Yeast extract rich in bases and base derivatives and method for producing same

Abstract

Provided are a yeast extract rich in bases and base derivatives and a method for producing the same. The provided yeast extract rich in bases and base derivatives contains 20,000 to 40,000 mg / kg of bases and base derivatives. The provided yeast extract is rich in bases and base derivatives, and bases and base derivatives are more easily absorbed by microorganisms than nucleotides, so that the provided product has a high ability to promote the growth of microorganisms.

Description

[Technical field]

[0001] The present invention belongs to the technical field of bioproducts, specifically to a yeast extract rich in bases and base derivatives and a method for producing the same. [Background technology]

[0002] Yeast extract is a powdered, paste or liquid product made by using fresh yeast as raw material, inducing many enzyme systems in the yeast itself by utilizing modern biotechnology or by changing the culture environment, and using several exogenous enzymes to break down intracellular proteins and nucleic acid substances under appropriate conditions, and then going through several purification processes. It is rich in proteins, amino acids, peptides, nucleotides, vitamin B and trace elements, and its main role is to supply the nitrogen source and provide various vitamins, amino acids and growth factors necessary for the growth of microorganisms. It is widely used in the fermentation medium industry and is a medium raw material with high growth promotion ability.

[0003] Nucleobases and base derivatives are different from nucleotides and are the products of further decomposition of nucleotides. They are the building blocks of yeast nucleic acid and can be obtained by decomposition of yeast nucleic acid in the autolysis process of yeast. The base derivatives are the products of further decomposition of bases. In the autolysis process of yeast, the decomposition enzyme of yeast nucleic acid can be activated to decompose yeast nucleic acid into bases and base derivatives. Summary of the Invention [Problem to be solved by the invention]

[0004] The bases and base derivatives abundant in yeast extract can provide special growth factors to microorganisms, significantly promote the growth of microorganisms, and promote the metabolism of microorganisms to produce some pharmaceutical intermediates, such as adenosine, inosine, etc.

[0005] In traditional yeast extracts, the decomposition of yeast nucleic acid is limited to the nucleotide level, and does not reach the base and base derivatives level. As a result, the content of base and base derivatives in traditional yeast extracts is very low, and cannot meet the efficient production needs of microbial fermentation enterprises.

[0006] The present invention provides a yeast extract rich in bases and base derivatives in order to solve the technical problem of the prior art that the contents of bases and base derivatives in yeast extracts are low.

[0007] The content of bases and base derivatives in the yeast extract provided by the present invention exceeds 20,000 mg / kg. [Means for solving the problem]

[0008] In a first aspect, the present invention provides a yeast extract rich in a base and a base derivative, the yeast extract containing the base and the base derivative in an amount of 20,000 to 40,000 mg / kg.

[0009] Preferably, the yeast extract contains 22,000 to 39,000 mg / kg of a base and a base derivative, Preferably, the base and base derivative are selected from one or a combination of two or more of adenine, guanine, uracil, cytosine, xanthine, and hypoxanthine; Preferably, the yeast extract contains 2000 to 5000 mg / kg of adenine, And / or preferably, the yeast extract contains 3000 to 6000 mg / kg of guanine, And / or preferably, the yeast extract contains 4000 to 7000 mg / kg of uracil, And / or preferably, the yeast extract contains 1500 to 5000 mg / kg of cytosine, And / or preferably, the yeast extract contains 8000 to 11000 mg / kg of xanthine, And / or preferably, the yeast extract contains 2000 to 5000 mg / kg of hypoxanthine.

[0010] Preferably, the yeast extract contains 10 to 12% total nitrogen by mass percentage, and preferably, the yeast extract contains 10.5 to 11.8% total nitrogen by mass percentage; Preferably, the yeast extract contains 3.5 to 5.5% amino acid nitrogen on a mass percentage basis, and preferably, the yeast extract contains 4 to 5% amino acid nitrogen on a mass percentage basis.

[0011] In a second aspect, the present invention provides a method for producing the yeast extract, the method comprising: The method includes the steps of heating yeast milk to 40 to 60°C, adjusting the pH to 5.0 to 6.0, adding an enzyme preparation in an amount of 0.1 to 1% by mass based on the dry weight of the yeast milk, adding a precursor in an amount of 1 to 5% by mass based on the dry weight of the yeast milk, and allowing the yeast milk to autolyze for 15 to 24 hours.

[0012] The precursors described in this invention are converted into bases and base derivatives in an autolytic process.

