JPH056996B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides vitamin _B12 , which has not been previously described in any known literature.
The present invention relates to producing bacteria, particularly propionic acid-resistant vitamin _B12 producing bacteria belonging to the genus Propionibacterium itself, and a method for producing the producing bacteria. Conventionally, vitamin _B12- producing bacteria belonging to the genus Propionibacterium, such as Propionibacterium shermanii and Propionibacterium freudenreichii, have been used.
A method for producing vitamin B ₁₂ is known in which B ₁₂ -producing bacteria are cultured and vitamin B ₁₂ accumulated within the cells is collected (for example, US Pat. No. 2,951,017 (1960)). These vitamin B _12- producing bacteria belonging to the genus Propionibacterium, which are also commonly called propionic acid bacteria, exhibit propionic acid fermentation metabolism and produce and accumulate large amounts of propionic acid in the extracellular culture system. The present inventors utilized vitamin _B12- producing bacteria belonging to the genus Propionibacterium to produce vitamin _B12 .
We have been conducting research on the fermentation method for producing vitamin _B12 . As a result, when producing vitamin B ₁₂ by fermentation using vitamin B ₁₂ producing bacteria belonging to the genus Propionibacterium, the growth of the vitamin B ₁₂ producing bacteria stops during culturing, causing problems such as the production of vitamin B ₁₂ stopping. As a result of investigating the cause, we found that propionic acid produced in the culture system gradually accumulates and increases, and when the propionic acid in the culture system accumulates and increases to a certain extent, I learned that this inhibits the growth of vitamin _B12- producing bacteria, stopping their growth and stopping the production of vitamin _B12 . The present inventors have developed a fermentation method using vitamin _B12 -producing bacteria belonging to the genus Propionibacterium.
Research has been carried out to overcome the above-mentioned troubles in the production of B ₁₂ and to develop a method that can produce vitamin B ₁₂ with an improved production amount. As a result, by subjecting a vitamin _B12- producing parental strain belonging to the genus Propionibacterium to a combination of artificial mutagenesis treatment and natural mutagenesis treatment, it was found that the vitamin B12-producing parent strain belonging to the genus Propionibacterium was resistant to propionic acid and significantly increased. We discovered that it is possible to create a strain that can produce vitamin _B12 with improved production. Furthermore, the strain can be cultured under the same culture conditions as the parent strain without requiring special culture conditions, and has a higher production amount of vitamin _B12 compared to the parent strain.
I learned that it is possible to produce vitamin _B12 at a production rate that is approximately double or more. Therefore, it is an object of the present invention to provide a method for producing vitamin B ₁₂ by fermentation, which can produce vitamin B ₁₂ with improved yield. Another object of the present invention is to provide a method for producing propionic acid-resistant vitamin B _12- producing bacteria suitable for use in the above-mentioned improvement method. The above objects and many other objects and advantages of the present invention will become more apparent from the following description. The propionic acid-resistant vitamin B _12- producing bacteria belonging to the genus Propionibacterium, which is a vitamin B ₁₂ -producing bacterium that has not been described in the prior literature of the present invention, is a vitamin B _12- producing bacteria that has not been described in the prior literature. Subjecting to mutagenesis treatment, and culturing the treated strain that survives after the treatment in a liquid medium containing, in addition to carbon and nitrogen sources, propionic acid at a concentration equal to or higher than the minimum growth-inhibiting concentration of the parent strain. subjecting the natural mutagenesis treatment to a vitamin B ₁₂ production amount that is at least about 1.5 times the vitamin B ₁₂ production amount of the parent strain under the same culture conditions; It can be manufactured by subjecting it to a combination process of repeating. Each of the above treatments can be performed multiple times, and the artificial mutagenesis process can be further combined at any point in the repetition of the natural mutagenesis process. The vitamin B _12- producing parental strain belonging to the genus Propionibacterium to be subjected to the above-mentioned artificial mutagenesis treatment includes, for example, Propionibacterium spp.
