Method for rich production of organic selenium by pediococcus acidilactici

Abstract

The invention relates to the field of biological fermentation, in particular to a method for rich production of organic selenium by pediococcus acidilactici, which comprises the following steps: inoculating pediococcus acidilactici H87 into a lactic acid bacteria culture medium, and when the pediococcus acidilactici is cultured to a logarithmic phase, adding a solution containing inorganic selenium for fermentation culture; the concentration of the inorganic selenium in the culture medium does not exceed 10mu g / mL due to the addition amount of the solution containing the inorganic selenium; the pediococcus acidilactici H87 is preserved in the Guangdong Microbial Culture Collection Center (GDMCC), and the preservation number of the pediococcus acidilactici H87 is GDMCC No.64845. The pediococcus acidilactici H87 has the advantages that the pediococcus acidilactici H87 can be used for preparing the pediococcus According to the method, the organic selenium conversion rate of pediococcus acidilactici reaches up to 80%, and important reference value and significance are provided for industrial application of selenium-rich lactic acid bacteria.

Description

Technical Field

[0001] The invention relates to the technical field of biological fermentation, and in particular to a method for enriching organic selenium by using Pediococcus acidilactici. Background Art

[0002] With the rapid development of nutrition science today, selenium has received more and more attention in nutrition science, and research on selenium-rich foods and additives has gradually deepened at home and abroad. Inorganic selenium is highly toxic and difficult to absorb. Organic selenium is less toxic than inorganic selenium and is more conducive to human absorption. Therefore, supplementing organic selenium is a safe way to supplement selenium. So far, the organicization of selenium is one of the current research hotspots. The distribution of organic selenium on the earth is extremely uneven, and it is difficult to synthesize organic selenium artificially. Due to the complex process of extracting selenoproteins and the high price, it is difficult to directly ingest selenoproteins. The traditional method of synthesizing organic selenium is relatively complicated and difficult to achieve large-scale production.

[0003] Selenium-enriched lactic acid bacteria is a microorganism with significant advantages. Its characteristics lie not only in its positive impact on the intestinal health of the host as a probiotic, but also in its ability to enrich organic selenium, thereby achieving dual nutritional and health functions for the human body. As a probiotic, selenium-enriched lactic acid bacteria grow and reproduce in the host's intestines, produce nutrients such as amino acids and organic acids, and promote the host's digestion and nutrient absorption. The production of organic acids also helps to make elements such as calcium, iron, and phosphorus in an ionic state, thereby improving their absorption and utilization rate in the intestine. The role of this probiotic is of great significance for maintaining the balance of intestinal microecology, enhancing immune function, and improving the health of the digestive system. Secondly, the selenium in the selenium-enriched lactic acid bacteria is mainly in the form of selenoproteins. In addition, a small amount of selenium is combined with polysaccharides and transfer RNA. The form of selenium polysaccharides or selenium transfer RNA in the bacteria is present, and the enriched organic selenium has a high biological value. Therefore, selenium-enriched lactic acid bacteria can not only provide the health care function of probiotics, but also provide the human body with efficient organic selenium supplementation, and play a protective role of selenium on human health. The dual nutritional and health functions of selenium-rich lactic acid bacteria give it broad application prospects in the fields of medicine, health food and drugs.

[0004] China is a country with a relatively low overall selenium content, and selenium is essential for human health. The organic selenium contained in selenium-rich lactic acid bacteria exists in the form of selenoproteins, which have a higher bioavailability than inorganic selenium. Therefore, using selenium-rich lactic acid bacteria as the main source of organic selenium can more effectively supplement the selenium required by the human body, thereby maintaining human health. Summary of the invention

[0005] In order to overcome the problem of low utilization rate of selenium in the prior art, the present invention provides a method for enriching organic selenium by Pediococcus acidilactici. The method can efficiently convert inorganic selenium into organic selenium without producing elemental selenium, and the organic selenium conversion rate is high. The method is used for fermenting food, which not only promotes nutrient absorption, but also is more conducive to the production of selenium-enriched products.