[0013] Preferably, the enzyme preparation is one or a combination of two or more of nuclease, adenine deaminase, and guanine deaminase; Preferably, the enzyme preparation is a combination of nuclease, adenine deaminase and guanine deaminase; Preferably, the mass ratio of the nuclease to the adenine deaminase to the guanine deaminase is 2.5 to 5:1:1.

[0014] Preferably, the precursor is one or a combination of two or more of yeast RNA or disodium tasty nucleotides.

[0015] Preferably, the method further comprises the steps of inactivating the enzyme after autolysis, separating the solid from the liquid, and concentrating the liquid to obtain the yeast extract; Preferably, the enzyme is inactivated at 65 to 75°C. Preferably, the method of concentration is evaporation under reduced pressure.

[0016] Preferably, the yeast is selected from one or a combination of two or more of Saccharomyces cerevisiae, Wickerhamomyces anomalus, and Cyberlindnera fabianii.

[0017] Preferably, the method for preparing yeast milk comprises: The method includes the steps of inoculating a yeast seed into a medium, culturing the medium at a pH of 4.0 to 6.0 and a temperature of 30 to 33° C. for 12 to 24 hours, and collecting the yeast cells to obtain yeast milk.

[0018] Preferably, the yeast milk contains 10 to 15 wt % yeast cells on a dry matter content basis, with the remainder being water.

[0019] Preferably, the inoculation amount is 1 to 5 wt %; Preferably, the medium contains, per 100 mL of water, 3 to 10 g of a carbon source, 0.5 to 1 g of yeast extract, 2 to 5 g of ammonium sulfate, 1 to 2 g of magnesium sulfate, 0.5 to 1 g of potassium dihydrogen phosphate, and 0.1 to 0.5 g of zinc sulfate; Preferably, the carbon source is selected from one or a combination of more of the following: sugar cane molasses, sugar beet molasses, or hydrolyzed sugars.

[0020] In a third aspect, the present invention further provides a yeast extract produced by the above-mentioned production method.

[0021] In a fourth aspect, the present invention further provides use of the yeast extract or the yeast extract produced by the production method in foods, feeds, and culture media. Effect of the Invention

[0022] Yeast extract is a complete organic nitrogen source that provides a nitrogen source for the growth of microorganisms and also provides growth factors such as trace elements and vitamins. Conventional yeast extracts are rich in nucleotides, but the yeast extract provided by the present invention is rich in bases and base derivatives, which are more easily absorbed by microorganisms than nucleotides, so the product provided by the present invention has a higher microbial growth promoting ability and is of better quality than conventional yeast extracts. The production method provided by the present invention can significantly increase the content of bases and base derivatives in the yeast extract. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The object of the present invention is to provide a yeast extract rich in bases and base derivatives. Traditional yeast extracts have low content of bases and base derivatives, and are insufficient in promoting microbial growth and promoting the production of products through microbial metabolism, which cannot meet the needs of efficient production of microbial fermentation enterprises. The yeast extract provided by the present invention is rich in bases and base derivatives, and has a high ability to promote microbial growth and metabolism. By using the method provided by the present invention, an enzyme preparation and a substrate are added to yeast milk, and conditions such as temperature and pH are controlled to promote the autolysis of yeast, and at the same time, promote the decomposition of yeast nucleic acid into bases and base derivatives, thereby obtaining a yeast extract rich in bases and base derivatives.

[0024] The yeast extract provided by the present invention has a base and base derivative content exceeding 20,000 mg / kg, the base being one or a combination of two or more of adenine, guanine, uracil, and cytosine, and the base derivative being one or two of hypoxanthine and xanthine.

[0025] The method for producing a yeast extract provided by the present invention includes the steps of: decomposing yeast milk with an autolytic enzyme; adding an enzyme preparation to the yeast milk; and subjecting the yeast milk to autolysis at 40-60°C and pH 5.0-6.0 for 15-24 hours to obtain the yeast extract; in a preferred embodiment of the present invention, the method further includes the steps of separating and purifying the product obtained by autolysis, preferably performing solid-liquid separation of the yeast autolysis liquid and concentrating the liquid to obtain a yeast extract; preferably, obtaining a paste-like yeast extract by evaporation under reduced pressure or obtaining a powder-like yeast extract by spray drying; in a specific embodiment of the present invention, the evaporation under reduced pressure is performed under conditions of 92-95 kPa and 80°C.

