A medium additive for improving yeast RNA and use thereof

Abstract

The application discloses a medium additive for improving yeast RNA and application thereof, and the medium additive comprises L-methionine 6-10 parts, sodium glutamate 5-9 parts and ammonium dihydrogen phosphate 27-31 parts in terms of weight parts. The medium additive can be used as an additive of any yeast culture medium for base material addition or flow addition, can effectively improve the content of yeast RNA, and can improve the content of yeast RNA by 4.1-5.8% in continuous fermentation culture and by 13.2-19.3% in batch fermentation culture. The application is helpful for improving the content of yeast RNA and industrial production, can better guarantee the quality, safety and quality standardization of products, and greatly reduces the cost of yeast extract.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of microbial technology, and particularly relates to a culture medium additive for improving yeast RNA and application thereof. BACKGROUND

[0002] Ribonucleic acid (RNA) not only performs important biological functions in cells, but also has extremely important effects on the growth and health of humans and animals, and has broad application and development prospects in many fields such as medicine, health products, food and aquaculture. Since the production of RNA is mostly obtained by microbial fermentation, yeast does not produce any toxin and is a food safety level microorganism, grows and passes at a relatively fast speed, is easy to culture, and the yeast itself is relatively high in nutrition, containing rich protein, nucleic acid and sugar and other nutritional ingredients, and is recognized as the most ideal source of RNA.

[0003] In recent years, with the increasing application range of yeast extract and the increasing market, food manufacturers have increasingly high requirements for yeast extract. As the main raw material of yeast extract, yeast plays a crucial role. Among them, the ribonucleic acid (RNA) content of edible yeast seriously affects the quality and production cost of yeast extract. The RNA content of yeast fermentation still needs to be further improved to meet market demand. SUMMARY

[0004] In view of the low RNA content of yeast extract on the current market, the present application provides a culture medium additive for improving yeast RNA and application thereof, which is helpful to improve the RNA content of yeast and industrialized production, can better guarantee the quality, safety and quality standardization of products, and greatly reduce the cost of yeast extract.

[0005] Specifically, the present application provides the following technical solutions:

[0006] Technical solution 1: A culture medium additive for improving yeast RNA, characterized in that the culture medium additive comprises L-methionine 6-10 parts, sodium glutamate 5-9 parts and ammonium dihydrogen phosphate 27-31 parts by weight.

[0007] Technical solution 2: The culture medium additive for improving yeast RNA according to technical solution 1, characterized in that the culture medium additive comprises L-methionine 7-9 parts, sodium glutamate 6-8 parts and ammonium dihydrogen phosphate 28-30 parts by weight.

[0008] Preferably, the culture medium additive comprises L-methionine 7-8 parts, sodium glutamate 6-7 parts and ammonium dihydrogen phosphate 28-29 parts by weight.

[0009] Technical solution 3: The medium additive for improving yeast RNA according to technical solutions 1 or 2, characterized in that the medium additive is added as a base material or a flow addition.

[0010] Technical solution 4: The medium additive for improving yeast RNA according to any one of technical solutions 1-3, characterized in that the medium additive can be used as an additive of any yeast culture medium.

[0011] Technical solution 5: The medium additive for improving yeast RNA according to technical solution 4, characterized in that the any yeast culture medium includes one selected from the group consisting of YPD medium, YNB medium, YSG medium and SD medium.

[0012] Technical solution 6: The medium additive for improving yeast RNA according to technical solution 4, characterized in that the any yeast culture medium is selected from the medium including the following components: 0.4-0.5L component A, 0.4-0.5L component B, 0.4-0.5L component C, 0.4-0.5L component D, 0.3-0.4L ammonium dihydrogen phosphate solution with a concentration of 27-31.5g / L, 3-3.5L hydrolyzed sugar solution with a mass volume ratio of 28-32% (g / L) (the mass of hydrolyzed sugar per liter of solution is g), and 0.2-0.3L ammonia water with a mass percentage concentration of 38-42%;

[0013] According to the weight of the substances contained in component A, component B, component C and component D per liter (L) of volume (g), the component A includes 21.5-23.5g / L yeast extract powder; the component B includes 2.5-3.5g / L anhydrous calcium chloride and 32.3-35.5g / L KCl; the component C includes 0.065-0.067g / L VB1, 0.011-0.013g / L VB2, 0.022-0.024g / L VB6, 0.118-0.120g / L nicotinic acid, 0.088-0.090g / L pantothenic acid and 4.5×10 -4 -4.7×10 -4 g / L biotin, and the component D includes 0.105-0.11g / L copper sulfate pentahydrate, 0.86-0.9g / L zinc sulfate heptahydrate, 17.75-18g / L magnesium sulfate heptahydrate and 0.69-0.71g / L ferrous sulfate heptahydrate;

[0014] Wherein, the yeast extract powder contains total nitrogen ≥10%, amino nitrogen ≥5%, ash ≤15%, NaCl ≤2% and moisture ≤6%, preferably, the yeast extract powder contains total nitrogen 10-12%, amino nitrogen 5-8%, NaCl 1-2% and moisture 3-6%; preferably, each component is added to the yeast liquid in a flow addition manner.

[0015] Preferably, the hydrolyzed sugar is glucose.

[0016] Technical solution 7: The medium additive for improving the yield of yeast RNA according to technical solution 4, characterized in that the arbitrary yeast culture medium is selected from the group consisting of the following components: 6.5-7.5 L of molasses solution with a mass volume ratio of 25-28% (g / L) (the mass of molasses in g per liter of solution), 0.5-0.6 L of ammonia water with a mass percentage concentration of 38-42%, and 0.5-0.6 L of ammonium dihydrogen phosphate solution with a concentration of 39.2-45.7 g / L.

[0017] Preferably, each component is added to the yeast liquid in a flow addition manner.

[0018] Technical solution 8: A method for improving the yield of yeast RNA, characterized in that the method comprises adding the medium additive for improving the yield of yeast RNA according to any one of technical solutions 1-7 to an arbitrary yeast culture medium.

[0019] Technical solution 9: The method for improving the yield of yeast RNA according to technical solution 8, characterized in that the medium additive is added in a weight part of the sugar contained in the arbitrary yeast culture medium, and relative to 1000 weight parts of the sugar contained, the medium additive for improving the yield of yeast RNA according to any one of technical solutions 1-7 is added.

[0020] Technical solution 10: A medium additive composition for improving the yield of yeast RNA, characterized in that the medium additive composition comprises the medium additive for improving the yield of yeast RNA according to any one of technical solutions 1-7 and an arbitrary yeast culture medium.

