Fermentation culture medium for improving fermentation production of monensin from streptomyces cinnamomi and application of fermentation culture medium

Abstract

The invention belongs to the technical field of biological fermentation, and particularly relates to a fermentation culture medium for improving fermentation production of monensin by streptomyces cinnamomi and application of the fermentation culture medium. The fermentation medium comprises a carbon source, a nitrogen source, inorganic salt, growth factors, vegetable oil and water, the nitrogen source comprises glutamic acid and cysteine, and the growth factors comprise nicotinamide, choline chloride and biotin; based on the weight volume percent concentration of the fermentation culture medium, the content of glutamic acid is 0.05 to 0.07 percent, the content of cysteine is 0.07 to 0.09 percent, the content of nicotinamide is 0.007 to 0.009 percent, the content of choline chloride is 0.002 to 0.005 percent, and the content of biotin is 0.003 to 0.005 percent. The fermentation culture medium provided by the invention obviously improves the yield of monensin in a shake flask fermentation stage, and can be applied to industrial production of monensin.

Description

Technical Field

[0001] The present invention belongs to the technical field of biological fermentation, and particularly relates to a fermentation medium for improving the fermentation production of monensin by Streptomyces cinnamonensis and its application. Background Art

[0002] Monensin is an antibiotic produced by Streptomyces cinnamonensis. It has broad-spectrum anti-coccidial activity and is used for the prevention and treatment of chicken coccidiosis and the growth promotion of beef cattle. It has no effect on Gram-negative bacteria, but has a certain inhibitory effect on staphylococci, bacilli, clostridia, streptococci, and molds (Penicillium, Candida).

[0003] Biological fermentation is the main production method of monensin. At present, related research focuses on the selection and breeding of biological strains and the optimization of fermentation processes at the fermenter level, and relatively less research has been carried out at the shake-flask fermentation level. CN117265035A discloses a method for improving the titer of monensin fermentation broth and the content of monensin A. Monensin is fermented and produced by Streptomyces cinnamonensis, and a combined fatty acid is added to the basic fermentation medium. The combined fatty acid is composed of 1-2 parts of oleic acid, 2-3 parts of linoleic acid, 0.2-0.4 parts of stearic acid, and 0.4-0.6 parts of palmitic acid, so that the titer of monensin reaches 15034 μg / mL after 12 days of fermentation in the shake-flask system. Li Ziyong, Li Yunfei, Zeng Xiaoning, etc. Breeding of high-yield monensin strains [J]. China Animal Health, 2021, 23(05): 116-117+119 discloses that the fermentation medium contains 3.5% soybean cake powder, 3.5% oral glucose, 2.0% soybean oil, 0.2% ammonium sulfate, 0.03% zinc chloride, 0.007% magnesium sulfate, 0.005% ferrous sulfate, 0.0002% VC, 0.005% dipotassium hydrogen phosphate, and 0.25% calcium carbonate, and the average relative titer in the shake flask is 27693 μg / mL. Shake-flask fermentation is an important part of monensin fermentation research and can lay a foundation for the scale-up and optimization at the fermenter level in the later stage. For the technologies reported above, the yields in the shake-flask fermentation stage are all relatively low, and it is necessary to study a more efficient shake-flask fermentation medium. Summary of the Invention

[0004] In view of the technical problem that the titers of existing monensin shake-flask fermentations are all relatively low, the present invention significantly improves the monensin shake-flask fermentation unit by adding growth factors and amino acids with specific compositions to the monensin basic fermentation medium, thereby obtaining the present invention.

[0005] In a first aspect, the present invention provides a fermentation medium for improving the fermentation production of monensin by Streptomyces cinnamonensis, which comprises a carbon source, a nitrogen source, inorganic salts, growth factors, vegetable oil and water; the nitrogen source comprises glutamic acid and cysteine, and the growth factors comprise nicotinamide, choline chloride and biotin; calculated by the weight - volume percentage concentration of the fermentation medium, the content of glutamic acid is 0.05 - 0.07%, the content of cysteine is 0.07 - 0.09%, the content of nicotinamide is 0.007 - 0.009%, the content of choline chloride is 0.002 - 0.005%, and the content of biotin is 0.003 - 0.005%.