[0026] In a specific embodiment provided by the present invention, the method for producing the yeast extract comprises the steps of: 1) Preparation of yeast milk, fermentation conditions are pH 4.0-6.0, culture temperature is 30-33°C, and culture time is 12-24 hours. The composition of the fermentation medium is 3-10% carbon source, 0.5-1% yeast extract, 2-5% ammonium sulfate, 1-2% magnesium sulfate, 0.5-1% potassium dihydrogen phosphate, and 0.1-0.5% zinc sulfate (all in mass to volume ratio w / v). Here, the carbon source is one or a combination of sugar cane molasses, sugar beet molasses, and hydrolyzed sugar. After the fermentation is completed, the fermentation liquid is centrifuged at 5000-7000 rpm, the supernatant is discarded, pure water is added to the heavy liquid, and then centrifuged again to obtain washed yeast, which is further diluted with pure water to obtain yeast milk with a dry matter content of 10-15%.

[0027] 2) A yeast autolysis process, in which yeast milk is heated to 40-60°C and maintained at this temperature. The pH is adjusted to 5.0-6.0, an enzyme preparation is added at 0.1-1% based on the dry weight of the yeast milk, and a substrate is added at 1-5% based on the dry weight of the yeast milk, and the autolysis is carried out for 15-24 hours. The enzyme preparation is nuclease, adenine deaminase, or guanine deaminase, and the substrate is yeast RNA or disodium tasty nucleotide.

[0028] 3) Separation and purification: after autolysis of the yeast, an autolysis liquid is obtained, which is then subjected to an enzyme inactivation treatment at 65-75°C, and centrifuged in a centrifuge at 5000-7000 rpm for 5-10 minutes to collect the supernatant, which is then evaporated under reduced pressure to obtain a yeast extract paste rich in bases and base derivatives (water content 30-35%), or spray-dried to obtain a powder (water content less than 5%).

[0029] The reagents used in the examples were provided by the sources shown in Table 1 below. [Table 1]

[0030] The budding yeast FX-2 (Saccharomyces cerevisiae FX-2) used in the examples of the present invention was deposited at the China Center for Typical Culture Collection (CCTCC) on August 1, 2016, with the deposit number CTCCC NO: M2016418 and the deposit address is Wuhan University, Wuhan, China. The strain is described in the patent disclosure of Chinese Patent Publication No. 108220175.

[0031] Wickerhamomyces anomalus C1.7 used in the examples of the present invention was deposited at the China Typical Culture Depository Center (CCTCC) on December 11, 2017, with the deposit number CTCCC NO: M2017782, and the deposit address is Wuhan University, Wuhan, China. The strain is described in the patent disclosure of Chinese Patent Publication No. 110959853.

[0032] The Cyberlindnera fabianii C1.8 used in the examples of the present invention was deposited at the China Typical Culture Depository Center (CCTCC) on December 11, 2017, with the deposit number CTCCC NO: M2017780, and the deposit address is Wuhan University, Wuhan, China. The strain is described in the patent disclosure of Chinese Patent Publication No. 110959853.

[0033] Example 1: Yeast Extract The yeast extract was produced by the following method. 1. Preparation of yeast medium: 100 L of pure water was used to prepare the medium with the following ingredients, calculated by mass ratio to water: sugar cane molasses 3%, yeast extract 0.8%, ammonium sulfate 2%, magnesium sulfate 1%, potassium dihydrogen phosphate 0.5%, and zinc sulfate 0.1%, and the pH was adjusted to 4.5.

[0034] 2. Cultivation of budding yeast FX-2. The inoculation amount of budding yeast FX-2 was 1% (w / v), the culture temperature was 30°C, the aeration amount was 50 L / min, the stirring speed was 300 rpm / min, and the culture was performed for 12 hours.

[0035] 3. Centrifuge at 5000 rpm for 5 minutes, collect the heavy liquid, add pure water to the heavy liquid, stir and when homogenous, centrifuge again at 5000 rpm for 5 minutes, collect the heavy liquid again, and add pure water in an amount of 10% (w / v) of the dry weight of the yeast cells.

[0036] 4. The above yeast milk was heated to 50°C, the pH was adjusted to 5.0, 0.1% adenine deaminase was added based on the dry weight of the yeast milk, and 1% disodium nucleotide was added as a substrate. The temperature and pH were maintained constant during autolysis, and the autolysis was allowed to proceed for 20 hours.

[0037] 5. The temperature of the autolysis liquid was raised to 65°C and maintained for 30 minutes. It was centrifuged at 5000 rpm for 5 minutes in a centrifuge. The supernatant was collected and concentrated by vacuum evaporation at 92-95 kPa and 80°C, and spray-dried to obtain a powdered finished product. The moisture content was 3.5%.

