CN116024155A - Method for promoting yeast to enrich selenomethionine and selenomethionine-enriched yeast - Google Patents
Method for promoting yeast to enrich selenomethionine and selenomethionine-enriched yeast Download PDFInfo
- Publication number
- CN116024155A CN116024155A CN202310020508.7A CN202310020508A CN116024155A CN 116024155 A CN116024155 A CN 116024155A CN 202310020508 A CN202310020508 A CN 202310020508A CN 116024155 A CN116024155 A CN 116024155A
- Authority
- CN
- China
- Prior art keywords
- fermentation
- selenomethionine
- selenium
- yeast
- total mass
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Micro-Organisms Or Cultivation Processes Thereof (AREA)
Abstract
The invention relates to a method for promoting yeast to enrich selenomethionine, which applies molasses and tannin after saccharose enzymolysis to selenium-enriched yeast fermentation, thereby improving the accumulation of selenomethionine in yeast cells. Specifically, the yeast seeds subjected to multistage culture are cultured by using a culture medium containing tannin and sucrose enzymatic hydrolysis molasses, so that the yeast with high L-selenomethionine content, wherein the total intracellular selenium content is more than 3000ppm and the L-selenomethionine content is more than 5000ppm, and the selenium in the selenomethionine form in the product accounts for more than 70% of the total selenium.
Description
Technical Field
The invention relates to the technical field of fermentation, in particular to a method for promoting yeast to enrich selenomethionine.
Background
Selenium-enriched yeast is the most widely used organic selenium source in the market, and has great market potential in the aspects of livestock breeding industry, food additives and medical health care: the selenium-enriched yeast has good free radical scavenging function, can inhibit the peroxidation of cell membrane lipid and improve the immunity of the organism, thereby delaying the aging process of tissue cells, and can be used as an active ingredient of anti-aging food; the selenium-enriched yeast has certain effects in animal performance and changing physiological characteristics, for example, the selenium-enriched yeast can be added into feed of broiler chickens to improve chicken yield of the broiler chickens; the selenium-enriched yeast can improve the activity of glutathione peroxidase, so that the selenium-enriched yeast has certain efficacy in the aspects of preventing and treating keshan, diabetes mellitus, auxiliary treatment of cancers and the like; the selenium-enriched yeast is beneficial to maintaining the normal structure and function of the cardiovascular system, can prevent arteriosclerosis and coronary heart disease, and can maintain the normal blood pressure level of the organism.
The maximum selenium amount that a yeast cell can theoretically bind depends on the methionine and cysteine (residue) content of the cell, about 6000mg/kg. However, complete replacement of methionine and cysteine by selenoamino acids is not possible, and in general, the maximum selenium content achievable in yeast is about 3000mg/kg, whereas the selenium content in common commercial selenium-enriched yeasts is generally 500-2000 mg/kg. 90% of the organic selenium of selenium-enriched yeast exists in the form of selenomethionine (selenomethionine), and the free selenocysteine content is low.
Selenomethionine is an important selenium supplement, has anti-inflammatory, anti-cancer and antioxidant effects, and can effectively prevent Alzheimer's disease and diabetes, enhance immunity, and reduce the incidence of cardiovascular diseases. As a selenium-containing amino acid, L-selenomethionine directly participates in the synthesis of proteins in organisms, and has high deposition efficiency in animal products (meat, eggs and milk).
Disclosure of Invention
Selenomethionine is the main selenium-containing compound in the cells of selenium-enriched yeast, the content of selenomethionine also affects the quality of selenium-enriched yeast, and the market has great demands for selenium-enriched yeast products with high selenomethionine content.
Aiming at the problem of lacking yeast products with high selenomethionine content in the market, the invention provides a process for promoting yeast to enrich selenomethionine, which takes Saccharomyces cerevisiae as a production strain, and the yeast strain after multistage culture is transferred to a fermentation tank for culture, so that the total selenium in the yeast finally reaches more than 3000ppm, meanwhile, the selenomethionine content reaches more than 5000ppm, and the selenium in the form of selenomethionine reaches 70% of the total selenium.
Preferably, the culture medium in the fermentation tank is a culture medium containing tannin, and molasses obtained by enzymolysis of sucrose is used as a carbon source and further contains ammonia water, diammonium hydrogen phosphate, sodium selenite, magnesium sulfate and zinc sulfate.
Preferably, the sucrose enzymolysis molasses is sucrose enzymolysis molasses with the mass content of glucose and fructose being more than 50% in total, and the mass of the molasses is 28% -40% of the total mass of the fermentation body.
