Culture medium additive for increasing yeast RNA (Ribonucleic Acid) and application of culture medium additive

Abstract

The invention discloses a culture medium additive for increasing yeast RNA and application thereof.The culture 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, and the culture medium additive can be used as an additive of any yeast culture medium for base material addition or fed-batch addition. The yeast RNA content can be effectively increased, the yeast RNA content can be increased by 4.1%-5.8% in continuous fermentation culture, and the yeast RNA content can be increased by 13.2%-19.3% in batch fermentation culture. The method disclosed by the invention is beneficial to improvement of the RNA content of the yeast and industrial production, the quality, the safety and the quality standardization of the product can be well ensured, and the cost of the yeast extract is greatly reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and particularly relates to a culture medium additive for increasing yeast RNA and application thereof. Background Art

[0002] Ribonucleic acid (RNA) not only performs crucial biological functions within cells but also plays a crucial role in the growth and health of humans and animals. It holds broad application prospects in a wide range of fields, including medicine, healthcare products, food, and aquaculture. Since RNA is primarily produced through microbial fermentation, yeast, a food-safe microorganism, produces no toxins, grows and propagates rapidly, and is easy to cultivate. Yeast itself is highly nutritious, containing abundant nutrients such as protein, nucleic acids, and carbohydrates, making it a recognized ideal source of RNA.

[0003] In recent years, as yeast extract has become increasingly widely used and its market has grown, food manufacturers have placed increasingly stringent demands on yeast extract. Yeast, as the primary raw material for yeast extract, plays a crucial role. The ribonucleic acid (RNA) content of edible yeast significantly impacts both the quality and production cost of yeast extract. The RNA content of yeast fermentation needs to be further increased to meet market demand. Summary of the Invention

[0004] In response to the low yeast RNA content in yeast extracts currently on the market, the present invention proposes a culture medium additive for increasing yeast RNA and its application, which helps to increase the yeast RNA content and promote industrial production, can better ensure the quality, safety and quality standardization of the product, and significantly reduce the cost of yeast extract.

[0005] Specifically, the present invention provides the following technical solutions: Technical Solution 1: A culture medium additive for increasing yeast RNA, characterized in that, by weight, the culture medium additive comprises 6-10 parts of L-methionine, 5-9 parts of sodium glutamate and 27-31 parts of ammonium dihydrogen phosphate.

[0006] Technical Solution 2: The culture medium additive for increasing yeast RNA according to Technical Solution 1, characterized in that, in parts by weight, the culture medium additive comprises 7-9 parts of L-methionine, 6-8 parts of sodium glutamate, and 28-30 parts of ammonium dihydrogen phosphate; Preferably, the culture medium additive comprises 7-8 parts of L-methionine, 6-7 parts of sodium glutamate and 28-29 parts of ammonium dihydrogen phosphate in parts by weight.

[0007] Technical Solution 3: The culture medium additive for increasing yeast RNA according to Technical Solution 1 or 2, characterized in that the culture medium additive is added as a base material or fed.

[0008] Technical Solution 4: The culture medium additive for increasing yeast RNA according to any one of Technical Solutions 1-3, characterized in that the culture medium additive can be used as an additive to any yeast culture medium.

[0009] Technical Solution 5: The culture medium additive for improving yeast RNA according to Technical Solution 4 is characterized in that the arbitrary yeast culture medium includes one selected from the group consisting of YPD medium, YNB medium, YSG medium and SD medium.

[0010] Technical Solution 6: The culture medium additive for increasing yeast RNA according to Technical Solution 4, characterized in that the arbitrary yeast culture medium is selected from a culture medium comprising the following components: 0.4-0.5 L of component A, 0.4-0.5 L of component B, 0.4-0.5 L of component C, 0.4-0.5 L of component D, 0.3-0.4 L of ammonium dihydrogen phosphate solution with a concentration of 27-31.5 g / L, 3-3.5 L of hydrolyzed sugar solution with a mass volume ratio of 28-32% (g / L) (the mass of hydrolyzed sugar per liter of solution is measured in g), and 0.2-0.3 L of ammonia water with a mass percentage concentration of 38-42%; According to the weight of the substances contained in component A, component B, component C and component D per liter (L), component A includes 21.5-23.5 g / L yeast extract; component B includes 2.5-3.5 g / L anhydrous calcium chloride and 32.3-35.5 g / L KCl; component C includes 0.065-0.067 g / L VB1, 0.011-0.013 g / L VB2, 0.022-0.024 g / L VB6, 0.118-0.120 g / L niacin, 0.088-0.090 g / L pantothenic acid and 4.5×10 -4 -4.7×10 -4 g / L biotin, the component D comprises 0.105-0.11 g / L copper sulfate pentahydrate, 0.86-0.9 g / L zinc sulfate heptahydrate, 17.75-18 g / L magnesium sulfate heptahydrate, and 0.69-0.71 g / L ferrous sulfate heptahydrate; The yeast extract powder contains ≥10% total nitrogen, ≥5% amino nitrogen, ≤15% ash, ≤2% NaCl, and ≤6% moisture. Preferably, the yeast extract powder contains 10-12% total nitrogen, 5-8% amino nitrogen, 1-2% NaCl, and 3-6% moisture. Preferably, all the components are added to the yeast solution by a fed-batch addition method. Preferably, the hydrolyzed sugar is glucose.

[0011] Technical Solution 7: The culture medium additive for increasing yeast RNA according to Technical Solution 4, characterized in that the arbitrary yeast culture medium is selected from a culture medium comprising the following components: 6.5-7.5 L of a molasses solution with a mass volume ratio of 25-28% (g / L) (the mass of molasses per liter of solution is measured in g), 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; Preferably, the components are added to the yeast solution by feeding.