[0038] Example 2: Yeast Extract The yeast extract was produced by the following method. 1. Preparation of yeast medium: 100 L of pure water was used to prepare the medium with the following ingredients, calculated by mass ratio to water: sugar cane molasses 5%, yeast extract 0.5%, ammonium sulfate 4%, magnesium sulfate 1.5%, potassium dihydrogen phosphate 0.5%, and zinc sulfate 0.3%, and the pH was adjusted to 5.0.

[0039] 2. Cultivation of Wickerhamomyces anomalus C1.7 yeast. The inoculation amount of Wickerhamomyces anomalus C1.7 yeast was 1% (w / v), the cultivation temperature was 30°C, the aeration amount was 50 L / min, and the stirring speed was 300 rpm / min, and the cultivation was performed for 20 hours.

[0040] 3. Centrifuge at 6000 rpm for 5 minutes, collect the heavy liquid, add pure water to the heavy liquid, and stir until homogenous. Centrifuge again at 6000 rpm for 5 minutes, collect the heavy liquid again, and add pure water in an amount of 12% (w / v) of the dry weight of the yeast cells.

[0041] 4. The above yeast milk was heated to 40°C, the pH was adjusted to 5.5, 0.25% nuclease and 0.1% guanine deaminase were added based on the dry weight of the yeast milk, and 3% yeast RNA was added as a substrate. The temperature and pH were maintained constant during autolysis, and the autolysis was carried out for 15 hours.

[0042] 5. The temperature of the autolysis liquid was raised to 65°C and maintained for 30 minutes. It was centrifuged at 5000 rpm for 5 minutes in a centrifuge. The supernatant was collected and concentrated by vacuum evaporation at 92-95 kPa and 80°C, and spray-dried to obtain a powdered finished product. The moisture content was 3.7%.

[0043] Example 3: Yeast Extract The yeast extract was produced by the following method. 1. Preparation of yeast medium: 100 L of pure water was used to prepare the medium with the following ingredients, calculated by mass ratio to water: sugar cane molasses 10%, yeast extract 1%, ammonium sulfate 5%, magnesium sulfate 2%, potassium dihydrogen phosphate 0.5%, and zinc sulfate 1%, and the pH was adjusted to 6.0.

[0044] 2. Cultivation of Cyberlindnera fabianii C1.8 yeast, in which the inoculation amount of Cyberlindnera fabianii C1.8 was 1% (w / v), the culture temperature was 33°C, the aeration amount was 50L / min, and the stirring speed was 300rpm / min, and the culture was performed for 24 hours.

[0045] 3. Centrifuge at 6000 rpm for 5 minutes, collect the heavy liquid, add pure water to the heavy liquid, and stir until homogenous. Centrifuge again at 6000 rpm for 5 minutes, collect the heavy liquid again, and add pure water in an amount of 15% (w / v) of the dry weight of the yeast cells.

[0046] 4. The above yeast milk was heated to 60°C, the pH was adjusted to 6.0, 0.5% nuclease, 0.1% adenine deaminase, and 0.1% guanine deaminase were added based on the dry weight of the yeast milk, 3% yeast RNA was added as a substrate, and 2% disodium flavor nucleotide was added as a substrate. The temperature and pH were maintained constant during autolysis, and the autolysis was allowed to proceed for 24 hours.

[0047] 5. The temperature of the autolysis liquid was raised to 70°C and maintained for 30 minutes. It was centrifuged at 5000 rpm for 5 minutes in a centrifuge. The supernatant was collected and concentrated by vacuum evaporation at 92-95 kPa and 80°C, and spray-dried to obtain a powdered finished product. The moisture content was 3.0%.

[0048] (Comparative Example 1: Effect of enzymes on the properties of yeast extract) The yeast extract was produced by the following method. 1. Preparation of yeast medium: 100 L of pure water was used to prepare the medium with the following ingredients, calculated by mass ratio to water: sugar cane molasses 6%, yeast extract 0.8%, ammonium sulfate 3.5%, magnesium sulfate 1%, potassium dihydrogen phosphate 0.3%, and zinc sulfate 0.6%, and the pH was adjusted to 5.5.

[0049] 2. Yeast cultivation: the inoculation amount of Saccharomyces cerevisiae FX-2 was 1% (w / v), the cultivation temperature was 30°C, the aeration amount was 50 L / min, the stirring speed was 300 rpm / min, and the cultivation was carried out for 20 hours.

