JP2916357B2 - New brewer's yeast - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to Saccharomyces cerevisiae, which has a high growth rate, is alcohol-tolerant, and has a high glycerol productivity.
es cerevisiae), i.e., a brewing yeast belonging to Saccharomyces cerevisiae TK-2 (Seikoken no. P-13831).

[0002]

2. Description of the Related Art In recent years, diversification of alcoholic beverages has been required.
Various studies have been conducted on the production of alcoholic beverages. Above all, research on yeast has been actively conducted. Research has also been conducted on yeast for shochu using various techniques, and attempts have been made to improve yeast using an analog technique that increases specific components. In general, yeast obtained by the analog method has an increase in specific components, but is inferior in alcohol fermentation ability and often has problems in practical use. In addition, yeast that causes an increase in specific components using the analog method tends to extremely deteriorate the flavor balance of shochu.

[0003]

In the production of barley shochu, Kagoshima yeast (Ko) and Miyazaki yeast (MK) are generally used. When these yeasts are used, the raw material (barley) is used. The rate is poor compared to the use of raw materials when rice is used, and a yeast suitable for barley shochu is required. Further, there is a demand for a yeast capable of obtaining a flavorful shochu without lowering the alcohol yield.

[0004]

Means for Solving the Problems Kagoshima yeast (Ko) has a practical problem that barley shochu mash has low alcohol productivity. In view of this problem, two of the present inventors have previously collaborated with others on Kagoshima yeast (K
The research was repeated for the purpose of improving the alcohol productivity of o), and as a result, a strain BAW-6 having a high alcohol productivity was obtained, and this strain was already deposited in the Institute of Biotechnology and Industrial Technology, National Institute of Advanced Industrial Science and Technology. Koken No. 12871). By the way, the present inventors have determined through various experiments that the more glycerol in the moromi, the more the flavored shochu can be given. From this viewpoint, the present inventors have examined BAW-6 strain. As a result, it was found that the BAW-6 strain had a problem that alcohol productivity was superior to that of Kagoshima yeast (Ko) but glycerol productivity was insufficient. From these facts, we have found that BA
The search was performed to obtain an alcohol-producing bacterium having a higher glycerol productivity than the W-6 strain. As a result, Saccharomyces cerevisiae (S. cerevisiae) having a high growth rate, having alcohol tolerance, and exhibiting glycerol productivity higher than conventional Kagoshima yeast (Ko) and BAW-6 strains.
siae). And when alcohol fermentation was performed using this, it was found that the alcohol yield was significantly improved, and the flavor of the obtained liquors was also improved.

It is an object of the present invention to provide a novel microorganism having a high growth rate in barley shochu mash, having alcohol tolerance, and having a high glycerol productivity.

[0006]

The novel microorganism provided by the present invention, which has a high growth rate, alcohol tolerance and high glycerol productivity in barley shochu mash, is Saccharomyces cerevisiae described below.
myces cerevisiae).

[0007] (i) TTC staining test according to the method of Furukawa and Akiyama (Toshio Furukawa and Yuichi Akiyama: 37,398 (1963)), that is, the cells were appropriately diluted (about 200 per plate). On the colonies plated on the TTC underlayer medium at 30 ° C. for 2 days.
After the agar was dissolved, the temperature was raised to about 45 ° C. and then gently overlaid. After hardening, the solution was left at 30 ° C. for 2 to 3 hours. When the staining of the colonies was observed, the color of the agar was pink, and (ii) Mizoguchi, Fujita Method (Haruhiko Mizoguchi, Eishin Fujita: Fermentation, 59,185)
(1981)). C. Staining test, that is, the cells were appropriately diluted (to approximately 200 per plate), dissolved on a colony which was cultured in a TTC lower layer medium at 30 ° C for 2 days, and dissolved on a soft agar for upper layer at approximately 45 ° C. This is a new strain belonging to Saccharomyces cerevisiae, which is distinguished by showing a white color when the colony is observed for 30 minutes at room temperature.

[0008] The new strain provided by the present invention has the following mycological properties.