[0006] In order to achieve the above object, the present invention provides a method for enriching organic selenium with Pediococcus acidilactici, the method comprising:

[0007] Inoculating Pediococcus acidilactici H87 into a lactic acid bacteria culture medium, and adding a solution containing inorganic selenium to carry out fermentation culture when the Pediococcus acidilactici reaches a logarithmic growth phase; the amount of the solution containing inorganic selenium added is such that the concentration of inorganic selenium in the culture medium does not exceed 10 μg / mL;

[0008] The Pediococcus acidilactici H87 is deposited in Guangdong Microbiological Culture Collection Center (GDMCC) with the deposit number of GDMCC No.64845.

[0009] Through the above technical scheme, the method of the present invention uses Pediococcus acidilactici H87 to efficiently convert inorganic selenium into organic selenium through biotransformation without producing elemental selenium, and the organic selenium conversion rate is high.

[0010] The inventors have found that selenium enrichment by lactic acid bacteria in selenium-containing culture medium is divided into two processes. One is that lactic acid bacteria converts inorganic selenium into organic selenium, which is a key conversion process in the selenium enrichment process. The other is that lactic acid bacteria also converts inorganic selenium into elemental selenium. When lactic acid bacteria produce elemental selenium, the assimilation ability of selenium-enriched lactic acid bacteria for inorganic selenium will be limited to a certain extent, which may lead to an increase in the selenium concentration in the cells. Further increase in the selenium concentration in the cells may lead to an enhanced ability of lactic acid bacteria to reduce sodium selenite to generate elemental selenium, which further leads to a decrease in the ability to convert organic selenium.

[0011] According to the method of the present invention, the amount of solution containing inorganic selenium added is such that the concentration of inorganic selenium in the culture medium does not exceed 10 μg / mL, and during the selenium enrichment process of Pediococcus acidilactici H87, only inorganic selenium is converted into organic selenium without generating elemental selenium.

[0012] By adopting the method of the present invention, the organic selenium conversion rate of Pediococcus acidilactici is as high as 80% without producing elemental selenium, which provides important reference value and significance for the industrial application of selenium-enriched lactic acid bacteria. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is the fitting curve diagram of the growth kinetic model of Pediococcus acidilactici H87;

[0014] Figure 2 This is the spectrophotometric standard curve of sodium selenite.

[0015] Biological Deposit

[0016] The Pediococcus acidilactici H87 strain of the present invention was deposited in the Guangdong Microbiological Culture Collection Center (address: 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou, Institute of Microbiology, Guangdong Academy of Sciences, Postal Code: 510070) on July 8, 2024 (the abbreviation of the depository unit is GDMCC), and the deposit number is GDMCC No. 64845. DETAILED DESCRIPTION

[0017] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0018] The present invention provides a method for enriching organic selenium by Pediococcus acidilactici, the method comprising:

[0019] Inoculating Pediococcus acidilactici H87 into a lactic acid bacteria culture medium, and adding a solution containing inorganic selenium to carry out fermentation culture when the Pediococcus acidilactici reaches a logarithmic growth phase; the amount of the solution containing inorganic selenium added is such that the concentration of inorganic selenium in the culture medium does not exceed 10 μg / mL;

[0020] The Pediococcus acidilactici H87 is deposited in the Guangdong Microbial Culture Collection Center (GDMCC) with a deposit number of GDMCC No. 64845. The method of the present invention can effectively improve the organic selenium conversion rate of Pediococcus acidilactici H87 without producing elemental selenium. In the present invention, the amount of the solution containing inorganic selenium added is such that the concentration of inorganic selenium in the culture medium does not exceed 10 μg / mL, and Pediococcus acidilactici does not convert inorganic selenium into elemental selenium, but converts all of it into organic selenium, thereby achieving an increase in the organic selenium conversion rate.

[0021] In the present invention, there is no particular limitation on the type of the lactic acid bacteria culture medium. All culture media used for culturing lactic acid bacteria in the art can be used in the present invention, such as MRS culture medium. According to a preferred embodiment of the present invention, the lactic acid bacteria culture medium contains the following components: N source, C source, dipotassium hydrogen phosphate (providing K ions), diammonium hydrogen citrate (providing ammonium ions), magnesium sulfate (providing magnesium ions), 4g yeast powder, 1mL Tween 80, 5g sodium acetate, 0.05g manganese sulfate, 15g agar powder, 1000mL distilled water, and the corrected pH is 6.2.