[0012] Technical Solution 8: A method for increasing yeast RNA production, characterized in that the method comprises adding the culture medium additive for increasing yeast RNA according to any one of Technical Solutions 1-7 to any yeast culture medium.

[0013] Technical Solution 9: The method for increasing yeast RNA production according to Technical Solution 8 is characterized in that the culture medium additive is added according to the weight of the sugar contained in any yeast culture medium, and the culture medium additive for increasing yeast RNA according to any one of Technical Solutions 1-7 is added relative to 1000 parts by weight of the sugar contained.

[0014] Technical Solution 10: A culture medium additive composition for increasing yeast RNA, characterized in that the culture medium additive composition comprises the culture medium additive for increasing yeast RNA described in any one of Technical Solutions 1-7 and any yeast culture medium.

[0015] Technical Solution 11: The culture medium additive composition for increasing yeast RNA according to Technical Solution 10 is characterized in that the culture medium additive is added as a base material or fed into any yeast culture medium.

[0016] Technical Solution 12: The culture medium additive composition for increasing yeast RNA according to Technical Solution 10 or 11, characterized in that the arbitrary yeast culture medium includes one selected from the group consisting of YPD medium, YNB medium, YSG medium and SD medium.

[0017] Technical Solution 13: The culture medium additive composition for increasing yeast RNA according to Technical Solution 10 or 11, characterized in that the arbitrary yeast culture medium is selected from a culture medium comprising the following components: 0.4-0.5 L of component A, 0.4-0.5 L of component B, 0.4-0.5 L of component C, 0.4-0.5 L of component D, 0.3-0.4 L of ammonium dihydrogen phosphate solution with a concentration of 27-31.5 g / L, 3-3.5 L of 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 measured in g), and 0.2-0.3 L of ammonia water with a mass percentage concentration of 38-42%; According to the weight of the substances contained in component A, component B, component C and component D per liter (L), component A includes 21.5-23.5 g / L yeast extract; component B includes 2.5-3.5 g / L anhydrous calcium chloride and 32.3-35.5 g / L KCl; component C includes 0.065-0.067 g / L VB1, 0.011-0.013 g / L VB2, 0.022-0.024 g / L VB6, 0.118-0.120 g / L niacin, 0.088-0.090 g / L pantothenic acid and 4.5×10 -4 -4.7×10 -4 g / L biotin, the component D comprises 0.105-0.11 g / L copper sulfate pentahydrate, 0.86-0.9 g / L zinc sulfate heptahydrate, 17.75-18 g / L magnesium sulfate heptahydrate, and 0.69-0.71 g / L ferrous sulfate heptahydrate; Preferably, each component is added to the yeast solution by feeding; Preferably, the hydrolyzed sugar is glucose.

[0018] Technical Solution 14: The culture medium additive composition for increasing yeast RNA according to Technical Solution 10 or 11, characterized in that the arbitrary yeast culture medium is selected from a culture medium comprising 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 per liter of solution is measured in g), 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; Preferably, the components are added to the yeast solution by feeding.

[0019] Technical Solution 15: Use of the culture medium additive for increasing yeast RNA according to any one of Technical Solutions 1-7 or the culture medium additive composition for increasing yeast RNA according to any one of Technical Solutions 10-14 in the preparation of a yeast product with a high RNA content.

[0020] Technical Solution 16: The application according to Technical Solution 15 is characterized in that the yeast product with a high RNA content includes a yeast extract with a high RNA content.

[0021] Beneficial effects of the present invention: The culture medium additive of the present invention can effectively increase yeast RNA content by 4.1-5.8% in continuous fermentation and by 13.2-19.3% in batch fermentation. This additive facilitates industrial production, effectively ensuring product quality, safety, and standardization, while significantly reducing the cost of yeast extract. DETAILED DESCRIPTION

[0022] The technical solutions of the present invention are further described in detail below with reference to specific embodiments and comparative examples, but the present invention is not limited to the following technical solutions.

[0023] The invention discloses a culture medium additive for improving yeast RNA. The culture 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.

[0024] The medium additive is added based on the weight of the sugar contained in any yeast culture medium, and the medium additive is added relative to 1000 parts by weight of the sugar contained.

[0025] In some specific embodiments, the weight percentage of L-methionine in the culture medium additive can be any two values between 6 and 10: 6, 6.5, 7.5, 8, 8.5, 9, 9.5 or 10, or a weight percentage within a numerical range consisting of any two of the above specific values as endpoints.

[0026] In some specific embodiments, the weight percentage of sodium glutamate in the culture medium additive can be any two values between 5-9: 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5 or 9, or a weight percentage within a numerical range consisting of any two of the above specific values as endpoints.

[0027] In some specific embodiments, the weight proportion of ammonium dihydrogen phosphate in the culture medium additive can be any two values between 27-31: 27, 27.5, 28, 28.5, 29, 29.5, 30, 30.5 or 31, or a weight proportion within a numerical range formed by using any two of the above specific values as endpoints.

[0028] Adding the medium additive to any yeast culture medium for yeast cultivation can increase the yeast RNA content by 4.1%-5.8% in continuous fermentation and by 13.2%-19.3% in batch fermentation. The yeast culture medium referred to herein includes conventional culture media used by those skilled in the art for yeast cultivation, including YPD, YNB, YSG, or SD.