(A) Morphology of bacteria when cultivated at 30 ° C. for 2 days using YM medium Size of vegetative cells: 4 to 8 μm Shape of vegetative cells: egg type Growth form: budding

(B) Morphology of colony when cultured on YM agar medium at 30 ° C. for 2 days: Morphology: Circular Protuberance: Convex Perimeter: Smooth Size (diameter): 2-3 mm Color: White, opaque Surface : Smooth and glossy

(C) Utilization of carbon source: Glucose, galactose, sucrose, D-maltose, trehalose, raffinose, inulin, mannose, ethanol, lactic acid, fructose and arabinose are used.
Cellobiose, lactose, melibiose, meleptose, starch, α-methylglucoside, D-xylose, D-ribose, L-rhamnose, glycerol, meso-erythritol, D-sorbitol, D-mannitol, salicin, succinic acid, citric acid and inositol Does not assimilate.

(D) Vitamin requirement: Calcium pantothenate and biotin are required, but pyridoxine, inositol and thiamine are not required.

(E) Salt tolerance: It can grow on a 2% YPD agar medium containing 18% sodium chloride.

The following describes how the present inventors have found a new strain TK-2 belonging to Saccharomyces cerevisiae of the present invention.

The present inventors have mutated Kagoshima yeast (Ko) to isolate high alcohol-producing bacteria having a high growth rate in barley koji juice, high glycerol productivity, and alcohol tolerance as described below. Induced treatment, among the yeasts obtained as a result of the mutagenesis treatment, has excellent alcohol tolerance, high glycerol productivity, prominent growth ability, especially growth ability at low temperature, and has A novel strain of the present invention, which is apparently different from Kagoshima yeast of the present invention, was unknown.

Hereinafter, the process of obtaining the novel strain of the present invention will be described.

1. Mutation treatment and acquisition of useful yeast

[Mutation treatment of Kagoshima yeast] Commercially available Kagoshima yeast (Ko) was cultured in a YPD slant medium at 30 ° C for 2 days. One platinum loop was inoculated into a 2 ml YPD medium, and this was shake-cultured at 30 ° C. for 12 hours. 100 μl of the obtained cells were inoculated into 10 ml of YPD medium, and cultured with shaking at 30 ° C. for 12 hours. Next, after shaking culture, that is, in the logarithmic growth phase (4 to 10 × 10 ⁷ cells)
1 / ml) in the culture solution was collected by centrifugation. The cells were washed with 10 ml of sterilized water and collected by centrifugation, then washed again with the same amount of sterilized water and collected by centrifugation. The washed cells were suspended in 10 ml of 0.1 M phosphate buffer (pH 7.0), and 0.3 ml of EMS (ethyl methanesulfonate) was added to the obtained suspension. Gently for 40 minutes to perform mutation treatment.

[Acquisition of BAW-6] Next, the mutated cells were centrifuged and collected. The collected cells are collected in 10
Washed once with a ml amount of 5% sodium thiosulfate solution and twice with 10 ml of sterile water. Then, the washed cells were suspended in 10 ml of sterilized water to obtain a suspension. 400 μl of the obtained suspension [400 μl contains about 2 × 10 ⁷ viable cells. The number of cells is the number in 400 μl (4%) of a 10 ml suspension (containing about 5 × 10 ⁸ viable cells) containing the cells whose survival rate became 50% by the EMS treatment. ] Containing 8% alcohol in Bllg °.
8 was introduced into 10 ml of barley koji juice, and cultured at 30 ° C. for 7 days. The obtained culture solution was diluted 10 ³ times with sterile water, and 1 ml of the obtained diluted solution was embedded in a YPD agar medium and cultured at 30 ° C. for 4 days. As a result, 43 colonies appeared, and each of the colonies was hooked on a YPD slant medium. Next, each of the obtained strains of Hook was 10m
1 YPD medium was cultured at 30 ° C. for 2 days. Then 1
After the culture of 00 μl, the suspension was diluted with Bl containing 9% alcohol.
The mixture was introduced into 10 ml of barley koji juice of lg ° 9 and cultured at 30 ° C for 7 days. The obtained culture was sterilized with 10 ³
The mixture was double-fold diluted, and 1 ml of the obtained diluted solution was embedded in a YPD agar medium and cultured at 30 ° C. for 4 days. As a result, 28 colonies appeared. These colonies were statically cultured in the same manner as described above. A 100 μl volume of the resulting post-culture suspension was further added to Bllg ° 1 containing 10% alcohol.
0 was introduced into 10 ml of barley koji juice, and cultured at 30 ° C. for 7 days. The obtained culture solution was diluted 10 ³ times with sterile water, and 1 ml of the obtained diluted solution was embedded in a YPD agar medium and cultured at 30 ° C. for 4 days. As a result, 10 colonies appeared, and 10 strains of yeast which grew rapidly in barley koji juice and were resistant to alcohol were obtained. Further, a fermentation ability test was performed using these strains. As a result, three strains of yeasts having extremely high growth rate and ethanol productivity, an extremely large number of bacteria after fermentation, and excellent alcohol tolerance were obtained. Furthermore, the temperature suitability of these three strains was examined, and the strain having the best growth ability even at low temperatures was isolated. This was isolated from BAW-6 (Microtechnical Lab.
No.).