[0022] In the present invention, the culture medium contains inorganic salt ions. According to a preferred embodiment of the present invention, the inorganic salt ions are selected from Mg 2+ , K + and NH4 + One or more of .

[0023] In the present invention, Mg in the culture medium 2+ The concentration range is relatively wide. According to a preferred embodiment of the present invention, the Mg content in the culture medium is 2+ The concentration is 1.1-1.4 mmol / L. Within the above range, the organic selenium conversion rate can be effectively improved.

[0024] In the present invention, K in the culture medium + The concentration range is relatively wide. According to a preferred embodiment of the present invention, K in the culture medium is + The concentration is 0.80-0.95 mmol / L. Within the above range, the organic selenium conversion rate can be effectively improved.

[0025] In the present invention, NH4 + The concentration range is relatively wide. According to a preferred embodiment of the present invention, the NH4 + The concentration is 0.35-0.55 mmol / L. Within the above range, the organic selenium conversion rate can be effectively improved.

[0026] According to a preferred embodiment of the present invention, Mg in the culture medium 2+ The concentration is 1.1-1.4mmol / L, K + The concentration is 0.80-0.95mmol / L, NH4 + The concentration is 0.35-0.55mmol / L; within the above range, the inorganic salt ions in the culture medium reach the optimal ratio, which can effectively improve the conversion rate of organic selenium.

[0027] In the present invention, the C source in the culture medium has a wide range of options, for example, it can be sucrose, maltose, glucose or lactose. According to a preferred embodiment of the present invention, the culture medium uses glucose as the C source. More preferably, the concentration of glucose in the culture medium is 20-24 g / L. Within the aforementioned range, the organic selenium conversion rate can be effectively improved.

[0028] In the present invention, the C source in the culture medium can be selected from a wide range, for example, it can be soy protein, trypsin, peptone or beef extract. According to a preferred embodiment of the present invention, the culture medium uses beef extract as the N source. More preferably, the concentration of beef extract in the culture medium is 16-20 g / L. Within the aforementioned range, the organic selenium conversion rate can be effectively improved.

[0029] In the present invention, the method for establishing the growth kinetic curve of the H87 strain of Pediococcus acidilactici comprises: injecting the H87 strain that has been activated for two generations into 100 mL of MRS medium at a 2% inoculation amount and continuing to culture. 600 The values ​​were measured every 1 hour; three parallels were set in each group, and the growth curve of the strain was drawn with time as the horizontal axis and the absorbance value as the vertical axis to obtain the growth kinetics curve of the lactic acid Pediococcus H87 strain, as shown in the figure. Figure 1 As shown, 0-2h is the slow growth period of the bacteria, and after 3h the bacteria enters the logarithmic growth period, which is 3-11h; the time to enter the stable period is 11h, and the bacteria enter the decay period after 37h.

[0030] In the present invention, the solution containing inorganic selenium is added when the Pediococcus acidilactici is cultured to the logarithmic growth phase. According to the growth kinetics curve of the Pediococcus acidilactici H87 strain, the logarithmic growth phase of the Pediococcus acidilactici is 3-11 hours after the culture. According to a preferred embodiment of the present invention, the solution containing inorganic selenium is added when the Pediococcus acidilactici enters the logarithmic growth phase, which can improve the conversion rate of organic selenium. Preferably, the solution containing inorganic selenium is added when the Pediococcus acidilactici enters the early logarithmic growth phase, that is, the solution containing inorganic selenium is added when the culture time of the Pediococcus acidilactici in the culture medium is 3-4 hours.

[0031] In the present invention, the source of inorganic selenium can be selected from a wide range, which is exemplary but does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the inorganic selenium is selected from sodium selenite and / or sodium selenate.

[0032] In the present invention, the inoculation amount of Pediococcus acidilactici can be selected in a wide range. According to a preferred embodiment of the present invention, the inoculation amount of Pediococcus acidilactici is 3.5-4.5% of the volume content of the culture medium. More preferably, the concentration of live bacteria in the culture medium after inoculation is 10 7 -10 8 cfu / mL; within the above range, the organic selenium conversion rate can be effectively improved.