[0050] 3. Centrifuge at 6000 rpm for 5 minutes, collect the heavy liquid, add pure water to the heavy liquid, and stir until homogenous. Centrifuge again at 6000 rpm for 5 minutes, collect the heavy liquid again, and add pure water in an amount of 13% (w / v) of the dry weight of the yeast cells.

[0051] 4. The above yeast milk was heated to 55°C, the pH was adjusted to 5.5, and the temperature and pH were maintained constant during autolysis, and the autolysis was carried out for 20 hours.

[0052] 5. The temperature of the autolysis liquid was raised to 65°C and maintained for 30 minutes. It was centrifuged at 5000 rpm for 5 minutes in a centrifuge. The supernatant was collected and concentrated by vacuum evaporation at 92-95 kPa and 80°C, and spray-dried to obtain a powdered finished product. The moisture content was 4.0%.

[0053] (Comparative Example 2: Effect of the amount of enzyme used on the characteristics of yeast extract) The yeast extract was produced by the following method. 1. Preparation of yeast medium: 100 L of pure water was used to prepare the medium with the following ingredients, calculated by mass ratio to water: sugar cane molasses 10%, yeast extract 1%, ammonium sulfate 5%, magnesium sulfate 2%, potassium dihydrogen phosphate 0.5%, and zinc sulfate 1%, and the pH was adjusted to 6.0.

[0054] 2. Cultivation of Cyberlindnera fabianii C1.8 yeast. The inoculation amount of Cyberlindnera fabianii C1.8 yeast was 1% (w / v), the culture temperature was 33°C, the aeration amount was 50L / min, and the stirring speed was 300rpm / min, and the culture was performed for 24 hours.

[0055] 3. Centrifuge at 6000 rpm for 5 minutes, collect the heavy liquid, add pure water to the heavy liquid, and stir until homogenous. Centrifuge again at 6000 rpm for 5 minutes, collect the heavy liquid again, and add pure water in an amount of 15% (w / v) of the dry weight of the yeast cells.

[0056] 4. The above yeast milk was heated to 60°C, the pH was adjusted to 6.0, 0.05% nuclease, 0.03% adenine deaminase, and 0.03% guanine deaminase were added based on the dry weight of the yeast milk, 3% yeast RNA was added as a substrate, and 2% disodium flavor nucleotide was added as a substrate. The temperature and pH were maintained constant during autolysis, and the autolysis was allowed to proceed for 24 hours.

[0057] 5. The temperature of the autolysis liquid was raised to 70℃ and maintained for 30 minutes. It was centrifuged at 5000 rpm for 5 minutes in a centrifuge. The supernatant was collected and concentrated by vacuum evaporation at 92-95 kPa and 80℃, and spray-dried to obtain a powdered finished product. The moisture content was 3.2%.

[0058] (Comparative Example 3: Effect of the amount of precursor used on the characteristics of yeast extract) The yeast extract was produced by the following method. 1. Preparation of yeast medium: 100 L of pure water was used to prepare the medium with the following ingredients, calculated by mass ratio to water: sugar cane molasses 3%, yeast extract 0.8%, ammonium sulfate 2%, magnesium sulfate 1%, potassium dihydrogen phosphate 0.5%, and zinc sulfate 0.1%, and the pH was adjusted to 4.5.

[0059] 2. Cultivation of budding yeast FX-2. The inoculation amount of budding yeast FX-2 was 1% (w / v), the culture temperature was 30°C, the aeration amount was 50 L / min, the stirring speed was 300 rpm / min, and the culture was performed for 12 hours.

[0060] 3. Centrifuge at 5000 rpm for 5 minutes, collect the heavy liquid, add pure water to the heavy liquid, stir and when homogenous, centrifuge again at 5000 rpm for 5 minutes, collect the heavy liquid again, and add pure water in an amount of 10% (w / v) of the dry weight of the yeast cells.

[0061] 4. The above yeast milk was heated to 50°C, the pH was adjusted to 5.0, 0.5% nuclease, 0.1% adenine deaminase, 0.1% guanine deaminase were added based on the dry weight of the yeast milk, 0.5% yeast RNA was added as a substrate, and 0.2% disodium flavor nucleotide was added as a substrate. The temperature and pH were maintained constant during autolysis, and the autolysis was allowed to proceed for 22 hours.

