Saccharomyces cerevisiae culture and culture method of saccharomyces cerevisiae

Abstract

The invention discloses a saccharomyces cerevisiae culture and a culture method of saccharomyces cerevisiae, and belongs to the technical field of saccharomyces cerevisiae cultivation, the saccharomyces cerevisiae culture comprises a nutrition medium, and the nutrition medium comprises, by weight, 40-60 parts of vinasse, 40-60 parts of cottonseed meal and 1-5 parts of wheat bran; the culture medium is mixed with the nutrient medium, the culture medium comprises yellow water, and the yellow water is vinasse extract. According to the saccharomyces cerevisiae culture designed by the invention, the high-quality saccharomyces cerevisiae culture is prepared by efficiently utilizing industrial byproducts (distillers' grains and cottonseed meal), so that the production cost is reduced, the cyclic utilization of resources is realized, and the application ways of the distillers' grains and the like are expanded.

Description

Technical Field

[0001] The present invention belongs to the technical field of Saccharomyces cerevisiae cultivation, and specifically relates to a Saccharomyces cerevisiae culture and a method for culturing Saccharomyces cerevisiae. Background Art

[0002] Distillers' grains are solid wastes generated during the brewing process, mainly composed of residual substances after grain fermentation, and are rich in components such as cellulose, hemicellulose, protein, vitamins, and minerals. Nevertheless, a large amount of distillers' grains are often directly discarded or simply used as feed, without fully realizing their potential value.

[0003] Cottonseed meal is the residue left after extracting oil from cottonseeds and is a high-quality source of plant protein. Similar to distillers' grains, cottonseed meal also faces the problem of low utilization rate. Although some cottonseed meal is used in animal feed, the presence of certain anti-nutritional factors (such as gossypol) limits its wide application in the feed industry.

[0004] The above are all applications of distillers' grains and cottonseed meal as feed or feed ingredients, but how to improve the application of distillers' grains and cottonseed meal in feed has become an urgent problem in the industry. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, an object of the present invention is to provide a Saccharomyces cerevisiae culture.

[0006] The present invention also provides a method for culturing Saccharomyces cerevisiae having the above-mentioned Saccharomyces cerevisiae culture.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] The present invention provides a Saccharomyces cerevisiae culture, comprising: a nutrient matrix, which, by weight, comprises 40-60 parts of distillers' grains, 40-60 parts of cottonseed meal, and 1-5 parts of wheat bran; a culture medium, which is mixed with the nutrient matrix, and the culture medium comprises yellow water, and the yellow water is the leachate of distillers' grains.

[0009] According to the Saccharomyces cerevisiae culture of the present invention, by efficiently utilizing industrial by-products (distillers' grains and cottonseed meal) to prepare a high-quality Saccharomyces cerevisiae culture, it not only reduces production costs but also realizes the recycling of resources. Moreover, by adding wheat bran to enrich the nutrients of the culture, it promotes the healthy growth of the entire culture for Saccharomyces cerevisiae, thereby improving the growth quality and efficiency of Saccharomyces cerevisiae. In addition, since both the nutrient matrix and the culture medium are based on natural raw materials, the quality and safety of the culture are improved.

[0010] Further, the nutrient matrix, by weight, comprises 40 parts of distillers' grains, 58 parts of cottonseed meal, and 2 parts of wheat bran.

[0011] Further, it also includes quicklime, which is suitable for mixing with the nutrient matrix and the culture medium to regulate the pH value of the Saccharomyces cerevisiae culture. The pH value of the Saccharomyces cerevisiae culture is 5 - 7.

[0012] Further, the proportion of water weight in the yeast culture is 42wt% - 47wt%.

[0013] Further, the distiller's grains are strong aroma distiller's grains.

[0014] Further, the cottonseed meal is of the pressing type.

[0015] Next, the culture method of the Saccharomyces cerevisiae according to the present invention will be briefly described.

[0016] The culture method of the Saccharomyces cerevisiae according to the present invention includes: mixing a biological fermentation agent with the Saccharomyces cerevisiae culture described in any one of the above embodiments; wherein the proportion of the biological fermentation agent is 0.1%, and the biological fermentation agent includes Saccharomyces cerevisiae and acid protease; wherein the Saccharomyces cerevisiae is: the preservation number is CGMCC 2.1030, the Latin name is Saccharomyces cerevisiae, and its preservation address is the China General Microbiological Culture Collection Center, affiliated to the Institute of Microbiology, Chinese Academy of Sciences (purchased directly).