Shermanii (Propionibacterium shermanii)
IF012391 stock and IFO12426 stock [Institute for
Fermentation, OSAKA, Japan; Freely distributed known bacteria]; Propionibacterium freudenreichii
IF012424 strain [Institute for Fermentation,
OSAKA, Japan; freely available publicly known bacteria] and the like can be exemplified. The above-mentioned exemplary bacterial strains are known freely available bacteria that have been deposited with the above-mentioned depository institutions under the above-mentioned deposit numbers. Also, other vitamins
_{Propionibacterium} siamanii NOC11011 strain [FERM BP-85;
Fermentation Research Institute Agency of
Industrial Science and Technology, Japan; Internationally deposited bacteria under the Budapest Treaty]. Propionibacterium siamanii above
The mycological properties of the NOC11011 strain are similar to those known for the parent strain, except that the sedimentation rate of the bacterial cells when the culture system is allowed to stand still is faster than that of the parent strain Propionibacterium siamanii IFO12391. They are the same. The propionic acid-resistant vitamin B _12- producing bacteria belonging to the genus Propionibacterium of the present invention can be obtained by subjecting a vitamin B _12- producing parent strain belonging to the genus Propionibacterium as exemplified above to artificial mutagenesis treatment, and It can be created by a combination of subjecting the treated strain to the natural mutagenesis treatment described above. The means for the artificial mutagenesis treatment itself is known and can be utilized in the present invention. Such treatment means include artificial mutagenic irradiation treatment such as ultraviolet irradiation treatment, X-ray irradiation treatment, radiation treatment using radioactive substances such as cobalt-60, and irradiation treatment with artificial mutagenic rays such as nitroguanidine and hydroxylamine. , 2-aminopurine, etc. can be exemplified by treatment with an artificial mutagen. Treatment conditions such as irradiation dose and irradiation time in the irradiation treatment can be selected as appropriate. For example, treatment conditions such as ultraviolet rays at a dose of 300 ergs/mm ² for 2 minutes can be exemplified. In addition, treatment conditions such as the amount of inducer used and treatment time in the inducer treatment can be selected as appropriate. For example, treatment conditions such as nitrosoguanidine at a concentration of 100 mg/30 minutes can be exemplified. In the present invention, the parent strain is subjected to artificial mutagenesis treatment as described above, and the treated strain that survives the treatment is used as a carbon source and a nitrogen source as well as a source that minimizes the growth inhibition of the parent strain. Subject to natural mutagenesis treatment by culturing in a liquid medium further containing propionic acid at a higher concentration. This natural mutagenesis treatment is _performed so that the amount of vitamin B ₁₂ produced by the created propionic acid-resistant vitamin B 12-producing strain reaches at least about 1.5 times the amount of vitamin B ₁₂ produced by the parent strain under the same culture conditions. This is repeated until the The minimum growth-inhibiting concentration of the parent strain described above varies depending on the parent strain used, but is about 10 g/medium, and in the present invention, the concentration is higher than this concentration, for example, about 10 g/medium.
~about 30g/medium, more preferably about 15 to about
A liquid medium containing propionic acid at a concentration of about 25 g/medium is used. Further, the number of repetitions of the above-mentioned natural mutagenesis treatment is usually about 5 to 20 times, and a propionic acid-resistant vitamin B _{12-producing strain that exhibits the desired amount of vitamin B 12 production} can be created. In the above-mentioned repeated culture, colonies that grew well in the first propionic acid-containing liquid medium were collected and placed in a separately prepared propionic acid-containing liquid medium.
The bacterial strain grown in the propionic acid-containing liquid medium collected above was inoculated and cultured, and colonies that grew well in this second propionic acid-containing liquid medium were collected,
This can be carried out by repeating inoculation and culturing in the same manner as above. At this time, the above culture can be repeated using a medium in which the propionic acid content in the medium is gradually increased. To illustrate one embodiment, for example, a treated strain that survives after an artificial mutagenesis treatment as described above.