[0033] In the present invention, the amount of solution containing inorganic selenium added is such that the concentration of inorganic selenium in the culture medium does not exceed 10 μg / mL, and Pediococcus acidilactici does not convert inorganic selenium into elemental selenium, but converts it all into organic selenium, thereby improving the conversion rate of organic selenium, for example, 1 μg / mL, 2 μg / mL, 3 μg / mL, 4 μg / mL, 5 μg / mL, 6 μg / mL, 7 μg / mL, 8 μg / mL, 9 μg / mL, 10 μg / mL; according to a preferred embodiment of the present invention, the solution containing inorganic selenium is added so that the concentration of inorganic selenium in the culture medium is 5-10 μg / mL.

[0034] According to a preferred embodiment of the present invention, Pediococcus acidilactici H87 is inoculated into the culture medium so that the concentration of live bacteria is 10 7 -10 8 cfu / mL, when the culture time of Pediococcus acidilactici H87 in the culture medium is 3-4h, a solution containing inorganic selenium is added to make the concentration of inorganic selenium in the culture medium reach 5-10 μg / mL.

[0035] In the method of the present invention, after Pediococcus acidilactici H87 is inoculated into a lactic acid bacteria culture medium, organic selenium can be produced for a long time, the organic selenium conversion rate is greatly improved when the fermentation culture time is 36 hours, and the high organic selenium conversion rate can still be maintained when the fermentation culture time is 60 hours.

[0036] In the present invention, when adding the solution containing inorganic selenium, a selenium-enriched auxiliary agent is simultaneously added so that the concentration of the selenium-enriched auxiliary agent in the culture medium is 2-5 μg / mL; the organic selenium conversion rate of Pediococcus acidilactici H87 can be effectively improved.

[0037] According to a preferred embodiment of the present invention, the selenium-enriched auxiliary agent is selected from one or more of sodium dodecyl sulfonate, sodium cyclamate and glycine.

[0038] According to a more preferred embodiment of the present invention, the selenium-rich auxiliary agent is selected from glycine and sodium dodecyl sulfonate and / or sodium cyclohexylaminosulfonate; more preferably, the content of glycine is not less than 40wt% of the total mass of the selenium-rich auxiliary agent, and not more than 80wt%; the use of the selenium-rich auxiliary agent in the aforementioned range can effectively improve the organic selenium conversion rate of Pediococcus acidilactici H87.

[0039] In the present invention, the standard curve of selenium is drawn: 1 mL of Se mother solution is added to 99 mL of ultrapure water, and then 0 mL, 2 mL, 4 mL, 6 mL, 8 mL, and 10 mL are taken from the 1 μg / mL standard solution in a separatory funnel, and water is added to each sample until the total volume is 35 mL. The remaining steps are the same as the 3-3 diaminobenzidine colorimetric method. Three parallels are taken for each group, and the average value is taken. The standard curve is drawn with the concentration as the horizontal axis and the absorbance value as the vertical axis, and the following is obtained: Figure 2The spectrophotometric standard curve of sodium selenite shown in the figure shows that the concentration of sodium selenite has a good correlation with the absorbance value.

[0040] In the context and embodiments of the present invention, the inorganic selenium content is determined by 3-3 diaminobenzidine colorimetry: sodium selenite can react with 3-3' diaminobenzidine under acidic or alkaline conditions to form a yellow complex, which can be extracted with toluene. This property enables spectrophotometry to be used to analyze the degree of color development in organic solvents, thereby determining the selenium content in the solvent, specifically: 1 mL of sample is added to a separatory funnel, and then the total volume is adjusted to 35 mL with ultrapure water. 1 mL of 5% EDTA-2Na solution is added to the sample, and the pH value is adjusted to 2-3 with 1 mol / L hydrochloric acid, 4 mL of 0.5% 3,3-diaminobenzidine solution is added, and the pH value is adjusted to neutral with 1 mol / L NaOH after being placed in a dark place for reaction for 10 minutes, followed by adding 10 mL of toluene and shaking for 1 minute. The sample is allowed to stand for 30 minutes to separate into layers. The sample was centrifuged using a high-speed centrifuge (5000 r / min, 10 min), and the toluene layer was taken out. The absorbance of the toluene layer was measured at a wavelength of 420 nm using a visible light spectrophotometer.

