JP4565137B2 - Novel yeast and method for obtaining the same - Google Patents

Description

【００１８】
６．薬剤に対する耐性
シクロヘキシミド（０．５μｇ／ｍｌ）含有ＹＭ培地、テノイルトリフルオロアセトン（０．１ｍｇ／ｍｌ）含有ＹＮＢＣ培地、５０ｗ／ｖ％オキシカルボキシンを含有する農薬プラントバックス〔５０ｗ／ｖ％オキシカルボキシンが３．２ｍｇ／ｍｌ：日本曹達（株）製〕含有ＹＮＢＣ培地（０．６７ｗ／ｖ％ディフコ社イーストニトロゲンベース、２ｗ／ｖ％クエン酸、２ｗ／ｖ％寒天、ｐＨ６．０）、メタ亜硫酸カリウム（０．２ｍｇ／ｍｌ）含有ＳＤ培地（０．６７ｗ／ｖ％ディフコ社イーストニトロゲンベース、２ｗ／ｖ％グルコース、２ｗ／ｖ％寒天）を用いて３０℃で７日間培養した。生育してこなかった株を−で示した。
薬剤含有培地での生育の結果を表２に示す。Ｍ２０株はいずれの薬剤に対しても生育せず、耐性を示さなかった。
【００１９】
【表２】

【００２０】
８．増殖性
１０ｍｌのＹＰＭ培地（１ｗ／ｖ％酵母エキス、２ｗ／ｖ％ポリペプトン、２ｗ／ｖ％マルトース）にＭ２０株を１０⁷個接種し、３０℃にて培養を行い、経時的に培養液のＯＤ６６０を測定した。対照として、Ｋ−７０１株と多酸酵母のＮｏ．２８を用いた。その結果を図１に示す。マルトースを炭素源に用いた場合、Ｍ２０株は対照株（Ｋ−７０１株、Ｎｏ．２８）と比較し、増殖性は低かった。図１において、縦軸はＯＤ６６０の値、横軸は時間（ｈｒ．）を示す。また白丸印はＮｏ．２８、白三角印はＫ−７０１、白四角印はＭ２０を示す。
なお、一般培地であるＹＰＤ培地（１ｗ／ｖ％酵母エキス、２ｗ／ｖ％ポリペプトン、２ｗ／ｖ％グルコース）を用いて、上記の条件にてＭ２０株及び親株であるＫ−７０１株増殖性を検討した結果、Ｍ２０株は親株であるＫ−７０１株と同程度の増殖性を示した。
【００２１】
９．多酸性酵母の比較
上記の結果より、マルトース及びガラクトースの資化性、シクロヘキシミド（以下、ＣＨＹと称す）耐性及びジメチルサクシネート（以下、ＤＭＳと称す）感受性の比較データを表３に示す。参考株として、特願平１１−２９０３８７号明細書にて取得した多酸性酵母（リンゴ酸及びコハク酸を高生産）である２ＯＧ−Ｒ３９株（工業技術院生命工学工業技術研究所にＦＥＲＭ Ｐ−１７４７０として寄託済み）のデータも記載した。
【００２２】
【表３】