100 colonies were cultured for the first time in a liquid medium containing 20 g of propionic acid for 5 days, and the amount of growth after culture was measured using optical density at 610 nm. The selected 50 strains were cultured for a second time in a liquid medium containing 20 g of propionic acid for 5 days. Similarly, half of the 25 strains with good growth were selected, and a third culture was performed. Repeated culturing can be performed by performing the second culturing for 5 days. By repeating such culture, mutant strains resistant to propionic acid will be induced and accumulated. Finally, culturing is repeated until, for example, a liquid medium containing 20 g of propionic acid can grow almost as well as a liquid medium containing no propionic acid, and the resulting mutant strain is grown. can be isolated as a propionic acid-resistant strain. The medium used to create the propionic acid-resistant vitamin B _12- producing bacteria described above, in addition to containing propionic acid, may also be used to culture the propionic acid-resistant vitamin B _12- producing bacteria described below to produce vitamin B ₁₂ . It is possible to use a medium containing the same carbon source and nitrogen source, and further containing minerals, vitamins, etc., if desired.
As an example of a preferable medium composition, the minimal medium shown below can be exemplified. The propionic acid-resistant vitamin B _12- producing bacteria belonging to the genus Propionibacterium that can be created as described above has greater resistance to propionic acid than its parent strain and has a lower vitamin B ₁₂ production amount than the parent strain. More vitamin B than ₁₂
It differs from the parent strain in that it produces , but other mycological properties are similar to those of the parent strain. For example, Propionibacterium siamanii
NOC11012 [FERM BP−86; Fermentation
Research Institute Agency of Industrial
The mycological properties of Propionibacterium freudenreich NOC11013 are similar to those of its parent strain, Propionibacterium schiermanii IFO12391 strain.
[FERM BP-87; Fermentation Research
Industria 1 Agency of Industrial Science
and Technology, Japan; Internationally Deposited Bacteria under the Budapest Treaty], the mycological properties of Propionibacterium Freudenreich, its parent strain.
It is similar to that of IFO12424 stock. The mycological properties of these parent strains are known, for example,
Bergy's Manual of Determinative
Bacteriology, 8th edition. According to the present invention, it is possible to culture propionic acid-resistant vitamin B ₁₂ -producing bacteria belonging to the genus Propionibacterium, which can be created as described above, and collect vitamin B ₁₂ accumulated within the bacterial cells. Improved fermentation method featuring vitamin B ₁₂
We can provide the manufacturing method. As for the usable medium, culture conditions, etc., those known for the parent strain can be used. As a medium, a medium containing a carbon source, a nitrogen source, and, if desired, further contains minerals, vitamins, vitamin _B12 constituents, etc. can be used. Such carbon sources include carbohydrates, sugars, organic acids,
Alcohols can be used, such as glucose, fructose, mannose, galactose,
Examples include lactic acid and tartaric acid. These other carbon sources can be used alone or in combination as appropriate. Examples of nitrogen sources include inorganic nitrogen compounds such as ammonia salts, nitrates, etc.; for example, peptone, yeast extract, casein, meat extract, corn staple liquor, sun gloss,
Examples include urea, soybean meal, fish meal, and fermentation waste. Additionally, vitamin _B12 components such as 5,6-dimethylbenzimidazole, phosphates, magnesium salts, potassium salts, calcium salts, manganese salts, cobalt salts, iron salts, zinc salts,
Examples include minerals and vitamins such as molybdenum salts, copper salts, aluminum salts, vitamins such as pantothenic acid, and vitamin _B12 constituent classes. The culture is preferably carried out under anaerobic conditions, and preferred examples of the culture method include a static culture method and an aerated agitation culture method using N ₂ gas or CO ₂ gas. The culture temperature is approx.
Temperature conditions of 25° to about 37°C, culture pH of about 4 to
Examples include pH conditions of about 8.5, more preferably about 6 to about 7. The culture pH can be adjusted by adding alkalis such as sodium carbonate, calcium hydroxide, sodium hydroxide, potassium hydroxide, aqueous ammonia, etc. to the culture system at appropriate times to adjust the culture pH according to the above-mentioned examples.