[0029] The saccharomyces cerevisiae used in the embodiment of the present invention ( Saccharomyces cerevisiae ) FX-2 strain was isolated from fermented dough, which contains a variety of wild fungi. The fermented dough was used as a sample to prepare a dough extract. A pure strain was isolated by the dilution plate separation method. The results of 16S rRNA sequencing showed that the sequence homology was greater than 99%, thus confirming that the strain isolated by the present invention belongs to Saccharomyces cerevisiae ( Saccharomycescerevisiae ), named Saccharomyces cerevisiae ( Saccharomyces cerevisiae ) FX-2 strain, deposited with the China Center for Type Culture Collection (CCTCC) on August 1, 2016, with accession number CCTCC NO: M 2016418. The isolation and identification methods for this strain have been disclosed in patent application publication number CN108220175A.

[0030] The saccharomyces cerevisiae used in the embodiments of the present invention ( Saccharomyces cerevisiae )AMCC Strain 30743 was deposited in the China Center for Type Culture Collection (CCTCC) on July 27, 2021. The deposit number is CCTCC NO: M 2021941. The strain was isolated from fermented milk products in Shannan City, Tibet. The separation and identification method thereof has been disclosed in the patent application with publication number CN113862164A. The various reagents and instruments used in the examples and comparative examples of the present invention are conventional unless otherwise specified. The sources of the instruments and reagents used in the examples and comparative examples of the present invention are shown in Table 1 below.

[0031] Table 1 The method for detecting the RNA content in the embodiment of the present invention is as follows: Principle: Use perchloric acid to break the cell wall of yeast and extract RNA from yeast cells by centrifugation. RNA has the property of absorbing ultraviolet rays, with maximum absorption at a wavelength of 260 nm. Within a certain concentration range, the light absorption value is proportional to the concentration, which conforms to the Lambert-Beer law.

[0032] Reagents: 0.5 mol / L perchloric acid (HClO4) solution: Add 21.5 mL of 70% (or 22.1 mL of 68%) perchloric acid to 400 mL of distilled water, and then dilute to 500 mL with distilled water.

[0033] 0.25 mol / L perchloric acid (HClO4) solution: Take 250 mL of 0.5 mol / L perchloric acid (HClO4) and dilute it to 500 mL with distilled water.

[0034] equipment: (1) A microgram-grade balance; (2) A 4000 rpm centrifuge capable of separating yeast; (3) Centrifuge tubes with a capacity of at least 10 mL; (4) A spectrophotometer (260 nm); (5) A 70°C hot water bath; (6) A 4°C cold water bath; (7) 10 mL and 1 mL pipettes; and (8) A 100 mL volumetric flask.

[0035] method: 1. Dilute yeast milk with water to a dry matter content of 18% and weigh 0.6g.

[0036] 2. Add 8 mL of cold 0.25 mol / L HClO4 to the centrifuge tube and incubate in a 4°C water bath for 15 min.

[0037] 3. Centrifuge at 4000 rpm for 10 min.

[0038] 4. Gently pour off the material floating on the surface, add 45 mL of 0.5 mol / L HClO, and vortex to mix thoroughly. Calculate volume V. Incubate in a 70°C water bath for 15 minutes, vortexing every 3-4 minutes. Centrifuge at 4000 rpm for 10 minutes. Pipette 1 mL of the supernatant and dilute to 100 mL with distilled water, a dilution factor of 100.

[0039] 5. Measure the absorbance at 260 nm and use distilled water as a blank control.

[0040] The calculation formula is: , wherein 0.03365 is the conversion coefficient. In the calculation process of the RNA content in the yeast milk of the present invention, the sample mass is measured in milligrams and the dilution factor is 100.

[0041] RNA content increase rate (%) = (RNA content of example or comparative example - RNA content of control group) / RNA content of control group*100% Example 1: Yeast RNA production is increased by adding a culture medium additive to the yeast during continuous fermentation. Example 1-1 1. Preparation of yeast fermentation medium and medium additives to increase yeast RNA (1) Yeast fermentation medium The yeast fermentation medium includes component A, component B, component C, component D, a carbon source, a nitrogen source and a phosphorus source.

[0042] Component A: Contains 21.5g / L yeast extract. Take 8.6g of yeast extract and dilute to 400ml. Sterilize at 115°C for 20min. Add at a rate of 21ml / h for the first hour, 29ml / h for the second hour, and 35ml / h for the third to 12th hour.

[0043] Component B: Contains 2.5g / L anhydrous calcium chloride and 32.3g / L KCl. Add 1g of anhydrous calcium chloride and 12.9g of potassium chloride to 400ml. Sterilize at 121°C for 30min. Add at a rate of 21ml / h for the first hour, 29ml / h for the second hour, and 35ml / h for the first 12 hours.

[0044] Component C: contains 0.065g / L VB1, 0.011g / L VB2, 0.022g / L VVB6, 0.118g / L nicotinic acid, 0.088g / L pantothenic acid and 4.5×10 -4 g / L biotin. Take 0.026 g VB1, 0.0043 g VB2, 0.0086 g VB6, 0.047 g niacin, 0.035 g pantothenic acid, and 0.00018 g biotin. Dissolve the biotin in 100 ml of hot water and then dilute the volume to 400 ml with the other vitamins. Add at 21 ml / h for the first hour, 29 ml / h for the second hour, and 35 ml / h for 3-12 hours.