[Mutation treatment of BAW-6]
The -6 strain was subjected to mutation treatment in the same manner as the above-described mutation treatment for Kagoshima yeast (Ko). That is, YP
BAW-6 was statically cultured at 30 ° C. for 2 days on a D-slope medium. This one loop is inoculated into a 2 ml YPD medium,
Shaking culture was performed at 30 ° C. for 12 hours. 100 μl of the obtained cells were inoculated into a 10 ml amount of YPD medium, and shake-cultured at 30 ° C. for 12 hours. Next, after shaking culture,
That is, the logarithmic growth phase (4 to 10 × 10 ⁷ cell / m
Cells in the culture solution corresponding to 1) were collected by centrifugation. The cells were washed with 10 ml of sterilized water, collected by centrifugation, washed again with the same amount of sterilized water, and collected by centrifugation. The washed cells were suspended in 10 ml of 0.1 M phosphate buffer (pH 7.0), and 0.3 ml of EMS (ethyl methanesulfonate) was added to the obtained suspension. Gently for 40 minutes to perform mutation treatment.

[Acquisition of mutant strain (R-3 strain)] Next, the mutated cells were collected by centrifugation. The cells were washed once with 10 ml of a 5% sodium thiosulfate solution, and then twice with 10 ml of sterilized water. Then, the washed cells were suspended in 10 ml of sterilized water to obtain a suspension.
400 μl of the obtained suspension [400 μl contains about 2 × 10 ⁷ viable cells. The number of cells was determined by measuring 10 m of the suspension containing the cells having a survival rate of 50% by the EMS treatment.
l (including about 5 × 10 ⁸ viable bacteria)
(4%). ] Was spread on each of a YPD agar plate medium containing 12% sodium chloride and a YPD agar plate medium containing 14% sodium chloride, and cultured at 30 ° C. for 7 days. As a result, no colonies appeared on the plate medium of 14% sodium chloride, but 20 colonies appeared on the plate medium of 12% sodium chloride.
Next, a glycerol productivity test (ratio of glycerol: ethanol) was performed on each of these colonies. The glycerol productivity test was performed by the following method. That is, each of the above-mentioned 20 colonies was replaced with 2% Y
After inoculating in a PD medium and culturing at 30 ° C. for 2 days, 2 ml of the culture was added to 100 ml of 5% YPD medium. After further culturing this 5% YPD medium at 30 ° C. for 4 days, the glycerol concentration in the culture solution was measured using HPLC.
The results are shown in Table 1. As a result, 20
Of the strains, only R-3 strain had a glycerol concentration of 104
It was remarkably high at 3 mg / l, indicating that the glycerol-producing ability was 1.12 times higher than that of the parent strain BAW-6 (see Table 2).

[Mutation treatment of strain R-3] However, as shown in Table 2, the glycerol productivity of strain R-3 was lower than that of conventional Kagoshima yeast. Therefore, in order to further enhance the salt tolerance of the thus obtained R-3 strain, the R-3 strain was mutated by the following method. That is, the R-3 strain was statically cultured for 2 days at 30 ° C. on a YPD slant medium, and one platinum loop was inoculated into 2 ml of the YPD medium, followed by shaking culture at 30 ° C. for 12 hours. 100 μl of the obtained cells was
Inoculate 10 ml amount of YPD medium, and at 30 ° C for 12 hours,
Shaking culture was performed. Next, the cells in the culture solution after shaking culture, that is, in the logarithmic growth phase (4 to 10 × 10 ⁷ cells / ml), were collected by centrifugation. 10 cells
After washing with sterile water and collecting cells by centrifugation,
The cells were washed again with the same amount of sterile water and collected by centrifugation.
The washed bacterial cells were added to a 0.1 M phosphate buffer (pH 7.
0) Suspend in 10 ml and add 0.3 ml to the resulting suspension
Of EMS (ethyl methanesulfonate)
Mutation treatment was performed by gently shaking at a liquid temperature of 30 ° C. for 40 minutes.