It is best to adjust the PH of the system to within the PH range. Examples of the number of days for culturing include about 3 to about 10 days. Vitamins accumulated in the cells of the propionic acid-resistant vitamin _B12 -producing bacteria formed as described above.
To collect B ₁₂ , culture broth is subjected to centrifugation treatment to separate and collect bacterial cells, and vitamin B ₁₂ is extracted from the bacterial cells.
This can be done by separating and collecting. The vitamin B ₁₂ can be isolated and collected from bacterial cells and further purified by various means. For example, when separating oxygen supplementary vitamin B ₁₂ (5,6-dimethylbenzimidazole cobamide enzyme) from bacterial cells, the collected bacterial cells or bacterial cell membranes are physically removed, such as by grinding. It is possible to extract and separate the crushed bacterial cells from the bacterial cells by extracting them in the dark using an alcohol such as methanol, ethanol, isopropanol, or a solvent such as pyridine. can. In addition, when extracting and separating hydroxocobalamin from bacterial cells, it can be converted to hydroxocobalamin by exposing the extract of oxygen supplementary vitamin _B12 obtained as described above to light. . Furthermore, when extracting and separating from bacterial cells in the form of cyanocobalamin,
Solvents and cyanide salts such as those mentioned above, such as KCN,
By extracting in the presence of NaCN, etc., it can be extracted and separated in the form of cyanocobalamin. According to another embodiment, a liquid of crushed bacterial cells obtained by crushing cell membranes of bacterial cells as described above, or an extract liquid obtained by extracting bacterial cells or their crushed substances with an extraction solvent as exemplified above, etc. Vitamins containing undesirable components such as
It is also possible to purify and separate the B _12- containing liquid all at once by subjecting it to adsorption-elution treatment using an adsorbent.
In this embodiment, it is possible to utilize the means related to the earlier invention of the same applicant. For example, patent applications filed in 1982 by the same applicant.
According to the proposal disclosed in No. 167375, for example, vitamin B ₁₂ containing extraneous components such as the above-mentioned solvent extract of bacterial cells or crushed bacterial cells or liquid of crushed bacterial cells.
The liquid containing divinylbenzene, styrene or a functional derivative thereof, such as an alkyl-substituted derivative having a C ₁ to _{C 6} alkyl group such as methylstyrene, ethylenestyrene, dimethylstyrene, propylstyrene, and the following formula: However, in the formula, R has a carbon-carbon double bond
Aromatic polycarboxylic acid unsaturated alkyl ester represented by _C3 - _C10 unsaturated alkyl residue, n is 2 or 3, for example, triisopropenyl 1,2,4-benzenetricarboxylate ester, di- or tri-C ₃ -C ₁₀ alkenyl esters such as terephthalic acid diisopropenyl ester, and has a surface area of about
Contact with resin of 700 m ² /g or more to adsorb vitamin B ₁₂ to the resin, and the adsorbed vitamin
This can be carried out in such a manner that B ₁₂ is eluted with an eluent to obtain an active elution fraction. The above adsorption and elution can be carried out either in batch mode or in column chromatography mode. The adsorption can be carried out at a pH of about 5 to about 8, preferably about 7, and at a temperature of about 10° to about 30°C. Further, after the adsorption treatment, an active elution fraction can be obtained by performing a washing treatment and an elution treatment if desired. The above-mentioned cleaning treatment includes, for example, water, a low concentration hydrous alcohol such as 5% methanol water, 2%
Examples of cleaning treatments include ethanol water, 1% isopropanol water, and the like. Further, as the above-mentioned eluent, a common eluent can be used, such as an aqueous solution containing an eluent selected from the group consisting of lower alcohols, acids, alkalis, and salts. Specific examples of such eluents include methanol, ethanol,
Lower alcohols such as isopropanol; Acids such as phosphoric acid, acetic acid, boric acid, and hydrochloric acid;
Examples include alkalis such as sodium hydroxide, ammonium phosphate, diammonium phosphate, and ammonium hydroxide; salts such as sodium carbonate, sodium acetate, sodium phosphate, and potassium phosphate. The type of such eluent can be selected as appropriate depending on the type and amount of interfering components, the type of adsorbent resin, etc., but it is preferable to use an aqueous solution of lower alcohols, for example, 25 to 50% Methanol, 15-40