Preferably, the mass of the tannin in the culture medium is 0.1% -5% of the total mass of the fermentation body; the mass of the diammonium hydrogen phosphate is 0.2-0.5% of the total mass of the fermentation body, the mass of the sodium selenite is 0.03-0.08% of the total mass of the fermentation body, the mass of the magnesium sulfate is 0.05-0.1% of the total mass of the fermentation body, and the mass of the zinc sulfate is 0.02-0.04% of the total mass of the fermentation body; the mass of the ammonia water is 1.5% -2.5% of the total mass of the fermentation body by the mass of the ammonia water with the mass content of 16%.
Preferably, the sodium selenite is fed into the culture medium in the form of an aqueous solution, and the feeding rate is 10-60mg/L per hour based on the sodium selenite.
Preferably, the concentration of the sodium selenite aqueous solution is 100-500g/L.
Preferably, the molasses is added only by a fed-batch mode, and the addition amount is regulated by ethanol feedback control, so as to keep the volume concentration of ethanol in the culture medium to be less than 0.1%.
Preferably, the tannin mass in the culture medium is 0.5-1.5% of the total mass of the fermentation body.
Preferably, the mass of sucrose enzymolysis molasses in the culture medium is 30-35% of the total mass of the fermentation body
Further preferably, the tannin mass in the culture medium is 1-1.5% of the total mass of the fermentation body;
further preferably, the concentration of the sodium selenite aqueous solution is 200-300g/L.
The culture fermentation conditions of the process comprise:
the ventilation amount is 0.5-1.5vvm, the culture temperature is controlled at 28-32 ℃, the pH value of the culture medium is 4.0-6.5, and the culture time is 20-24 hours.
The beneficial effects of the invention are as follows:
the molasses and the tannin after saccharose enzymolysis are firstly applied to the fermentation of the selenium-enriched yeast, and are more favorable for the enrichment of selenomethionine and total selenium, so that the total selenium content in the yeast cell is improved to more than 3000ppm, the method belongs to a higher level, the selenomethionine content is more than 5000ppm, and the selenium in the form of selenomethionine accounts for more than 70% of the total selenium.
Detailed Description
1. Enrichment of selenomethionine
The method for enriching selenomethionine by using molasses and tannin obtained after saccharose enzymolysis in a selenium-enriched yeast fermentation medium comprises the following steps: transferring the yeast strain after multi-stage seed culture into a fermentation tank, and culturing with a culture medium containing sucrose enzymolysis molasses, tannin, 16% ammonia water, diammonium hydrogen phosphate, sodium selenite, magnesium sulfate and zinc sulfate, wherein the fermentation process keeps the temperature at 28-32deg.C, the pH value at 4.0-6.5, the ventilation amount at 0.5-1.5vvm, and the fermentation time period at 20-24 hours.
The yeast strain is selenium-enriched Saccharomyces cerevisiae, and is biologically preserved in China center for type culture collection (CCTCC, university of Wuhan, post code 430072) at 10 months and 25 days 2005, and the preservation number is CCTCC NO: M205124. Available in connection with China center for type culture Collection or Angel Yeast, inc. and seed resource technology center.
The sources of the components of the culture medium and the model of the equipment in the experimental process are shown in Table 1
TABLE 1 Medium composition and equipment model and Source
2. Detection method
a. Method for detecting total selenium content of product
The method for detecting the total selenium content of the product is detected by referring to a test method for the total selenium content of the yeast in a new feed and new feed additive product standard NYSL-1004-2009: 1) About 0.2500g of yeast sample was weighed, and 20ml of nitric acid and perchloric acid were added in a volume ratio of 7:1, and the solution digested on a hot plate at 260 ℃ becomes clear and colorless with white smoke, and is heated to a remaining volume of about 2 ml. Cooled, 5ml hydrochloric acid (6 mol/L) was added and heated until the solution became clear and colorless with the appearance of white smoke. Transferring the mixture after cooling to a volumetric flask with volume of 100ml to be used as sample digestive juice, and simultaneously performing a digestion blank test; 2) Sucking 5ml of sample digestion solution, transferring to constant volume to 100ml, and shaking to obtain diluent 1; sucking 5ml of the diluent 1 liquid into a 50ml volumetric flask, adding 2.5ml of concentrated hydrochloric acid (12 mol/L) and 2.5ml of potassium ferricyanide solution (100 g/L), and uniformly mixing to a volume of 50 ml; blank digests were treated as well.
And (3) measuring the selenium content in the sample diluent by adopting a double-channel atomic fluorescence photometer.
