JPS6258987A - Novel yeast for assimilating ethanol - Google Patents

Abstract

PURPOSE:The titled yeast useful for determining ethanol, etc., having resistance to acid, growing prosperously, having resistance to ethanol, capable of growing in a medium with high ethanol concentration, having high ethanol decomposition ability, capable of being multiplied and producible from an expensive raw material. CONSTITUTION:Novel ethanol assimilating yeast which has resistance to acid, grows prosperously even in 2.5-5.0pH range, has resistance to ethanol, can grow in a medium having high ethanol concentration of about 8% and has high ethanol decomposition ability is cultivated in an ethanol-containing medium, multiplied and produced. The yeast belongs to the genus Candida or Issatchenkia strain IM-10 (FERM P-8377), WY-1 (FERM P-8378), WY-2 (FERM P-8379), WY-3 (FERM P-8380), WY-4 (FERM P-8381), NK-4 (FERM P-8382), etc., may be cited as the yeast.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ethanol-assimilating yeast, and more particularly to an ethanol-assimilating yeast that is resistant to acids and tolerant to alcohol.

[Conventional technology]

This kind of yeast, which has been discovered in the past, is used for the purpose of mass multiplication of the bacterial cells themselves, that is, the utilization of bacterial cell proteins, and many strains are resistant to acid and heat, but this resistance is used for the purpose of yeast production, i.e. The purpose is to prevent bacterial contamination during culture and reduce the cost of removing generated heat (see, for example, Japanese Patent Publication No. 53-28984, Japanese Patent Publication No. 10028-1981, and Japanese Patent Publication No. 58-17589). It is sufficient to grow in a medium containing a high concentration of ethanol, and there is no problem with decomposing or assimilating ethanol in a medium containing a high concentration of ethanol.

In other words, this kind of conventional yeast is only eaten as a nutritional supplement or as a protein source, and there have been no examples to date of its use for direct decomposition of alcohol. Therefore, there is a need for yeast that can decompose ethanol with high efficiency.

[Problem that the invention seeks to solve]

The present invention has acid resistance and temperature resistance, which is advantageous for industrial production, and can decompose and assimilate ethanol in high concentrations. The purpose is to obtain yeast that can be propagated and produced as a yeast.

[Means for solving problems]

In order to achieve the above object, the inventors of the present invention have conducted intensive search and study and have arrived at the present invention. That is, according to the present invention,
It is resistant to acids and grows vigorously even in the pH range of 2.5 to 5.0. It is also resistant to ethanol and can grow in a medium with a high ethanol concentration of about 8%, and has a high level of ethanol decomposition ability. A novel ethanol-assimilating yeast characterized by the following is provided.

The novel ethanol-assimilating yeast according to the present invention belongs to the genus Candida or the genus Isachenchia (
Strains IM-10, wy-1, and WY-2 belong to 15satchenkia) and have the mycological properties shown in the table below.
, WY-3, WY-4, and NK-4, each of which was deposited with the Institute of Microbial Technology, Japan Agency of Industrial Science and Technology on July 30, 1985, and assigned the following accession number. Yes: 1M-10: Microtechnical Laboratory No. 8377 WY-1.
〃 No. 8378 WY-2 〃 〃 No. 8379 WY-3 〃 〃 No. 8382 WY-4 〃 〃 No. 8382 NK-4 〃 〃 No. 8382 Next, the mycology of these new ethanol-utilizing yeasts. The following Table 1 and Table 2 show the composition of the medium used for the isolation of yeast according to the present invention: ,・7 H2O0.5g F e SO (t ・7 Hz 0 30 mg
Ca C(l x ・2 H, Z O3OKM n S
O4・7 Hz 0 5 mgCu SO4
t ・5 H200-5■Ethanol
6% (v/v) Fujitome water
ll2pi 3.0 Table 2 Polypeptone 5g Yeast extract 3g Malt extract 3g Glucose 10g Agar
15g Tap water 1β [Operation] The novel ethanol-assimilating yeast according to the present invention has the above-mentioned mycological properties, is taxonomically found to be a new bacterial species, and is resistant to acid and temperature. Not only is it resistant to high concentrations of ethanol, but it also has high ethanol decomposition ability.

〔Effect of the invention〕

The novel ethanol-assimilating yeast of the present invention is resistant to acids and temperatures, so it is not only advantageous for industrial production; 2. Furthermore, since high-concentration ethanol can be decomposed and assimilated, ethanol, which is available at low cost and in large quantities, can be used as a raw material for multiplication production, and the high resolution of ethanol can be used to create analytical reagents for quantifying ethanol. Alternatively, it could be used to remove ethanol from ethanol-containing foods and drinks (for example, for decomposing ethanol after drinking alcohol).

〔Example〕

The following is a pure isolation method for the yeast of the present invention.

Reproducibility, resistance and ethanol degradability will be explained with examples.

Example 1 5 ml of the separation medium shown in Table 1 above was dispensed into test tubes and sterilized in an autoclave at 120° C. for 15 minutes.

After cooling, 6% by volume of ethanol was added, and about 0.5% of ethanol was added to this.
g of sample was added. After shaking culture at 30°C for 4 to 6 days, add 50μ of the culture solution to the cloudy sample.
1 was inoculated into a new medium, and similarly cultured with shaking at 30°C for 2 to 5 days. After repeating this transplant operation a total of three times,
The mixture was spread on the plate medium shown in Table 2 and cultured at 30°C for 1 to 2 days. All colonies on the culture medium were confirmed to be macroscopically and microscopically identical. Five of these colonies were each inoculated onto a slant culture medium prepared by adding 2% agar to the medium listed in Table 1 adjusted to p) 14,
Culture was performed at 30°C for 1 to 2 days. The growth status and physiological properties of the bacteria on these five slanted media were examined on each medium, and it was confirmed that these bacteria were the same.

In addition, the growth status and physiological properties under each culture condition were as follows.

Acid-resistant medium listed in Table 1, ethanol concentration 2%, culture temperature 30°C,
Under conditions of a culture time of 20 hrs.

pH 2.5 3 4 5 6 Growth rate 10+ +++ +N +++ ++
(IM-10) pH 2,53456 Growth rate 10+ +++ +++ +++
+++ (WY-4) +++: Very good growth ++: Considerable growth +: Slight growth Ethanol tolerance Medium, pi (3, culture temperature 30°C, culture time 4)
Under conditions of 0 hrs.

Ethanol concentration 0.2 0.5 1 2 4 Growth rate (IM-10) ++ +++ +++
+++ +++++++ Nord concentration 0.2 0.5
1 2 4 growth rate (WY -4) ++
＋＋＋ ＋＋＋ ＋＋＋ ＋Mo＋＋＋＋：Extremely good growth＋＋：Considerable growth＋：Slight growth Next, the yeast cultured in the slant medium shown in Table 2 was treated with a protective agent consisting of 10% skim milk and 1% monosodium glutamate. was added to create a uniform yeast suspension. Approximately 1 ml of this suspension was dispensed into ampoules for freeze-drying, and freeze-drying was performed. Freeze-drying was carried out according to a conventional method under reduced pressure at a high degree of vacuum after freezing the ampoule containing the yeast suspension. After drying, it was air-sealed with a gas burner and then stored at 4°C. After 3 months, the freeze-dried bacteria stored in this way were allowed to reconstitute with sterile distilled water for 1 hour, and the growth status and physiological properties under each culture condition were examined in the same manner as above, and the results were the same as before freezing. Obtained.

Reference Example 1 One platinum loop of the yeast isolated in Example 1 was inoculated into 5 ml of the medium listed in Table 1 containing 2% ethanol by volume and pH 4, and after culturing with shaking at 30°C for about 20 hours, the same medium 10
The turbidity (OD6
60 Dragon) The culture solution was inoculated to a concentration of 0.1 to 0.2.

After culturing with shaking at 30°C for about 20 hours, 40ml of culture solution
1 was collected and centrifuged. After suspending the sediment in sterile water or the medium shown in Table 1 without addition of ethanol, it is centrifuged and the sediment is dissolved in pH 2.0 with an ethanol concentration of 5% by volume.
The cells were suspended in 5 ml of the medium shown in Table 1 adjusted to a concentration of 5.5 and cultured with shaking at 37° C. for 48 hours. The culture solution was centrifuged, and the supernatant was collected. Ethanol in the culture solution was removed by gas chromatography according to the throat space method. This results in
The following results were obtained: IM-10 (cultured for 24 hours): Approximately 47% of the added ethanol was decomposed WY-4 (cultured for 4 hours): Approximately 64% of the added ethanol was decomposed in the same way as WY-1 and WY -2, WY-3 and NK-
As a result of testing each of the 4 strains, results similar to those of Habo were obtained.

Claims (2)

[Claims] (1) It is resistant to acids and grows vigorously even in the pH range of 2.5 to 5.0, and it is resistant to ethanol and can grow in a medium with a high ethanol concentration of about 8%. A novel ethanol-assimilating yeast characterized by having the ability to degrade ethanol. (2) Belongs to the genus Candida or Isachenchia;
Bacterial strain IM-10 having the mycological properties indicated in the text,
WY-1, WY-2, WY-3, WY-4 and NK-
4. The novel ethanol-assimilating yeast according to claim 1, which is selected from the group consisting of 4.