[0021] Technical solution 11: The medium additive composition for improving the yield of yeast RNA according to technical solution 10, characterized in that the medium additive is added as a base material or in a flow addition manner to an arbitrary yeast culture medium.

[0022] Technical solution 12: The medium additive composition for improving the yield of yeast RNA according to technical solution 10 or 11, characterized in that the arbitrary yeast culture medium comprises one selected from the group consisting of YPD medium, YNB medium, YSG medium, and SD medium.

[0023] Technical solution 13: The medium additive composition for improving yeast RNA according to technical solutions 10 or 11, characterized in that the arbitrary yeast culture medium is selected from the medium comprising the following components: 0.4-0.5L component A, 0.4-0.5L component B, 0.4-0.5L component C, 0.4-0.5L component D, 0.3-0.4L ammonium dihydrogen phosphate solution with a concentration of 27-31.5g / L, 3-3.5L hydrolyzed sugar solution with a mass volume ratio of 28-32% (g / L) (the mass of hydrolyzed sugar contained in each liter of solution is g), and 0.2-0.3L ammonia water with a mass percentage concentration of 38-42%;

[0024] According to the weight of the substances contained in component A, component B, component C and component D in each liter (L) of volume (g), the component A comprises 21.5-23.5g / L yeast extract powder; the component B comprises 2.5-3.5g / L anhydrous calcium chloride and 32.3-35.5g / L KCl; the component C comprises 0.065-0.067g / L VB1, 0.011-0.013g / L VB2, 0.022-0.024g / L VB6, 0.118-0.120g / L nicotinic acid, 0.088-0.090g / L pantothenic acid and 4.5×10 -4 -4.7×10 -4 g / L biotin, and the component D comprises 0.105-0.11g / L copper sulfate pentahydrate, 0.86-0.9g / L zinc sulfate heptahydrate, 17.75-18g / L magnesium sulfate heptahydrate and 0.69-0.71g / L ferrous sulfate heptahydrate;

[0025] Preferably, each component is added to the yeast liquid in a flow addition manner.

[0026] Preferably, the hydrolyzed sugar is glucose.

[0027] Technical solution 14: The medium additive composition for improving yeast RNA according to technical solutions 10 or 11, characterized in that the arbitrary yeast culture medium is selected from the medium comprising the following components: 6.5-7.5L molasses solution with a mass volume ratio of 25-28% (g / L) (the mass of molasses contained in each liter of solution is g), 0.5-0.6L ammonia water with a mass percentage concentration of 38-42%, and 0.5-0.6L ammonium dihydrogen phosphate solution with a concentration of 39.2-45.7g / L;

[0028] Preferably, each component is added to the yeast liquid in a flow addition manner.

[0029] Technical solution 15: The use of the medium additive for increasing the RNA content of yeast or the medium additive composition for increasing the RNA content of yeast according to any one of technical solutions 1-7 or 10-14 in the preparation of a yeast product with high RNA content.

[0030] Technical solution 16: The use according to technical solution 15, characterized in that the yeast product with high RNA content comprises a yeast extract with high RNA content.

[0031] Advantages of the present application:

[0032] The medium additive of the present application can effectively increase the RNA content of yeast. In continuous fermentation culture, the RNA content of yeast can be increased by 4.1-5.8%, and in batch fermentation culture, the RNA content of yeast can be increased by 13.2%-19.3%. This is helpful for industrial production, can better guarantee the quality, safety and quality standardization of the product, and greatly reduce the cost of yeast extract. DETAILED DESCRIPTION

[0033] The technical solutions of the present application will be further described in detail below in combination with specific examples and comparative examples, but the present application is not limited to the following technical solutions.

[0034] The present application discloses a medium additive for increasing the RNA content of yeast. The medium additive comprises, by weight, 6-10 parts of L-methionine, 5-9 parts of sodium glutamate and 27-31 parts of ammonium dihydrogen phosphate.

[0035] The medium additive is added according to the weight parts of the sugar contained in any yeast culture medium, and the medium additive is added relative to 1000 weight parts of the sugar contained.

[0036] In some specific embodiments, the weight parts of L-methionine in the medium additive can be any two numerical values between 6 and 10: 6, 6.5, 7.5, 8, 8.5, 9, 9.5 or 10, or the weight parts within the numerical range constituted by any two of the above specific numerical values as end points.

[0037] In some specific embodiments, the weight parts of sodium glutamate in the medium additive can be any two numerical values between 5 and 9: 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5 or 9, or the weight parts within the numerical range constituted by any two of the above specific numerical values as end points.

[0038] In some specific embodiments, the weight parts of ammonium dihydrogen phosphate in the culture medium additive can be any two values ​​between 27 and 31: 27, 27.5, 28, 28.5, 29, 29.5, 30, 30.5 or 31, or any two of the above specific values ​​as endpoints within a numerical range.

[0039] Adding the aforementioned culture medium additive to any yeast culture medium during yeast culture can increase the yeast RNA content by 4.1-5.8% in continuous fermentation culture and by 13.2%-19.3% in batch fermentation culture. The "any yeast culture medium" mentioned in this invention includes conventional culture media used by those skilled in the art for yeast culture, including YPD medium, YNB medium, YSG medium, or SD medium.

[0040] The brewing yeast used in the embodiments of the present invention ( Saccharomyces cerevisiae The FX-2 strain was isolated from fermented dough, which contains various wild-type microorganisms. Using the fermented dough as a sample, a dough extract was prepared, and a pure strain was isolated via dilution plating. Identification was performed using 16S rRNA sequencing, which showed a sequence homology greater than 99%, thus confirming that the strain isolated in this invention belongs to *Saccharomyces cerevisiae*. Saccharomyces cerevisiae ), named brewer's yeast ( Saccharomyces cerevisiae The FX-2 strain was deposited at the China Center for Type Culture Collection (CCTCC) on August 1, 2016, with accession number CCTCC NO: M 2016418. The method for isolating and identifying this strain has been disclosed in patent application CN108220175A.

[0041] The brewing yeast used in the embodiments of the present invention ( Saccharomyces cerevisiae AMCC

[0042] Strain 30743 was deposited at the China Center for Type Culture Collection (CCTCC) on July 27, 2021.

[0043] The strain has the accession number CCTCC NO: M 2021941. It was isolated from fermented dairy products in Shannan City, Tibet Autonomous Region.

[0044] The separation and identification method has been disclosed in patent application CN113862164A. Unless otherwise stated, all reagents and instruments used in the embodiments and comparative examples of this invention are conventional.