[0045] Component D: 0.105 g / L copper sulfate pentahydrate, 0.86 g / L zinc sulfate heptahydrate, 17.75 g / L magnesium sulfate heptahydrate, and 0.69 g / L ferrous sulfate heptahydrate. Add 0.042 g copper sulfate pentahydrate, 0.344 g zinc sulfate heptahydrate, 7.1 g magnesium sulfate heptahydrate, and 0.275 g ferrous sulfate heptahydrate to 400 ml. Sterilize at 121°C for 30 minutes. Add at a rate of 21 ml / h for the first hour, 29 ml / h for the second hour, and 35 ml / h for hours 3-12.

[0046] Carbon source: Include 30% (g / L) glucose by weight. Dissolve 900g of glucose in 3L of water to create a 30% sugar concentration by weight solution. Sterilize at 115°C for 20 minutes. Add at a rate of 150ml / h for the first hour, 200ml / h for the second hour, and 240ml / h for the first 3-12 hours.

[0047] Nitrogen source: Ammonia water with a mass percentage concentration of 38% was added by flow addition at a rate of 16 ml / h in the first hour, 19 ml / h in the second hour, and 23 ml / h from 3 to 12 hours.

[0048] Phosphorus source: 27 g / L ammonium dihydrogen phosphate was added by flow addition at a 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.

[0049] (2) Culture medium additives to increase yeast RNA Based on the weight of sugar in the yeast fermentation medium, the medium additives are: 6 parts L-methionine, 5 parts sodium glutamate, and 27 parts monoammonium phosphate per 1000 parts by weight of sugar. Based on the glucose content in the yeast fermentation medium (900g), 5.4g L-methionine, 4.5g sodium glutamate, and 24.3g monoammonium phosphate were added, respectively, to a volume of 400ml. The mixture was then prepared with 80-90°C hot water and sterilized at 115°C for 20 minutes. The mixture was fed at a rate of 21ml / h for the first hour, 29ml / h for the second hour, and 35ml / h for the first 3-12 hours.

[0050] 2. Seed Fermentation After activating Saccharomyces cerevisiae FX-2 from a glycerol tube, inoculate a loopful of the culture into 10 L of seed fermentation medium consisting of 100 g / L sucrose, 20 g / L yeast extract, 1 g / L magnesium sulfate heptahydrate, and 1 g / L potassium dihydrogen phosphate. Incubate at 30°C, 150-180 RPM in a shaker for 24 hours to obtain the seed fermentation broth.

[0051] 3. Commercial fermentation The entire seed fermentation broth was added to a 50-L fermentor, and continuous fermentation was performed by feeding yeast fermentation medium and a medium additive to enhance yeast RNA. The fermentation temperature for commercial fermentation was 31°C, with stirring at 500 rpm for the first two 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 two hours, 22 L / min for the third hour, and 30 L / min for the fourth to 12 hours. Starting in the third hour, the fermentation broth was discharged at a rate of 2.2 L per hour, while process water was fed to maintain a constant fermentation volume of approximately 10 L. Continuous fermentation is performed by continuously adding nutrients and draining the fermentation broth to maintain a stable system, thereby promoting sustained and efficient yeast growth and metabolic activity. After 12 hours of continuous fermentation, the RNA content (%) in the yeast milk was measured. The RNA content increase rate was calculated using a control without the medium additive to enhance yeast RNA. The results are shown in Table 2.

[0052] Example 1-2 Compared to Example 1-1, the medium additives, based on the weight of sugars contained in the yeast fermentation medium, were: 7 parts L-methionine, 6 parts sodium glutamate, and 28 parts diammonium phosphate, relative to 1000 parts by weight of sugars. Based on the glucose content (900 g) in the yeast fermentation medium, 6.3 g L-methionine, 5.4 g sodium glutamate, and 25.2 g diammonium phosphate were added, and the volume was adjusted 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 measured. Using a control without yeast RNA-enhancing medium additives, the RNA content increase rate was calculated. The results are shown in Table 2.

[0053] Examples 1-3 Compared to Example 1-1, the medium additives, based on the weight of sugars contained in the yeast fermentation medium, were: 9 parts L-methionine, 8 parts sodium glutamate, and 30 parts diammonium phosphate, relative to 1000 parts by weight of sugars. Based on the glucose content (900 g) in the yeast fermentation medium, 8.1 g L-methionine, 7.2 g sodium glutamate, and 27 g diammonium phosphate were added, and the volume was adjusted 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 measured. A control without yeast RNA-enhancing medium additives was used, and the RNA content increase rate was calculated. The results are shown in Table 2.

[0054] Examples 1-4 Compared to Example 1-1, the medium additives used were: 10 parts L-methionine, 9 parts sodium glutamate, and 31 parts diammonium phosphate, based on the weight of sugars contained in the yeast fermentation medium, relative to 1000 parts by weight of sugars. Based on the glucose content (900 g) in the yeast fermentation medium, 9 g L-methionine, 8.1 g sodium glutamate, and 27.9 g diammonium phosphate were added, and the volume was adjusted 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 measured. Using a control without yeast RNA-enhancing medium additives, the RNA content increase rate was calculated. The results are shown in Table 2.

[0055] Table 2 As shown in Table 2, in the continuous culture of Example 1, after adding the culture medium additive containing yeast RNA, the yeast RNA content can be increased by 4.1%-5.8% compared with the control culture medium. Among them, Example 1-2 has the best effect. The culture medium additive contains 7 parts of L-methionine, 6 parts of sodium glutamate, and 28 parts of ammonium dihydrogen phosphate.

[0056] Example 2: Yeast RNA production is increased by adding a culture medium additive to the yeast in continuous fermentation. Example 2-1 1. Preparation of yeast fermentation medium and medium additives to increase yeast RNA (1) Yeast fermentation medium The yeast fermentation medium includes component A, component B, component C, component D, a carbon source, a nitrogen source and a phosphorus source.