【００２３】
【実施例】
次に、本発明を実施例により更に具体的に示すが、本発明はこれらの実施例に限定されるものではない。
【００２４】
実施例１ マルトース低資化性有機酸高生産株の取得
Ｋ−７０１株をＹＰＤ液体培地（１ｗ／ｖ％酵母エキス、２ｗ／ｖ％ポリペプトン、２ｗ／ｖ％グルコース）５ｍｌで３０℃にて一夜振とう培養後、遠心分離で集菌し、滅菌水で洗浄した。洗浄菌体を４．３５ｍｌの０．２Ｍリン酸バッファー（ｐＨ８．０）に懸濁し、２０ｗ／ｖ％グルコース溶液を０．５ｍｌ添加してかくはんした後、エチルメタンスルホネートを０．１５ｍｌ添加して、３０℃にて１時間穏やかに振とうした。振とう後、そのうちの１ｍｌを４９ｍｌの６ｗ／ｖ％チオ硫酸ナトリウム溶液に加えて、室温で１０〜１５分放置後、遠心分離で集菌し、５ｍｌのＹＰＤ液体培地に懸濁し、３０℃、６時間静置培養した。次に以下のようにナイスタチン濃縮を実施した。集菌、滅菌水で洗浄後、０．６７ｗ／ｖ％イーストニトロゲンベース含有滅菌水１０ｍｌに懸濁し３０℃で一夜静置した。集菌後、ＳＭ液体培地（０．６７ｗ／ｖ％イーストニトロゲンベース、２ｗ／ｖ％マルトース）１０ｍｌに懸濁、３０℃、４時間振とう培養した後、５μｇ／ｍｌになるようにナイスタチンを添加し、３０℃、１時間振とうしマルトースを資化する株を死滅させた。この操作を３回繰り返した後、３０枚のＳＤ平板培地に、１枚当りの生菌数が約１０００個になるように植菌した。ＳＤ平板培地で適当な大きさにコロニーが生育した時、ＴＴＣ（０．０５ｗ／ｖ％ＴＴＣ、０．５ｗ／ｖ％マルトース、１．５ｗ／ｖ％寒天）寒天培地を重層し、ピンク色を呈するコロニーを６６株選択し、以下に示す麹汁培養試験を実施した。すなわち、各株を５ｍｌのＹＰＤ（１ｗ／ｖ％酵母エキス、２ｗ／ｖ％ポリペプトン、５ｗ／ｖ％グルコース）液体培地に懸濁し、３０℃、一晩、振とう培養した。次に各培養液３ｍｌを集菌し、１ｍｌの滅菌蒸留水に懸濁した後、３０ｍｌの麹汁培地（Ｂｒｉｘ １０．０）に植菌し、１５℃、１３日間発酵させた。次に、発酵させた培養液を遠心（３０００ｒｐｍ，５分間）処理後、上澄を０．４５μｍのフィルターにてろ過し、島津高速液体クロマトグラフ有機酸分析システム〔島津（株）製〕にて有機酸分析を行った。その結果、これら選択株すべてが親株であるＫ−７０１株よりも有機酸を高生産する株であった。これらのうち顕著に酸度が高い１４株を表４に示す仕込条件にて小仕込試験を実施した。表４に示す仕込配合において、掛米は７７％精白のα化米を使用した。麹は、精米歩合７５％の白米を使用して製造した。酵母は、５．０ｍｌ中に１０⁹個含むものを用いた。発酵温度は１５℃一定で仕込後１５日目で上槽した。
【００２５】
【表４】