[0045] Commercially available products. Information on the sources of instruments and reagents used in the embodiments and comparative examples of this invention is shown in Table 1 below.

[0046] Table 1

[0047]

[0048] The detection method of the RNA content in the embodiment of the application is as follows:

[0049] Principle: perchloric acid is used to break the cell wall in the yeast and centrifugal extraction is used to extract the RNA in the yeast cell. The RNA has the property of absorbing ultraviolet light, has the maximum absorption at the wavelength of 260 nm, and the light absorption value is proportional to the concentration within a certain concentration range, which conforms to the Lambert-Beer law.

[0050] Reagent:

[0051] 0.5 mol / L perchloric acid (HClO4) solution: 21.5 mL of 70 % (or 22.1 mL of 68 %) perchloric acid is added into 400 mL of distilled water, and then distilled water is used to make up to 500 mL.

[0052] 0.25 mol / L perchloric acid (HClO4) solution: 250 mL of 0.5 mol / L perchloric acid (HClO4) is diluted with distilled water to make up to 500 mL.

[0053] Equipment:

[0054] (1) milligram scale; (2) 4000 rpm centrifuge, which can separate the yeast; (3) centrifugal test tube, the capacity of which is at least 10 mL; (4) spectrophotometer (260 nm); (5) 70 °C hot water bath; (6) 4 °C cold water bath; (7) 10 mL and 1 mL pipette; (8) 100 mL volumetric flask.

[0055] Method:

[0056] 1. The yeast milk is diluted with water to have a dry matter content of 18 % of the yeast milk, and 0.6 g is weighed.

[0057] 2. 8 mL of cold 0.25 mol / L HClO4 is added into the centrifugal tube, and the 4 °C water bath is maintained for 15 min.

[0058] 3. 4000 rpm centrifugation is performed for 10 min.

[0059] 4. The material floating on the surface is poured out, 5 mL of 0.5 mol / L HClO4 is added, and oscillation is performed for mixing, which is taken as the volume V, and the 70 °C water bath is maintained for 15 min, and oscillation is performed every 3-4 min. 4000 rpm centrifugation is performed for 10 min, 1 mL of supernatant is taken, and distilled water is used to make up to 100 mL, and the dilution multiple is 100.

[0060] 5. The absorbance is measured at 260 nm, and distilled water is used as the blank control.

[0061] The calculation formula is: wherein 0.03365 is the conversion coefficient, the sample mass is measured in milligrams, and the dilution factor is 100 in the calculation of the RNA content in the yeast milk of the present application.

[0062] RNA content improvement rate (%) = (RNA content of the example or the comparative example - RNA content of the control group) / RNA content of the control group * 100%

[0063]

[0064] Example 1: Adding a medium additive for improving yeast RNA in continuous fermentation to ferment yeast to improve the RNA yield of yeast

[0065] Example 1-1

[0066] 1. Preparation of yeast fermentation medium and medium additive for improving yeast RNA

[0067] (1) Yeast fermentation medium

[0068] The yeast fermentation medium comprises component A, component B, component C, component D, carbon source, nitrogen source and phosphorus source.

[0069] Component A: contains 21.5 g / L yeast extract powder. Take 8.6 grams of yeast extract powder, dilute to 400 ml, then sterilize at 115 degrees for 20 minutes, add at a flow rate of 21 ml / h in the first hour, 29 ml / h in the second hour, and 35 ml / h from 3 to 12 hours.

[0070] Component B: contains 2.5 g / L anhydrous calcium chloride and 32.3 g / L KCl. Take 1 gram of anhydrous calcium chloride and 12.9 grams of potassium chloride, dilute to 400 ml, then sterilize at 121 degrees for 30 minutes, add at a flow rate of 21 ml / h in the first hour, 29 ml / h in the second hour, and 35 ml / h from 3 to 12 hours.

[0071] Component C: contains 0.065 g / L VB1, 0.011 g / L VB2, 0.022 g / L VB6, 0.118 g / L nicotinic acid, 0.088 g / L pantothenic acid and 4.5 x 10 -4 g / L biotin. Take 0.026 grams of VB1, 0.0043 grams of VB2, 0.0086 grams of VB6, 0.047 grams of nicotinic acid, 0.035 grams of pantothenic acid and 0.00018 grams of biotin, dissolve the biotin in 100 ml of hot water first, then dilute to 400 ml with other vitamins, add at a flow rate of 21 ml / h in the first hour, 29 ml / h in the second hour, and 35 ml / h from 3 to 12 hours.​

[0072] Component D: including copper sulfate pentahydrate 0.105g / L, zinc sulfate heptahydrate 0.86g / L, magnesium sulfate heptahydrate 17.75g / L and ferrous sulfate heptahydrate 0.69g / L. Take 0.042 grams of copper sulfate pentahydrate, 0.344 grams of zinc sulfate heptahydrate, 7.1 grams of magnesium sulfate heptahydrate, 0.275 grams of ferrous sulfate heptahydrate, make up to 400ml, then sterilize at 121 degrees for 30 minutes, add at a flow rate of 21ml / h in the first hour, 29ml / h in the second hour, and 35ml / h from 3-12h.

[0073] Carbon source: including 30% (g / L) glucose. Take 900g of glucose and dissolve in 3L of water to prepare a 30% (g / L) sugar concentration solution, then sterilize at 115 degrees for 20 minutes, add at a flow rate of 150ml / h in the first hour, 200ml / h in the second hour, and 240ml / h from 3-12h.

[0074] Nitrogen source: 38% ammonia water with a mass percentage concentration of 38% is added at a flow rate of 16ml / h in the first hour, 19ml / h in the second hour, and 23ml / h from 3-12h.

[0075] Phosphorus source: 27g / L ammonium dihydrogen phosphate is added at a flow rate of 21ml / h in the first hour, 29ml / h in the second hour, and 35ml / h from 3-12h.

[0076] (2) Improve the culture medium additives of yeast RNA

[0077] According to the weight of the sugar contained in the yeast fermentation medium, relative to 1000 parts by weight of the sugar contained, the medium additives are: 6 parts of L-methionine, 5 parts of sodium glutamate and 27 parts of ammonium dihydrogen phosphate. According to the glucose content in the yeast fermentation medium (900g), take 5.4g of L-methionine, 4.5g of sodium glutamate and 24.3g of ammonium dihydrogen phosphate, make up to 400ml, use 80-90 degree hot water to prepare, then sterilize at 115 degrees for 20 minutes, add at a flow rate of 21ml / h in the first hour, 29ml / h in the second hour, and 35ml / h from 3-12h.

