JP2006304780A - New bread yeast and method for acquiring the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable stable production by improving proliferation of bread yeast in a low-syrup culture medium or a synthetic culture medium entirely not adding syrup and providing bread yeast not influenced by syrup component. <P>SOLUTION: A bread yeast (acclimatized strain) having good proliferation property also in a low-syrup culture medium and a synthetic culture medium entirely not adding syrup is acquired by acclimatizing bread yeast (original strain) in the low-syrup culture medium and/or the synthetic culture medium to enable production of stable bread yeast not influenced by variation of components required for proliferation of bread yeast contained in syrup. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a novel baker's yeast and a method for obtaining the same.

  Baker's yeast requires various components such as saccharides as energy sources, essential components such as nitrogen, phosphorus, potassium, and other vitamins during growth. In industrial production and cultivation of baker's yeast at present, molasses is added as an energy source, and inorganic salts such as ammonium sulfate, diammonium hydrogen phosphate, and potassium chloride are added as essential ingredients, and other inorganic salts and vitamins are added as necessary. Is doing. Among them, molasses is not only a sufficient addition of sugars such as sugar, but sufficient baker's yeast growth cannot be obtained. Therefore, molasses is a source of ingredients necessary for growth in addition to its role as an energy source. In addition, in the culture of baker's yeast at laboratory level, in addition to molasses, natural products such as yeast extract and polypeptone are added to supply necessary ingredients for growth.

  Because molasses has different component contents depending on the lot of production area, fiscal year, etc., even if baker's yeast is cultured with the same amount of sugar, the growth or production amount fluctuates, and as a result, the quality is also affected. Therefore, realization of stable baker's yeast production is desired.

  The first attempt to realize stable production is to homogenize the components by confirming the quality of molasses itself and mixing several production lots. However, it requires a lot of effort for many proliferation tests and proper blends.

  The second is an attempt to identify the components necessary for the growth of baker's yeast from the molasses and add them to the culture. The molasses is fractionated by various methods, the components are identified from the fractions that affect the growth and added to the culture. It is a method to do. Molasses is an inexpensive source of energy and enables inexpensive production of baker's yeast, but the addition of the specified necessary components naturally increases the cost. In addition, there is a possibility that necessary components that are rate-limiting differ depending on the molasses lot, and it is expected that it is difficult to identify components that can be stably grown with any molasses.

  On the other hand, when looking at organisms other than yeast, there are examples of animal cells that have acquired adaptability to the environment and are less susceptible to influence in terms of stable growth. There are known reports (Patent Document 1, Non-Patent Document 1). However, no examples of such adaptation to the environment and improved growth have been reported or suggested in yeast.

JP-A 63-196268 H. Muzik et al., 6 “Adaptation Of Human Long-term B Lymphoblastoid Cell Lines To Chemically Defined, Serum-free Media,” June 1982, Vol. 18, 51-65.

  In view of the above, the present inventors did not adjust the medium by adding a necessary ingredient for the growth of baker's yeast contained in a molasses blend or molasses, but baker's yeast in a low molasses medium and a synthetic medium not added with molasses at all. We aimed to enable stable production by improving baker's growth and obtaining baker's yeast that is not affected by molasses components.

  As a result of intensive studies to solve the above problems, the present inventors have conditioned baker's yeast in a medium with a low natural product content such as molasses or a medium that does not contain any at all. The present inventors have succeeded in obtaining a baker's yeast that has good growth on a synthetic medium that is completely free of completely contained components and that can be easily passaged, thereby completing the present invention.