[0057] Component A: Prepare 400 ml of 23.5 g / L yeast extract powder, then sterilize at 115 degrees for 20 minutes. Add at 21 ml / h for the first hour, 29 ml / h for the second hour, and 35 ml / h for 3-12 hours.

[0058] Component B: Prepare 400 mL of 3.5 g / L anhydrous calcium chloride and 35.5 g / L KCl solution, sterilize at 121°C for 30 min, add at 21 ml / h for the first hour, 29 ml / h for the second hour, and 35 ml / h for 3-12 hours.

[0059] Component C: contains 0.067 g / L VB1, 0.013 g / L VB2, 0.024 g / L VB6, 0.120 g / L nicotinic acid, 0.090 g / L pantothenic acid and 4.7×10 -4400ml of 1g / L biotin solution. Dissolve 100ml of biotin in hot water and dilute to 400ml with other vitamins. Add at 21ml / h for the first hour, 29ml / h for the second hour, and 35ml / h for 3-12 hours.

[0060] Component D: Prepare 400 mL of a solution containing 0.11 g / L copper sulfate pentahydrate, 0.9 g / L zinc sulfate heptahydrate, 18 g / L magnesium sulfate heptahydrate, and 0.71 g / L ferrous sulfate heptahydrate. Sterilize at 121°C for 30 minutes. Add at a rate of 21 mL / h for the first hour, 29 mL / h for the second hour, and 35 mL / h for hours 3-12.

[0061] Carbon source: including 3L of glucose solution with a mass-to-volume ratio of 32% (g / L). Take 960g of glucose and dissolve it in 3L of water to prepare a solution with a mass-to-volume ratio of 32% sugar concentration. Then sterilize it at 115 degrees for 20 minutes. Add it at a rate of 150ml / h in the first hour, 200ml / h in the second hour, and 240ml / h in the 3-12h period.

[0062] Nitrogen source: Ammonia water with a mass percentage concentration of 42% was added by flow addition at a rate of 16 ml / h in the first hour, 19 ml / h in the second hour, and 23 ml / h from 3 to 12 hours.

[0063] Phosphorus source: 31.5 g / L ammonium dihydrogen phosphate was added by flow addition at a 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.

[0064] (2) Culture medium additives to increase yeast RNA Based on the weight of sugar in the yeast fermentation medium, the medium additives are: 10 parts L-methionine, 9 parts sodium glutamate, and 31 parts monoammonium phosphate, relative to 1000 parts by weight of sugar. Based on the glucose content in the yeast fermentation medium (960g), 9.6g L-methionine, 8.64g sodium glutamate, and 29.76g monoammonium phosphate were added, respectively, to a volume of 400ml. The mixture was then prepared with 80-90°C hot water and sterilized at 115°C for 20 minutes. The medium was fed at a rate of 21ml / h for the first hour, 29ml / h for the second hour, and 35ml / h for the first 3-12 hours.

[0065] 2. Seed Fermentation After activating Saccharomyces cerevisiae FX-2 from a glycerol tube, inoculate a loopful of the culture into 10 L of seed fermentation medium consisting of 100 g / L sucrose, 20 g / L yeast extract, 1 g / L magnesium sulfate heptahydrate, and 1 g / L potassium dihydrogen phosphate. Incubate at 30°C, 150-180 RPM in a shaker for 24 hours to obtain the seed fermentation broth.

[0066] 3. Commercial fermentation The entire seed fermentation broth was added to a 50L fermentor, and yeast fermentation medium and a medium additive to increase yeast RNA were fed into the fermentor for continuous fermentation. The commercial fermentation temperature was 31°C, with stirring at 500 rpm for the first two hours, 550 rpm for the third hour, and 600 rpm for the fourth to sixth hours. The air flow was 14 L / min for the first two hours, 22 L / min for the third hour, and 30 L / min for the fourth to 12 hours. Starting in the third hour, the fermentation broth was discharged at a rate of 2.2 L per hour, while process water was fed into the fermentor to maintain a constant fermentation volume of approximately 10 L. Continuous fermentation is performed after the yeast culture enters the logarithmic growth phase. Once the yeast culture enters the logarithmic growth phase, nutrients are continuously added to the fermentor and the fermentation broth is continuously discharged to maintain a stable system, thereby ensuring continued and efficient yeast growth and metabolic activity. After 12 hours of continuous fermentation, the RNA content (%) in the yeast milk was measured. The culture medium without yeast RNA-enhancing additives was used as a control, and the RNA content increase rate was calculated. The results are shown in Table 3.

[0067] Example 2-2 Compared to Example 2-1, the medium additives, based on the weight of sugars contained in the yeast fermentation medium, were: 7 parts L-methionine, 6 parts sodium glutamate, and 28 parts diammonium phosphate, relative to 1000 parts by weight of sugars. Based on the glucose content (960 g) in the yeast fermentation medium, 6.72 g L-methionine, 5.76 g sodium glutamate, and 26.88 g diammonium phosphate were added, and the volume was adjusted to 400 ml. The remaining steps were the same as in Example 2-1. After 12 hours of continuous fermentation, the RNA content (%) in the yeast milk was measured. Using a control without yeast RNA-enhancing medium additives, the RNA content increase rate was calculated. The results are shown in Table 3.