[Acquisition of Salt-Tolerant Yeast TK-2 Strain] The thus-mutated cells were centrifuged and collected. The collected cells were washed once with 10 ml of a 5% sodium thiosulfate solution and then twice with 10 ml of sterilized water. Then, the washed cells were suspended in 10 ml of sterilized water to obtain a suspension. 400 μl of the obtained suspension was spread on a 2% YPD agar plate medium containing 14% sodium chloride, and
Static culture was performed at 0 ° C for 7 days. As a result, as shown in Table 3, 40 colonies S-1 to S-40 appeared. In addition, each of these 40 colonies was
The cells were smeared on a 2% YPD agar plate medium containing 6% sodium chloride, and cultured at 30 ° C. for 7 days. As a result S
S-2 ', 40 out of 40 colonies of -1 to S-40
7 ', 9', 12 ', 13', 16 ', 18', 1
9 ', 23', 28 ', 29', 33 ', 35', 4
A total of 15 colonies of 0 'appeared. Further, each of these 15 colonies was smeared on a 2% YPD agar plate medium containing 17% sodium chloride, and cultured at 30 ° C. for 7 days. As a result, S-7 ″, 12 ″, 1
A total of 7 colonies of 8 ", 19", 28 ", 33" and 35 "appeared. Furthermore, each of these 7 colonies was spread on a 2% YPD agar plate medium containing 18% sodium chloride. The culture was allowed to stand for 7 days at 30 ° C. At this concentration, no visible colonies appeared.
Therefore, the site where each colony was inoculated on the surface of the medium was further hooked, smeared on a 2% YPD agar flat medium, and cultured at 30 ° C. for 3 days. As a result, S-12 ", 18", 33 "
Colonies appeared only for. From this result, four among the seven colonies, i.e. S-7 ", 1
9 ", 28", 35 "died due to lack of salt tolerance in 2% YPD agar containing 18% sodium chloride, and the remaining S-12", 18 ", 33" contained 18% chloride. It was found that it grew because it was salt-tolerant in the same medium containing sodium. Therefore, those three colonies (that is, three strains of S-12 ″ and 18 ″ 33 ″) were identified as 18% salt-tolerant yeasts.
-1 strain, TK-2 strain and TK-3 strain. A glycerol productivity test (ratio of glycerol: ethanol) in a 5% YPD medium was performed on these TK-1, TK-2, and TK-3 strains in the same manner as described above. The results were as shown in Table 4. From the results shown in Table 4, it was understood that the glycerol concentration of the TK-2 strain was extremely high at 1194 mg / l among the three strains. Further, the glycerol productivity of the TK-2 strain is 1.23 times higher than that of the parent strain BAW-6, and 1.14 times higher than that of the R-3 strain. understood. From the facts found out,
The TK- 2 strain was found to have a high glycerol-producing ability and an extremely excellent proliferation ability.

2. Bacteriological properties The strain TK-2 isolated in the above 1 is the parent strain BA
In addition to W-6 and Kagoshima yeast (Ko), Miyazaki yeast (MK) and association shochu yeast (SH) known as yeasts for shochu
-4) In order to determine whether or not it is distinguished from any of the above, mycological properties (morphological properties and physiological properties) were observed.

2- (1). Morphological properties Using YM medium, cells of each of the five yeasts of Ko, MK, SH-4, BAW-6 and TK-2 were statically cultured at a temperature of 30 ° C. for 2 days, and obtained. Those were observed with an optical microscope. Table 5 summarizes the observation results. Table 5
As is clear from the above, all vegetative cells were 4 to 8 μm in size and were egg-shaped. In addition, on the YM agar medium, white colonies having a lustrous appearance were formed.