【００２６】
Ｍ２０株及び親株のＫ−７０１株を用いた上槽液の分析結果を表５に示す。
【表５】

【００２７】
表５に示すように、Ｍ２０株は、親株のＫ−７０１株に比べて、酸度が２倍と高く、爽快な酸味を呈するリンゴ酸が約６．７倍高生産であり、高級アルコールであるイソブタノール及びイソアミルアルコールが親株と比較して各々約２．６倍、１．４倍であった。また、残存グルコース濃度は、親株の約５８％であり、原料利用率が良くなっていた。これを反映して日本酒度も親株に比べて高くなっていた。
なお、醸造協会より販売されているリンゴ酸高生産酵母のＮｏ．２８及びＮｏ．７７は、Ｋ−７０１株と比較してリンゴ酸をそれぞれ約６．８倍及び約４．６倍生産しているが、親株と比較して増殖が悪く、使用するのに大量の酵母を必要としており、日本酒度の切れも良くない（日本醸造協会誌、第９０巻、第１０号、ｐ７５１−７５８、１９９５年）。本発明で得られたＭ２０株は、親株であるＫ−７０１株と比較してリンゴ酸を約６．７倍生産しており、しかも増殖性が親株と同程度であり、日本酒度の切れ及び原料利用率も良く、実用性に優れていることが示された。
【００２８】
【発明の効果】
本発明により、有機酸、特にリンゴ酸並びに高級アルコールを高生産し、親株と遜色のない増殖性を示す、原料利用率の良い新規酵母を提供することができる。これらの酵母は実用性が高く、従来の酒類、食品に比べ酸味が強い酒類、食品を製造できる。これらの特性を生かして、貴醸酒への応用や、割り水しても味が薄くならず幅のある爽やかな酸味を有する低アルコール酒類等の製造への応用も可能となる。また、本発明により、有機酸高生産性酵母の効率的な取得方法を提供できる。
【図面の簡単な説明】
【図１】ＹＰＭ培地（１ｗ／ｖ％酵母エキス、２ｗ／ｖ％ポリペプトン、２ｗ／ｖ％マルトース）での各酵母の増殖性を示す図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a novel yeast with high productivity of organic acids and a method for obtaining the same, which is low-efficiency with respect to a specific sugar and has a high raw material utilization rate.
[0002]
[Prior art]
The following reports are examples of obtaining strains that produce malic acid from the parent strain by acclimatizing or mutating sake yeast. As yeast that produces a high amount of malic acid about 1.7 to 2.1 times that of the parent strain, tenoyl trifluoroacetone or oxycarboxyn resistant yeast (JP-A-6-121670), which is an inhibitor of succinate dehydrogenase, An inhibitor-sensitive, substrate-resistant or substrate-sensitive yeast of aconitic acid hydratase (Japanese Patent Laid-Open No. 11-46757) is known. As for yeast that produces about three times as much malic acid as the parent strain, dimethyl succinate sensitive yeast (JP-A-3-175975), which is an inhibitor of succinate dehydrogenase, and non-foamed sake yeast that produces a refreshing acidity (JP-A-5-317036) and yeast obtained by acclimatization to potassium metasulfite (JP-A-7-203951). In addition, cycloheximide-resistant haploid yeast (Japan Brewing Association Journal, Vol. 88, No. 8, 645-647, 1993) that produces about 5-6 times as much malic acid as the parent strain and about 4 of the parent strain. Cycloheximide-resistant yeast (Japan Brewing Association Journal, Vol. 90, No. 10, pp. 751-758, 1995) that produces about 6 times as much malic acid is known. However, the former was haploid yeast, and the latter was mutated and crossed repeatedly, so the growth was low, and both were low in sake, that is, the raw material utilization rate was poor.
[0003]
[Problems to be solved by the invention]
In view of the prior art, an object of the present invention is to provide a novel yeast that has a high raw material utilization rate, a high practicality for producing an organic acid, and a method for obtaining the same.
[0004]
[Means for Solving the Problems]
To summarize the present invention, the first invention of the present invention is a maltose and / or galactose low -utilizing ability, a high organic acid-producing yeast Saccharomyces cerevisiae with good raw material utilization rate (Saccharomyces cerevisiae) M20 (FERM P-17980) ) relates to the second invention, on how to obtain an organic acid and high-producing yeast which an index maltose low assimilating.
[0005]
The present inventors thought that by selecting a yeast in which sugar assimilation was changed, the balance of organic acid biosynthesis was changed, so that a strain having a changed amount of organic acid could be selected. In particular, focusing on maltose and / or galactose utilization of yeast, colonies with reduced maltose and / or galactose utilization are selected from the mutant-treated yeast by TTC (triphenyltetrazolium chloride) staining, As a result of examining the organic acid productivity, it was found that a strain having a high organic acid productivity can be frequently separated from a colony in which maltose and / or galactose utilization is reduced.
Among them, a mutant strain that produced a high amount of malic acid was included, and this mutant strain showed malic acid productivity equal to or higher than that of a conventionally known high malic acid-producing strain, and was proliferative. Was inferior to the parent strain and the raw material utilization rate was good. The present invention has been made based on these findings.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be specifically described below.
[0007]
Yeast maltose and / or galactose-reducing ability of yeast in the present invention means that yeast is maltose-containing medium or galactose-containing medium, for example, SM liquid medium (0.67 w / v% yeast nitrogen base, 2 w / v% maltose). Or when it is cultured in SGal liquid medium (0.67 w / v% yeast nitrogen base, 2 w / v% galactose) for 3 days, it means that it is difficult to grow or grows poorer than the parent strain.
[0008]
Although there is no limitation in particular in the acquisition method of the maltose and / or galactose low-utilization yeast of this invention, Generally, it carries out as follows. First, the parent strain collected by preculture is subjected to mutation treatment with an appropriate mutagen. Next, the mutated yeast is cultured in a medium containing maltose and / or galactose for several hours, and nystatin is added thereto for further culture, thereby killing the yeast having maltose and / or galactose-utilizing ability (hereinafter referred to as nystatin). Called concentration). The yeast that survived repeated nystatin concentration is inoculated on an agar medium containing glucose and cultured, and then an agar medium containing maltose and / or galactose and TTC is overlaid to give a pink colony, that is, maltose and / or galactose Select low-utilizing colonies. Although the evaluation method of organic acid productivity of these colonies is arbitrary, for example, after culturing each colony in a broth medium, the supernatant can be evaluated for organic acid productivity using an organic acid analyzer or the like. it can.