The total selenium content in the sample is calculated according to the formula (1):
wherein: x_is the total selenium content in milligrams per kilogram (mg/kg) of the sample;
p is the concentration measured in nanograms per milliliter (ng/mL) of the sample digestion diluent
p 0 The concentration was measured for blank digestion dilutions in units ofNanograms per milliliter (ng/mL)
m 1 The mass of the sample weighed for the total selenium measurement is given in grams (g).
b. Selenomethionine detection method
Selenomethionine in yeast is detected by adopting a liquid phase atomic fluorescence combined method: 1) Preparing a sample according to GB/T20195, at least 200g, crushing to enable the sample to completely pass through an analysis sieve with the aperture of 0.42mm, fully and uniformly mixing, and filling the mixture into a grinding bottle for later use; 2) Accurately weighing 50mg (0.1 mg) of the sample in a 50mL centrifuge tube, adding 5mL of buffer solution, screwing a tube cover, putting the centrifuge tube into a constant-temperature water bath kettle at 90 ℃ for heating for 10min, taking out, cooling to room temperature, adding 10mg of streptococcus suicided protease, reacting for 3 hours in a water bath oscillator at 37 ℃ and 150 revolutions per minute, and centrifuging to collect supernatant; 3) And (3) secondary enzymolysis: adding 10mg of streptococcus griseus protease and 5mL of buffer solution into the centrifugal residue, uniformly mixing, reacting for 3 hours in a water bath oscillator with the temperature of 37 ℃ and the rotation speed of 150 r/min, and centrifugally collecting supernatant; 4) And (3) performing enzymolysis for the third time: repeating the step of secondary enzymolysis; 5) Collecting supernatant obtained in each step, diluting to enable selenomethionine analysis concentration to be 200-450 mug/L, and performing membrane filtration or centrifugation at a rotating speed of not less than 10000 revolutions per minute (the centrifugation time is not less than 10 min), detecting by using a liquid phase-atomic fluorescence combined instrument, and quantifying by an external standard method.
The buffer solution is TRIS buffer solution, 12.11g of TRIS is accurately weighed, 900mL of water is added for dissolution, and then hydrochloric acid and water with the volume ratio of 1:1 to adjust the pH to 7.5 and to fix the volume to 1L.
The concentration of selenomethionine in the sample is calculated from equation (2):
wherein: omega is the selenomethionine content of the sample in milligrams per kilogram (mg/kg)
c is the concentration of selenomethionine in the test sample solution in micrograms per liter (μg/L)
v is the volume of preliminary constant volume after sample enzymolysis, and the unit is milliliter (mL)
m is the mass of the weighed sample, and the unit is milligrams (mg)
n is the multiple of the dilution of the sample liquid again
The model of the medicines and the equipment used in the experimental process are shown in Table 2
TABLE 2 pharmaceutical and equipment model and Source
Example 1
1. Second-level seed culture of strain
Selecting 1 loop from the selenium-enriched saccharomyces cerevisiae inclined plane strain, inoculating the strain into a primary culture medium, taking a 250ml shake flask as an example, and culturing the strain in the primary culture medium for 24 hours, wherein the liquid loading amount of the culture medium is 50 ml; the primary culture medium with bacteria liquid after the culture is mixed with the next primary culture medium according to the volume ratio of 1:200 was transferred to the second medium and cultured for 24 hours according to the culture conditions in the first medium.
2. Fermentation culture
The strain subjected to the secondary culture is subjected to secondary culture according to the volume ratio of 1:200, inoculating a culture medium bacterial liquid into a tannin fermentation culture medium, wherein the culture medium comprises: the total mass of the fermentation body is 40 percent of the molasses after enzymolysis treatment, wherein the mass content of glucose and fructose accounts for 65 percent of the total sugar; ammonia water with the mass concentration of 16% accounting for 2.5% of the total mass of the fermentation body; diammonium phosphate with the total mass of 0.5% of the fermentation body; sodium selenite accounting for 0.08 percent of the total mass of the fermentation body; magnesium sulfate accounting for 0.1 percent of the total mass of the fermentation body; zinc sulfate accounting for 0.04 percent of the total mass of the fermentation body; food-grade tannins accounting for 0.1% of the total mass of the fermentation body; wherein, molasses after enzymolysis treatment is fed in the fermentation process, and the fed-in amount per hour is based on controlling the alcohol concentration in the fermentation liquid to be not more than 0.1 percent; sodium selenite is fed in the fermentation process, and the feeding amount per hour is 60mg/L (calculated by sodium selenite).