[0041] In the context and examples of the present invention, organic selenium conversion rate = (amount of selenium added to the culture medium - residual inorganic selenium content in the supernatant) / amount of selenium added to the culture medium × 100%.

[0042] In the context and embodiments of the present invention, the method for determining the dry weight of the bacterial cells is as follows: 100 mL of bacterial solution is centrifuged at 6000 r / min for 8 min, the precipitate is fully washed with 30 mL of ultrapure water, and then centrifuged at 6000 r / min for 10 min, and the washing is repeated three times. Finally, the centrifuge is centrifuged at 8000 r / min for 10 min, and the precipitate is dried at 65°C after the centrifugation until the weight no longer changes. Three parallels are performed in each group, and the results are averaged.

[0043] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0044] In the following examples, the culture medium contained the following ingredients: a N source, a C source, 4 g yeast powder, dipotassium hydrogen phosphate (providing potassium ions), diammonium hydrogen citrate (providing ammonium ions), magnesium sulfate (providing magnesium ions), 1 mL Tween 80, 5 g sodium acetate, 0.05 g manganese sulfate, 15 g agar powder, 1000 mL distilled water, and the pH was corrected to 6.2.

[0045] Example 1

[0046] The lactic acid Pediococcus H87 was inoculated in MRS medium at a rate of 3.9%. After inoculation, the live bacterial concentration of lactic acid Pediococcus H87 in the medium was 1*10 8 cfu / mL; in the culture medium, the carbon source was glucose, the nitrogen source was beef extract, the concentration of glucose was 20g / L, the concentration of beef extract was 16g / L, and Mg 2+ The concentration is 1.25mmol / L, K + The concentration is 0.85mmol / L, NH4 + The concentration was 0.45mmol / L, and after 3.4h of culture, sodium selenite solution was added so that the concentration of sodium selenite in the culture medium was 10μg / mL;

[0047] After culturing for 37 hours, the conversion rate of organic selenium was calculated, and the results showed that the conversion rate of organic selenium was 82.61%.

[0048] Example 2

[0049] The lactic acid Pediococcus H87 was inoculated in MRS medium at a rate of 3.5%. After inoculation, the live bacterial concentration of lactic acid Pediococcus H87 in the medium was 5*10 7 cfu / mL; in the culture medium, the carbon source is glucose, the nitrogen source is beef extract, the concentration of glucose is 22g / L, the concentration of beef extract is 18g / L, and the Mg 2+ The concentration is 1.4mmol / L, K + The concentration is 0.8mmol / L, NH4 + The concentration was 0.4 mmol / L, and after 3.5 h of culture, sodium selenite solution was added to make the concentration of sodium selenite in the culture medium 5 μg / mL;

[0050] After culturing for 36 hours, the conversion rate of organic selenium was calculated, and the results showed that the conversion rate of organic selenium was 83.09%.

[0051] Example 3

[0052] The lactic acid Pediococcus H87 was inoculated in MRS medium at a 4.5% inoculum. After inoculation, the live bacterial concentration of lactic acid Pediococcus H87 in the medium was 6*10 8 cfu / mL; in the culture medium, the carbon source is glucose, the nitrogen source is beef extract, the concentration of glucose is 24g / L, the concentration of beef extract is 20g / L, and Mg 2+ The concentration is 1.1mmol / L, K + The concentration is 0.95mmol / L, NH4 + The concentration was 0.55mmol / L, and after 4.5h of culture, sodium selenite solution was added to make the concentration of sodium selenite in the culture medium 8μg / mL;

[0053] After 60 hours of cultivation, the conversion rate of organic selenium was calculated, and the results showed that the conversion rate of organic selenium was 82.13%.