[0078] 2. Seed fermentation

[0079] The glycerol tube stored Saccharomyces cerevisiae FX-2 strain was activated, and a ring was picked and inoculated into a seed fermentation medium. The medium was composed of 100 g / L sucrose, 20 g / L yeast extract powder, 1 g / L magnesium sulfate heptahydrate, and 1 g / L potassium dihydrogen phosphate, and the total volume was 10 L. The seed fermentation liquid was obtained by culturing at 30 °C and 150-180 RPM for 24 hours.

[0080] 3. Commercial fermentation

[0081] The seed fermentation liquid was added into a 50 L fermentation tank, and continuous fermentation culture was carried out by adding yeast fermentation medium and medium additive for increasing yeast RNA. The fermentation temperature of commercial fermentation was 31 °C, the stirring speed was 500 rpm for the first 2 hours, 550 rpm for the third hour, and 600 rpm for the fourth to sixth hours, the air flow rate was 14 L / min for the first 2 hours, 22 L / min for the third hour, and 30 L / min for the fourth to twelfth hours. From the third hour, the fermentation liquid was discharged at a rate of 2.2 L per hour, and process water was supplemented at the same time to maintain the fermentation volume at about 10 L. Continuous fermentation was carried out, which is a process of continuously adding nutrients in the fermentation tank while continuously discharging fermentation liquid to keep the system in a stable state, so that the growth and metabolic activity of yeast can be sustained and efficient. After 12 hours of continuous fermentation, the RNA content (%) in the yeast milk was determined, and the RNA content increase rate was calculated by taking the case without adding medium additive for increasing yeast RNA as a control. The results are shown in Table 2.

[0082] Example 1-2

[0083] Compared with Example 1-1, the medium additive was 7 parts of L-methionine, 6 parts of sodium glutamate, and 28 parts of ammonium dihydrogen phosphate, based on the weight of the sugar contained in the yeast fermentation medium, relative to 1000 parts by weight of the sugar contained. According to the glucose content (900 g) in the yeast fermentation medium, 6.3 g of L-methionine, 5.4 g of sodium glutamate, and 25.2 g of ammonium dihydrogen phosphate were taken respectively, and the volume was made up to 400 ml. The remaining steps were the same as in Example 1-1. After 12 hours of continuous fermentation, the RNA content (%) in the yeast milk was determined, and the RNA content increase rate was calculated by taking the case without adding medium additive for increasing yeast RNA as a control. The results are shown in Table 2.

[0084] Example 1-3

[0085] Compared with Example 1-1, the medium additive is: 9 parts of L-methionine, 8 parts of sodium glutamate and 30 parts of ammonium dihydrogen phosphate, based on the weight of the sugar contained in the yeast fermentation medium, relative to 1000 parts by weight of the sugar contained. According to the glucose content (900 g) in the yeast fermentation medium, 8.1 g of L-methionine, 7.2 g of sodium glutamate and 27 g of ammonium dihydrogen phosphate were taken respectively, and the volume was made up to 400 ml. The remaining steps are the same as Example 1-1. After 12 h of continuous fermentation, the RNA content (%) in the yeast milk was determined, and the RNA content improvement rate was calculated with the control of not adding the medium additive for improving yeast RNA. The results are shown in Table 2.

[0086] Example 1-4

[0087] Compared with Example 1-1, the medium additive is: 9 parts of L-methionine, 8 parts of sodium glutamate and 30 parts of ammonium dihydrogen phosphate, based on the weight of the sugar contained in the yeast fermentation medium, relative to 1000 parts by weight of the sugar contained. According to the glucose content (900 g) in the yeast fermentation medium, 8.1 g of L-methionine, 7.2 g of sodium glutamate and 27 g of ammonium dihydrogen phosphate were taken respectively, and the volume was made up to 400 ml. The remaining steps are the same as Example 1-1. After 12 h of continuous fermentation, the RNA content (%) in the yeast milk was determined, and the RNA content improvement rate was calculated with the control of not adding the medium additive for improving yeast RNA. The results are shown in Table 2.

[0088] Table 2

[0089]

[0090] As shown in Table 2, in the continuous culture of Example 1, after adding the medium additive for improving yeast RNA, the yeast RNA content can be increased by 4.1%-5.8% compared with the control medium, and the effect of Example 1-2 is the best, and the medium additive is 7 parts of L-methionine, 6 parts of sodium glutamate and 28 parts of ammonium dihydrogen phosphate.

[0091] Example 2 of adding the medium additive for improving yeast RNA in the continuous fermentation of yeast to improve the yield of yeast RNA

[0092] Example 2-1

[0093] 1. Preparation of yeast fermentation medium and medium additive for improving yeast RNA

[0094] (1) Yeast fermentation medium

[0095] The yeast fermentation medium includes component A, component B, component C, component D, carbon source, nitrogen source and phosphorus source.

[0096] Component A: 400ml of yeast extract powder 23.5g / L was prepared, then sterilized at 115 degrees for 20 minutes, added at a flow rate of 21ml / h in the first hour, 29ml / h in the second hour, and 35ml / h from the third to the twelfth hour.

[0097] Component B: 400ml of a solution containing 3.5g / L anhydrous calcium chloride and 35.5g / L KCl was prepared, then sterilized at 121 degrees for 30 minutes, added at a flow rate of 21ml / h in the first hour, 29ml / h in the second hour, and 35ml / h from the third to the twelfth hour.

[0098] Component C: 400ml of a solution containing 0.067g / L VB1, 0.013g / L VB2, 0.024g / L VB6, 0.120g / L nicotinic acid, 0.090g / L pantothenic acid, and 4.7×10 -4 g / L biotin was prepared. Biotin was first dissolved in 100ml of hot water and then made up to 400ml with other vitamins. Added at a flow rate of 21ml / h in the first hour, 29ml / h in the second hour, and 35ml / h from the third to the twelfth hour.

[0099] Component D: 400ml of a solution containing copper sulfate pentahydrate 0.11g / L, zinc sulfate heptahydrate 0.9g / L, magnesium sulfate heptahydrate 18g / L, and ferrous sulfate heptahydrate 0.71g / L was prepared. Then sterilized at 121 degrees for 30 minutes, added at a flow rate of 21ml / h in the first hour, 29ml / h in the second hour, and 35ml / h from the third to the twelfth hour.