Examples include the use of hydroalcohols having an alcohol content of about 50% or less, such as % ethanol, 6-20% isopropanol, and the like. The elution operation can also be carried out at room temperature, and heating or cooling is not particularly necessary, but may be carried out if desired. For example, operating temperatures of about 30°C to about 60°C can be exemplified. The active elution fraction thus eluted can be obtained and, if desired, subjected to concentration, recrystallization, etc. For example, patent applications filed in 1983 by the same applicant
According to the proposal disclosed in No. 24519, a vitamin _B12 -containing solution containing the above-mentioned impurities was mixed with the most frequent pore size
200 Å or more, preferably about 250 Å or more, for example, about 200 to about
1200 Å and a pore volume of more than 0.6 ml/g,
For example, by contacting with a divinylbenzene/styrene copolymer resin in a range of more than 0.6 ml/g to about 1.2 ml/g, vitamin B ₁₂ is adsorbed to the resin, and the adsorbed vitamin B ₁₂ is eluted. It can also be carried out in such a manner that an active elution fraction is obtained by elution with an agent. Examples of commercially available resins that can be used in this case include Diaion HP-10, HP-20, HO
-30, HP-40, HP-50 (product name: Mitsubishi Kasei Products), etc. Such resins can also be produced by copolymerization reactions of divinylbenzene and styrene or its functional derivatives, such as those exemplified above. The adsorption and elution operations and conditions can be carried out in the same manner as described for the above proposal. After adsorption, the operations and conditions for the washing treatment and elution treatment, which may be carried out as desired, can be carried out under the same operations and conditions as those described for the above proposal. When carrying out the method of the present invention, vitamin _B12 can be collected from bacterial cells as described above and further purified if desired. As the purification means, other known means can be used, for example, phenol extraction means, adsorption means using activated carbon, adsorption means using polymer resin, column chromatography means, etc. can be used in appropriate combinations. Hereinafter, some examples of implementing the method of the present invention will be explained in more detail by way of examples. Example 1 (1) Induction of propionic acid resistant strain Prop. shermanii IFO12391 was subjected to mutation treatment by irradiating it with ultraviolet light (using two 15W germicidal lamps) from a height of 40 cm for 2 minutes. Next, the cells were cultured for 20 days on a flat plate medium containing the minimal medium shown in Table 1 and supplemented with 20 g/propionic acid, which is a concentration higher than that inhibiting the growth of the parent strain, and growing colonies were collected. Table 1 Minimal medium (plate) Glucose 50g Corn steep liquor 40g NH ₄ NO ₃ 3g Na ₂ HPO ₄・12H ₂ O 1.5g KH ₂ PO ₄ 0.4g MgSO ₄・7H ₂ O 0.5g MnSO ₄・4H ₂ O 5mg FeSO ₄・7H ₂ O 10mg ZnSO ₄・7H ₂ O 10mg CuSO ₄・5H ₂ O 0.05mg (NH ₄ ) ₆ Mo ₇ O ₂₄・4H ₂ O 0.01mg Co(NO ₃ ) ₂・6H ₂ O 15mg Calcium pantothenate 5 mg CaCO ₃ 10 g Agar 20 g Ion-exchanged pure water 1 The obtained colonies were cultured 10 times for 5 days in a liquid medium containing the minimum medium shown in Table 2 with 20 g/propionic acid added at a concentration higher than that which inhibits the growth of the parent strain. A strain that did not suffer from growth inhibition was collected. Table 2 Minimal medium (liquid) Glucose 25g Corn steep liquor 40g NH ₄ NO ₃ 3g Na ₂ HPO ₄・12H ₂ O 1.5g KH ₂ PO ₄ 0.4g MgSO ₄・7H ₂ O 0.5g MnSO ₄・4H ₂ O 5mg FeSO ₄・7H ₂ O 10mg ZnSO ₄・7H ₂ O 10mg CuSO ₄・5H ₂ O 0.05mg (NH ₄ ) ₆ Mo ₇ O ₂₄・4H ₂ O 0.01mg Co(NO ₃ ) ₂・6H ₂ O 15mg Calcium pantothenate 5 mg CaCO ₃ 10 g Ion-exchanged pure water 1 Initial pH 7.0 (2) Vitamin B ₁₂ productivity evaluation test 200 ml of the culture medium having the composition shown in Table 3 was placed in a 500 ml Erlenmeyer flask and sterilized with steam at 120° C. for 10 minutes. Add 2 cultures of the parent strain and mutant strain, which were previously cultured for 5 days in the medium shown in Table 2, to the above medium.