[0054] Example 4

[0055] The lactic acid Pediococcus H87 was inoculated in MRS medium at a rate of 3.9%. After inoculation, the live bacterial concentration of lactic acid Pediococcus H87 in the medium was 1*10 8 cfu / mL; in the culture medium, the carbon source is maltose, the nitrogen source is beef extract, the concentration of maltose is 28g / L, the concentration of beef extract is 16g / L, and Mg 2+ The concentration is 1.25mmol / L, K + The concentration is 0.85mmol / L, NH4 + The concentration was 0.45mmol / L, and after 3.4h of culture, sodium selenite solution was added so that the concentration of sodium selenite in the culture medium was 10μg / mL;

[0056] After 37 hours of cultivation, the conversion rate of organic selenium was calculated. The results showed that the conversion rate of organic selenium was 72.34%.

[0057] Example 5

[0058] The lactic acid Pediococcus H87 was inoculated in MRS medium at a rate of 3.9%. After inoculation, the live bacterial concentration of lactic acid Pediococcus H87 in the medium was 1*10 8 cfu / mL; in the culture medium, the carbon source was glucose, the nitrogen source was peptone, the concentration of glucose was 20g / L, the concentration of peptone was 23g / L, and the Mg 2+ The concentration is 1.25mmol / L, K + The concentration is 0.85mmol / L, NH4 + The concentration was 0.45mmol / L, and after 3.4h of culture, sodium selenite solution was added so that the concentration of sodium selenite in the culture medium was 10μg / mL;

[0059] After 37 hours of cultivation, the conversion rate of organic selenium was calculated. The results showed that the conversion rate of organic selenium was 73.05%.

[0060] Example 6

[0061] The lactic acid Pediococcus H87 was inoculated in MRS medium at a rate of 3.9%. After inoculation, the live bacterial concentration of lactic acid Pediococcus H87 in the medium was 1*10 8 cfu / mL; in the culture medium, the carbon source was glucose, the nitrogen source was beef extract, the concentration of glucose was 20g / L, the concentration of beef extract was 16g / L, and Mg 2+ The concentration is 1.5mmol / L, K + The concentration is 0.85mmol / L, NH4+ The concentration was 0.45mmol / L, and after 3.4h of culture, sodium selenite solution was added so that the concentration of sodium selenite in the culture medium was 10μg / mL;

[0062] After culturing for 37 hours, the conversion rate of organic selenium was calculated. The results showed that the conversion rate of organic selenium was 76.09%.

[0063] Example 7

[0064] The lactic acid Pediococcus H87 was inoculated in MRS medium at a rate of 3.9%. After inoculation, the live bacterial concentration of lactic acid Pediococcus H87 in the medium was 1*10 8 cfu / mL; in the culture medium, the carbon source was glucose, the nitrogen source was beef extract, the concentration of glucose was 20g / L, the concentration of beef extract was 16g / L, and Mg 2+ The concentration is 1.25mmol / L, K + The concentration is 1.15mmol / L, NH4 + The concentration was 0.45mmol / L, and after 3.4h of culture, sodium selenite solution was added so that the concentration of sodium selenite in the culture medium was 10μg / mL;

[0065] After 37 hours of cultivation, the conversion rate of organic selenium was calculated. The results showed that the conversion rate of organic selenium was 75.57%.

[0066] Example 8

[0067] The lactic acid Pediococcus H87 was inoculated into the MRS medium at a 5% inoculation rate. After inoculation, the live bacterial concentration of lactic acid Pediococcus H87 in the medium was 1*10 9 cfu / mL; in the culture medium, the carbon source was glucose, the nitrogen source was beef extract, the concentration of glucose was 20g / L, the concentration of beef extract was 16g / L, and Mg 2+ The concentration is 1.25mmol / L, K + The concentration is 0.85mmol / L, NH4 + The concentration was 0.45mmol / L, and after 3.4h of culture, sodium selenite solution was added so that the concentration of sodium selenite in the culture medium was 10μg / mL;

[0068] After culturing for 37 hours, the conversion rate of organic selenium was calculated. The results showed that the conversion rate of organic selenium was 74.25%.

[0069] Example 9

[0070] The lactic acid Pediococcus H87 was inoculated in MRS medium at a rate of 3.9%. After inoculation, the live bacterial concentration of lactic acid Pediococcus H87 in the medium was 1*10 8cfu / mL; in the culture medium, the carbon source was glucose, the nitrogen source was beef extract, the concentration of glucose was 20g / L, the concentration of beef extract was 16g / L, and Mg 2+ The concentration is 1.25mmol / L, K + The concentration is 0.85mmol / L, NH4 + The concentration was 0.45mmol / L, and after 5h of culture, sodium selenite solution was added to make the concentration of sodium selenite in the culture medium 10μg / mL;

[0071] After 37 hours of cultivation, the conversion rate of organic selenium was calculated. The results showed that the conversion rate of organic selenium was 75.74%.