[0100] Carbon source: 3L of a 32% (g / L) glucose solution was prepared by dissolving 960g of glucose in 3L of water, then sterilized at 115 degrees for 20 minutes. Added at a flow rate of 150ml / h in the first hour, 200ml / h in the second hour, and 240ml / h from the third to the twelfth hour.

[0101] Nitrogen source: 42% ammonia water was added at a flow rate of 16ml / h in the first hour, 19ml / h in the second hour, and 23ml / h from the third to the twelfth hour.

[0102] Phosphorus source: 31.5g / L ammonium dihydrogen phosphate was added at a flow rate of 21ml / h in the first hour, 29ml / h in the second hour, and 35ml / h from the third to the twelfth hour.

[0103] (2) Improve the culture medium additives of yeast RNA

[0104] According to the weight of the sugar contained in the yeast fermentation medium, relative to 1000 parts by weight of the contained sugar, the medium additives are: 10 parts of L-methionine, 9 parts of sodium glutamate and 31 parts of ammonium dihydrogen phosphate. According to the glucose content (960 g) in the yeast fermentation medium, 9.6 g of L-methionine, 8.64 g of sodium glutamate and 29.76 g of ammonium dihydrogen phosphate are taken respectively, and the volume is made up to 400 ml, using 80-90 degree hot water, and then sterilized at 115 degrees for 20 minutes. The first hour is added at a flow rate of 21 ml / h, the second hour is added at a flow rate of 29 ml / h, and the third to twelfth hours are added at a flow rate of 35 ml / h.

[0105] 2. Seed fermentation

[0106] After the glycerol tube preserved Saccharomyces cerevisiae FX-2 strain is activated, a ring is picked and inoculated into the seed fermentation medium, and the composition of the medium is: 100 g / L sucrose, 20 g / L yeast extract powder, 1 g / L magnesium sulfate heptahydrate and 1 g / L potassium dihydrogen phosphate, a total of 10 L. Cultured at 30°C in a 150-180 RPM shaker for 24 hours to obtain the seed fermentation broth.

[0107] 3. Commercial fermentation

[0108] The seed fermentation broth is added to the 50 L fermenter, and the yeast fermentation medium and the medium additive for increasing yeast RNA are added continuously to carry out continuous fermentation culture. The fermentation temperature of the commercial fermentation is 31°C, the stirring speed is 500 rpm for the first 2 hours, 550 rpm for the third hour, 600 rpm for the fourth to sixth hours, the air flow is 14 L / min for the first 2 hours, 22 L / min for the third hour, and 30 L / min for the fourth to twelfth hours. From the third hour, the fermentation broth is discharged at a rate of 2.2 L per hour, while the process water is supplemented to maintain the fermentation volume constant at about 10 L, and continuous fermentation is carried out. Continuous fermentation is when the yeast culture enters the logarithmic growth phase, nutrients are continuously added in the fermenter, while the fermentation broth is continuously discharged, so as to keep the system in a stable state, so that the growth and metabolic activity of the yeast is continuously efficient. After 12 hours of continuous fermentation, the RNA content (%) in the yeast milk is measured, the RNA content increase rate is calculated by taking the medium additive for increasing yeast RNA as a control, and the results are shown in Table 3.

[0109] Example 2-2

[0110] Compared to Example 2-1, based on the weight of sugar in the yeast fermentation medium, the medium additives relative to 1000 parts by weight of sugar were: 7 parts L-methionine, 6 parts monosodium glutamate, and 28 parts ammonium dihydrogen phosphate. According to the glucose content (960g) in the yeast fermentation medium, 6.72g of L-methionine, 5.76g of monosodium glutamate, and 26.88g of ammonium dihydrogen phosphate were taken and the volume was adjusted to 400ml. The remaining steps were the same as in Example 2-1. After continuous fermentation for 12 hours, the RNA content (%) in the yeast milk was measured. Using the medium additive without added yeast RNA as a control, the RNA content increase rate was calculated, and the results are shown in Table 3.

[0111] Example 2-3

[0112] Compared to Example 2-1, based on the weight of sugar in the yeast fermentation medium, the medium additives relative to 1000 parts by weight of sugar were: 9 parts L-methionine, 8 parts monosodium glutamate, and 30 parts ammonium dihydrogen phosphate. According to the glucose content (960g) in the yeast fermentation medium, 8.64g of L-methionine, 7.68g of monosodium glutamate, and 28.8g of ammonium dihydrogen phosphate were taken and the volume was adjusted to 400ml. The remaining steps were the same as in Example 2-1. After continuous fermentation for 12 hours, the RNA content (%) in the yeast milk was measured. Using the medium additive without added yeast RNA as a control, the RNA content increase rate was calculated, and the results are shown in Table 3.

[0113] Examples 2-4

[0114] Compared to Example 2-1, based on the weight of sugar in the yeast fermentation medium, the medium additives relative to 1000 parts by weight of sugar were: 6 parts L-methionine, 5 parts monosodium glutamate, and 27 parts ammonium dihydrogen phosphate. According to the glucose content (960g) in the yeast fermentation medium, 5.76g of L-methionine, 4.8g of monosodium glutamate, and 25.92g of ammonium dihydrogen phosphate were taken and the volume was adjusted to 400ml. The remaining steps were the same as in Example 2-1. After continuous fermentation for 12 hours, the RNA content (%) in the yeast milk was measured. Using the medium additive without added yeast RNA as a control, the RNA content increase rate was calculated, and the results are shown in Table 3.

[0115] Table 3

[0116]

[0117] As shown in Table 3, in the continuous culture of Example 2, after adding the culture medium additive containing yeast RNA, the yeast RNA content can be increased by 4.3%-5.7% compared with the control culture medium. Among them, Example 2-2 showed the best effect. The culture medium additive consisted of 7 parts L-methionine, 6 parts monosodium glutamate and 28 parts ammonium dihydrogen phosphate.

[0118] Example 3 Batch fermentation with the addition of a medium additive for increasing yeast RNA

[0119] Example 3-1

[0120] 1. Preparation of yeast fermentation medium and medium additive for increasing yeast RNA

[0121] (1) Yeast fermentation medium

[0122] The yeast fermentation medium includes a carbon source, a nitrogen source, and a phosphorus source.

[0123] Carbon source: 7 L of molasses at a mass / volume ratio of 28% (g / L) was prepared by dissolving 1960 g of molasses in 7 L of water. The mixture was then sterilized at 115°C for 20 min and added dropwise at the flow rates shown in Table 4.

[0124] Nitrogen source: 42% ammonia water was added dropwise at the flow rates shown in Table 4.