  That is, the first of the present invention relates to a baker's yeast characterized by good growth in a low molasses medium. Preferably, it relates to the above baker's yeast, wherein the baker's yeast is Saccharomyces cerevisiae KCY1172 (FERM P-20829). The second of the present invention relates to a baker's yeast characterized by good growth in a synthetic medium. Preferably, it relates to the above baker's yeast, wherein the baker's yeast is FERM P-20829. The third aspect of the present invention relates to the above-described method for obtaining baker's yeast, which is adapted to a low molasses medium and / or a synthetic medium. Preferably, the present invention relates to a method for obtaining baker's yeast, wherein the acclimatization is subculture. In addition, the present invention preferably relates to a method for obtaining baker's yeast having a step of repeating passage 20 times or more in a low molasses medium or 10 times or more in a synthetic medium.

  The baker's yeast of the present invention has good growth in a low molasses medium or a synthetic medium to which no molasses is added and can be easily passaged, so that molasses is used only as a source of sugar. Thus, it is possible to stably produce baker's yeast that is not affected by fluctuations in components necessary for the growth of baker's yeast contained in molasses.

  Further, the method for obtaining the novel yeast of the present invention is widely applicable not only to baker's yeast, but also to sake yeast, wine yeast, beer yeast and other various brewing yeasts as long as they belong to Saccharomyces cerevisiae. In addition, the method only requires acclimatization of yeast in a medium composed of known components, and is very simple and industrially effective.

  Hereinafter, the present invention will be described in more detail.

  First, the terms used in this specification are the same as the meanings of terms used in the art, unless otherwise specified.

  In the present invention, the standard medium is a medium containing sugar derived from molasses at a final concentration of 1% by weight or more, and an example thereof is shown in Table 2 described later. The low molasses medium is a medium in which molasses derived from molasses is added to the synthetic medium in an amount corresponding to a final concentration of less than 1% by weight, and an example is shown in Table 2. As shown in Table 3 below, the synthetic medium is a medium containing saccharides that can be assimilated by yeast as an energy source and composed of other inorganic salts and vitamins. Molasses, yeast extract, polypeptone It is a medium that does not contain any natural products such as malt extract. Examples of assimilable saccharides include sucrose, glucose, maltose, and galactose.

  In the present invention, that the growth property is good means that when 5 L jar culture is carried out under the conditions shown in Tables 1, 2, and 3 (see Examples in Tables 2 and 3), the low molasses medium or the synthesis It means that the growth ability when cultured in a medium is at least 90% or more when cultured in a standard medium. Such baker's yeast can be easily grown and passaged even in a low molasses medium or a synthetic medium because the requirement for components necessary for growth is reduced.

  In the present invention, acclimatization refers to growing baker's yeast in the low molasses medium and / or synthetic medium, and can be carried out by a culture method common in this field. As a preferred acclimatization method, there is a method of subculture. The passage mentioned here is a general “repeating operation of culturing yeast in a certain medium and planting a part of the yeast in a new medium”. By continuing the acclimatization, baker's yeast acquires adaptability to the medium, and as shown in FIG. 1, the growth ability in the low molasses medium or the synthetic medium is improved, and the same growth ability as the standard medium is exhibited.

  In the subculture, the number of times the subculture is repeated is preferably 30 times or more, and more preferably 50 times or more in the low molasses medium (1) described later. Furthermore, in low molasses culture medium-(2), 20 times or more are preferable and 25 times or more are more preferable. Furthermore, in the synthetic medium, 10 times or more is preferable, and 15 times or more is more preferable.

  Although an example of acclimatization is shown below, the present invention is not limited to this.

  Inoculate baker's yeast cultured in a standard medium into a low molasses medium and start acclimatization. After culturing at 30 ° C., a certain amount of the culture solution having reached a dry cell weight of 2 mg or more per 1 ml of the culture solution is further subcultured to a low molasses medium. Thereafter, the same operation is continued until the baker's yeast has good growth in the low molasses medium. The acclimatization to the synthetic medium can be carried out by the same method. The next passage time can be determined by measuring the yeast cell concentration in the medium.

  In the present invention, the acclimatized strain is a baker's yeast that has good growth by acclimatization and can be easily passaged even in a low molasses medium or a synthetic medium.

  The original strain is baker's yeast passaged on a standard medium. Since the original strain is not acclimatized, components necessary for growth are deficient with an increase in the number of divisions, and the growth on a low molasses medium or a synthetic medium becomes poor, and cannot be easily passaged.

  In the present invention, Kaneka's commercial baker's yeast “Yeast SG” is used as the original strain, and this strain belongs to Saccharomyces cerevisiae. The acclimatized strain of the present invention was founded on March 1, 2006 as Saccharomyces cerevisiae KCY1172 (FERM P-20829). Deposited at No. 1 center 6).

  The baker's yeast of the present invention has good growth on the low molasses medium or synthetic medium.

  Here, the original strain used in the present invention is not limited to the yeast “yeast SG”, and it goes without saying that various yeasts can be used without departing from the gist of the present invention.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
<Medium composition>

  The composition of the standard medium and the low molasses medium is shown in Table 2, and the composition of the synthetic medium is shown in Table 3.

<Dry cell weight measurement>
Collect 5 ml of the culture end solution in a test tube, centrifuge at 3000 rpm for 5 minutes, discard the supernatant, suspend the cell pellet in 5 ml of water, centrifuge at 3000 rpm for 5 minutes, discard the supernatant, and leave the cell pellet at 105 ° C. It was dried for 5 hours to remove moisture, and used for measuring the weight of cells. The difference between the weight of the test tube after drying and the weight of the test tube before collecting the culture solution was taken as the dry cell weight.

(Example 1) Acclimatization to low molasses medium Inoculation of yeast SG (manufactured by Kaneka Co., Ltd. (commercially available)) into standard medium (50 ml / 500 ml Sakaguchi flask) After incubating at 30 ° C. for 1 day, 5 ml was inoculated into low molasses medium- (1) (50 ml / 500 ml Sakaguchi flask), and habituation was started. By shaking culture at 30 ° C., 5 ml of the culture solution that reached a dry cell weight of 2 mg or more per 1 ml of the culture solution was subcultured to a new low molasses medium- (1). Thereafter, the same operation was repeated and acclimatized, and as a result, the growth was improved as shown in FIG. Moreover, the time required for the culture was shortened as the passage was repeated, and it took 2-3 days until the 17th passage, but 1 day after the 18th passage. Thus, the passage was repeated 50 times to obtain a low molasses medium- (1) conditioned strain.

  Furthermore, as a result of inoculating the low molasses medium- (1) conditioned strain into the low molasses medium- (2) and repeating the same acclimation, the improvement in growth was observed as in FIG. 2, and after 25 passages Low molasses medium— (2) Acquired strain was obtained.

(Example 2) Low molasses medium-(2) Requirement for components necessary for growth of conditioned strain The low molasses medium-(2) Requirement for components necessary for growth of conditioned strain is as follows. Compared with stocks. After preparing the seed mother in the standard medium, inoculate 5 ml of the seed mother into the low molasses medium- (2) (liquid volume 50 ml / 500 ml Sakaguchi flask) (inoculated amount: one platinum ear) and culture at 30 ° C. for 24 hours with shaking. And it was the first passage. Here, the seed mother is a low molasses medium- (2) a cultivated strain or a former strain. Furthermore, the operation of inoculating 5 ml of the low molasses medium (2) and culturing at 30 ° C. for 24 hours was repeated, and the growth was examined by the weight of the dry cells.

  As a result, as shown in Table 4 and FIG. 3, in the first passage, the original strain showed growth using necessary components derived from the seed mother, but as the passage number increased, the growth decreased. It was observed. On the other hand, the low molasses medium- (2) conditioned strain did not show a decrease in growth even after passage, so the baker's yeast obtained by acclimation has acquired adaptability to the low molasses medium, It has been shown that the requirement for ingredients necessary for growth is reduced.

(Example 3) Acclimatization to a synthetic medium The low molasses medium- (2) acclimated strain obtained in Example 1 was acclimated to a synthetic medium. Low molasses medium-(2) As a result of inoculating 5 ml of cultured cells into a synthetic medium (liquid volume 50 ml / 500 ml Sakaguchi flask) and acclimating in the same manner as in the low molasses medium, the growth was improved as in FIG. After 15 passages, a synthetic medium-conditioned strain [Saccharomyces cerevisiae KCY1172 (FERM P-20829)] was obtained.

Example 4 Requirements for Components Necessary for Growth of Synthetic Medium Conditioned Strains The requirements for components necessary for the growth of the synthetic medium conditioned strains were compared with the original strains as follows. After preparing the seed mother with the standard medium, 5 ml of the seed mother is inoculated (inoculated amount: one platinum loop) into the synthetic medium (liquid volume 50 ml / 500 ml Sakaguchi flask), cultured at 30 ° C. for 24 hours with shaking, passage 1 It was a generation. Here, the seed mother is a synthetic medium conditioned strain or a former strain. Furthermore, the operation of inoculating 5 ml of the synthetic medium and culturing at 30 ° C. for 24 hours was repeated, and the growth was examined by the weight of the dried cells.

  As a result, as shown in Table 5 and FIG. 4, in the first passage, the original strain showed growth using necessary components derived from the seed mother, but as the passage number increased, the growth decreased. It was observed. On the other hand, since the growth of the synthetic medium-adapted strain was not observed even after passage, baker's yeast obtained by acclimatization has acquired adaptability to the synthetic medium, and it has no It has been shown that demandability has declined.

(Example 5) Confirmation of growth of cultivated strains by 5L jar culture Generally, in a flask culture, when a standard medium is used, molasses has a pH buffering effect, so there is little pH drop during the cultivation, but low molasses medium and synthetic medium When is used, the pH drop during the culture is remarkable. Since the pH drop during the cultivation affects the growth of baker's yeast, the growth of cells corresponding to the amount of sugar is not observed in the culture of the low molasses medium and the synthetic medium. Therefore, in order to accurately compare the growth on the synthetic medium with the growth on the standard medium, jar culture was performed in which the pH could be controlled to be constant.

  The original strain was a standard medium, and the synthetic medium-conditioned strain was a synthetic medium. The pH of the standard medium during the culture changed between 6.2 and 4.9. The pH of one synthetic medium was controlled as shown in Table 1. As a result, as shown in Table 6 and FIG. 5, the culture time was 22 hours and the dry cell weight was almost the same. Therefore, the growth of the cultivated strain in the synthetic medium was the same as that in the standard medium of the original strain. Thus, it can be said that the synthetic medium-conditioned strain is a baker's yeast that has good growth and can be easily passaged.

The conceptual diagram which shows the growth improvement by acclimatization to a low molasses culture medium and a synthetic medium. Explanatory drawing which shows the growth property of the baker's yeast acclimatized to the low molasses culture medium-(1). Low molasses medium-(2) Explanatory drawing which shows the requirement with respect to a component required for growth of a habituation strain. Explanatory drawing which shows the request | requirement with respect to the component required for the growth of a synthetic culture medium acclimatization strain. Explanatory drawing which shows the proliferation property by 5L jar culture | cultivation.

Claims (6)

  A baker's yeast characterized by good growth in a low molasses medium.   A baker's yeast characterized by good growth in a synthetic medium.   The baker's yeast according to claim 1 or 2, wherein the baker's yeast is Saccharomyces cerevisiae KCY1172 (FERM P-20829).   The method for obtaining baker's yeast according to any one of claims 1 to 3, wherein the method is adapted to a low molasses medium and / or a synthetic medium.   The method for obtaining baker's yeast according to claim 4, wherein the acclimatization is subculture. The method for obtaining baker's yeast according to claim 5, comprising a step of repeating passage 20 times or more in a low molasses medium or 10 times or more in a synthetic medium.

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