[0072] Example 10

[0073] The lactic acid Pediococcus H87 was inoculated in MRS medium at a rate of 3.9%. After inoculation, the live bacterial concentration of lactic acid Pediococcus H87 in the medium was 1*10 8 cfu / mL; in the culture medium, the carbon source was glucose, the nitrogen source was beef extract, the concentration of glucose was 20g / L, the concentration of beef extract was 16g / L, and Mg 2+ The concentration is 1.25mmol / L, K + The concentration is 0.85mmol / L, NH4 + The concentration is 0.45mmol / L. After culturing for 3.4 hours, a sodium selenite solution is added to make the concentration of sodium selenite in the culture medium 10μg / mL; at the same time, a 5μg / mL mixed solution of glycine and sodium dodecyl sulfate is added, wherein the glycine content is 75wt% and the sodium dodecyl sulfate content is 25wt%;

[0074] After 37 hours of cultivation, the conversion rate of organic selenium was calculated. The results showed that the conversion rate of organic selenium was 84.46%.

[0075] Embodiment 11

[0076] The lactic acid Pediococcus H87 was inoculated in MRS medium at a rate of 3.9%. After inoculation, the live bacterial concentration of lactic acid Pediococcus H87 in the medium was 1*10 8 cfu / mL; in the culture medium, the carbon source was glucose, the nitrogen source was beef extract, the concentration of glucose was 20g / L, the concentration of beef extract was 16g / L, and Mg 2+ The concentration is 1.25mmol / L, K + The concentration is 0.85mmol / L, NH4 +The concentration is 0.45mmol / L. After culturing for 3.4 hours, a sodium selenite solution is added to make the concentration of sodium selenite in the culture medium 10μg / mL; at the same time, a 2μg / mL mixed solution of glycine and sodium dodecyl sulfate is added, wherein the content of glycine is 50wt% and the content of sodium dodecyl sulfate is 50wt%;

[0077] After 37 hours of cultivation, the conversion rate of organic selenium was calculated. The results showed that the conversion rate of organic selenium was 84.10%.

[0078] Example 12

[0079] The lactic acid Pediococcus H87 was inoculated into the MRS medium at a 5% inoculation rate. After inoculation, the live bacterial concentration of lactic acid Pediococcus H87 in the medium was 1*10 9 cfu / mL; in the culture medium, the carbon source was glucose, the nitrogen source was beef extract, the concentration of glucose was 20g / L, the concentration of beef extract was 16g / L, and Mg 2+ The concentration is 1.25mmol / L, K + The concentration is 0.85mmol / L, NH4 + The concentration was 0.45mmol / L, and sodium selenite solution was added after 11h of culture so that the concentration of sodium selenite in the culture medium was 9μg / mL;

[0080] After 37 hours of cultivation, the conversion rate of organic selenium was calculated. The results showed that the conversion rate of organic selenium was 71.92%.

[0081] Comparative Example 1

[0082] The lactic acid Pediococcus H87 was inoculated in MRS medium at a rate of 3.9%. After inoculation, the live bacterial concentration of lactic acid Pediococcus H87 in the medium was 1*10 8 cfu / mL; in the culture medium, the carbon source was glucose, the nitrogen source was beef extract, the concentration of glucose was 20g / L, the concentration of beef extract was 16g / L, and Mg 2+ The concentration is 1.25mmol / L, K + The concentration is 0.85mmol / L, NH4 + The concentration was 0.45 mmol / L, and after 3.4 h of culture, sodium selenite solution was added so that the concentration of sodium selenite in the culture medium was 11 μg / mL;

[0083] After culturing for 37 hours, the conversion rate of organic selenium was calculated. The results showed that the conversion rate of organic selenium was 80.33%.