The fermentation culture conditions include: the temperature is 32 ℃, the pH is 6.5, the ventilation is 1.5vvm (the ratio of ventilation per minute to the actual feed liquid volume of the tank body), the culture time is 24 hours, and the dry weight of the yeast cells reaches 50-70g/L at the end of fermentation.
After fermentation, separating by a centrifuge, and washing for 2 times by using process water to finally obtain the yeast milk with 16.5% dry matter. Through detection, the total selenium content is 3075ppm, the selenomethionine content is 5483ppm, and the selenomethionine form selenium accounts for 71.8% of the total selenium.
Example 2
After the selenium-enriched yeast strain is cultured according to the secondary seed culture mode described in the embodiment 1, the selenium-enriched yeast strain is prepared according to the volume ratio of 1:200 ratio the medium-carrying broth was inoculated into the tannin fermentation medium. The culture medium comprises: the total mass of the fermentation body is 40 percent of the molasses after enzymolysis treatment, wherein the mass content of glucose and fructose accounts for 65 percent of the total sugar; ammonia water with the mass concentration of 16% accounting for 2.5% of the total mass of the fermentation body; diammonium phosphate with the total mass of 0.5% of the fermentation body; sodium selenite accounting for 0.08 percent of the total mass of the fermentation body; magnesium sulfate accounting for 0.1 percent of the total mass of the fermentation body; zinc sulfate accounting for 0.04 percent of the total mass of the fermentation body; food-grade tannins in an amount of 5% of the total mass of the fermentation broth; wherein, molasses after enzymolysis treatment is fed in the fermentation process, and the fed-in amount per hour is based on controlling the alcohol concentration in the fermentation liquid to be not more than 0.1 percent; sodium selenite is fed in the fermentation process, and the feeding amount per hour is 60mg/L (calculated by sodium selenite).
The fermentation culture conditions include: the temperature is 32 ℃, the pH is 6.5, the aeration rate is 1.5vvm, the culture time is 24 hours, and the dry weight of the yeast cells reaches 50-70g/L at the end of fermentation.
After fermentation, separating by a centrifuge, and washing for 2 times by using process water to finally obtain the yeast milk with 16.5% dry matter. Through detection, the total selenium content is 3298ppm, the selenomethionine content is 5669ppm, and the selenomethionine form selenium accounts for 72% of the total selenium.
Example 3
After the selenium-enriched yeast strain is cultured according to the secondary seed culture mode described in the embodiment 1, the selenium-enriched yeast strain is prepared according to the volume ratio of 1:200 ratio the medium-carrying broth was inoculated into the tannin fermentation medium. The culture medium comprises: the total mass of the fermentation body is 35 percent of the molasses after enzymolysis treatment, wherein the mass content of glucose and fructose accounts for 65 percent of the total sugar; ammonia water with the mass concentration of 16% accounting for 2.5% of the total mass of the fermentation body; diammonium phosphate with the total mass of 0.5% of the fermentation body; sodium selenite accounting for 0.08 percent of the total mass of the fermentation body; magnesium sulfate accounting for 0.1 percent of the total mass of the fermentation body; zinc sulfate accounting for 0.04 percent of the total mass of the fermentation body; food-grade tannins accounting for 1.5% of the total mass of the fermentation body; wherein, molasses after enzymolysis treatment is fed in the fermentation process, and the fed-in amount per hour is based on controlling the alcohol concentration in the fermentation liquid to be not more than 0.1 percent; sodium selenite is fed in the fermentation process, and the feeding amount per hour is 60mg/L (calculated by sodium selenite).
The fermentation culture conditions include: the temperature is 32 ℃, the pH is 6.5, the aeration rate is 1.5vvm, the culture time is 24 hours, and the dry weight of the yeast cells reaches 50-70g/L at the end of fermentation.
After fermentation, separating by a centrifuge, and washing for 2 times by using process water to finally obtain the yeast milk with 16.5% dry matter. Through detection, the total selenium content is 3159ppm, the selenomethionine content is 5487ppm, and the selenomethionine form selenium accounts for 71.5% of the total selenium.