[0017] Further, the cultivation temperature is 25°C - 35°C.

[0018] Other advantages, objectives and features of the present invention will be described in the subsequent specification, and to some extent, they are obvious to those skilled in the art, or those skilled in the art can obtain teachings from the practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the following specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to make the objectives, technical solutions and beneficial effects of the present invention clearer, the present invention provides the following drawings for illustration:

[0020] Figure 1 It is a schematic diagram of the components of the brewing culture of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the embodiments and the drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0022] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that: the present invention may be practiced without these specific details. In other instances, well-known structures, circuits, materials, or methods have not been specifically described in order to avoid obscuring the present invention.

[0023] Throughout the specification, references to "one embodiment", "an embodiment", "an example", or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Thus, the phrases "one embodiment", "an embodiment", "an example", or "an example" appearing throughout the specification do not necessarily all refer to the same embodiment or example. Additionally, the specific features, structures, or characteristics may be combined in any suitable combination and / or sub-combination in one or more embodiments or examples. Further, those of ordinary skill in the art will understand that the diagrams provided herein are for illustrative purposes only and are not necessarily drawn to scale. The term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0024] In the description of the present invention, it is to be understood that the orientation or positional relationships indicated by the terms "front", "rear", "left", "right", "upper", "lower", "vertical", "horizontal", "high", "low", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and thus should not be construed as limiting the scope of protection of the present invention.

[0025] Embodiment 1:

[0026] As Figure 1 shown, the present invention provides a Saccharomyces cerevisiae culture, comprising: a nutrient substrate and a culture medium. The nutrient substrate, by weight, comprises 40 - 60 parts of distiller's grains, 40 - 60 parts of cottonseed meal, and 1 - 5 parts of wheat bran. The culture medium is mixed with the nutrient substrate, and the culture medium comprises yellow water, which is the leachate of distiller's grains.

[0027] In some embodiments, the distiller's grains serve as the main carbon source and nitrogen source to provide the sugars, amino acids, and trace elements required for the growth of yeast, and at the same time contain a small amount of alcohol to inhibit the growth of miscellaneous bacteria. The cottonseed meal is rich in protein (about 35 - 40%) and oil to supplement the nitrogen source and essential fatty acids and promote the synthesis of the yeast cell membrane structure. The wheat bran contains B vitamins, minerals (such as phosphorus, magnesium), and a carbon source. The B vitamins and minerals (such as phosphorus, magnesium) can assist the activity of yeast metabolic enzymes, and the carbon source provides the sugars required for the growth of yeast.

[0028] Yellow water is the leaching extract of distillers' grains. Yellow water contains organic acids, residual sugars and fermentation by-products (such as esters and aldehydes) dissolved in distillers' grains, which can adjust the osmotic pressure and pH value of the culture medium and provide the initial nutrients for the rapid proliferation of yeast.

[0029] It can be understood that distillers' grains are the products remaining after brewing, and cottonseed meal is the product after cottonseed oil extraction. This application mainly uses distillers' grains and cottonseed meal as cultures to cultivate Saccharomyces cerevisiae for the efficient utilization of distillers' grains and cottonseed meal. At the same time, the addition of wheat bran can supplement sugars and minerals in the cultures.

[0030] It is worth mentioning that yellow water is also a waste product of the winery. By using yellow water to culture yeast, circular production can be achieved. Moreover, through the mixing of solid substrates (distillers' grains, cottonseed meal and wheat bran) and liquid medium (yellow water), the soluble nutrient components in the liquid and the structural nutrient components provided by the solid are combined to form an environment with comprehensive nutrition and easy for yeast to absorb and utilize. Moreover, the state of the solid-liquid mixture is conducive to maintaining appropriate humidity and air permeability, helping to create an environment that is neither too dry nor too wet, thus promoting the healthy growth of yeast. Of course, the presence of the liquid makes it easier for nutrients to disperse in the culture medium and also promotes the effective contact between yeast and nutrients, improving the nutrient absorption efficiency.