[0084] The results showed that although Pediococcus acidilactici H87 maintained a high conversion rate of organic selenium, the bacteria appeared red, and the bacterial precipitate appeared brick red after centrifugation, indicating that elemental selenium was generated.

[0085] Comparative Example 2

[0086] The lactic acid Pediococcus H87 was inoculated into the MRS medium at a 5% inoculation rate. After inoculation, the live bacterial concentration of lactic acid Pediococcus H87 in the medium was 1*10 9 cfu / mL; in the culture medium, the carbon source was glucose, the nitrogen source was beef extract, the concentration of glucose was 20g / L, the concentration of beef extract was 16g / L, and Mg 2+ The concentration is 1.25mmol / L, K + The concentration is 0.85mmol / L, NH4 + The concentration was 0.45mmol / L, and after 11h of culture, sodium selenite solution was added to make the concentration of sodium selenite in the culture medium 11μg / mL;

[0087] After 37 hours of cultivation, the conversion rate of organic selenium was calculated. The results showed that the conversion rate of organic selenium was 68.31%.

[0088] The results showed that the bacteria of Pediococcus acidilactici H87 appeared red, and the bacterial precipitate appeared brick red after centrifugation, indicating that elemental selenium was produced.

[0089] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for enriching organic selenium by Pediococcus acidilactici, characterized in that: The method includes: Inoculating Pediococcus acidilactici H87 into a lactic acid bacteria culture medium, and adding a solution containing inorganic selenium to carry out fermentation culture when the Pediococcus acidilactici reaches a logarithmic growth phase; the amount of the solution containing inorganic selenium added is such that the concentration of inorganic selenium in the culture medium does not exceed 10 μg / mL; The Pediococcus acidilactici H87 is deposited in Guangdong Microbiological Culture Collection Center (GDMCC) with the deposit number of GDMCC No.64845.

2. The method according to claim 1, wherein: The culture medium contains inorganic salt ions, and the inorganic salt ions are selected from Mg 2+ , K + and NH4 + One or more of; Preferably, The Mg content of the culture medium 2+ Concentration of 1.1-1.4mmol / L; and / or The K + Concentration of 0.80-0.95mmol / L; and / or NH4 + The concentration is 0.35-0.55mmol / L.

3. The method according to claim 1 or 2, wherein: The culture medium uses glucose as a C source; preferably, the concentration of glucose is 20-24 g / L; and / or The culture medium uses beef extract as the N source; preferably, the concentration of beef extract is 16-20 g / L.

4. The method according to claim 1 or 2, wherein: When the culture time of Pediococcus acidilactici H87 in the lactic acid bacteria culture medium is 3-4 hours, a solution containing inorganic selenium is added.

5. The method according to claim 1 or 2, wherein: The inorganic selenium is selected from sodium selenite and / or sodium selenate.

6. The method according to claim 1 or 2, wherein: The inoculum amount of Pediococcus acidilactici H87 is 3.5-4.5% of the volume content of the culture medium; Preferably, the viable bacteria concentration in the culture medium after inoculation is 10 7 -10 8 cfu / mL.

7. The method according to claim 1 or 2, wherein: The solution containing inorganic selenium is added so that the concentration of inorganic selenium in the culture medium is 5-10 μg / mL.

8. The method according to claim 1 or 2, wherein: Pediococcus acidilactici H87 was inoculated into the culture medium so that the concentration of live bacteria in the culture medium was 10 7 -10 8 cfu / mL, and after culturing for 3-4 hours, a solution containing inorganic selenium was added to make the concentration of inorganic selenium in the culture medium reach 5-10 μg / mL.

9. The method according to claim 1 or 2, wherein: When adding the solution containing inorganic selenium, a selenium-enriched auxiliary is added at the same time so that the concentration of the selenium-enriched auxiliary in the culture medium is 2-5 μg / mL; Preferably, the selenium-enriched auxiliary agent is selected from one or more of sodium dodecyl sulfonate, sodium cyclamate and glycine.

10. The method according to claim 9, wherein: The selenium-enriched auxiliary agent is selected from glycine and sodium dodecyl sulfonate and / or sodium cyclamate; Preferably, the content of glycine is not less than 40wt% and not more than 80wt% of the total mass of the selenium-enriched auxiliary agent.

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