[0068] Example 2-3 Compared to Example 2-1, the medium additives, based on the weight of sugars in the yeast fermentation medium, were 9 parts L-methionine, 8 parts sodium glutamate, and 30 parts diammonium phosphate per 1000 parts by weight of sugars. Based on the glucose content (960 g) in the yeast fermentation medium, 8.64 g L-methionine, 7.68 g sodium glutamate, and 28.8 g diammonium phosphate were added, and the volume was adjusted to 400 ml. The remaining steps were the same as in Example 2-1. After 12 hours of continuous fermentation, the RNA content (%) in the yeast milk was measured. Using a control without yeast RNA-enhancing medium additives, the RNA content increase rate was calculated. The results are shown in Table 3.

[0069] Examples 2-4 Compared to Example 2-1, the medium additives, based on the weight of the sugar content in the yeast fermentation medium, were: 6 parts L-methionine, 5 parts sodium glutamate, and 27 parts diammonium phosphate, relative to 1000 parts by weight of the sugar content. Based on the glucose content (960 g) in the yeast fermentation medium, 5.76 g L-methionine, 4.8 g sodium glutamate, and 25.92 g diammonium phosphate were added, and the volume was adjusted to 400 ml. The remaining steps were the same as in Example 2-1. After 12 hours of continuous fermentation, the RNA content (%) in the yeast milk was measured. Using a control without yeast RNA-enhancing medium additives, the RNA content increase rate was calculated. The results are shown in Table 3.

[0070] Table 3 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 has the best effect. The culture medium additive contains 7 parts of L-methionine, 6 parts of sodium glutamate, and 28 parts of ammonium dihydrogen phosphate.

[0071] Example 3: Batch fermentation with yeast culture medium additives to increase yeast RNA production Example 3-1 1. Preparation of yeast fermentation medium and medium additives to increase yeast RNA (1) Yeast fermentation medium Yeast fermentation medium includes carbon, nitrogen and phosphorus sources.

[0072] Carbon source: 7 L of molasses (28% g / L by mass) 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 fed-batch added. The feed rates are shown in Table 4.

[0073] Nitrogen source: Ammonia water with a mass percentage concentration of 42% was added by flow addition. The flow rate is shown in Table 4.

[0074] Phosphorus source: 39.2 g / L ammonium dihydrogen phosphate was added by flow addition. The flow rate is shown in Table 4.

[0075] (2) Culture medium additives to increase yeast RNA Based on the weight of sugar in the yeast fermentation medium, the medium additives are: 6 parts L-methionine, 5 parts sodium glutamate, and 27 parts monoammonium phosphate per 1000 parts by weight of sugar. Based on the molasses content in the yeast fermentation medium (1960g), 11.76g L-methionine, 9.8g sodium glutamate, and 52.92g monoammonium phosphate were added, adjusted to 600ml, and then prepared with hot water at 80-90°C. Sterilize at 115°C for 20 minutes. Feed addition was performed according to Table 4.

[0076] 2. Seed Fermentation After activating Saccharomyces cerevisiae FX-2 from a glycerol tube, inoculate a loopful of the culture into 10 L of seed fermentation medium consisting of 100 g / L sucrose, 20 g / L yeast extract, 1 g / L magnesium sulfate heptahydrate, and 1 g / L potassium dihydrogen phosphate. Incubate in a shaker at 30°C, 150-180 RPM for 24 hours to obtain a seed fermentation broth.

[0077] 3. Commercial fermentation The entire seed fermentation broth was added to a 50L fermentor. Batch fermentation was performed by feeding yeast fermentation medium and a yeast RNA-enhancing medium additive. During batch fermentation, certain materials were added to the fermentation system, but continuous addition of fermentation broth was not required. Yeast growth and metabolic activity progressed through a lag phase, a logarithmic phase, a stationary phase, and a decay phase. The fermentation temperature was 30°C, and the culture conditions were shown in Table 4. After 11 hours of incubation, yeast RNA content was measured. A control without yeast RNA-enhancing medium additives was used to calculate the RNA content increase rate. The results are shown in Table 5.

[0078] Example 3-2 Compared to Example 3-1, the medium additives, based on the weight of the sugar content in the yeast fermentation medium, were: 7 parts L-methionine, 6 parts sodium glutamate, and 28 parts diammonium phosphate, relative to 1000 parts by weight of the sugar content. Based on the molasses content in the yeast fermentation medium (1960 g), 13.72 g L-methionine, 11.76 g sodium glutamate, and 54.88 g diammonium phosphate were added, respectively, and the volume was adjusted to 600 ml. The remaining steps were the same as in Example 3-1. After 11 hours of culture, the yeast RNA content was measured. A control without yeast RNA-enhancing medium additives was used, and the rate of increase in RNA content was calculated. The results are shown in Table 5.

[0079] Example 3-3 Compared to Example 3-1, the medium additives, based on the weight of the sugar content in the yeast fermentation medium, were: 9 parts L-methionine, 8 parts sodium glutamate, and 30 parts diammonium phosphate, relative to 1000 parts by weight of the sugar content. Based on the molasses content in the yeast fermentation medium (1960 g), 17.64 g L-methionine, 15.68 g sodium glutamate, and 58.8 g diammonium phosphate were added, and the volume was adjusted to 600 ml. The remaining steps were the same as in Example 3-1. After 11 hours of culture, the yeast RNA content was measured. A control without yeast RNA-enhancing medium additives was used, and the rate of increase in RNA content was calculated. The results are shown in Table 5.

[0080] Examples 3-4 Compared to Example 3-1, the medium additives, based on the weight of the sugar content in the yeast fermentation medium, were: 10 parts L-methionine, 9 parts sodium glutamate, and 31 parts diammonium phosphate, relative to 1000 parts by weight of the sugar content. Based on the molasses content in the yeast fermentation medium (1960 g), 19.6 g L-methionine, 17.64 g sodium glutamate, and 60.76 g diammonium phosphate were added, respectively, and the volume was adjusted to 600 ml. The remaining steps were the same as in Example 3-1. After 11 hours of culture, the yeast RNA content was measured. A control without yeast RNA-enhancing medium additives was used, and the rate of increase in RNA content was calculated. The results are shown in Table 5.