2- (2). Physiological properties

A. Carbon source utilization was tested by the replica method using a solid medium. That is, with respect to 1 liter of Bacto's medium for assimilation of carbon source, each yeast cell was inoculated (stamped) on an agar plate in which 10 g of each carbon compound (glucose, galactose, etc.) was dissolved, and assimilation was observed. did. Table 6 shows the results of carbon source utilization. From the results shown in Table 6, the following was found. That is, Ko differs from TK-2 in that it has no assimilation of ethanol and glycerol and succinic acid; MK has the assimilation of glycerol and succinic acid. Different from TK-2; SH-
No. 4 differs from TK-2 in that it assimilates glycerol, succinic acid, and citric acid; and BAW-6 differs from TK-2 in that it assimilates glycerol and citric acid.

B. Vitamin Requirement Nakata et al.'S method (Kubo Nakata, Ken Hosaka, Satoshi Sakai: Fermentation, 6
8,509 (1985)). That is, 2 mg of calcium pantothenate and 400 mg of pyridoxine were used per liter of a liquid medium for a vitamin requirement test manufactured by Bacto.
μg, 200 μg of biotin, 10 mg of inositol, and 400 μg of thiamine were removed by Komit, MK, SH-4, BAW-6 and TK-
8 × 10 ⁸ c of the diluted suspension of the washed cells of the five yeasts
The cells were inoculated at a concentration of ell / ml, cultured at 30 ° C. for 7 days, and observed for vitamin requirement. Table 7 shows the results of observation of vitamin requirement. MK was different from TK-2 in that it required thiamine. Other vitamin requirements were the same for the five yeasts.

C. TTC dyeing method Furukawa, Akiyama method (Toshio Furukawa, Yuichi Akiyama: Agricultural Chemistry, 37,
398 (1963)). That is, K
o, MK, SH-4, BAW-6 and TK-2 were appropriately diluted with the respective cells (2 per plate).
TTC agar was dissolved on a colony that had been plated in a lower medium at 30 ° C. for 2 days, and then dissolved at 45 ° C.
And then gently layer, and after hardening,
The mixture was left for 3 hours, and the state of staining of the colony was observed. Table 5 shows the results of observation of TTC stainability. As is clear from the results shown in Table 5, Ko, SH-4 and BAW-6 were all pink and the same as TK-2. MK was red and different from TK-2.

D. D. C. Dyeability Mizoguchi, Fujita's method (Haruhiko Mizoguchi, Eishin Fujita: Fermentation, 59,
185 (1981)). That is, K
o, MK, SH-4, BAW-6 and TK-2 were appropriately diluted with each of the yeast cells (about 200 per plate) and placed in a TTC underlayer medium at 30 ° C. for 2 hours. After dissolving the soft agar for the upper layer on the colonies that had been cultured for one day, the temperature was raised to about 45 ° C., and then gently overlaid. Table 5 shows D. C. The results of observation of the dyeability were shown. As is clear from the results shown in Table 5, Ko and SH-4 are brown,
Different from TK-2. MK and BAW-6 are white and T
Same as K-2.

From the observation of the above mycological properties, the present bacterium,
TK-2 is different from MK in that (a) assimilates Ko and ethanol and does not assimilate glycerol and succinic acid, and MK does not assimilate glycerol and succinic acid. In addition, SH-4 does not assimilate glycerol, succinic acid and citric acid.
It differs from AW-6 in that it does not assimilate glycerol and citric acid. (B) Among the vitamin requirements, it differs from MK in that there is no requirement for thiamine. (C) TT
C dyeability and D.C. C. Among the dyeing properties, Ko and SH-4
Is D. C. Differs in staining properties and differs from MK in TTC staining properties. Furthermore, these properties are maintained even after subculture for 20 generations, and are unique properties of the present bacterium, that is, TK-2. Therefore, the present bacterium, that is, TK-2, was found to be objectively distinguished from conventional yeast, and the present inventors identified it as a new bacterium, and designated this strain as TK-2.
It was named. This strain was deposited on September 1, 1993 with the National Institute of Bioscience and Biotechnology, National Institute of Advanced Industrial Science and Technology.
No. 3831 was obtained.

3. Comparison of alcohol tolerance 5 of Ko, MK, SH-4, BAW-6 and TK-2
Each of the yeast species was tested for alcohol tolerance as follows. That is, 30 ml in 10 ml of YPD medium.
Each yeast-washed microbial cell that had been allowed to stand at 2 ° C. for 2 days was placed in a 0.1 M acetate buffer (pH 4.3) having a ethanol concentration of 8, 11, 14% and a glucose concentration of 1% for 6 m each.
The suspension was autolyzed at 30 ° C. for 3 days, and the survival rate was measured. Table 8 shows the results. The survival rate of TK-2 at an ethanol concentration of 8% was about 74 times higher than that of Ko.
And at ethanol concentration of 11%, about 2 times higher than SH-4.
It turned out to be five times.

4. Comparison of alcohol productivity The alcohol productivity of each of the five yeasts Ko, MK, SH-4, BAW-6 and TK-2 was examined as follows. That is, 30 ml of 10 ml YPD medium is used.
Each yeast cell which had been allowed to stand at 2 ° C. for 2 days was suspended in 10 ml of sterilized water. Next, 1 ml of this yeast suspension was added to Bll.
100 ml of barley koji soup of g ° 8 was inoculated and cultured at 30 ° C. for 2 days. After culturing, 10 g of glucose is added to the barley koji juice.
g of glucose, and after standing culture for 2 days, glucose 10 g
Was further added and 10 g of glucose was added after stationary culture for 2 days. After further standing culture for 2 days, the alcohol concentration of the culture solution was measured. Table 9 shows the results. As a result, the alcohol concentration of TK-2 was 13.0%.
It was found that the alcohol productivity was clearly higher than any of Ko, MK, SH-4 and parent strain BAW-6.

5. Glycerol productivity Ko, MK, SH-4, BAW-6 and TK-2
Glycerol for each of the yeasts
The productivity was examined. That is, in a 10 ml amount of YPD medium, 3
Each yeast cell which had been statically cultured at 0 ° C. for 2 days was sterilized with 10 ml of water.
Suspended in water. Then add 1 ml of this yeast suspension to Bl
lg Inoculate 100ml of barley koji soup at 8 ℃, 30 ℃, 2 days
The culture was allowed to stand for a while. After the culture, glucose 1
0 g, and after culturing for 2 days, glucose 10
g of glucose, and after standing culture for 2 days, glucose 10 g
Was added. After two more days of stationary culture, the culture
The glycerol concentration of the liquid was measured. Table 10 shows the results.
Indicated. From the results shown in Table 10, glycerol of TK-2
Is 3859 mg / l, which is lower than that of conventional shochu yeast.
Clearly higher glycerol productivity than either
all right. Glycerol productivity
Was examined. That is, a YPD medium containing 2% glucose
Each yeast pre-cultured in 10 ml contains 10% glucose.
Cultivation in 100 ml YPD medium at 30 ° C for 4 days.
Measure the concentrations of ethanol and glycerol,
And the production characteristics of the same. The results are shown in Table 11.
From the results shown in Table 11, TK-2 was found to be the parent strain BAW-6.
About 1.4 times higher glycerol productivity
understood. TK in any of these different methods
-2 showed high glycerol productivity.

[0035]

[Test Examples] The present invention is further described by the following test examples, but the present invention is not limited thereto.

Test Example 1 and Comparative Examples 1 and 2

[0037]

Test Example 1 A barley shochu was produced using Saccharomyces cerevisiae TK-2. Table 1 shows the ratio of preparation
As shown in FIG. Barley (70% refined) was used as a raw material. The primary preparation was fermented for 5 days using barley koji (300 g as barley), water 360 ml, and TK-2 as yeast produced by the method described below. Also, 2
The next charge is 1140m of water in the moromi produced in the first charge
l, steamed barley (700 g as barley) and add 12-20
Fermented for days.

For the production of koji, barley was made to absorb 40% (W / W), steamed for 40 minutes, allowed to cool to 40 ° C., and inoculated with 1 g of seed koji (white koji mold) per kg of barley. , RH95
% For 24 hours, 32 ° C., RH 92% for 20 hours. Steamed barley was made to absorb 40% (W / W) of barley, steamed for 40 minutes, allowed to cool to 40 ° C., and added to the primary preparation. Yeast (TK-2) was precultured in 10 ml of a 2% YPD medium, and the total amount of the yeast (2 × 10 ⁹ yeasts) was added to the primary preparation. The fermentation temperature was 25 ° C. for both primary and secondary charges. Thus, barley shochu was produced. The progress of the fermentation at that time was examined by measuring the weight including the charging vessel every day to determine the amount of reduction in carbon dioxide gas. Also,
The alcohol concentration after completion of the fermentation was examined by the flotation method according to the comment provided by the National Tax Agency. Further, the alcohol yield per ton of the raw material was determined by dividing the pure alcohol calculated by multiplying the mash capacity and the alcohol concentration by the used amount of the raw material.