[0031] Therefore, in this application, by combining distillers' grains, cottonseed meal and wheat bran in the above proportions, an environment with balanced nutrition and suitable for the growth of Saccharomyces cerevisiae is created. Each component has its specific role, such as providing carbon source, nitrogen source or trace elements to meet the needs of yeast at different growth stages. At the same time, as a natural culture medium, yellow water can not only provide necessary moisture but also further supplement some soluble nutrient substances required for microbial growth, thus promoting the healthy growth of yeast.

[0032] According to the Saccharomyces cerevisiae culture of the present invention, by efficiently using industrial by-products (distillers' grains and cottonseed meal) to prepare high-quality Saccharomyces cerevisiae culture, it not only reduces production costs but also realizes the recycling of resources. Moreover, by adding wheat bran to enrich the nutrition of the culture, it promotes the healthy growth of the whole culture for Saccharomyces cerevisiae, thus improving the growth quality and efficiency of Saccharomyces cerevisiae. In addition, since both the nutrient matrix and the culture medium are based on natural raw materials, the quality and safety of the culture are improved.

[0033] Example 2:

[0034] Based on Example 1, the nutrient matrix includes 40 parts of distillers' grains, 58 parts of cottonseed meal and 2 parts of wheat bran by weight.

[0035] In some embodiments, 40 parts of distillers' grains can provide sufficient carbon sources (such as residual starch) and nitrogen sources (such as protein), and avoid carbon-nitrogen ratio imbalance caused by excessive amounts. 58 parts of cottonseed meal are used to maximize the supplementation of nitrogen sources (protein content is about 46%) and sulfur-containing amino acids (such as methionine) to promote the protein synthesis of yeast. 2 parts of wheat bran are used to avoid excessive fiber interfering with nutrient absorption and at the same time provide sufficient B vitamins (such as thiamine, niacin).

[0036] It can be understood that the combination of distillers' grains (C / N≈10) and cottonseed meal (C / N≈6) controls the overall C / N ratio at 12 - 14, close to the optimal growth range of Saccharomyces cerevisiae (C / N≈10 - 15). Moreover, the granular characteristics of wheat bran together enhance the air permeability of the substrate, reduce anaerobic areas, and improve the respiratory efficiency of yeast.

[0037] It is worth mentioning that 40 parts of distillers' grains can not only make full use of brewing waste residues but also avoid the increase in viscosity caused by excessive amounts (affecting the mixing uniformity). 58 parts of cottonseed meal are used to consume cottonseed meal as much as possible. 2 parts of wheat bran are used to supplement vitamins and carbon sources, thus enriching the nutrition of the nutrient substrate, and at the same time avoiding excessive introduction of phytic acid (an antinutritional factor), thereby avoiding inhibiting the growth of yeast.

[0038] According to some embodiments of the present invention, the Saccharomyces cerevisiae culture also includes: quicklime, which is suitable for mixing with the nutrient substrate and the culture medium to regulate the pH value of the Saccharomyces cerevisiae culture, and the pH value of the Saccharomyces cerevisiae culture is 5 - 7.

[0039] In some embodiments, after quicklime is dissolved in water, it forms calcium hydroxide (Ca(OH)2), which is strongly alkaline, to neutralize organic acids in the culture medium (such as lactic acid, acetic acid), thereby raising the pH value from acidic (the initial pH of yellow water is approximately 4 - 5) to 5 - 7. After the organic acids in distillers' grains and cottonseed meal are neutralized, the toxicity to yeast can be reduced, and at the same time, more available carbon sources and nitrogen sources are released. Moreover, quicklime can provide calcium ions (Ca 2 +), to enhance the cell wall strength, thereby improving the stress resistance of yeast (calcium ions are essential elements for the synthesis of yeast cell walls).

[0040] It is worth mentioning that a pH value of 5 - 7 is the optimal growth range of Saccharomyces cerevisiae (when the pH is lower than 5, the metabolic activity of yeast is inhibited; when the pH is higher than 7, it will lead to the proliferation of miscellaneous bacteria (such as bacteria)).

[0041] Thus, within the pH range of 5 - 7, the glycolytic pathway and ethanol fermentation efficiency of yeast can be significantly improved, thereby increasing the cell density (OD600 value) of yeast by 10 - 20%. At the same time, after the pH value is adjusted to 5 - 7, the growth of bacteria (optimal pH ≈ 6.5 - 7.5) and molds (optimal pH ≈ 4 - 6) can be effectively inhibited, reducing the risk of contamination. Of course, the addition of quicklime stabilizes the pH value within the target range, reducing the impact of pH fluctuations during fermentation on yeast. Moreover, the supplementation of calcium ions enhances the ethanol tolerance of yeast, prolongs the metabolic activity of yeast, and the buffering effect of calcium ions can delay the acidification process of the culture medium and extend the fermentation cycle.

[0042] Example Three:

[0043] In this example, based on Example Two, the weight percentage of water in the yeast culture is 42wt% - 47wt%.

[0044] In some embodiments, water is the basis for the metabolic activities of yeast, directly affecting the dissolution and transportation of nutrients. The water content affects the viscosity and porosity of the substrate, thereby affecting oxygen diffusion and carbon dioxide emission.

[0045] It is worth mentioning that when the weight percentage of water in the yeast culture is less than 42wt%, the nutrient substrate is too dry, and the nutrients are not fully dissolved, resulting in limited growth of yeast. When the weight percentage of water in the yeast culture is higher than 47wt%, the nutrient substrate is too wet, leading to an increase in anaerobic areas, thereby inhibiting the aerobic metabolism of yeast.

[0046] Thus, stabilizing the water content at 42wt% - 47wt% can reduce the risk of substrate drying or over - wetness during fermentation, and is beneficial to oxygen diffusion, reducing anaerobic areas and improving fermentation efficiency. It should be noted that within the water content range of 42wt% - 47wt%, the metabolic activity of yeast is the highest, and the cell density (OD600 value) can be increased by 15 - 20%. Preferably, the weight percentage of water in the yeast culture is 45wt%.

[0047] According to some embodiments of the present invention, the distiller's grains are strong - aroma distiller's grains. In some embodiments, strong - aroma distiller's grains are rich in residual starch, protein, organic acids (such as lactic acid, acetic acid) and ester substances (such as ethyl acetate, ethyl hexanoate). The above components can provide rich carbon sources, nitrogen sources and flavor precursor substances for yeast. Moreover, strong - aroma distiller's grains contain various microorganisms (such as lactic acid bacteria, acetic acid bacteria), and the metabolic products of these microorganisms can promote the growth and metabolism of yeast.

[0048] It is understandable that as a by-product of brewing, the strong aroma distiller's grains are low in cost. The efficient utilization of the strong aroma distiller's grains can reduce production costs, and the high nutritional value of the strong aroma distiller's grains reduces the dependence on other carbon and nitrogen sources. At the same time, after the organic acids (such as lactic acid and acetic acid) in the strong aroma distiller's grains react with quicklime, a buffer system can be formed to stabilize the fermentation environment. Of course, the ester substances (such as ethyl acetate) in the strong aroma distiller's grains can enhance the ethanol tolerance of yeast and extend the metabolic activity of yeast.

[0049] According to some embodiments of the present invention, the cottonseed meal is of the pressed type.

[0050] It is understandable that the cottonseed meal is directly obtained by pressing with a press. It has not undergone pre-extraction treatment and has a relatively high residual oil rate (about 13 - 15%), but due to the high processing temperature, the nutritional loss of the cottonseed meal is relatively large.

[0051] Therefore, 58 parts of cottonseed meal are used in this application to reduce the production cost of the culture. Of course, wheat bran contains about 15 - 17% protein to supplement the nitrogen source that may be lost in the cottonseed meal. Moreover, wheat bran is rich in thiamine (B1), riboflavin (B2), niacin (B3), etc., which can promote the metabolic enzyme activity of yeast. Of course, wheat bran contains minerals such as phosphorus, magnesium, and potassium, which support the cell wall synthesis and energy metabolism of yeast.

[0052] It should be noted that the protein and vitamins in wheat bran supplement the nutritional loss of cottonseed meal, forming a balanced nutritional system. Moreover, the fiber content of wheat bran (about 10 - 15%) improves the porosity of the nutritional matrix, promotes oxygen diffusion, and reduces anaerobic areas. Of course, wheat bran is low in price, and the addition amount is only 2 parts, which will not significantly increase the cost while enhancing the nutritional value of the nutritional matrix.

[0053] Example 4:

[0054] The present invention provides a method for culturing Saccharomyces cerevisiae for brewing, including: mixing a biological fermentation agent with the Saccharomyces cerevisiae culture described in any one of the above embodiments; wherein the proportion of the biological fermentation agent is 0.1%, and the biological fermentation agent includes Saccharomyces cerevisiae and acid protease.