Example 4
After the selenium-enriched yeast strain is cultured according to the secondary seed culture mode described in the embodiment 1, the selenium-enriched yeast strain is prepared according to the volume ratio of 1:200 ratio the medium-carrying broth was inoculated into the tannin fermentation medium. The culture medium comprises: the molasses is subjected to enzymolysis treatment, wherein the mass content of glucose and fructose accounts for 65% of the total sugar; ammonia water with the mass concentration of 16% accounting for 2.5% of the total mass of the fermentation body; diammonium phosphate with the total mass of 0.5% of the fermentation body; sodium selenite accounting for 0.08 percent of the total mass of the fermentation body; magnesium sulfate accounting for 0.1 percent of the total mass of the fermentation body; zinc sulfate accounting for 0.04 percent of the total mass of the fermentation body; food-grade tannins in an amount of 0.5% of the total mass of the fermented mass; wherein, molasses after enzymolysis treatment is fed in the fermentation process, and the fed-in amount per hour is based on controlling the alcohol concentration in the fermentation liquid to be not more than 0.1 percent; sodium selenite is fed in the fermentation process, and the feeding amount per hour is 60mg/L (calculated by sodium selenite).
The fermentation culture conditions include: the temperature is 32 ℃, the pH is 6.5, the aeration rate is 0.5vvm, the culture time is 24 hours, and the dry weight of the yeast cells reaches 50-70g/L at the end of fermentation.
After fermentation, separating by a centrifuge, and washing for 2 times by using process water to finally obtain the yeast milk with 16.5% dry matter. Through detection, the total selenium content is 3058ppm, the selenomethionine content is 5328ppm, and the selenomethionine form selenium accounts for 70.23% of the total selenium. .
Example 5
After the selenium-enriched yeast strain is cultured according to the secondary seed culture mode described in the embodiment 1, the selenium-enriched yeast strain is prepared according to the volume ratio of 1:200 ratio the medium-carrying broth was inoculated into the tannin fermentation medium. The culture medium comprises: the total mass of the fermentation body is 35 percent of the molasses after enzymolysis treatment, wherein the mass content of glucose and fructose accounts for 65 percent of the total sugar; ammonia water with the mass concentration of 16% accounting for 2.5% of the total mass of the fermentation body; diammonium phosphate with the total mass of 0.5% of the fermentation body; sodium selenite accounting for 0.08 percent of the total mass of the fermentation body; magnesium sulfate accounting for 0.1 percent of the total mass of the fermentation body; zinc sulfate accounting for 0.04 percent of the total mass of the fermentation body; food-grade tannins in an amount of 1% of the total mass of the fermentation broth; wherein, molasses after enzymolysis treatment is fed in the fermentation process, and the fed-in amount per hour is based on controlling the alcohol concentration in the fermentation liquid to be not more than 0.1 percent; sodium selenite is fed in the fermentation process, and the feeding amount per hour is 60mg/L (calculated by sodium selenite).
The fermentation culture conditions include: the temperature is 32 ℃, the pH is 6.5, the aeration rate is 1.5vvm, the culture time is 24 hours, and the dry weight of the yeast cells reaches 50-70g/L at the end of fermentation.
After fermentation, separating by a centrifuge, and washing for 2 times by using process water to finally obtain the yeast milk with 16.5% dry matter. Through detection, the total selenium content is 3218ppm, the selenomethionine content is 5980ppm, and the selenomethionine form selenium accounts for 74.9% of the total selenium.
Comparative example 1
After the selenium-enriched yeast strain is cultured according to the secondary seed culture mode described in the embodiment 1, the selenium-enriched yeast strain is prepared according to the volume ratio of 1:200 ratio the medium-carrying broth was inoculated into the tannin fermentation medium. The culture medium comprises: sucrose molasses accounting for 30% of the total mass of the fermentation body; ammonia water with the mass concentration of 16% accounting for 1.5% of the total mass of the fermentation body; diammonium phosphate with the total mass of 0.2% of the fermentation body; sodium selenite accounting for 0.03 percent of the total mass of the fermentation body; magnesium sulfate accounting for 0.05 percent of the total mass of the fermentation body; zinc sulfate accounting for 0.02 percent of the total mass of the fermentation body; wherein molasses is fed in the fermentation process, and the feeding amount per hour is controlled to control the alcohol concentration in the fermentation liquid to be not more than 0.1 percent; sodium selenite is fed in the fermentation process, and the feeding amount per hour is 10mg/L (calculated by sodium selenite).
The fermentation culture conditions include: the temperature is 28-32 ℃, the pH is 4.0, the aeration rate is 0.5vvm, the culture time is 20 hours, and the dry weight of the yeast cells reaches 50-70g/L at the end of fermentation.
After fermentation, separating by a centrifuge, and washing for 2 times by using process water to finally obtain the yeast milk with 16.5% dry matter. Through detection, the total selenium content is 2614ppm, the selenomethionine content is 4064ppm, and the selenium in the form of selenomethionine accounts for 62.6% of the total selenium.