[0009]
The parent strain used for obtaining the maltose and / or galactose-reducing yeast in the present invention is not particularly limited, but yeast belonging to Saccharomyces cerevisiae (sake yeast, shochu yeast, wine yeast, brewer's yeast or baker's yeast, etc. ). In addition to the mutant-treated strain, the parent strain includes wild strains, cultivated strains, hybrid strains, cell fusion strains, and transformed strains such as plasmids. As a mutation treatment method, a known mutation induction method for yeast, for example, a method of irradiating ultraviolet rays or radiation, or N-methyl-N′-nitro-N-nitrosoguanidine, ethimethanesulfonate (hereinafter referred to as EMS), etc. What is necessary is just to use a chemical | medical agent suitably, and an EMS process is preferable as an effective mutation process.
[0010]
Good raw material utilization in the present invention means that, under general culture conditions, the remaining glucose concentration is lower than that of controls (for example, K-701 strain and No. 28 strain), and small charge In the test, it means that the residual glucose concentration and the sake level are lower and higher than the control, respectively.
[0011]
The organic acid highly productive yeast in the present invention is a total of the malic acid concentration and the succinic acid concentration of 2500 ppm or more, more preferably 2800 ppm or more, under the charging conditions described in Example 1 described later. A yeast having a concentration of 1500 ppm or more, more preferably 2110 ppm or more.
[0012]
The yeast obtained in the present invention is a novel yeast that is low in maltose and / or galactose and produces high organic acids, particularly malic acid, and grows in a medium containing glucose as a carbon source compared to the parent strain. Because there is no inferiority, if you produce alcoholic beverages such as sake, shochu, wine and beer, or foods such as bread, you will produce a product with a refreshing taste, excellent aroma, improved acidity, and good raw material utilization. Can do. The raw materials of these alcoholic beverages or foods are not particularly limited, and examples thereof include polished and / or unpolished polished rice, polished rice, barley, wheat, rye, buckwheat, millet, millet, sorghum, buckwheat, corn, sorghum, milo Although general cereals are mentioned, a general raw material can be used suitably. Moreover, the novel yeast of this invention may be used individually by 1 type, or 2 or more types may be used together, and well-known yeasts, such as K-701 strain, may be used in combination with this novel yeast. Furthermore, alcoholic beverages and foods produced using the novel yeast or the known yeasts can be mixed to produce novel alcoholic beverages and foods.
[0013]
The present invention provides a yeast with high acidity, high production of organic acids, particularly malic acid and higher alcohols, high growth rate comparable to the parent strain, high utilization rate of raw materials, and high practicality. Is done. Moreover, the efficient acquisition method of organic acid high productivity yeast is provided by this invention.
[0014]
The M20 strain, which is a representative strain of the present invention, is named and displayed as Saccharomyces cerevisiae M20, and is deposited as FERM P-17980 at the Institute of Biotechnology, Institute of Industrial Science and Technology.
[0015]
The M20 strain, which is a representative strain of the present invention, is a mutant strain of the K-701 strain, and their mycological properties are shown below.
(Mycological properties)
1. Morphological properties After culturing in YPD medium (1 w / v% yeast extract, 2 w / v% polypeptone, 2 w / v% glucose) at 30 ° C. for 2 days, it was observed with a microscope.
a) Shape: oval b) Size: length 4.7-7.9 μm, width 3.8-5.5 μm
2. 2. Form of growth: budding 3. Biochemical observation a) Fermentability of sugar 0.67 w / v% yeast nitrogen base (manufactured by Difco), sugar described below (2 w / v%) is dispensed into a test tube containing a Durham tube, and the strain Was inoculated and cultured at 30 ° C. for 5 days, and the presence or absence of carbon dioxide was observed.
Glucose (+) Galactose (±)
Sucrose (+) Maltose (±)
Lactose (-) Melibiose (-)
b) Sugar assimilation 0.67 w / v% yeast nitrogen base (Difco) and the following sugar (2 w / v%) were observed for 14 days at 30 ° C. by oxanograph method. did.
Glucose (+) Galactose (±)
Sucrose (+) Maltose (±)
Lactose (-)
c) Nitrate assimilation: (-)
The growth of the nitrate was observed by the oxanograph method using a Wickerham carbon assimilation test medium (manufactured by Difco) as potassium nitrate.
d) TTC staining: Pink e) Growth in β-alanine medium at 35 ° C. for 3 days: (−)
4). Formation of high foam When a small amount of sake was prepared, formation of high foam was not observed.
As described above, morphological and biochemical results indicate that the yeast strain of the present invention belongs to Saccharomyces cerevisiae. In addition, in the β-alanine medium, growth at 35 ° C. is negative, and no high foam formation is observed in the sake preparation test, indicating that the strain is a mutant of the K-701 strain. It is.
[0016]
5). YM medium (0.3 w / v% yeast extract, 0.3 w / v% malt extract, 0.5 w / v% peptone, 2 w / v% glucose) containing dimethyl succinate (1.5 v / v%) ) For 7 days at 30 ° C. Strains grown in the same manner as the parent strain (K-701 strain) were represented by +. The sensitivity results for dimethyl succinate are shown in Table 1. No. of the polyacid yeast marketed by the parent strain K-701, its mutant M20 and the brewing association. No. 28 grew and did not show sensitivity, but it was a polyacid yeast No. 28 commercially available from the Brewing Association. 77 did not grow and showed sensitivity.
[0017]
[Table 1]