[0006] In some embodiments, the carbon source is one or a combination of two or more of glucose, maltose, sucrose, fructose, mannitol, lactose, starch, dextrin, soluble starch, and the content of the carbon source is 2 - 6%; the nitrogen source further comprises one or a combination of two or more of soybean meal powder, casein, cottonseed meal, corn steep liquor, yeast extract, fish meal, and the content of the nitrogen source is 2 - 6%; the inorganic salts are one or a combination of two or more of sodium sulfate, sodium nitrate, manganese chloride, aluminum sulfate, ferrous sulfate, dipotassium hydrogen phosphate, calcium carbonate, sodium chloride, magnesium chloride, magnesium sulfate, potassium dihydrogen phosphate, and the content of the inorganic salts is 0.3 - 2%; the growth factors further comprise L - ascorbic acid, and the content of L - ascorbic acid is 0.001 - 0.003%; the vegetable oil is any one or a combination of two or more of soybean oil, corn oil, peanut oil, cottonseed oil, linseed oil, sunflower oil, coconut oil, and the content of the vegetable oil is 1 - 3%.

[0007] In some embodiments, the carbon source is glucose and maltose, the nitrogen source is soybean meal powder, casein, glutamic acid and cysteine, the inorganic salts are sodium sulfate, sodium nitrate, manganese chloride, aluminum sulfate, ferrous sulfate, dipotassium hydrogen phosphate and calcium carbonate, the growth factors are nicotinamide, choline chloride, biotin and L - ascorbic acid, and the vegetable oil is soybean oil.

[0008] In some embodiments, the fermentation medium comprises the following components in weight - volume percentage concentration: glucose 1 - 3%, maltose 1 - 3%, soybean meal powder 2 - 4%, casein 0.5 - 2%, glutamic acid 0.05 - 0.07%, cysteine 0.07 - 0.09%, sodium sulfate 0.1 - 0.5%, sodium nitrate 0.1 - 0.5%, manganese chloride 0.01 - 0.05%, aluminum sulfate 0.02 - 0.2%, ferrous sulfate 0.005 - 0.02%, dipotassium hydrogen phosphate 0.005 - 0.02%, calcium carbonate 0.1 - 0.5%, nicotinamide 0.007 - 0.009%, choline chloride 0.002 - 0.005%, biotin 0.003 - 0.005%, L - ascorbic acid 0.001 - 0.003%, soybean oil 1 - 3%, and the balance is water.

[0009] In some embodiments, the pH of the fermentation medium is 6.8 ± 0.2.

[0010] In a second aspect, the present invention provides a method for fermentatively producing monensin using Streptomyces cinnamonensis, comprising: inoculating a fermentation seed liquid of Streptomyces cinnamonensis into the aforementioned fermentation medium for shake flask culture to obtain a fermentation liquid containing monensin.

[0011] In some embodiments, the temperature of the shake flask culture is 32 ± 1 °C, the time of the shake flask culture is 8 - 12 d, and the shaking speed of the shake flask culture is 220 - 250 rpm.

[0012] In some embodiments, the fermentation seed liquid of Streptomyces cinnamonensis is prepared as follows: inoculating Streptomyces cinnamonensis into a slant medium for a first culture to obtain an activated strain; and inoculating the activated strain into a seed medium for a second culture to obtain the fermentation seed liquid of Streptomyces cinnamonensis; the slant medium consists of components with the following weight - volume percentage concentrations: potassium nitrate 0.05 - 0.15%, sodium chloride 0.025 - 0.075%, dipotassium hydrogen phosphate 0.025 - 0.075%, yeast powder 0.1 - 0.3%, magnesium sulfate 0.025 - 0.075%, ferrous sulfate 0.0005 - 0.0015%, soluble starch 1 - 3%, agar powder 1 - 3%, with the balance being water, and the pH being 6.8 ± 0.2; the seed medium consists of components with the following weight - volume percentage concentrations: glucose 0.25 - 0.75%, soybean meal powder 1 - 2%, yeast powder 0.2 - 0.3%, corn dextrin 1 - 3%, calcium carbonate 0.05 - 0.15%, with the balance being water, and the pH being 6.8 ± 0.2.

[0013] In some embodiments, the conditions for the first culture are: the culture temperature is 32 ± 0.2 °C, and the culture time is 5 - 7 days; the conditions for the second culture are: the culture temperature is 32 ± 0.2 °C, the shaking speed is 220 - 250 rpm, and the culture time is 20 - 22 h.

[0014] The beneficial effects of the present invention are as follows:

[0015] The fermentation medium provided by the present invention specifically adds growth factors and amino acids with defined compositions to the basal medium. The amino acids provide a nitrogen source and precursors for monensin biosynthesis for the fermentation, and the growth factors greatly promote the synthesis of monensin - biosynthetic enzymes. Through their synergistic effect, the yield in the shake flask fermentation stage is significantly increased, and it can be applied to the industrial production of monensin. Detailed embodiments

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following clearly and completely describes the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0017] 1. Instruments and Reagents

[0018] 1.1 Strain: Streptomyces cinnamonensis BIOK-Mn-040203 was provided by the Technology Center of Zhejiang Biok Biotechnology Co., Ltd.