[0081] Table 4 Table 5 As shown in Table 5, in the fed-batch fermentation of Example 3, after adding the culture medium additive containing yeast RNA, the yeast RNA content can be increased by 13.3%-18.3% compared with the control culture medium. Among them, Example 3-2 has the best effect. The culture medium additive contains 7 parts of L-methionine, 6 parts of sodium glutamate, and 28 parts of ammonium dihydrogen phosphate.

[0082] Example 4: Batch fermentation with yeast to increase RNA production by adding a medium additive that increases RNA production in yeast Compared with Example 3-1, the fermentation strain used was Saccharomyces cerevisiae AMCC 30743, and the remaining steps were the same as in Example 3-1. The culture was carried out for 11 hours, and the yeast RNA content was measured, which was 9.08%. The culture medium without yeast RNA-enhancing additives was used as a control, and the RNA content increase rate was calculated. The RNA content (%) in the control culture medium was 7.61%, and the RNA increase rate was 19.3%.

[0083] Example 5: Batch fermentation with yeast to increase RNA production by adding a culture medium additive Example 5-1 1. Preparation of yeast fermentation medium and medium additives to increase yeast RNA (1) Yeast fermentation medium Yeast fermentation medium includes carbon, nitrogen and phosphorus sources.

[0084] Carbon source: 7 L of molasses (25% g / L by mass / volume ratio) was prepared by dissolving 1750 g of molasses in 7 L of water. The mixture was then sterilized at 115°C for 20 min and fed-batch added. The feed rates are shown in Table 4.

[0085] Nitrogen source: Ammonia water with a mass percentage concentration of 38% was added by flow addition. The flow rate is shown in Table 4.

[0086] Phosphorus source: 45.7 g / L ammonium dihydrogen phosphate was added by flow addition. The flow rate is shown in Table 4.

[0087] (2) Culture medium additives to increase yeast RNA Based on the weight of sugar in the yeast fermentation medium, the medium additives are: 6 parts L-methionine, 5 parts sodium glutamate, and 27 parts monoammonium phosphate per 1000 parts by weight of sugar. Based on the molasses content in the yeast fermentation medium (1750g), 10.5g L-methionine, 8.75g sodium glutamate, and 47.25g monoammonium phosphate were added, adjusted to 600ml, and then prepared with hot water at 80-90°C. Sterilize at 115°C for 20 minutes. Feed addition was performed according to Table 4.

[0088] 2. Seed Fermentation After activating Saccharomyces cerevisiae FX-2 from a glycerol tube, inoculate a loopful of the culture into 10 L of seed fermentation medium consisting of 100 g / L sucrose, 20 g / L yeast extract, 1 g / L magnesium sulfate heptahydrate, and 1 g / L potassium dihydrogen phosphate. Incubate at 30°C, 150-180 RPM in a shaker for 24 hours to obtain the seed fermentation broth.

[0089] 3. Commercial fermentation The entire seed fermentation broth was added to a 50L fermentor. Batch fermentation was performed by feeding yeast fermentation medium and a yeast RNA-enhancing medium additive. During batch fermentation, certain materials were added to the fermentation system, but continuous addition of fermentation broth was not required. Yeast growth and metabolic activity progressed through a lag phase, a logarithmic phase, a stationary phase, and a decay phase. The fermentation temperature was 30°C, and the culture conditions were shown in Table 4. The yeast RNA content and wet weight were measured for 11 hours. A control without yeast RNA-enhancing medium additives was used to calculate the RNA content increase rate. The results are shown in Table 6.

[0090] Example 5-2 Compared to Example 4-1, the medium additives, based on the weight of the sugar content in the yeast fermentation medium, were: 7 parts L-methionine, 6 parts sodium glutamate, and 28 parts diammonium phosphate, relative to 1000 parts by weight of the sugar content. Based on the molasses content in the yeast fermentation medium (1750 g), 12.25 g L-methionine, 10.5 g sodium glutamate, and 49 g diammonium phosphate were added, and the volume was adjusted to 600 ml. The remaining steps were the same as in Example 4-1. After 11 hours of culture, the yeast RNA content was measured. A control without yeast RNA-enhancing medium additives was used to calculate the RNA content increase rate. The results are shown in Table 6.

[0091] Example 5-3 Compared to Example 4-1, the medium additives, based on the weight of the sugar content in the yeast fermentation medium, were: 9 parts L-methionine, 8 parts sodium glutamate, and 30 parts diammonium phosphate, relative to 1000 parts by weight of the sugar content. Based on the molasses content in the yeast fermentation medium (1750 g), 15.75 g L-methionine, 14 g sodium glutamate, and 52.5 g diammonium phosphate were added, and the volume was adjusted to 600 ml. The remaining steps were the same as in Example 4-1. After 11 hours of culture, the yeast RNA content was measured. A control without yeast RNA-enhancing medium additives was used to calculate the RNA content increase rate. The results are shown in Table 6.