[0018]
6). YM medium containing cycloheximide (0.5 μg / ml) resistant to drugs, YNBC medium containing tenoyltrifluoroacetone (0.1 mg / ml), pesticide plantbax containing 50 w / v% oxycarboxyl [50 w / v% oxycarboxyl 3.2 mg / ml: manufactured by Nippon Soda Co., Ltd.]-Containing YNBC medium (0.67 w / v% Difco East Nitrogen Base, 2 w / v% citric acid, 2 w / v% agar, pH 6.0), The cells were cultured for 7 days at 30 ° C. using SD medium (0.67 w / v% Difco yeast nitrogen base, 2 w / v% glucose, 2 w / v% agar) containing potassium metasulfite (0.2 mg / ml). Strains that did not grow are indicated by-.
The results of growth on the drug-containing medium are shown in Table 2. The M20 strain did not grow against any drug and did not show resistance.
[0019]
[Table 2]

[0020]
8). Proliferative 10 ml YPM medium (1 w / v% yeast extract, 2 w / v% polypeptone, 2 w / v% maltose) was inoculated with 10 ⁷ strains of M20, cultured at 30 ° C. OD660 was measured. As a control, K-701 strain and polyacid yeast No. 28 was used. The result is shown in FIG. When maltose was used as the carbon source, the M20 strain was less proliferative compared to the control strain (K-701 strain, No. 28). In FIG. 1, the vertical axis represents the value of OD660, and the horizontal axis represents time (hr.). The white circle is No. 28, white triangle mark indicates K-701, and white square mark indicates M20.
In addition, using the YPD medium (1 w / v% yeast extract, 2 w / v% polypeptone, 2 w / v% glucose) that is a general medium, the growth of the M20 strain and the parent strain K-701 strain was enhanced under the above conditions. As a result of the examination, the M20 strain showed the same level of growth as the parent strain K-701.
[0021]
9. Comparison of Multiacid Yeast From the above results, Table 3 shows comparison data of maltose and galactose utilization, cycloheximide (hereinafter referred to as CHY) resistance and dimethyl succinate (hereinafter referred to as DMS) sensitivity. As a reference strain, 2OG-R39 strain (multi-acid yeast (high production of malic acid and succinic acid) obtained in Japanese Patent Application No. 11-290387) (FERM P- The data of (deposited as 17470) are also shown.
[0022]
[Table 3]