[0019] 1.2 Instruments

[0020] Instruments Model Manufacturer UV Spectrophotometer SP-752 Shanghai Spectrum Instruments Co., Ltd. Electronic Balance JA2003 Shanghai Tianping Instrument Factory Constant Temperature Incubator 2020 Shanghai Zhicheng Analytical Instrument Co., Ltd. High-Speed Centrifuge <![CDATA[AccuSpinFR M > BACKMAN Laminar Flow Hood TH-CB-103A Wuxi Purification Equipment Factory Shaker ZHWY-1112B Shanghai Zhicheng Analytical Instrument Company Optical Microscope E100 Nikon Corporation Ultrasonic Cleaner SB-5200D Ningbo Xinzhi Biotechnology Vertical Pressure Steam Sterilizer YXQ-LS-50S11 Shanghai Boxun Industry Co., Ltd. Electric Thermostatic Water Bath DK-8D Shanghai Yiheng Technology Co., Ltd.

[0021] 1.3 Reagents

[0022]

[0023]

[0024]

[0025] 2. Detection Methods

[0026] 2.1 Preparation of main reagents:

[0027] Preparation of 500 μg / ml monensin standard solution: Accurately weigh 0.05 g of monensin standard in a 100 ml volumetric flask, add absolute ethanol to make up the volume to obtain a monensin standard solution with a final concentration of 500 μg / ml, and store it in the refrigerator for later use. Dilute it to 20 μg / ml, 50 μg / ml, 100 μg / ml, 200 μg / ml, 250 μg / ml, 500 μg / ml, and plot the standard curve y = 230.2x - 5.3698.

[0028] Preparation of chromogenic reagent: Weigh 1.5 g of p-dimethylaminobenzaldehyde in a 500 ml volumetric flask, dissolve it with 300 ml of absolute ethanol, add 2 ml of concentrated sulfuric acid and shake well, and make up the volume with absolute ethanol, and store it in a brown bottle.

[0029] 2.2 Sample treatment:

[0030] Take 2 ml of the shake flask fermentation broth, centrifuge it, discard the supernatant, make up the volume to 8 ml with absolute ethanol, shake well and sonicate for 1 h, centrifuge again, take 40 μl of the supernatant and dilute it 50 times with absolute ethanol. Pipette 500 μl into a test tube, add 4.5 ml of absolute ethanol and 5 ml of the color reagent, shake well, heat in a water bath at 70 °C for 20 min, quickly cool down, and measure the absorbance at 600 nm using a UV-visible spectrophotometer.

[0031] 2.3 Calculation of fermentation unit:

[0032] The concentration of monensin = (absorbance × 230.2 - 5.3698) × 200.

[0033] 3. Term Definitions

[0034] In this article, the "%" used refers to the weight / volume percentage, which can be understood as the weight of the solute in 100 ml of the solution.

[0035] Example 1 Fermentation medium for improving the fermentation production of monensin by Streptomyces cinnamonensis

[0036] Glucose 2.5%, maltose 2.0%, soybean meal powder 3.0%, casein 1.0%, sodium sulfate 0.22%, sodium nitrate 0.22%, manganese chloride 0.033%, aluminum sulfate 0.07%, ferrous sulfate 0.01%, L-ascorbic acid 0.0019%, dipotassium hydrogen phosphate 0.0075%, calcium carbonate 0.25%, nicotinamide 0.008%, choline chloride 0.003%, biotin 0.003%, glutamic acid 0.07%, cysteine 0.09%, soybean oil 2.0%, the balance is water, pH 6.8.

[0037] Example 2 Method for fermenting and producing monensin using Streptomyces cinnamonensis

[0038] 1. Slant culture:

[0039] Slant medium (%): potassium nitrate 0.1, sodium chloride 0.05, dipotassium hydrogen phosphate 0.05, imported yeast powder 0.2, magnesium sulfate 0.05, ferrous sulfate 0.001, soluble starch 2, agar powder 1.8, the balance is water. Adjust the pH to 6.8 and sterilize at 121 °C for 20 min. Using Streptomyces cinnamonensis as the strain, inoculate it into the sterilized slant medium and place it in an incubator at 32 °C for 6 days.