[0125] Phosphorus source: 39.2 g / L ammonium dihydrogen phosphate was added dropwise at the flow rates shown in Table 4.

[0126] (2) Medium additive for increasing yeast RNA

[0127] The medium additive was prepared by adding 6 parts of L-methionine, 5 parts of sodium glutamate, and 27 parts of ammonium dihydrogen phosphate, based on 1000 parts by weight of the sugar contained in the yeast fermentation medium. Based on the molasses content (1960 g) of the yeast fermentation medium, 11.76 g of L-methionine, 9.8 g of sodium glutamate, and 52.92 g of ammonium dihydrogen phosphate were added, and the volume was adjusted to 600 ml. The mixture was prepared using hot water at 80-90°C, sterilized at 115°C for 20 min, and added dropwise at the flow rates shown in Table 4.

[0128] 2. Seed fermentation

[0129] After the Saccharomyces cerevisiae FX-2 strain stored in a glycerol tube was activated, a loopful of the activated strain was inoculated into a seed fermentation medium, which consisted of 100 g / L sucrose, 20 g / L yeast extract powder, 1 g / L magnesium sulfate heptahydrate, and 1 g / L potassium dihydrogen phosphate, and the total volume was 10 L. The seed fermentation medium was incubated at 30°C for 24 hours in a 150-180 RPM shaker to obtain a seed fermentation broth.

[0130] 3. Commercial fermentation

[0131] The seed fermentation broth was added into a 50 L fermenter, and fed-batch fermentation culture was carried out by adding yeast fermentation medium and medium additive for increasing yeast RNA. During the fed-batch fermentation of the yeast, certain materials were added to the fermentation system, but the fermentation broth was not continuously discharged. The growth and metabolic activity of the yeast went through a lag phase, a logarithmic phase, a stationary phase and a decline phase. The fermentation temperature was 30°C, and the culture conditions are shown in Table 4. After 11 hours of culture, the yeast RNA content was determined. The RNA content increase rate was calculated by taking the case without adding the medium additive for increasing yeast RNA as a control, and the results are shown in Table 5.

[0132] Example 3-2

[0133] Compared with Example 3-1, the medium additive was 7 parts of L-methionine, 6 parts of sodium glutamate and 28 parts of ammonium dihydrogen phosphate, based on the weight of the sugar contained in the yeast fermentation medium, relative to 1000 parts by weight of the sugar contained. According to the content of molasses in the yeast fermentation medium (1960 g), 13.72 g of L-methionine, 11.76 g of sodium glutamate and 54.88 g of ammonium dihydrogen phosphate were taken respectively, and the volume was made up to 600 ml. The remaining steps were the same as in Example 3-1. After 11 hours of culture, the yeast RNA content was determined. The RNA content increase rate was calculated by taking the case without adding the medium additive for increasing yeast RNA as a control, and the results are shown in Table 5.

[0134] Example 3-3

[0135] Compared with Example 3-1, the medium additive was 9 parts of L-methionine, 8 parts of sodium glutamate and 30 parts of ammonium dihydrogen phosphate, based on the weight of the sugar contained in the yeast fermentation medium, relative to 1000 parts by weight of the sugar contained. According to the content of molasses in the yeast fermentation medium (1960 g), 17.64 g of L-methionine, 15.68 g of sodium glutamate and 58.8 g of ammonium dihydrogen phosphate were taken respectively, and the volume was made up to 600 ml. The remaining steps were the same as in Example 3-1. After 11 hours of culture, the yeast RNA content was determined. The RNA content increase rate was calculated by taking the case without adding the medium additive for increasing yeast RNA as a control, and the results are shown in Table 5.

[0136] Example 3-4

[0137] Compared with Example 3-1, the medium additive is: 10 parts of L-methionine, 9 parts of sodium glutamate and 31 parts of ammonium dihydrogen phosphate, relative to 1000 parts by weight of the contained sugar, according to the weight of the sugar contained in the yeast fermentation medium. According to the molasses content (1960 g) in the yeast fermentation medium, 19.6 g of L-methionine, 17.64 g of sodium glutamate and 60.76 g of ammonium dihydrogen phosphate are taken respectively, and the volume is made up to 600 ml. The remaining steps are the same as in Example 3-1, the yeast RNA content is determined after 11 hours of culture, the RNA content increase rate is calculated taking the culture medium without the addition of the medium additive for increasing the yeast RNA as a control, and the results are shown in Table 5.

[0138] Table 4

[0139]

[0140] Table 5

[0141]

[0142] As shown in Table 5, in the fed-batch fermentation of Example 3, after the addition of the medium additive for increasing the yeast RNA, the yeast RNA content can be increased by 13.3%-18.3% compared with the control medium, among which Example 3-2 has the best effect, and the medium additive is 7 parts of L-methionine, 6 parts of sodium glutamate and 28 parts of ammonium dihydrogen phosphate.

[0143] Example 4 Fermentation of yeast with the addition of medium additive for increasing the yeast RNA in batch fermentation to increase the yield of yeast RNA

[0144] Compared with Example 3-1, the strain used for fermentation is Saccharomyces cerevisiae AMCC 30743 strain, and the remaining steps are the same as in Example 3-1, the yeast RNA content is determined after 11 hours of culture, the RNA content is 9.08%, and the RNA content increase rate is calculated taking the culture medium without the addition of the medium additive for increasing the yeast RNA as a control, the RNA content (%) in the control medium is 7.61%, and the RNA increase rate is 19.3%.

[0145] Example 5 Fermentation of yeast with the addition of medium additive for increasing the yeast RNA in batch fermentation to increase the yield of yeast RNA

[0146] Example 5-1

[0147] 1. Preparation of yeast fermentation medium and medium additive for increasing the yeast RNA

[0148] (1) Yeast fermentation medium

[0149] The yeast fermentation medium includes carbon source, nitrogen source and phosphorus source.

[0150] Carbon source: 7L of molasses with 25% (g / L) of sugar, 1750g of molasses was dissolved in 7L of water. Then sterilized at 115 degrees for 20 minutes, and added by flow rate, see Table 4.

[0151] Nitrogen source: 38% ammonia water was added by flow rate, see Table 4.

[0152] Phosphorus source: 45.7 g / L of ammonium dihydrogen phosphate was added by flow rate, see Table 4.