Comparative example 2
After the selenium-enriched yeast strain is cultured according to the secondary seed culture mode described in the embodiment 1, the selenium-enriched yeast strain is prepared according to the volume ratio of 1:200 ratio the medium-carrying broth was inoculated into the tannin fermentation medium. The culture medium comprises: the molasses is subjected to enzymolysis treatment, wherein the mass content of glucose and fructose accounts for 50% of the total sugar; ammonia water with the mass concentration of 16% accounting for 1.5% of the total mass of the fermentation body; diammonium phosphate with the total mass of 0.2% of the fermentation body; sodium selenite accounting for 0.03 percent of the total mass of the fermentation body; magnesium sulfate accounting for 0.05 percent of the total mass of the fermentation body; zinc sulfate accounting for 0.02 percent of the total mass of the fermentation body; wherein, molasses after enzymolysis treatment is fed in the fermentation process, and the fed-in amount per hour is based on controlling the alcohol concentration in the fermentation liquid to be not more than 0.1 percent; sodium selenite is fed in the fermentation process, and the feeding amount per hour is 10mg/L (calculated by sodium selenite).
The fermentation culture conditions include: the temperature is 28 ℃, the pH value is 4.0, the ventilation is 0.5vvm, the culture time is 20 hours, and the dry weight of the yeast cells reaches 50-70g/L at the end of fermentation.
After fermentation, separating by a centrifuge, and washing for 2 times by using process water to finally obtain the yeast milk with 16.5% dry matter. Through detection, the total selenium content is 3115ppm, the selenomethionine content is 5336ppm, and the selenomethionine form selenium accounts for 68.9% of the total selenium;
comparative example 3
After the selenium-enriched yeast strain is cultured according to the secondary seed culture mode described in the embodiment 1, the selenium-enriched yeast strain is prepared according to the volume ratio of 1:200 ratio the medium-carrying broth was inoculated into the tannin fermentation medium. The culture medium comprises: the total mass of the fermentation body is 25 percent of the molasses after enzymolysis treatment, wherein the mass content of glucose and fructose accounts for 45 percent of the total sugar; ammonia water with the mass concentration of 16% accounting for 1.5% of the total mass of the fermentation body; diammonium phosphate with the total mass of 0.2% of the fermentation body; sodium selenite accounting for 0.03 percent of the total mass of the fermentation body; magnesium sulfate accounting for 0.05 percent of the total mass of the fermentation body; zinc sulfate accounting for 0.02 percent of the total mass of the fermentation body; food-grade tannins accounting for 5.5% of the total mass of the fermentation body; wherein, molasses after enzymolysis treatment is fed in the fermentation process, and the fed-in amount per hour is based on controlling the alcohol concentration in the fermentation liquid to be not more than 0.1 percent; sodium selenite is fed in the fermentation process, and the feeding amount per hour is 10mg/L (calculated by sodium selenite).
The fermentation culture conditions include: the temperature is 28 ℃, the pH value is 4.0, the ventilation is 0.5vvm, the culture time is 20 hours, and the dry weight of the yeast cells reaches 50-70g/L at the end of fermentation.
After fermentation, separating by a centrifuge, and washing for 2 times by using process water to finally obtain the yeast milk with 16.5% dry matter. Through detection, the total selenium content is 2580ppm, the selenomethionine content is 3980ppm, and the selenomethionine form selenium accounts for 62.18 percent of the total selenium
Comparative example 4
After the selenium-enriched yeast strain is cultured according to the secondary seed culture mode described in the embodiment 1, the selenium-enriched yeast strain is prepared according to the volume ratio of 1:200 ratio the medium-carrying broth was inoculated into the tannin fermentation medium. The culture medium comprises: the total mass of the fermentation body is 42 percent of the molasses after enzymolysis treatment, wherein the mass content of glucose and fructose accounts for 45 percent of the total sugar; ammonia water with the mass concentration of 16% accounting for 1.5% of the total mass of the fermentation body; diammonium phosphate with the total mass of 0.2% of the fermentation body; sodium selenite accounting for 0.03 percent of the total mass of the fermentation body; magnesium sulfate accounting for 0.05 percent of the total mass of the fermentation body; zinc sulfate accounting for 0.02 percent of the total mass of the fermentation body; food-grade tannins accounting for 5.5% of the total mass of the fermentation body; wherein, molasses after enzymolysis treatment is fed in the fermentation process, and the fed-in amount per hour is based on controlling the alcohol concentration in the fermentation liquid to be not more than 0.1 percent; sodium selenite is fed in the fermentation process, and the feeding amount per hour is 10mg/L (calculated by sodium selenite).