[0040] 2. Seed culture:

[0041] Seed culture medium: glucose 0.5, soybean meal powder 8488 1.5, imported yeast powder 0.25, corn dextrin 2.0, calcium carbonate 0.1, with the balance being water. Adjust the pH to 6.8 and sterilize at 121 °C for 20 min. Take the strain cultured on the slant and inoculate it into the sterilized seed culture medium, and culture it on a shaker at 32 °C for 21 h to obtain the fermented seed liquid.

[0042] 3. Flask fermentation:

[0043] Inoculate the fermented seed liquid into a flask containing the fermentation medium of Example 1, and culture it on a shaker at 32 °C for 10 days to obtain the fermentation liquid containing monensin.

[0044] Experimental example Screening test research on the fermentation medium formula of the present invention

[0045] 1. Screening of growth factors

[0046] 1.1 Influence of different growth factors on the fermentation unit of monensin

[0047] Based on the medium with glucose 2.5%, maltose 2.0%, soybean meal powder 8488 3.0%, casein 1.0%, sodium sulfate 0.22%, sodium nitrate 0.22%, manganese chloride 0.033%, aluminum sulfate 0.07%, ferrous sulfate 0.01%, L-ascorbic acid 0.0019%, dipotassium hydrogen phosphate 0.0075%, calcium carbonate 0.25%, and soybean oil 2.0%, add 0.005% of growth factors respectively.

[0048]

[0049] The results show that the fermentation unit of monensin in the fermentation medium added with biotin, compound VB, and nicotinamide is relatively high.

[0050] 1.2 Influence of different biotin addition amounts on the fermentation unit of monensin

[0051] Based on the medium with glucose 2.5%, maltose 2.0%, soybean meal powder 8488 3.0%, casein 1.0%, sodium sulfate 0.22%, sodium nitrate 0.22%, manganese chloride 0.033%, aluminum sulfate 0.07%, ferrous sulfate 0.01%, L-ascorbic acid 0.0019%, dipotassium hydrogen phosphate 0.0075%, calcium carbonate 0.25%, and soybean oil 2.0%, add 0.0005%, 0.001%, 0.002%, 0.003%, 0.005%, and 0.008% of biotin respectively.

[0052]

[0053] The results show that the fermentation unit of monensin in the fermentation medium added with 0.003% of biotin is the highest.

[0054] 1.3 Effects of Different Addition Amounts of Compound VB on Monensin Fermentation Unit

[0055] Using glucose 2.5%, maltose 2.0%, soybean meal powder 84883.0%, casein 1.0%, sodium sulfate 0.22%, sodium nitrate 0.22%, manganese chloride 0.033%, aluminum sulfate 0.07%, ferrous sulfate 0.01%, L-ascorbic acid 0.0019%, dipotassium hydrogen phosphate 0.0075%, calcium carbonate 0.25%, and soybean oil 2.0% as the basal medium, compound VB was added at 0.0005%, 0.001%, 0.002%, 0.003%, 0.005%, and 0.008% respectively.

[0056]

[0057] The results showed that the fermentation unit of monensin in the fermentation medium with 0.005% compound VB added was the highest.

[0058] 1.4 Effects of Different Addition Amounts of Nicotinamide on Monensin Fermentation Unit

[0059] Using glucose 2.5%, maltose 2.0%, soybean meal powder 84883.0%, casein 1.0%, sodium sulfate 0.22%, sodium nitrate 0.22%, manganese chloride 0.033%, aluminum sulfate 0.07%, ferrous sulfate 0.01%, L-ascorbic acid 0.0019%, dipotassium hydrogen phosphate 0.0075%, calcium carbonate 0.25%, and soybean oil 2.0% as the basal medium, nicotinamide was added at 0.001%, 0.002%, 0.003%, 0.005%, 0.008%, and 0.01% respectively.

[0060]

[0061] The results showed that the fermentation unit of monensin in the fermentation medium with 0.008% nicotinamide added was the highest.

[0062] 1.5 Effects of Combinations of Nicotinamide with Other Growth Factors on Monensin Fermentation Unit

[0063] Using glucose 2.5%, maltose 2.0%, soybean meal powder 84883.0%, casein 1.0%, sodium sulfate 0.22%, sodium nitrate 0.22%, manganese chloride 0.033%, aluminum sulfate 0.07%, ferrous sulfate 0.01%, L-ascorbic acid 0.0019%, dipotassium hydrogen phosphate 0.0075%, calcium carbonate 0.25%, nicotinamide 0.008%, and soybean oil 2.0% as the basal medium, other types of growth factors were added at 0.005% respectively.