[0062] 5. The temperature of the autolysis liquid was raised to 65℃ and maintained for 30 minutes. It was centrifuged at 5000 rpm for 5 minutes in a centrifuge. The supernatant was collected and concentrated by vacuum evaporation at 92-95 kPa and 80℃, and spray-dried to obtain a powdered finished product. The moisture content was 3.8%.

[0063] The contents of total nitrogen, amino acid nitrogen, water, bases and base derivatives, and each of the bases and base derivatives of the yeast extracts produced in Examples 1 to 3 and Comparative Examples 1 to 3 were measured, and the methods for measuring each physical and chemical index were as follows. The results are shown in Tables 2 and 3.

[0064] (1) Moisture measurement The method of 6.2 of Chinese standard GB / T 23530-2009 was adopted. A certain mass of sample was used, dried at 103℃ for 4 hours until constant weight was reached, and then weighed to calculate the moisture content. The results are shown in Table 2.

[0065] (2) Measurement of total nitrogen The Kjeldahl method of the Chinese standard GB / T 23530-2009, 6.4, was used. Samples (equivalent to 30-440 mg of total nitrogen) were digested by adding 20 mL of concentrated sulfuric acid and boiling in an environment where 5 g of mixed catalyst a (a mixture of potassium sulfate and copper sulfate pentahydrate in a ratio of 97:3) and 2.5 g of catalyst b (a mixture of powdered selenium and potassium sulfate in a ratio of 0.1:100) were acting. The mixture was further distilled and the ammonia product was absorbed with boric acid. The sample was titrated with 0.1 mol / L hydrochloric acid, the data was read, and the total nitrogen content was calculated. The results are shown in Table 2.

[0066] (3) Amino acid nitrogen measurement The method for measuring amino acid nitrogen described in 6.5 of the Chinese standard GB / T 23530-2009 was adopted. 5g of sample was used, diluted, and titrated with 0.5mol / L sodium hydroxide solution until pH reached 8.2, and maintained for 1 minute. 10mL of 36% formaldehyde solution was slowly added to react with the non-dissociable amino groups in the neutral amino acids to produce monohydroxymethyl derivatives and dihydroxymethyl derivatives, and this reaction was carried out completely quantitatively. The hydrogen ions released at this time were titrated with the sodium hydroxide, and the amino acid nitrogen content was calculated from the amount of alkaline solution consumed. The results are shown in Table 2.

[0067] (4) pH measurement The pH measurement method described in 7.2.1 of the Chinese standard GB / T 35536-2017 was used. Aqueous solutions of a given mass percent concentration were prepared, and the pH was measured after sterilization using a glass electrode. The difference between two measurements of the same sample should not exceed 0.04.

[0068] (5) Measurement of bases and base derivatives The contents of various bases and base derivatives were determined using high performance liquid chromatography.

[0069] High-performance liquid chromatograph: with UV detector and 250mm x 4.6mm 5μm SCX column Mobile phase: 0.1% phosphoric acid Column temperature: 35℃ Detection wavelength: 267 nm Various bases and base derivatives were prepared as standard solutions of predetermined concentrations, which were then loaded into a high performance liquid chromatograph for measurement and a calibration curve was created. The test samples were dissolved in water, passed through a 0.22 μm membrane film, loaded and analyzed by high performance liquid chromatography, and the concentrations of each base and base derivative in the sample were calculated from the calibration curve. The results are shown in Tables 2 and 3. [Table 2] [Table 3]

[0070] As shown in Tables 2 and 3 above, the yeast extracts produced in Examples 1 to 3 had base and base derivative contents of 22,000 to 39,000 mg / kg, while the yeast extracts produced in Comparative Examples 1 to 3 had base and base derivative contents of 3,000 to 4,500 mg / kg. This demonstrates that the yeast extracts produced by the production method provided by the present invention have high contents of base and base derivatives.

[0071] (Experimental Example 1) The yeast extracts of Examples 1 to 3, Comparative Examples 1 to 3 and the prior art CN106282242A were used to culture Bacillus subtilis CCTCC 131157, and the OD 600 The final amount of adenosine produced was measured. The specific experimental procedure was as follows. 1. Preparation of fermentation medium. 1L of pure water was used to prepare the medium with the following ingredients based on the mass ratio to water: glucose 150g / L, yeast extract powder (yeast extract of Examples 1-3, Comparative Examples 1-3 and China Patent Publication No. 106282242) 35g / L, magnesium sulfate 10g / L, potassium dihydrogen phosphate 10g / L, manganese sulfate 0.05g / L, and copper sulfate 0.01g / L. After preparation, the medium was sterilized at 121°C for 20 minutes.