[0023]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited to these Examples.
[0024]
Example 1 Acquisition of maltoose low-utilization organic acid high-producing strain K-701 strain was obtained overnight at 30 ° C. in 5 ml of YPD liquid medium (1 w / v% yeast extract, 2 w / v% polypeptone, 2 w / v% glucose). After shaking culture, the cells were collected by centrifugation and washed with sterile water. The washed cells were suspended in 4.35 ml of 0.2 M phosphate buffer (pH 8.0), stirred with 0.5 ml of 20 w / v% glucose solution, and then added with 0.15 ml of ethyl methanesulfonate. And gently shaken at 30 ° C. for 1 hour. After shaking, 1 ml of the mixture was added to 49 ml of 6 w / v% sodium thiosulfate solution, left at room temperature for 10-15 minutes, collected by centrifugation, suspended in 5 ml of YPD liquid medium, 30 ° C., The culture was stationary for 6 hours. Next, nystatin concentration was performed as follows. The collected bacteria and washed with sterilized water were suspended in 10 ml of 0.67 w / v% yeast nitrogen base-containing sterilized water and allowed to stand at 30 ° C. overnight. After collection, nystatin was suspended in 10 ml of SM liquid medium (0.67 w / v% yeast nitrogen base, 2 w / v% maltose), cultured at 30 ° C. for 4 hours with shaking, and then nystatin was adjusted to 5 μg / ml. Then, the strain that assimilate maltose was killed by shaking at 30 ° C. for 1 hour. After repeating this operation three times, the cells were inoculated into 30 SD plate media so that the number of viable bacteria per plate was about 1000. When colonies grow to a suitable size on the SD plate medium, overlay the TTC (0.05 w / v% TTC, 0.5 w / v% maltose, 1.5 w / v% agar) agar medium with a pink color. Sixty-six colonies to be exhibited were selected, and the following broth culture test was performed. That is, each strain was suspended in 5 ml of YPD (1 w / v% yeast extract, 2 w / v% polypeptone, 5 w / v% glucose) liquid medium, and cultured with shaking at 30 ° C. overnight. Next, 3 ml of each culture was collected, suspended in 1 ml of sterile distilled water, inoculated into 30 ml of broth medium (Brix 10.0), and fermented at 15 ° C. for 13 days. Next, the fermented culture solution is centrifuged (3000 rpm, 5 minutes), and then the supernatant is filtered with a 0.45 μm filter, and the Shimadzu high-performance liquid chromatograph organic acid analysis system [manufactured by Shimadzu Corporation] is used. Organic acid analysis was performed. As a result, all of these selected strains produced higher organic acids than the parent strain K-701. Of these, 14 stocks with remarkably high acidity were subjected to a small preparation test under the preparation conditions shown in Table 4. In the feed composition shown in Table 4, 77% polished white pre-gelatinized rice was used as the rice. Rice bran was produced using 75% polished rice. Yeast contained 10 ⁹ pieces in 5.0 ml. The fermentation temperature was fixed at 15 ° C., and the upper tank was added on the 15th day after the preparation.
[0025]
[Table 4]

[0026]
Table 5 shows the analysis results of the upper tank solution using the M20 strain and the parent K-701 strain.
[Table 5]

[0027]
As shown in Table 5, the M20 strain is a higher alcohol, with a high acidity of about twice as high as that of the parent strain K-701, and about 6.7 times higher production of malic acid with a refreshing acidity. Isobutanol and isoamyl alcohol were about 2.6 times and 1.4 times as much as the parent strain, respectively. Moreover, the residual glucose concentration was about 58% of the parent strain, and the raw material utilization rate was improved. Reflecting this, the degree of sake was also higher than the parent stock.
In addition, No. of high malic acid production yeast marketed by the Brewing Association. 28 and no. 77 produces malic acid approximately 6.8 times and 4.6 times, respectively, compared with K-701 strain, but grows poorer than the parent strain and requires a large amount of yeast to use. The sake level is not good (Japan Brewing Association, Vol. 90, No. 10, p751-758, 1995). The M20 strain obtained in the present invention produces about 6.7 times as much malic acid as the parent strain K-701, and has the same growth ability as the parent strain. The raw material utilization rate was also good and it was shown that it was excellent in practical use.
[0028]
【The invention's effect】
According to the present invention, it is possible to provide a novel yeast having a high raw material utilization rate, which produces organic acids, particularly malic acid and higher alcohols, and exhibits a growth ability comparable to that of the parent strain. These yeasts are highly practical and can produce alcoholic beverages and foods that have a stronger acidity than conventional alcoholic beverages and foods. Taking advantage of these characteristics, it is possible to apply to pre-brewed liquor and to manufacture low alcoholic alcoholic beverages having a refreshing acidity with a wide range even when water is split. Moreover, according to the present invention, an efficient method for obtaining organic acid highly productive yeast can be provided.
[Brief description of the drawings]
FIG. 1 is a graph showing the growth of each yeast in YPM medium (1 w / v% yeast extract, 2 w / v% polypeptone, 2 w / v% maltose).

Claims (3)

A novel yeast Saccharomyces cerevisiae M20 (FERM P-17980) that is low in maltose and / or galactose and has good raw material utilization and high productivity .    The novel yeast according to claim 1, wherein the organic acid is malic acid. Maltose low assimilating a method for obtaining an organic acid and high productivity novel yeast as an indicator.

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