Comparative Example 1-a Barley shochu was produced in the same manner as in Test Example 1 except that Kagoshima yeast was used as the brewing yeast. The fermentation process at that time was examined by the same method as in Test Example 1.

Comparative Example 1-b Barley shochu was produced in the same manner as in Test Example 1 except that BAW-6 was used as the brewing yeast. The fermentation process at that time was examined by the same method as in Test Example 1.

FIG. 1 is a graph showing the progress of fermentation in each of Test Example 1 and Comparative Examples 1-a and 1-b. Table 13 shows the glycerol concentration and the yield of alcohol per ton of raw material after the fermentation in Test Example 1 and Comparative Examples 1-a and 1-b.

As is clear from the results of Test Example 1 and Comparative Examples 1-a and 1-b, according to the present invention using the above-mentioned novel brewer's yeast, namely, Saccharomyces cerevisiae TK-2, Rather than the shochu manufacturing method,
It was found that the yield of alcohol per ton of raw material was improved. It was also found that the glycerol concentration after the completion of fermentation was high.

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

[Table 3]

[0046]

[Table 4]

[0047]

[Table 5]

[0048]

[Table 6]

[0049]

[Table 7]

[0050]

[Table 8]

[0051]

[Table 9]

[0052]

[Table 10]

[0053]

[Table 11]

[0054]

[Table 12]

[0055]

[Table 13]

[0056]

SUMMARY OF THE INVENTION The novel brewer's yeast Saccharomyces cerevisiae TK-2 provided by the present invention has a high growth rate, is resistant to alcohol, and has a high glycerol productivity. By doing so, it is possible to improve the yield of alcohol per ton of raw material compared to conventional shochu production, to produce alcoholic beverages at low cost, and to improve glycerol productivity. Can be manufactured.

[Brief description of the drawings]

FIG. 1 is a fermentation curve showing the fermentation state in the production of barley shochu at a fermentation temperature of 25 ° C.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI C12R 1: 865) (72) Inventor Hideharu Takashita 223-1-1, Yamaji, Osa, Usa-shi, Oita Sanwa Sake Co., Ltd. (56) References Patent 2663095 (JP, B2) Journal of Fermentation Engineering, Vol. 69, No. 4, pp. 203-209 (1991) (58) Fields investigated (Int. Cl. ⁶ , DB name) C12N 1/16 C12G 3/02 BIOSIS CA (STN)

Claims (2)

(57) [Claims] 1. A brewer's yeast (Saccharomyces cerevisiae) that have a bacteriological characteristics following strains. (A) Form of bacterium when cultured at 30 ° C. for 2 days using YM medium: size of vegetative cell: 4 to 8 μm form of vegetative cell: oval type of growth: budding (b) Using YM agar medium Morphology of colonies when cultured at 30 ° C. for 2 days: Morphology: Circular Protuberance: Convex circle Perimeter: Smooth Size (diameter): 2-3 mm Color tone: White and opaque Surface: Smooth and glossy (c) Carbon source Assimilation: Glucose, galactose, sucrose, D-maltose, trehalose, raffinose, inulin, mannose, ethanol, lactic acid, fructose and arabinose assimilate , cellobiose, lactose, melibiose, melediose, starch, α-methylglucoside, D-xylose, D-ribose, L-rhamnose, glycerol, meso-erythritol, D-sorbitol, D -Mannitol, salicin, succinic acid, citric acid and inositol are not assimilated . (D) Vitamin requirement: Requirement for calcium pantetonate and biotin, but no requirement for pyridoxine, inositol and thiamine , ( e) Salt tolerance: It can grow on 2% YPD agar medium containing 18% sodium chloride. 2. The brewer's yeast (Saccharomyces)
Cerevisiae) TK-2 (Seikoken Bacteria No. P-13831)
Strain of claim 1 is No.).