The fermentation culture conditions include: the temperature is 28 ℃, the pH value is 4.0, the ventilation is 0.5vvm, the culture time is 20 hours, and the dry weight of the yeast cells reaches 50-70g/L at the end of fermentation.
After fermentation, separating by a centrifuge, and washing for 2 times by using process water to finally obtain the yeast milk with 16.5% dry matter. Through detection, the total selenium content is 2890ppm, the selenomethionine content is 4229ppm, and the selenomethionine form selenium accounts for 58.98 percent of the total selenium
Analysis of the experimental results shows that: comparative example 1 compared with comparative example 2, the latter was fermented with enzymatically hydrolyzed cane molasses, which increased the total selenium content by 461ppm by 17.6% over the direct fermentation with cane molasses; the yield of selenomethionine is improved by 1272ppm, the improvement range is 31.3%, the selenium in the form of selenomethionine accounts for 6.3% of the total selenium, and the selenomethionine enrichment effect is obvious; compared with the example 1, the comparative example 1 uses the saccharose molasses and tannin after enzymolysis for fermentation, and compared with the single use of the saccharose molasses for fermentation, the proportion of selenium in total selenium, selenomethionine and selenomethionine in total selenium is greatly improved, wherein the total selenium content is 3075ppm, the selenomethionine content is 5483ppm, the proportion of selenium in selenomethionine in total selenium is more than 70%, and the selenomethionine enrichment effect is obvious; comparative example 2, which was added with tannin, has a total selenium content of 3298ppm and a selenomethionine content of 5669ppm, and has a greatly improved fermentation effect compared with that of the sugar cane molasses after only enzymolysis, as compared with example 2. Examples 3, 4 and 5 compared with examples 1 and 2, the molasses concentration in the culture medium is between 30 and 35%, the tannin addition amount is between 0.5 and 1.5%, the total selenium content is 3159ppm, 3058ppm and 3218ppm respectively, and the selenomethionine content is 5487ppm, 5328ppm and 5980ppm respectively. It is known that the selenium-enriched yeast is cultivated by using the culture medium added with the sucrose enzymatic hydrolysis molasses and the tannin, so that the accumulation of selenomethionine in the yeast cell is remarkably improved, and when the dosages of the sucrose enzymatic hydrolysis molasses and the tannin are in a preferred range, the yield is relatively higher and more stable.
The foregoing description is only a preferred embodiment of the present invention, and the present invention is not limited thereto, but it is to be understood that modifications and equivalents of some of the technical features described in the foregoing embodiments may be made by those skilled in the art, although the present invention has been described in detail with reference to the foregoing embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (16)
1. A method for promoting yeast to enrich selenomethionine is characterized in that cultured yeast seeds are transferred into a culture medium containing tannin for culturing, so that yeast with high L-selenomethionine content is obtained.
2. The method according to claim 1, wherein the mass of tannin in the medium is 0.1-5%, preferably 0.5-1.5%, further preferably 1-1.5% of the total mass of the fermentation broth.
3. The method of claim 1 or 2, the medium further comprising a carbon source, a nitrogen source, a phosphorus source, a sulfate, and a selenium source.
4. A method according to claims 1-3, wherein the carbon source in the medium comprises sucrose enzymatic molasses, the nitrogen source comprises ammonia, the phosphorus source comprises diammonium phosphate, the sulphate comprises magnesium sulphate and/or zinc sulphate, and the selenium source comprises selenite.
5. The method according to any one of claims 1 to 4, wherein the sucrose enzymolyzed molasses has a combined mass content of glucose and fructose of greater than 50%.
6. The method according to any one of claims 1 to 5, wherein the mass of molasses in the medium is 28-40%, preferably 30-35% of the total mass of the fermentation body.
7. The method of any one of claims 1-5, wherein the selenite is sodium selenite.
8. The method of any one of claims 1-7, further comprising zinc sulfate and magnesium sulfate in the medium.
9. The method according to any one of claims 1 to 8, wherein the molasses is added by feeding, and the feeding amount per hour is maintained so that the volume concentration of ethanol in the culture medium is less than 0.1%.
10. The method according to any one of claims 1 to 9, wherein the sodium selenite is added to the culture medium in a fed-batch manner, and the feeding rate is 10 to 60mg/L per hour based on the sodium selenite.
11. The process according to any one of claims 1 to 10, wherein the sodium selenite is fed as an aqueous solution having a concentration of 100-500g/L, preferably 200-300g/L.