[0072] 2. Bacillus subtilis CCTCC 131157 was inoculated into the medium and cultured for 48 hours, and the OD 600 The results are shown in Table 4 below. [Table 4]

[0073] As can be seen from Table 4 above, when the yeast extracts provided in Examples 1 to 3 of the present invention are used in a microbial culture medium, the growth of microorganisms can be further promoted.

[0074] The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Those skilled in the art may make various modifications and changes to the present invention. Any modifications, equivalent replacements, improvements, etc. made without departing from the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0075] (Additional Note) (Appendix 1) A yeast extract rich in bases and base derivatives, characterized in that it contains 20,000 to 40,000 mg / kg of bases and base derivatives.

[0076] (Appendix 2) The yeast extract contains 22,000 to 39,000 mg / kg of a base and a base derivative, Preferably, the base and the base derivative are selected from one or a combination of two or more of adenine, guanine, uracil, cytosine, xanthine, and hypoxanthine; Preferably, the yeast extract contains 2000 to 5000 mg / kg of adenine, And / or preferably, the yeast extract contains 3000 to 6000 mg / kg of guanine, And / or preferably, the yeast extract contains 4000 to 7000 mg / kg of uracil, And / or preferably, the yeast extract contains 1500 to 5000 mg / kg of cytosine, And / or preferably, the yeast extract contains 8000 to 11000 mg / kg of xanthine, And / or preferably, the yeast extract contains 2000 to 5000 mg / kg of hypoxanthine. A yeast extract as described in Appendix 1.

[0077] (Appendix 3) The yeast extract contains 10 to 12% total nitrogen by mass percentage, and preferably contains 10.5 to 11.8% total nitrogen by mass percentage; Preferably, the yeast extract contains 3.5 to 5.5% amino acid nitrogen by mass percentage, and preferably, the yeast extract contains 4 to 5% amino acid nitrogen by mass percentage. Attachment 1 or 2, a yeast extract.

[0078] (Appendix 4) A method for producing a yeast extract according to any one of appendix 1 to 3, The method comprises the steps of heating the yeast milk to 40 to 60°C, adjusting the pH to 5.0 to 6.0, adding an enzyme preparation in an amount of 0.1 to 1% by mass based on the dry weight of the yeast milk, adding a precursor in an amount of 1 to 5% by mass based on the dry weight of the yeast milk, and allowing the yeast milk to autolyze for 15 to 24 hours. Manufacturing method.

[0079] (Appendix 5) The enzyme preparation is one or a combination of two or more of nuclease, adenine deaminase, and guanine deaminase, Preferably, the enzyme preparation is a combination of nuclease, adenine deaminase and guanine deaminase; Preferably, the mass ratio of the nuclease, adenine deaminase, and guanine deaminase is 2.5 to 5:1:1. The manufacturing method described in Appendix 4.

[0080] (Appendix 6) The method according to claim 4 or 5, wherein the precursor is one or a combination of two or more of yeast RNA or disodium tasty nucleotides.

[0081] (Appendix 7) The method further comprises the steps of inactivating the enzyme after autolysis, and removing and concentrating the liquid after solid-liquid separation to obtain a yeast extract; Preferably, the enzyme is inactivated at 65 to 75°C. Preferably, the concentration method is reduced pressure evaporation. The method for producing the same according to any one of claims 4 to 6.

[0082] (Appendix 8) The method according to any one of claims 4 to 7, wherein the yeast is selected from one or a combination of two or more of budding yeast, Wickerhamomyces anomalus, and Cyberlindnera fabianii.

[0083] (Appendix 9) The method for preparing the yeast milk comprises the steps of: The method includes the steps of inoculating a yeast seed into a medium, culturing the medium at a pH of 4.0 to 6.0 and a temperature of 30 to 33 ° C for 12 to 24 hours, and collecting yeast cells to obtain yeast milk. The method for producing the same according to any one of claims 4 to 8.

[0084] (Appendix 10) The production method according to claim 9, characterized in that the yeast cell content in the yeast milk is 10 to 15 wt% based on the dry matter content, with the remainder being water.

[0085] (Appendix 11) The inoculation amount was 1-5 wt%. Preferably, the medium contains 3 to 10 g of a carbon source, 0.5 to 1 g of yeast extract, 2 to 5 g of ammonium sulfate, 1 to 2 g of magnesium sulfate, 0.5 to 1 g of potassium dihydrogen phosphate, and 0.1 to 0.5 g of zinc sulfate per 100 mL of water; Preferably, the carbon source is selected from the group consisting of sugar cane molasses, sugar beet molasses, and hydrolyzed sugars, or a combination of several of these. The method for producing the method according to claim 9 or 10.