[0055] In some embodiments, Saccharomyces cerevisiae is the main microbial component. Saccharomyces cerevisiae is responsible for growing and reproducing in the culture. Acid protease helps to decompose complex proteins into amino acids and other small peptide molecules. Amino acids and other small peptide molecules can not only directly serve as nutrient sources for Saccharomyces cerevisiae, but also improve the pH value of the culture environment, creating more suitable conditions for the growth of Saccharomyces cerevisiae. The precise addition (0.1%) of the biological fermentation agent ensures the maximization of the activities of yeast and enzymes, thereby reducing resource waste.

[0056] According to some embodiments of the present invention, the cultivation temperature is 25°C - 35°C. In some embodiments, 25°C - 35°C is the optimal growth temperature range for Saccharomyces cerevisiae. When the temperature is lower than 25°C, the metabolic activity of yeast decreases and the fermentation rate slows down; when the temperature is higher than 35°C, the yeast may be inactivated due to heat stress.

[0057] It is worth mentioning that the optimal temperature of acid protease is about 30°C - 40°C. In the range of 25°C - 35°C, the activity of acid protease is relatively high, which can effectively decompose proteins and release nitrogen sources, thus supporting the rapid proliferation of yeast.

[0058] In some embodiments, the following are the experimental data of this application:

[0059] Experimental fixed values: 40 parts of strong-flavor distiller's grains, the culture temperature is 30°C, the moisture content of the culture is 45 wt%, the biological fermentation agent is 0.1%, and the culture time is 16 hours.

[0060] Experimental variable values: parts by weight of cottonseed meal, parts by weight of wheat bran.

[0061]

[0062]

[0063] At the same time, as the share of wheat bran increases (0 → 5 parts), both the OD600 value and the ethanol yield first increase and then decrease. When the wheat bran is 2 parts, the growth and fermentation efficiency of yeast reach the best (the B vitamins and minerals in wheat bran significantly promote the metabolic activity of yeast).

[0064] When wheat bran is added, the growth and fermentation efficiency of yeast are significantly better than those without addition. When the wheat bran is 2 parts, the OD600 value reaches 2.0, the ethanol yield is 12.5 g / L, and at this ratio, the growth of yeast is the best and the fermentation efficiency is the highest.

[0065] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A Saccharomyces cerevisiae culture, characterized in that, Comprising: A nutrient matrix which, by weight parts, comprises 40 - 60 parts of distillers' grains, 40 - 60 parts of cottonseed meal, and 1 - 5 parts of wheat bran; A culture medium which is mixed with the nutrient matrix, and the culture medium comprises yellow water, and the yellow water is the leachate of distillers' grains.

2. The Saccharomyces cerevisiae culture according to claim 1, characterized in that, The nutrient matrix, by weight parts, comprises 40 parts of distillers' grains, 58 parts of cottonseed meal, and 2 parts of wheat bran.

3. The Saccharomyces cerevisiae culture according to claim 2, wherein Further comprising: Quicklime which is suitable for mixing with the nutrient matrix and the culture medium to regulate the pH value of the Saccharomyces cerevisiae culture, and the pH value of the Saccharomyces cerevisiae culture is 5 - 7.

4. The Saccharomyces cerevisiae culture according to claim 3, characterized in that, The water weight proportion in the yeast culture is 42wt% - 47wt%.

5. The Saccharomyces cerevisiae culture according to claim 4, wherein The distillers' grains are strong aroma distillers' grains.

6. The Saccharomyces cerevisiae culture according to claim 5, characterized in that, The cottonseed meal is of the pressing type.

7. A cultivation method of Saccharomyces cerevisiae, characterized in that, Comprising: Mixing a biological fermentation agent with the Saccharomyces cerevisiae culture according to any one of claims 1 - 6; Wherein, the proportion of the biological fermentation agent is 0.1%, and the biological fermentation agent comprises Saccharomyces cerevisiae and acid protease; Wherein, the Saccharomyces cerevisiae is: deposit number CGMCC 2.1030, Latin name Saccharomyces cerevisiae, and its deposit address is China General Microbiological Culture Collection Center, affiliated to Institute of Microbiology, Chinese Academy of Sciences.

8. The cultivation method of Saccharomyces cerevisiae according to claim 7, characterized in that, The cultivation temperature is 25°C - 35°C.

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