for 4 days. A 10% polyvinyl alcohol aqueous solution was added to the culture solution obtained in this manner in an amount of % by volume, and the suspension was freeze-dried to prepare immobilized bacterial cells. The same medium was used for the main culture, and 10% (V
/V), and electrification dialysis fermentation was carried out in the same manner as in Example 1 while controlling the pH to 4.5. Also, in place of 4-metaphosphoric acid, 0.2. ! i
'/dl was used. The total concentration of acetic acid produced (1!
/Ω) changes over time are shown in Table 1.

Table 1 Also, the energized dialysis fermentation could be operated continuously for about 3 months.

Example 4 Chiyandida guiyamandi IFO0566, which has citric acid-producing ability, was used as the microorganism. Cane sugar 5.0.9
/dJ? , asparagine 0.25.9/d1.5 phosphorus @
0.02 fl/dl, magnesium sulfate 7 water 0.05
#/cu, calcium carbonate! (1/dj liquid medium (PH 6,0), 1 platinum ear scion from the medium, 3
After culture with shaking at 0°C for 2 days, the bacteria were collected by centrifugation. This bacterial cell 81 was suspended in 0.9% saline solution 50114, and this R suspension was added to N,N-dimethylvinylbenzylamine poly!
Acetone 50-41 and 5 mg of 4,4'-bis(dimethylamino)benzophenone were added to emulsify the mixture, and the mixture was irradiated with light using an ultra-high pressure mercury lamp at 25°C for 2 hours. Vacuum dry the generated immobilized gel for 2 to 3*d
A fixed tooth body was prepared using the particles. The medium for main culture is glucose 10.017d1. m-7 mmoni 7
0.41/dj.

5 phosphate α021/dt, magnesium sulfate 71 m o
, osi, /d1. jllz cow suo, 39/dltp
Immobilized bacterial cells were inoculated at 10.0% (V/V) into a liquid medium (PH6,0),
C9200 rpm of aerated stirring was performed, and electrification dialysis fermentation was performed for 5 days while controlling the pH at 4.8, and 1317 dl of citric acid was produced in terms of the medium used. In addition, we were able to continue conducting electrification dialysis for more than 3 months.

Example 5 L-glutamic acid producing Brevibacterium 7 labum AT CC13826 was used as the inoculum. As a seed medium, glucose 5.0g7d1. urea 10g
/dj, 51 fi') >FR power! J Tsu Ao
, 0211/'#+magnesium sulfate 7 water mound 0.04.
9 /clj, 1llllji-a 7 Wed 11211
9/d-g.

Bionashi α4μm1fud1. Thiamin acid #A2op&
/ dl, Corn X t Evely Power o, 5p7c
A liquid medium (PH7,0) consisting of u was used. One platinum loopful of slant culture was inoculated into this medium, and the temperature was kept at 30°C.

Shaking culture was performed for 36 hours and collected by centrifugation.

This itself 10.9 was clouded with 0.9% saline solution 50d&:M,
4. Heat the slurry together with the No. 4 copper carrageenan and drop it into a 2≦potassium chloride solution from a syringe.
The cells were left to gel in a spherical shape to obtain immobilized bacterial cells.

As a medium for main culture, glucose 1o-oF/d! , Urea L 8 Ji' / "J p 51 Potassium talate 0.04.f/dj, Magnesium sulfate 7 Water 0
．． 041 /dj, am ferrous 7 water 2 Q/dl.

Manganese sulfate 4 water 2 liters 7 dl, biotin 0.4μ
m17di, thiamine hydrochloride 10 μm7/d1. Casamino acids o, 11/d1. Neutral red 0.3m9
A liquid medium consisting of /dj was used. This medium was inoculated with 1000% (V/V) of immobilized microbial cells, and the pH was adjusted at 30°C.
When electrification dialysis fermentation was carried out for 3 days while controlling the temperature to 7.5, the result was 4.11/dl in terms of the medium used.
of L-glutamic acid was produced.

1. The energized dialysis fermentation system could be operated continuously for more than three months.

[Brief explanation of the drawing]

Figure N1 and Figure 2g:J are schematic diagrams showing a preferred example of an electrodialysis tank used in the electrification dialysis fermentation method of the present invention. In the figure, l is an electrostatic chamber, 2 is an anode, 3 is a cathode, 4 is a cation exchange membrane, 5 is an anion exchange membrane, 6 is an anode chamber, and 7 is a concentration chamber. 8 is a dilution chamber, 9 is a cathode chamber, and 10 is a DC power supply. 11 is a fermentation tank, 12 is a collection tank, 13 is a PH controller, and 14 is a circulation pump. Further, FIG. 3 is a graph showing the relationship between the culture time and the amount of milk powder produced by the current dialysis fermentation method of the present invention and the conventional method, and the relationship between the culture time and the produced whole milk powder.

Claims (1)

[Claims] (1) Electrodialysis in which the products obtained by fermentation are separated from the fermentation solution by electrodialysis in an electrodialysis tank with a cation exchange membrane and an anion exchange membrane arranged between the anode and the cathode. An electric dialysis fermentation method characterized in that polyphosphoric acid or a salt thereof is present in the fermentation liquid.