12. The method according to any one of claims 1 to 11, wherein the amount of ammonia in the medium is 1.5 to 2.5% of the total mass of the fermentation body, based on 16% ammonia by mass; the dosage of diammonium phosphate is 0.2-0.5% of the total mass of the fermentation body, the dosage of sodium selenite is 0.03-0.08% of the total mass of the fermentation body, the dosage of magnesium sulfate is 0.05-0.1% of the total mass of the fermentation body, and the dosage of zinc sulfate is 0.02-0.04% of the total mass of the fermentation body.
13. The method of any one of claims 1-12, wherein the fermentation culture conditions further comprise: the ventilation amount is 0.5-1.5vvm in the culture process, and the temperature is controlled at 28-32 ℃ in the fermentation process; the pH of the medium is preferably set to 4.0 to 6.5, more preferably the incubation time is 20 to 24 hours.
14. The L-selenomethionine-enriched yeast prepared by the method of any one of claims 1 to 13, wherein the total selenium mass content is 3000ppm or more, preferably 3100ppm or more; the selenomethionine content is 5300ppm or more, preferably 5600ppm or more.
15. The application of tannin in selenium-enriched yeast culture medium is provided.
16. The application of tannin in promoting yeast to enrich selenomethionine is provided.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310020508.7A CN116024155A (en) | 2023-01-06 | 2023-01-06 | Method for promoting yeast to enrich selenomethionine and selenomethionine-enriched yeast |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310020508.7A CN116024155A (en) | 2023-01-06 | 2023-01-06 | Method for promoting yeast to enrich selenomethionine and selenomethionine-enriched yeast |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116024155A true CN116024155A (en) | 2023-04-28 |
Family
ID=86070289
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310020508.7A Pending CN116024155A (en) | 2023-01-06 | 2023-01-06 | Method for promoting yeast to enrich selenomethionine and selenomethionine-enriched yeast |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116024155A (en) |
-
2023
- 2023-01-06 CN CN202310020508.7A patent/CN116024155A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108220175B (en) | High-density culture method and pH regulation and control method for saccharomyces cerevisiae | |
| EP1478732B1 (en) | A selenium yeast product, a method of preparing a selenium yeast product and the use of the product for preparing food, a dietary supplement or a drug | |
| CN112760271B (en) | Process for producing clostridium butyricum through high-density fermentation under negative pressure condition and application | |
| WO2023098678A1 (en) | High-protein saccharomyces cerevisiae and application thereof | |
| CN104250659A (en) | L-lysine fermenting method | |
| CN114276942A (en) | Glutathione yeast, preparation method and application of glutathione yeast product | |
| CN111040982B (en) | Saccharomyces cerevisiae promoter and preparation method and application thereof | |
| CN106967606B (en) | Method for breaking cell wall of bivalent saccharomycete | |
| CN113475634A (en) | Pig feed containing 5-aminolevulinic acid, preparation method and application of pig feed to piglets | |
| CN109234334A (en) | A kind of method of fermenting and producing tremella polysaccharides and fermentation medium used | |
| CN109943511B (en) | Brevibacterium flavum capable of producing L-valine and application thereof | |
| CN113046253A (en) | Culture method for improving heat resistance of kluyveromyces marxianus | |
| WO2010096382A1 (en) | Processes for the production of proteins containing selenium using yeast cells | |
| CN116024155A (en) | Method for promoting yeast to enrich selenomethionine and selenomethionine-enriched yeast | |
| CN113025510B (en) | Function-enhanced yeast culture rich in organic trace elements and preparation method thereof | |
| JP2003116342A (en) | New method for producing vegetative wasp, the resultant vegetative wasp and its use | |
| CN111979171B (en) | Method for producing selenium-enriched yeast by using isomaltulose mother liquor and chlorella waste liquor | |
| CN110878325B (en) | Optimized glutamic acid fermentation medium | |
| CN110885865B (en) | Method for producing alpha-glutamic acid by fermentation | |
| CN107760611B (en) | Liquid fermentation process optimization method and process of selenium-rich boletus flavus | |
| CN111213792A (en) | Biological fermentation feed for improving piglet anemia and preparation method thereof | |
| KR100193748B1 (en) | Method for producing chlorella of high concentration by heterotrophic growth | |
| CN110016450B (en) | Brevibacterium flavum for producing L-proline and application thereof | |
| CN114686383B (en) | Chromium-enriched yeast with high chromium absorptivity, and preparation method and application thereof | |
| CN117625418A (en) | Selenium-zinc-enriched yeast product and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |