Oxygen and moisture resistant yeast strain

Abstract

A new yeast strain is obtained which has satisfactory resistance to oxidation and moisture, and which is particularly suitable for preparation and use in dry form, as well as the yeasts derived from it and their uses, and the resulting bread doughs.

Description

Title of the invention: Oxygen and moisture resistant yeast strain Technical field

[0001] The present invention relates to the field of food, in particular to the field of baker's yeast strains. The present invention relates to a new yeast strain exhibiting satisfactory resistance to oxidation and moisture, and which is particularly suitable for preparation and use in dry form, the yeasts produced from this strain and their uses, as well as the resulting bread doughs. The yeast strain was deposited on October 4, 2023, with the National Collection of Microorganism Cultures (CNCM) under the Treaty of Budapest, under number CNCM 1-5988. Technical background

[0002] The yeast Saccharomyces cerevisiae, commonly known as baker's yeast, is widely used in human and animal food for its fermentative properties. It is notably used in bread making. Yeast can be used in various forms, particularly fresh or dehydrated. The dehydrated form is also called dry yeast or instant dry yeast. Conventional drying processes are disclosed in the publication by Akbari et al., 2012; Food And Bioproducts Processing 90: 52-57 and in French patent application FR2022909 published on August 7, 1970.

[0003] The choice of yeast form will depend on the intended industrial, artisanal or domestic uses, the means of transport, the conditions and duration of storage, etc. For example, yeasts in dry form are marketed under the names Saf-Instant®, Bruggeman Instant and Red Star®.

[0004] Yeast in dry form has the advantage of being easily transported and stored. This form is particularly well-suited to industrial use, especially in the production of bread and bread-based products. However, yeasts in dry form present an increased risk of oxidation, particularly during the dehydration stage – see the article entitled “Protection against oxidation during dehydration of yeast” by E. de Jesús Pereira et al., Cell Stress & Chaperones (2003) 8 (2), 120-124.

[0005] However, yeast in dry form requires special precautions in terms of drying, preparation and packaging, so that it exhibits Fermentation activities that are satisfactory, and which are particularly compatible with industrial use. Fermentation activity is determined by measuring the release of carbon dioxide gas (expressed in absolute volume or relative percentage) from a given dough piece using, for example, a Burrows and Harrison fermentometer described in the "Journal of Institute of Brewing", vol. LXV, No. 1, January-February 1959.

[0006] In particular, yeasts in dry form are generally sensitive to oxygen and moisture. Exposure of dry yeasts to oxygen leads to oxidation, which can degrade their fermentation activity and / or shelf life. To limit, or even eliminate, any oxidation, dry yeasts are currently packaged in containers that are substantially impermeable to oxygen.

[0007] As part of the continuous improvement of yeast strains, yeast producers seek to obtain more resistant and efficient strains, particularly with regard to resistance to oxidation and humidity, which are two key parameters, especially when it comes to adapting yeasts to less protective packaging (less barrier to oxygen and humidity), recyclable packaging and / or in the context of formulating mixes (preparations in which the yeast is influenced by other ingredients that do not have the same level of water activity, which risks rehydrating the dry yeast).

[0008] There is therefore a need to supply a yeast, particularly a yeast in dry form, exhibiting improved resistance to oxidation and moisture. There is also a need to supply a yeast, particularly a yeast in dry form, exhibiting improved resistance to oxidation and moisture while maintaining satisfactory, or even improved, fermentation activity. There is also a need to supply a yeast, particularly a yeast in dry form, exhibiting improved resistance to oxidation and moisture while maintaining a satisfactory shelf life. There is also a need to supply a yeast, particularly a yeast in dry form, exhibiting improved resistance to oxidation and / or moisture while maintaining satisfactory drying resistance. Summary of the invention

[0009] The invention relates to a yeast strain deposited on October 4, 2023 with the National Collection of Microorganism Cultures (CNCM) under the Treaty of Budapest under the number CNCM 1-5988.

[0010] In some embodiments, the yeast strain exhibits improved preservation to oxygen and moisture, preferably improved conservation of at least 30%, very preferably of at least 50%, more preferably of at least 100%, compared to the reference yeast strain deposited on March 22, 2018 with the CNCM under the Budapest Treaty under number CNCM 1-5298.

[0011] The invention also relates to a yeast derived from the yeast strain as defined opposite.

[0012] In some embodiments, the yeast is in dry form.

[0013] In some embodiments, the yeast is obtained by multiplication of the strain of yeast 1-5988 or by any strain derived from it.

[0014] In embodiments, the yeast is a hybrid yeast obtained by crossing with another yeast strain different from the yeast strain 1-5988, preferably the yeast being a yeast obtained by hybridization by sporulation, cytoduction or cell fusion.

[0015] The invention also relates to the use of yeast as defined opposite in a bread-making process.

[0016] The invention also relates to a bread dough obtained by using yeast as defined opposite in a bread-making process.

[0017] Surprisingly, the inventors have demonstrated that the yeast strain filed on October 4, 2023, with the CNCM under number CNCM 1-5988 (referred to as yeast strain 1-5988 below) exhibits better oxygen and moisture resistance compared to the reference yeast strain. This strain also displays satisfactory, or even improved, fermentation activity compared to the reference yeast strain. The performance of yeast strain 1-5988, particularly with regard to its moisture resistance and fermentation activity, is surprising given that it was selected solely under oxidative stress conditions. Detailed description

[0018] The invention is now described in more detail and in a non-limiting manner in the following description. Definitions

[0019] The term "yeast" is a generic term designating eukaryotic microorganisms capable of causing fermentation of organic matter. Among yeasts, the genera Saccharomyces, Candida, Pichia, and Kluyveromyces are examples, but not limited to. The terms "yeast (singular)" and "yeasts (plural)" are currently used interchangeably.

[0020] The term "yeast strain" refers to a relatively homogeneous population of yeast cells. A yeast strain is obtained from a clone, a clone being a population of cells obtained from a single yeast cell. The terms "yeast strain (singular)" and "yeast strains (plural)" are currently used interchangeably.

[0021] The term "yeast cream" refers to a yeast suspension obtained after multiplication in a tank and after centrifugation, which separates the suspension from the surrounding liquid, also known as the fermented must. This multiplication process can also be called culture or, by extension, fermentation.

[0022] By "derived yeast strain" is meant a yeast strain derived by any transformation whatsoever, for example by crossing(s), by mutation(s) and / or by genetic transformation(s).

[0023] By "mutagenesis" is meant mutagenesis achieved by radiation (for example by ultraviolet radiation, X-rays and / or gamma radiation, ARTP - "Atmospheric Room Temperature Plasma"), mutagenesis achieved by the use of mutagenic chemical agents (for example ethyl methanesulfonate or EMS, ethyl ethanesulfonate or EES, nitrosoguanidine, nitrous acid, aflatoxin Bl, hydroxylamine, 5-bromouracil, 2-aminopurine, proflavin, acridine orange) and / or insertional mutagenesis by transposition or by integration of an exogenous DNA fragment (for example by use of a plasmid or by integration into the genome).

[0024] By “breadmaking”, we mean the set of operations consisting of transforming flour into bread. Yeast strain

[0025] After multiple trials, the inventors identified and selected a new yeast strain exhibiting better preservation to oxygen and moisture, as well as satisfactory, or even improved, fermentation activity, particularly compared to the reference strain.

[0026] The yeast strain was deposited on October 4, 2023 with the CNCM (National Collection of Microorganism Cultures located at the Pasteur Institute, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France) on behalf of the company Lesaffre et Compagnie (located at 41 rue Etienne Marcel, 75001 Paris, France) and received the CNCM registration number 1-5988.

[0027] Yeast strain 1-5988 is a strain belonging to the species Saccharomyces cerevisiae.

[0028] Yeast strain 1-5988 was obtained from the reference strain. The reference strain was filed on March 22, 2018, with the CNCM on behalf of Lesaffre et Compagnie and received CNCM registration number 1-5298 (referred to as yeast strain 1-5298 below). This reference yeast strain exhibits satisfactory fermentation activity and is compatible with industrial use.

[0029] Yeast strain 1-5988 exhibits better preservation to oxygen and moisture, preferably better preservation of at least 30%, very preferably of at least 50%, more preferably of at least 100%, compared to the reference yeast strain (14 days, 30°C, 68%RH).

[0030] Yeast strain 1-5988 exhibits improved fermentation activity compared to the reference yeast strain.

[0031] Yeast strain 1-5988 exhibits satisfactory drying resistance compared to the reference yeast strain.

[0032] Yeast strain 1-5988 has a satisfactory shelf life compared to the reference yeast strain, preferably at least 6 months, very preferably at least 1 year, more preferably at least 18 months, for example between 2 and 3 years.

[0033] Yeast strain 1-5988 (and yeasts obtained from it) can be used in a bread-making process, in particular an industrial-scale bread-making process. Yeast

[0034] The invention also relates to a yeast derived from the yeast strain 1-5988 defined above.

[0035] The yeasts are obtained by multiplication of the yeast strain 1-5988, or by multiplication of any yeast strain derived from the yeast strain 1-5988 which share the same properties as the yeast strain 1-5988. The derived strain can be obtained by crossing(s), by mutation(s) and / or by genetic transformation(s).

[0036] A yeast strain derived by crossing can be obtained by crossing with the same yeast strain or with another yeast strain. A derived yeast strain obtained by crossing with another yeast strain is a hybrid yeast strain. A hybrid yeast strain can be obtained by carrying out the following steps: culturing yeast strain 1-5988 with a second yeast strain different from yeast strain 1-5988 under conditions allowing genetic recombination between the two strains, in particular recombination of their DNA; then selecting and / or screening the derived strains obtained that exhibit better oxygen and moisture stability, and optionally satisfactory or even improved fermentation activity, compared to the reference yeast strain. The culturing and selection and / or screening steps can be repeated.

[0037] The second yeast strain may be any strain whose genetic material, in particular DNA, can be recombined with the genetic material, in particular DNA, of yeast strain 1-5988. The second yeast strain may be a strain belonging to the species Saccharomyces cerevisiae. The second strain may have genotypic and phenotypic properties that are adapted to the genotypic and phenotypic properties of yeast strain 1-5988.

[0038] The culture step can be carried out by sporulation hybridization, cytoduction, or cell fusion. The methods of sporulation hybridization, cytoduction, and cell fusion are well known to those skilled in the art. For example, the sporulation hybridization method involves the production of spores by yeast strain 1-5988 and by the second yeast strain, followed by hybridization of the spores produced by yeast strain 1-5988 with those of the second yeast strain.

[0039] A yeast strain derived by mutation(s) may be a yeast strain that has undergone at least one spontaneous mutation in its genome and / or at least one induced mutation, for example by mutagenesis. The mutation may be silent or not.

[0040] Yeast can be prepared and used in various forms, depending in particular on the industrial, artisanal or domestic uses envisaged, the means of transport used, the conditions and duration of storage envisaged, etc. Yeast, prepared and used in a given form, is generally called a "yeast product".

[0041] Yeast can be prepared and used in dry form. Dry yeast generally has a dry matter content of at least 86%, preferably at least 88%, most preferably at least 90%, and most preferably at least 92% by weight per total weight of the yeast product. Dry yeast may generally have a dry matter content of 100% or less, preferably 99% or less, and most preferably 98% or less, by weight per total weight of the yeast product.For example, dry yeast can have a dry matter content of about 88%, about 88.5%, about 89%, about 89.5%, about 90%, about 90.5%, about 91%, about 91.5%, about 92%, about 92.5%, about 93%, about 93.5%, about 94%, about 94.5%, about 95%, about 95.5%, about 96%, about 96.5%, about 97%, about 97.5%, about 98%, about 98.5%, about 99%, about 99.5%, about 100%.

[0042] Alternatively, the yeast can be prepared and used in the form of yeast cream, pressed yeast or frozen yeast.

[0043] Yeast creams, also called “liquid yeasts”, are aqueous suspensions of live yeast cells with a cream-like viscosity. Yeast creams generally have a dry matter content of at least 12%, preferably 12 to 40%, most preferably 12 to 30%, more preferably 16 to 28%, by weight per total weight of the yeast product.

[0044] Pressed yeasts include pressed block yeasts, also called "yeast loaves," as well as crumbled yeasts. Pressed block yeasts generally have a dry matter content of 26 to 35% by weight of the total weight of the yeast product. Crumbled pressed yeasts generally have a dry matter content of 30 to 35% by weight of the total weight of the yeast product.

[0045] Frozen yeasts generally have a dry matter content of 74 to 80% by weight per total weight of the yeast product. Breadmaking process and product

[0046] Yeast is particularly effective in breadmaking processes.

[0047] The bread-making process includes at least one yeast fermentation step as defined above.

[0048] The baked bread product can be bread. Breads can vary from country to country, for example, and not exhaustively, scored breads such as bastard bread, baguette, pizza dough, sandwich bread, pastries or pita bread.

[0049] A baked bread product can be prepared with bread dough according to a conventional preparation process.

[0050] By way of example, a conventional preparation process can be described as follows: -1- Weigh the solid and liquid ingredients; -2- Measure the ambient temperature and the temperature of the flour; -3- adjust the water temperature to obtain the target paste temperature; -4- Place the ingredients in the mixing bowl; -5- to obtain a bread dough by kneading; -6- proof the bread dough (resting time of the dough in bulk after kneading) or “bulk fermentation”; -7- divide the bread dough into dough balls; -8- to shape the dough balls; -9- Let the dough balls rest; -10- shaping the dough pieces or "molding"; -11- to carry out the final growth, and -12- Bake the dough balls in an oven. Baker's dough

[0051] The invention also relates to a bread dough obtained by using the yeast defined above, as well as baked bakery products.

[0052] Bread dough can be obtained using yeasts, of which at least 10%, preferably 25%, most preferably 50%, and more preferably 75%, are the yeasts as defined above. In one embodiment, only the yeasts as defined above (approximately 100%) are used to prepare and obtain the bread dough.

[0053] In the baking industry, ingredient contents are generally expressed as a "percentage of the baker" or "relative to the flour." In other words, the ingredient content is expressed relative to the total mass of the flour, which therefore always represents 100%. Baking dough contains flour.

[0054] Baking doughs comprise water, for example between 40 and 80% by weight of flour. Baking doughs may also comprise additional ingredients, for example sugar and / or fats.

[0055] The bread dough includes baker's yeast obtained from the strain registered under number 1-5988. The bread dough may include from 0.05 to 3%, preferably from 0.5 to 2.0%, most preferably from 0.7 to 1.7% of baker's yeast (dry matter), relative to the total mass of the flour.

[0056] The bread dough may include an improver. The improver may include, in particular, enzymes and / or ascorbic acid and / or emulsifiers and / or other active ingredients classically considered as bread improvers by those skilled in the art.

[0057] Bread dough may contain salt. In some countries, bread dough does not contain salt.

[0058] Bread dough may contain a preservative commonly used in breadmaking. The choice of preservative may vary according to region or country, depending on traditions and regulations.

[0059] Bread dough may include fats traditionally used in breadmaking, for example, fats of animal origin (such as butter) or fats of vegetable origin (such as vegetable oils). The choice of fats may vary according to region or country, depending on traditions and regulations.

[0060] Bread dough may include eggs or egg products traditionally used in breadmaking. The choice of eggs or egg products may vary according to region or country, depending on traditions and regulations.

[0061] Bread dough may include milk or milk-derived products traditionally used in breadmaking. The choice of milk or milk-derived products may vary according to region or country, depending on traditions and regulations.

[0062] The bread dough may be sugar-free, lightly sweetened, or sweetened. The sugar may be sucrose syrup, glucose sugar, invert sugar (sucrose cleaved into glucose and fructose), or any other suitable sugar. A lightly sweetened bread dough contains 10% or less, for example, 0.1 to 5%, of added sugar, relative to the total mass of flour. A sweetened bread dough contains at least 10%, for example, 10 to 40%, of added sugar, relative to the total mass of flour. Examples

[0063] The following examples illustrate the invention without limiting it. Example 1#: Obtaining strain 1-5988

[0064] Strain 1-5988 was obtained, selected and identified by implementing the following protocol: Yeast strains used

[0065] Reference strain: strain filed on March 22, 2018 with the CNCM under number CNCM 1-5298. Methods used

[0066] Method of exposure to UV radiation: Mixed populations exposed to UV (100 to 400 j / cm2) with survival rates between 0.3 and 4.2%.

[0067] FACS Method: Analysis of cell populations based on viability (DIBAC) and resistance to oxidation (dihydroethidium or DHE).

[0068] Riso test: the determination method is the so-called Risograph method carried out using the Burrows and Harris fermentometer (Journal of Institute of Brewing, vol LXV, no. 1, January-February 25, 1959). Experimental protocol

[0069] Step 1: Exposure of a population of reference yeast strains 1-5298 to ultraviolet (UV) radiation.

[0070] Step 2: carrying out the growth and stress cycles in YPG medium (20 g / L of glucose, 20 g / L of bactopeptone, 10 g / L of a yeast extract - sterilized by 0.22 pm filtration) comprising 100 mM of H2O2.

[0071] Step 3: selection of yeast strains obtained in step 2 by the FACS method based on viability (DIBAC) and resistance to oxidation (dihydroethidium or DHE).

[0072] Step 4: Culture of the yeast strains selected in step 3 on a YM medium (3 g / L yeast extract, 3 g / L malt extract, 5 g / L peptone, 10 g / L glucose and 20 g / L agar 20g / L) comprising oxytetracycline.

[0073] Steps 2-4 were repeated five times (five cycles), allowing the obtaining of approximately 1400 strains of mutated yeast.

[0074] Step 5: Triple culture of the yeast strains obtained in step 4 of the last cycle on a deep-well plate in YPG medium containing 15 mM H2O2 compared with the reference strain (negative control). Step 5 yielded approximately 40 mutated yeast strains exhibiting relatively high resistance to H2O2.

[0075] Step 6: Duplicate culture of the yeast strains obtained in step 5 on a YPG medium containing 15 mM H2O2. Step 6 enabled the obtaining and selection of three mutated yeast strains systematically exhibiting resistance to H2O2.

[0076] Step 7: culture of the two yeast strains preserved in step 6 in a 7 L reactor.

[0077] Step 8: Evaluation of the yeast strains obtained in step 7 using a riso test. Step 8 allowed the selection of a single yeast strain – corresponding to strain 1-5988 – exhibiting behavior similar to the reference strain and satisfactory preservation in accelerated aging tests under vacuum or humid air.

[0078] Example 2: Performance tests of strain 1-5988 by comparison with the reference strain 1-5298 Yeast strains

[0079] Strain (invention): strain 1-5988.

[0080] Reference strain: strain 1-5298. Yeast (form)

[0081] Yeast 1: Yeast in dry form (immediate use in the risograph test).

[0082] Yeast 2: Yeast in dry form after preservation in accelerated aging test under vacuum (absence of air). Baker's dough

[0083] Dough A (without added sugar): 63% water, 2% salt, 1.2% dry yeast per 100g of flour (moisture of 14.6%, quantity of protein of 11.2% and quantity of ash of 0.56%).

[0084] Dough B (4% sugar): dough A further comprising 4% sugar per 100 g of flour.

[0085] Dough C (10% sugar): dough A further comprising 10% sugar per 100 g of flour.

[0086] Preparation: The ingredients are mixed in a Hobart Mc Duffy mixer for 7 minutes at speed 1 and for 30 seconds at speed 2. Methods used

[0087] Measurement of fermentation activity (risograph): see above.

[0088] Measurement of proofing time: proofing time is the measured time required for a bakery dough to reach a given height in the mold, corresponding to the desired development of the dough before it is put in the oven.

[0089] Measurement of specific volume: the specific volume is measured using the Volcan device in accordance with the standard AACC 10-16.01 method (entitled "Baking volumetry and dimensional profile of baked products by laser topography - Volcan profiler method").

[0090] Measurement of gas evolution: Gas evolution is measured in accordance with the AACC standard method 89-01.01 (entitled "Yeast Activity. Gas Production"). Experimental protocol

[0091] After preparing the bread dough, a 50 g sample is immediately placed in the risograph pot for measuring gas evolution (CO2). The bread doughs are tested at a temperature of 30°C.

[0092] The remaining dough is divided into three 320 g samples, which are left to rest for 35 min before being rolled and placed in molds. The molds, into which the three samples have been placed, are placed in a fermentation chamber at a temperature of 35°C and a relative humidity of 90%, in order to measure the proofing time, specific volume, and gas release. Experimental results (fermentation activity)

[0093] The results comparing the fermentation activity of strain 1-5988 (invention) and strain 1-5298 (reference) are presented in Table 1 below.

[0094] [Tables 1] Yeast 1 Yeast 2 Dough A Dough B Dough A Dough B Difference in fermentative activity between 1-5988 and 1-5298 +8% +15% +22% +40%

[0095] Strain 1-5988 exhibits improved fermentation activity compared to reference strain 1-5298, immediately after drying and after a period of vacuum storage, both on dough without added sugar and on dough with added sugar.

[0096] Experimental results (priming time, specific volume, gas evolution)

[0097] The results comparing the priming time, specific volume and gas release of strain 1-5988 (invention) and strain 1-5298 (reference) are presented in Table 2 below.

[0098] [Tables2] Yeast 1 Yeast 2 Dough A Dough C Dough A Dough C Proofing time -7% -13% -10% -14% Specific volume +10% +6% +4% +10% Gas release +8% +13% +14% +26%

[0099] Strain 1-5988 exhibits a reduced preparation time, a higher specific volume and a higher gas release compared to the reference strain 1-5298, immediately after drying and after a period of vacuum storage, both on a dough without added sugar and on a dough with added sugar.