[0092] Example 5-4 Compared to Example 4-1, the medium additives, based on the weight of the sugar content in the yeast fermentation medium, were: 10 parts L-methionine, 9 parts sodium glutamate, and 31 parts diammonium phosphate, relative to 1000 parts by weight of the sugar content. Based on the molasses content in the yeast fermentation medium (1750 g), 17.5 g L-methionine, 15.75 g sodium glutamate, and 54.25 g diammonium phosphate were added, and the volume was adjusted to 600 ml. The remaining steps were the same as in Example 4-1. After 11 hours of culture, the yeast RNA content was measured. A control without yeast RNA-enhancing medium additives was used to calculate the RNA content increase rate. The results are shown in Table 6.

[0093] Table 6 As shown in Table 6, in the fed-batch culture of Example 5, after adding the culture medium additive containing yeast RNA, the yeast RNA content can be increased by 13.2%-17.9% compared with the control culture medium. Among them, Example 5-2 has the best effect. The culture medium additive contains 7 parts of L-methionine, 6 parts of sodium glutamate, and 28 parts of ammonium dihydrogen phosphate.

[0094] Comparative Example 1 Compared with Example 3-1, based on the weight of the sugar contained in the yeast fermentation medium, the medium additive was 27 parts of ammonium dihydrogen phosphate relative to 1000 parts by weight of the sugar contained. The medium additive lacked L-methionine and sodium glutamate. Based on the molasses content in the yeast fermentation medium (1960 g), 52.92 g of ammonium dihydrogen phosphate was added and the volume was adjusted to 400 ml. The remaining steps were the same as those in Example 3-1. After 11 hours of culture, the yeast RNA content was measured and found to be 6.54%. Using a medium without yeast RNA-enhancing additive as a control, the RNA content increase rate was calculated. The RNA content (%) in the control medium was 6.38%, and the RNA increase rate was 2.5%, which was much lower than the RNA increase rate of 13.8% in Example 3-1. It can be seen that the medium additive of the present invention is helpful for increasing the RNA content of yeast and promoting industrial production.

[0095] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A culture medium additive for increasing yeast RNA, characterized in that In parts by weight, the culture medium additive comprises 6-10 parts of L-methionine, 5-9 parts of sodium glutamate and 27-31 parts of ammonium dihydrogen phosphate.

2. The culture medium additive for increasing yeast RNA according to claim 1, characterized in that In parts by weight, the culture medium additive comprises 7-9 parts of L-methionine, 6-8 parts of sodium glutamate and 28-30 parts of ammonium dihydrogen phosphate.

3. The culture medium additive for increasing yeast RNA according to claim 1, characterized in that In parts by weight, the culture medium additive comprises 7-8 parts of L-methionine, 6-7 parts of sodium glutamate and 28-29 parts of ammonium dihydrogen phosphate.

4. The culture medium additive for increasing yeast RNA according to claim 1, characterized in that The culture medium additive is added as a base material or fed.

5. The culture medium additive for increasing yeast RNA according to claim 1, characterized in that The culture medium additive can be used as an additive for any yeast culture medium.

6. The culture medium additive for increasing yeast RNA according to claim 5, characterized in that The medium additive is added based on the weight of the sugar contained in any yeast culture medium, and the medium additive is added relative to 1000 parts by weight of the sugar contained.

7. The culture medium additive for increasing yeast RNA according to claim 5, characterized in that The arbitrary yeast culture medium includes one selected from the group consisting of YPD medium, YNB medium, YSG medium and SD medium.

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

9. The culture medium additive for increasing yeast RNA according to claim 8, characterized in that All the components are added to the yeast solution in a feeding addition manner.

10. The culture medium additive for increasing yeast RNA according to claim 8, characterized in that The hydrolyzed sugar is glucose.

11. The culture medium additive for increasing yeast RNA according to claim 5, characterized in that The arbitrary yeast culture medium is selected from a culture medium comprising the following components: 6.5-7.5 L of molasses solution with a mass volume ratio of 25-28% (g / L), 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.

12. The culture medium additive for increasing yeast RNA according to claim 11, characterized in that All the components are added to the yeast solution in a feeding addition manner.

13. A method for increasing yeast RNA production, characterized in that: The method comprises adding the culture medium additive for increasing yeast RNA according to any one of claims 1 to 12 to any yeast culture medium.

14. The method for increasing yeast RNA production according to claim 13, characterized in that: The culture medium additive is added according to the weight of the sugar contained in any yeast culture medium. The culture medium additive for increasing yeast RNA according to any one of claims 1 to 12 is added relative to 1000 parts by weight of the sugar contained.

15. A culture medium additive composition for increasing yeast RNA, characterized in that: The culture medium additive composition comprises the culture medium additive for increasing yeast RNA according to any one of claims 1 to 12 and any yeast culture medium.

16. The medium additive composition for increasing yeast RNA according to claim 15, characterized in that The medium additive is added as a base or fed into any yeast culture medium.

17. The medium additive composition for increasing yeast RNA according to claim 15, characterized in that The arbitrary yeast culture medium includes one selected from the group consisting of YPD medium, YNB medium, YSG medium and SD medium.

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

19. The medium additive composition for increasing yeast RNA according to claim 18, characterized in that All the components are added to the yeast solution in a feeding addition manner.

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

21. The culture medium additive composition for increasing yeast RNA according to claim 15, characterized in that The arbitrary yeast culture medium is selected from a culture medium comprising the following components: 6.5-7.5 L of molasses solution with a mass volume ratio of 25-28% (g / L), 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.

22. The culture medium additive composition for increasing yeast RNA according to claim 21, characterized in that All the components are added to the yeast solution in a feeding addition manner.

23. Use of the culture medium additive for increasing yeast RNA according to any one of claims 1 to 12 or the culture medium additive composition for increasing yeast RNA according to any one of claims 15 to 22 in the preparation of a yeast product with a high RNA content.

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

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