[0086] (Appendix 12) A yeast extract produced by the method according to any one of claims 4 to 11.

[0087] (Appendix 13) Use of the yeast extract according to any one of Appendices 1 to 3 or 12, or the yeast extract produced by the production method according to any one of Appendices 4 to 11, in a food, feed, or culture medium.

Claims

1. A yeast extract rich in bases and base derivatives, characterized in that it contains 20,000 to 40,000 mg / kg of bases and base derivatives.

2. The yeast extract contains 22,000 to 39,000 mg / kg of a base and a base derivative, Preferably, the base and the base derivative are selected from one or a combination of two or more of adenine, guanine, uracil, cytosine, xanthine, and hypoxanthine; Preferably, the yeast extract contains 2000 to 5000 mg / kg of adenine, And / or preferably, the yeast extract contains 3000 to 6000 mg / kg of guanine; And / or preferably, the yeast extract contains 4000 to 7000 mg / kg of uracil, And / or preferably, the yeast extract contains 1500 to 5000 mg / kg of cytosine; And / or preferably, the yeast extract contains 8000 to 11000 mg / kg of xanthine, And / or preferably, the yeast extract contains 2000 to 5000 mg / kg of hypoxanthine. The yeast extract according to claim 1.

3. The yeast extract contains 10 to 12% total nitrogen by mass percentage, preferably 10.5 to 11.8% total nitrogen by mass percentage, Preferably, the yeast extract contains 3.5 to 5.5% amino acid nitrogen by mass percentage, and preferably, the yeast extract contains 4 to 5% amino acid nitrogen by mass percentage. The yeast extract according to claim 1 or 2.

4. A method for producing a yeast extract according to any one of claims 1 to 3, The yeast milk is heated to 40-60°C, pH is adjusted to 5.0-6.0, an enzyme preparation is added in an amount of 0.1-1% by mass based on the dry weight of the yeast milk, a precursor is added in an amount of 1-5% by mass based on the dry weight of the yeast milk, and the yeast milk is autolyzed for 15-24 hours. Manufacturing method.

5. The enzyme preparation is one or a combination of two or more of nuclease, adenine deaminase, and guanine deaminase, Preferably, the enzyme preparation is a combination of nuclease, adenine deaminase and guanine deaminase; Preferably, the mass ratio of the nuclease to the adenine deaminase to the guanine deaminase is 2.5 to 5:1:

1. The method according to claim 4.

6. 6. The method according to claim 4 or 5, wherein the precursor is one or a combination of two or more of yeast RNA or disodium tasty nucleotides.

7. The method further comprises the steps of inactivating the enzyme after autolysis, and removing and concentrating the liquid after solid-liquid separation to obtain a yeast extract; Preferably, the enzyme is inactivated at 65-75°C; Preferably, the method of concentration is reduced pressure evaporation. The method according to any one of claims 4 to 6.

8. The method according to any one of claims 4 to 7, wherein the yeast is selected from one or a combination of two or more of budding yeast, Wickerhamomyces anomalus, and Cyberlindnera fabianii.

9. The method for preparing the yeast milk comprises the steps of: The method includes the steps of inoculating a yeast seed into a medium, culturing the medium at a pH of 4.0 to 6.0 and a temperature of 30 to 33° C. for 12 to 24 hours, and collecting yeast cells to obtain yeast milk. The method according to any one of claims 4 to 8.

10. The method according to claim 9, wherein the yeast milk has a yeast cell content of 10 to 15 wt % based on the dry matter content, and the remainder is water.

11. The inoculation amount is 1-5 wt %; Preferably, the medium contains 3 to 10 g of a carbon source, 0.5 to 1 g of yeast extract, 2 to 5 g of ammonium sulfate, 1 to 2 g of magnesium sulfate, 0.5 to 1 g of potassium dihydrogen phosphate, and 0.1 to 0.5 g of zinc sulfate per 100 mL of water; Preferably, the carbon source is selected from the group consisting of sugar cane molasses, sugar beet molasses, and hydrolyzed sugars, or a combination of several of these. The method according to claim 9 or 10.

12. A yeast extract produced by the method according to any one of claims 4 to 11.

13. Use of the yeast extract according to any one of claims 1 to 3 or claim 12, or the yeast extract produced by the production method according to any one of claims 4 to 11, in food, feed, or culture medium.

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