[0100] Example 3: Performance tests of strain 1-5988 by comparison with the reference strain 1-5298 Yeast strains

[0101] Strain (invention): strain 1-5988.

[0102] Reference strain: strain 1-5298. Yeast (form)

[0103] Yeast 3: Yeast in dry form (immediate use in the risograph test).

[0104] Yeast 4: Yeast in dry form after preservation in accelerated aging test under vacuum (absence of air).

[0105] Yeast 5: Yeast in dry form after storage for 7 days at a temperature of 30°C and 20% relative humidity.

[0106] Yeast 6: Yeast in dry form after storage for 14 days at a temperature of 30°C and 20% relative humidity.

[0107] Yeast 7: Yeast in dry form after storage for 7 days at a temperature of 30°C and 68% relative humidity.

[0108] Yeast 8: Yeast in dry form after storage for 14 days at a temperature of 30°C and 68% relative humidity. Yeast preparation process

[0109] For preservation in the presence of air, the yeasts in dry form were placed in a pillbox (10 g of cells) left open in an enclosure under the desired conditions of duration, temperature and relative humidity. Baker's dough

[0110] Dough C (without added sugar): 63% water, 2% salt, 1.2% dry yeast per 100g of flour (moisture of 14.6%, quantity of protein of 11.2% and quantity of ash of 0.56%). Methods used

[0111] Measurement of fermentation activity (risograph): see above.

[0112] Measurement of priming time, specific volume and gas evolution: see above. Experimental protocol

[0113] After preparing the bread dough, a 50 g sample is immediately placed in the risograph pot for measuring gas evolution (CO2). The bread doughs are tested at a temperature of 30°C. Experimental results (dry matter)

[0114] The results comparing the percentage of dry matter present in each yeast sample are presented in Table 3 below.

[0115] [Tableaux3] Yeast 3 Yeast 4 Yeast 5 Yeast 6 Yeast 7 Yeast 8 1-5988 95.9% 95.9% 95.0% 94.9% 90.0% 87.3% 1-5298 95.5% 95.5% 94.9% 94.8% 89.6% 87.8% Experimental results (fermentation activity)

[0116] The results comparing the fermentation activity of strain 1-5988 (invention) and strain 1-5298 (reference) are presented in Table 4 below.

[0117] [Tables4] Yeast 4 Yeast 5 Yeast 6 Yeast 7 Yeast 8 Dough C Dough C Dough C Dough C Dough C Difference in fermentation activity between 1-5988 and 1-5298 +5% +11% +12% +5% +11%

[0118] Strain 1-5988 exhibits improved fermentation activity compared to reference strain 1-5298, immediately after drying, after a period of storage under vacuum or after a period of storage in the presence of oxygen and moderate or high relative humidity.

[0119] Experimental results (priming time, gas evolution)

[0120] The results comparing the priming time and gas release of strain 1-5988 (invention) and strain 1-5298 (reference) are presented in Table 5 below.

[0121] [Tables5] Yeast 7 Yeast 8 Dough C Dough C Proofing time -6% -15% Gas release +9% +26%

[0122] Strain 1-5988 exhibits a reduced preparation time and a higher gas release compared to the reference strain 1-5298, after a period of storage on a dough with added sugar.

Claims

Demands

1. Yeast strain deposited on October 4, 2023 with the National Collection of Microorganism Cultures (CNCM) under the Budapest Treaty under number CNCM 1-5988.

2. Yeast strain according to claim 1, the yeast strain having better preservation to oxygen and moisture, preferably better preservation of at least 30%, very preferably of at least 50%, more preferably of at least 100%, compared to the reference yeast strain filed on March 22, 2018 with the CNCM under the Budapest Treaty under number CNCM 1-5298.

3.

4.

5. Yeast derived from the yeast strain according to claim 1 or 2. Yeast according to claim 3, the yeast being in dry form. Yeast according to claim 3 or 4, the yeast being a hybrid yeast obtained by crossing with another yeast strain different from yeast strain 1-5988; preferably the yeast being a yeast obtained by hybridization by sporulation, cytoduction or cell fusion.

6. Use of yeast according to one of claims 2 or 3 in a bread-making process.

7. Bread dough obtained by using yeast according to claim 4 in a bread-making process.