[0153] (2) Medium additive for improving yeast RNA

[0154] According to the weight of sugar contained in the yeast fermentation medium, relative to 1000 parts by weight of sugar contained, the medium additive is: 6 parts of L-methionine, 5 parts of sodium glutamate and 27 parts of ammonium dihydrogen phosphate. According to the molasses content (1750g) in the yeast fermentation medium, 10.5g of L-methionine, 8.75g of sodium glutamate and 47.25g of ammonium dihydrogen phosphate were taken respectively, and the volume was made up to 600ml, and then hot water of 80-90 degrees was used to configure, and then sterilized at 115 degrees for 20 minutes. Added by flow rate, see Table 4.

[0155] 2. Seed fermentation

[0156] After the glycerol tube stored Saccharomyces cerevisiae FX-2 strain was activated, a ring was picked and inoculated into the seed fermentation medium, the composition of the medium was: 100g / L sucrose, 20g / L yeast extract powder, 1g / L magnesium sulfate heptahydrate and 1g / L potassium dihydrogen phosphate, a total of 10L. Cultured at 30℃ in a 150-180RPM shaker for 24 hours to obtain seed fermentation broth.

[0157] 3. Commercial fermentation

[0158] The seed fermentation broth was added into a 50L fermenter, and the yeast fermentation medium and the medium additive for improving yeast RNA were added by flow rate for batch fermentation culture. During the batch fermentation of yeast, certain materials were added to the fermentation system, but it was not necessary to continuously discharge the fermentation broth outside, and the growth and metabolic activity of yeast went through a lag phase, a logarithmic phase, a stationary phase and a decline phase. The fermentation temperature was 30℃, and the culture conditions were as shown in Table 4. After 11 hours of culture, the yeast RNA content and the yeast wet weight were determined, and the RNA content improvement rate was calculated by taking the yeast RNA content without adding the medium additive for improving yeast RNA as a control, and the results were shown in Table 6.

[0159] Example 5-2

[0160] Compared to Example 4-1, based on the weight of sugar in the yeast fermentation medium, the medium additives relative to 1000 parts by weight of sugar were: 7 parts L-methionine, 6 parts monosodium glutamate, and 28 parts ammonium dihydrogen phosphate. According to the molasses content (1750g) in the yeast fermentation medium, 12.25g of L-methionine, 10.5g of monosodium glutamate, and 49g of ammonium dihydrogen phosphate were taken and the volume was adjusted to 600ml. The remaining steps were the same as in Example 4-1. After culturing for 11 hours, the yeast RNA content was measured, with the medium additive without added yeast RNA serving as a control. The RNA content increase rate was calculated, and the results are shown in Table 6.

[0161] Example 5-3

[0162] Compared to Example 4-1, based on the weight of sugar in the yeast fermentation medium, the medium additives relative to 1000 parts by weight of sugar were: 9 parts L-methionine, 8 parts monosodium glutamate, and 30 parts ammonium dihydrogen phosphate. According to the molasses content (1750g) in the yeast fermentation medium, 15.75g of L-methionine, 14g of monosodium glutamate, and 52.5g of ammonium dihydrogen phosphate were taken and the volume was adjusted to 600ml. The remaining steps were the same as in Example 4-1. After culturing for 11 hours, the yeast RNA content was measured, with the medium additive without added yeast RNA serving as a control. The RNA content increase rate was calculated, and the results are shown in Table 6.

[0163] Example 5-4

[0164] Compared to Example 4-1, based on the weight of sugar in the yeast fermentation medium, the medium additives relative to 1000 parts by weight of sugar were: 10 parts L-methionine, 9 parts monosodium glutamate, and 31 parts ammonium dihydrogen phosphate. According to the molasses content (1750g) in the yeast fermentation medium, 17.5g of L-methionine, 15.75g of monosodium glutamate, and 54.25g of ammonium dihydrogen phosphate were taken and the volume was adjusted to 600ml. The remaining steps were the same as in Example 4-1. After culturing for 11 hours, the yeast RNA content was measured, with the medium additive without added yeast RNA serving as a control. The RNA content increase rate was calculated, and the results are shown in Table 6.

[0165] Table 6

[0166]

[0167] As shown in Table 6, in the fed-batch culture of Example 5, after adding yeast RNA as a culture medium additive, the yeast RNA content can be increased by 13.2%-17.9% compared with the control culture medium. Among them, Example 5-2 had the best effect. The culture medium additive was 7 parts L-methionine, 6 parts monosodium glutamate and 28 parts ammonium dihydrogen phosphate.

[0168] Comparative Example 1

[0169] Compared with Example 3-1, according to the weight of the sugar contained in the yeast fermentation medium, the medium additive is: 27 parts of ammonium dihydrogen phosphate, L-methionine and sodium glutamate are absent in the medium additive, according to the content of molasses in the yeast fermentation medium (1960 g), 52.92 g of ammonium dihydrogen phosphate is taken, and the volume is made up to 400 ml, the remaining steps are the same as in Example 3-1, the culture is carried out for 11 hours, the yeast RNA content is determined to be 6.54%, the RNA content in the control medium without the addition of the medium additive for increasing the yeast RNA is calculated to be 6.38%, and the RNA increase rate is 2.5%, which is far less than the RNA increase rate of 13.8% in Example 3-1, so it can be seen that the medium additive of the present application is helpful to the increase of the yeast RNA content and the industrialized production.

[0170] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Any modification, equivalent replacement and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A medium additive for improving yeast RNA, characterized by, The medium additive consists of L-methionine 6-10 parts, sodium glutamate 5-9 parts and ammonium dihydrogen phosphate 27-31 parts by weight.

2. The medium additive for improving yeast RNA according to claim 1, characterized by, The medium additive consists of L-methionine 7-9 parts, sodium glutamate 6-8 parts and ammonium dihydrogen phosphate 28-30 parts by weight.

3. The medium additive for improving yeast RNA according to claim 1, characterized by, The medium additive consists of L-methionine 7-8 parts, sodium glutamate 6-7 parts and ammonium dihydrogen phosphate 28-29 parts by weight.

4. The medium additive for improving yeast RNA according to claim 1, characterized by, The medium additive is added as a base or is added by flow addition.

5. The medium additive for improving yeast RNA according to claim 1, characterized by, The medium additive for increasing yeast RNA is added to any yeast culture medium, and the L-methionine is 6-10 parts, the sodium glutamate is 5-9 parts and the ammonium dihydrogen phosphate is 27-31 parts by weight based on 1000 parts by weight of sugar contained in any yeast culture medium.

6. The medium additive for improving yeast RNA according to claim 2, characterized by, The medium additive for increasing yeast RNA is added to any yeast culture medium, and the L-methionine is 7-9 parts, the sodium glutamate is 6-8 parts and the ammonium dihydrogen phosphate is 28-30 parts by weight based on 1000 parts by weight of sugar contained in any yeast culture medium.