ml was inoculated and statically cultured at 30°C for 7 days. The pH during the culture was intermittently adjusted to around 7 using 20% Na ₂ CO ₃ once a day. Table 3 Medium composition Glucose 50g Corn steep liquor 40g NH ₄ NO ₃ 3g Na ₂ HPO ₄・12H ₂ O 1.5g KH ₂ PO ₄ 0.4g MgSO ₄・7H ₂ O 0.5g MnSO ₄・4H ₂ O 5mg FeSO ₄・7H ₂ O 10mg ZnSO ₄・7H ₂ O 10mg CuSO ₄・5H ₂ O 0.05mg (NH ₄ ) ₆ Mo ₇ O ₂₄・4H ₂ O 0.01mg Co(NO ₃ ) ₂・6H ₂ O 15mg Calcium pantothenate 5mg 5, 6-Dimethylbenzimidazole 10mg CaCO ₃ 10g Ion exchange pure water 1 Initial pH 7.0 Quantification of B ₁₂ was performed as follows. In other words, add 4.5 ml of acetic acid buffer (PH4.7) to 0.3 ml of culture solution.
and 1 g of KCN/1 ml of solution were added and boiled at 85°C or higher for 15 minutes to extract _B12 in the bacterial cells with hot water and at the same time convert it into a stable CN form. This is a _B12- requiring bacterium.
Using Lactobacillus leichmannii ATCC7830,
Microorganisms were quantified using cyanocobalamin as a standard. Table 4 shows the results of B ₁₂ quantification of five types of parent strain and mutant strain (propionic acid resistant strain: expressed as PAr). The B ₁₂ production of the mutant strain was twice that of the parent strain.

[Table] Example 2 Using Prop. freudenreichii IFO12424 as the parent strain, a propionic acid resistant strain was induced in the same manner as in Example 1, and a vitamin B ₁₂ productivity evaluation test was conducted. The results are shown in Table 5. The B ₁₂ production amount of the mutant strain is 2 that of the parent strain.
It had doubled.

【table】

Claims (1)

[Claims] 1. A propionic acid-resistant vitamin selected from the group consisting of Propionibacterium schyamanii and Propionibacterium Freudenreich.
_B12 producing bacteria. 2 subjecting a vitamin _B12 -producing parental strain selected from the group consisting of Propionibacterium shermanii and Propionibacterium freudenreichii to an artificial mutagenesis treatment, and Subjecting the treated strain that survives the treatment to a natural mutagenesis treatment in which it is cultured in a liquid medium that further contains propionic acid at a concentration equal to or higher than the minimum growth-inhibiting concentration of the parent strain, in addition to a carbon source and a nitrogen source, The natural mutation induction treatment is performed such that the vitamin B ₁₂ production amount is at least 1.5 of the vitamin B ₁₂ production amount of the parent strain under the same culture conditions.
A propionic acid resistant vitamin selected from the group consisting of Propionibacterium schyamanii and Propionibacterium freudenreich, characterized by repeating until double the amount.
Method for producing _B12 -producing bacteria.