7. The medium additive for improving yeast RNA according to claim 3, characterized by, The medium additive for increasing yeast RNA is added to any yeast culture medium, and the L-methionine is 7-8 parts, the sodium glutamate is 6-7 parts and the ammonium dihydrogen phosphate is 28-29 parts by weight based on 1000 parts by weight of sugar contained in any yeast culture medium.

8. The medium additive for improving yeast RNA according to any one of claims 5 to 7, characterized in that, The any yeast culture medium comprises one selected from the group consisting of YPD medium, YNB medium, YSG medium and SD medium.

9. The medium additive for enhancing yeast RNA according to any one of claims 5 to 7, characterized by, The any yeast culture medium is selected from a medium comprising the following components: 0.4-0.5L component A, 0.4-0.5L component B, 0.4-0.5L component C, 0.4-0.5L component D, 0.3-0.4L ammonium dihydrogen phosphate solution with a concentration of 27-31.5g / L, 3-3.5L hydrolyzed sugar solution with a mass volume ratio of 28-32%g / L and 0.2-0.3L ammonia water with a mass percentage concentration of 38-42%; respectively, in grams (g) per liter (L) of volume of the components A, B, C and D, said component A comprising 21.5-23.5 g / L of yeast extract; said component B comprising 2.5-3.5 g / L of anhydrous calcium chloride and 32.3-35.5 g / L of KCl; said component C comprising 0.065-0.067 g / L of VB1, 0.011-0.013 g / L of VB2, 0.022-0.024 g / L of VB6, 0.118-0.120 g / L of niacin, 0.088-0.090 g / L of pantothenic acid and 4.5 x 10 -4 -4.7 x 10 -4 g / L of biotin, said component D comprising 0.105-0.11 g / L of copper sulfate pentahydrate, 0.86-0.9 g / L of zinc sulfate heptahydrate, 17.75-18 g / L of magnesium sulfate heptahydrate and 0.69-0.71 g / L of ferrous sulfate heptahydrate.

10. The medium additive for improving yeast RNA according to claim 9, characterized by, Each component is added to the yeast liquid by flow addition.

11. The medium additive for improving yeast RNA according to claim 9, characterized by, The hydrolyzed sugar is glucose.

12. The medium additive for enhancing yeast RNA according to any one of claims 5 to 7, characterized by, The any yeast culture medium is selected from a medium comprising the following components: 6.5-7.5L molasses solution with a mass volume ratio of 25-28%g / L, 0.5-0.6L ammonia water with a mass percentage concentration of 38-42% and 0.5-0.6L ammonium dihydrogen phosphate solution with a concentration of 39.2-45.7g / L.

13. The medium additive for improving yeast RNA according to claim 12, characterized by, Each component is added to the yeast liquid by flow addition.

14. A method of increasing the production of yeast RNA, characterized by, The method comprises adding the medium additive for increasing yeast RNA according to any one of claims 1-13 to any yeast culture medium, and when the medium additive for increasing yeast RNA is added to any yeast culture medium, the weight parts of the L-methionine, the sodium glutamate and the ammonium dihydrogen phosphate in the medium additive are weight parts determined with respect to 1000 weight parts of sugar contained in any yeast culture medium.

15. A medium additive composition for enhancing yeast RNA, characterized by, The culture medium additive composition comprises the culture medium additive for increasing yeast RNA according to any one of claims 1-13 and any yeast culture medium.

16. The culture medium additive composition for enhancing yeast RNA according to claim 15, characterized by, The culture medium additive is added as a base or fed-batch to any yeast culture medium.

17. The culture medium additive composition for enhancing yeast RNA according to claim 15, characterized by, The any yeast culture medium comprises one selected from the group consisting of YPD culture medium, YNB culture medium, YSG culture medium and SD culture medium.

18. The medium additive composition for enhancing yeast RNA according to claim 15, characterized by, The any yeast culture medium is selected from the group consisting of culture medium comprising 0.4-0.5L component A, 0.4-0.5L component B, 0.4-0.5L component C, 0.4-0.5L component D, 0.3-0.4L ammonium dihydrogen phosphate solution with a concentration of 27-31.5g / L, 3-3.5L hydrolyzed sugar solution with a mass volume ratio of 28-32%g / L and 0.2-0.3L ammonia water with a mass percentage concentration of 28-42%. respectively, in grams (g) per liter (L) of volume of the components A, B, C and D, said component A comprising 21.5-23.5 g / L of yeast extract; said component B comprising 2.5-3.5 g / L of anhydrous calcium chloride and 32.3-35.5 g / L of KCl; said component C comprising 0.065-0.067 g / L of VB1, 0.011-0.013 g / L of VB2, 0.022-0.024 g / L of VB6, 0.118-0.120 g / L of niacin, 0.088-0.090 g / L of pantothenic acid and 4.5 x 10 -4 -4.7 x 10 -4 g / L of biotin, said component D comprising 0.105-0.11 g / L of copper sulfate pentahydrate, 0.86-0.9 g / L of zinc sulfate heptahydrate, 17.75-18 g / L of magnesium sulfate heptahydrate and 0.69-0.71 g / L of ferrous sulfate heptahydrate.

19. The culture medium additive composition for enhancing yeast RNA according to claim 18, characterized by, Each component is added to the yeast liquid in a fed-batch manner.

20. The culture medium additive composition for enhancing yeast RNA according to claim 18, characterized by, The hydrolyzed sugar is glucose.

21. The culture medium additive composition for improving yeast RNA according to claim 15, characterized by, The any yeast culture medium is selected from the group consisting of culture medium comprising 6.5-7.5L molasses solution with a mass volume ratio of 25-28%g / L, 0.5-0.6L ammonia water with a mass percentage concentration of 38-42% and 0.5-0.6L ammonium dihydrogen phosphate solution with a concentration of 39.2-45.7g / L.

22. The culture medium additive composition for enhancing yeast RNA according to claim 21, characterized by, Each component is added to the yeast liquid in a fed-batch manner.

23. Use of the culture medium additive for increasing yeast RNA according to any one of claims 1-13 or the culture medium additive composition for increasing yeast RNA according to any one of claims 15-22 in the preparation of a yeast product with high RNA content.

24. The use according to claim 23, characterized in that, The yeast product with high RNA content comprises a yeast extract with high RNA content. The yeast product with high RNA content comprises a yeast extract with high RNA content.

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