[0064]

[0065] The results showed that the highest fermentation unit of monensin was obtained in the fermentation medium supplemented with 0.008% nicotinamide and 0.005% choline chloride, followed by the addition of 0.008% nicotinamide and 0.005% biotin.

[0066] 1.6 Effects of combinations of nicotinamide, biotin and choline chloride on the fermentation unit of monensin

[0067] The basic medium consisted of 2.5% glucose, 2.0% maltose, 84883.0% soybean meal powder, 1.0% casein, 0.22% sodium sulfate, 0.22% sodium nitrate, 0.033% manganese chloride, 0.07% aluminum sulfate, 0.01% ferrous sulfate, 0.0019% L-ascorbic acid, 0.0075% dipotassium hydrogen phosphate, 0.25% calcium carbonate, and 2.0% soybean oil. Nicotinamide, biotin and choline chloride were added in combination.

[0068]

[0069] The results showed that compared with the pairwise combinations of nicotinamide and choline chloride, and the pairwise combinations of nicotinamide and biotin, the fermentation unit using the combination of nicotinamide, biotin and choline chloride was significantly higher. The dosage ranges of nicotinamide, biotin and choline chloride were 0.007 - 0.009%, 0.003 - 0.005%, and 0.002 - 0.005% respectively, and the highest fermentation unit of monensin was obtained in the fermentation medium supplemented with 0.008% nicotinamide, 0.003% choline chloride and 0.003% biotin.

[0070] 2. Screening of amino acids

[0071] 2.1 Effects of different types of amino acids on the fermentation unit of monensin

[0072] The basic medium consisted of 2.5% glucose, 2.0% maltose, 84883.0% soybean meal powder, 1.0% casein, 0.22% sodium sulfate, 0.22% sodium nitrate, 0.033% manganese chloride, 0.07% aluminum sulfate, 0.01% ferrous sulfate, 0.0019% L-ascorbic acid, 0.0075% dipotassium hydrogen phosphate, 0.25% calcium carbonate, 0.008% nicotinamide, 0.003% choline chloride and 0.003% biotin, and 2.0% soybean oil. 0.05% of different types of amino acids were added.

[0073]

[0074] The results showed that the fermentation units of monensin in the fermentation media supplemented with leucine, cysteine and glutamic acid were relatively high.

[0075] 2.2 Effects of different addition amounts of leucine on the fermentation unit of monensin

[0076] 2.5% glucose, 2.0% maltose, 84883.0% soybean meal powder, 1.0% casein, 0.22% sodium sulfate, 0.22% sodium nitrate, 0.033% manganese chloride, 0.07% aluminum sulfate, 0.01% ferrous sulfate, 0.0019% L-ascorbic acid, 0.0075% dipotassium hydrogen phosphate, 0.25% calcium carbonate, 0.008% nicotinamide, 0.003% choline chloride and 0.003% biotin, 2.0% soybean oil as the basal medium, and 0.01%, 0.03%, 0.05%, 0.07%, 0.09% leucine were added respectively.

[0077]

[0078] The results showed that the fermentation unit of monensin in the fermentation medium supplemented with 0.03% leucine was the highest.

[0079] 2.3 Effect of different cysteine addition amounts on the fermentation unit of monensin

[0080] 2.5% glucose, 2.0% maltose, 8488 3.0% soybean meal powder, 1.0% casein, 0.22% sodium sulfate, 0.22% sodium nitrate, 0.033% manganese chloride, 0.07% aluminum sulfate, 0.01% ferrous sulfate, 0.0019% L-ascorbic acid, 0.0075% dipotassium hydrogen phosphate, 0.25% calcium carbonate, 0.008% nicotinamide, 0.003% choline chloride and 0.003% biotin, 2.0% soybean oil as the basal medium, and 0.01%, 0.03%, 0.05%, 0.07%, 0.09% cysteine were added respectively.

[0081]

[0082] The results showed that the fermentation unit of monensin in the fermentation medium supplemented with 0.09% cysteine was the highest.

[0083] 2.4 Effect of different glutamic acid addition amounts on the fermentation unit of monensin

[0084] 2.5% glucose, 2.0% maltose, 84883.0% soybean meal powder, 1.0% casein, 0.22% sodium sulfate, 0.22% sodium nitrate, 0.033% manganese chloride, 0.07% aluminum sulfate, 0.01% ferrous sulfate, 0.0019% L-ascorbic acid, 0.0075% dipotassium hydrogen phosphate, 0.25% calcium carbonate, 0.008% nicotinamide, 0.003% choline chloride and 0.003% biotin, 2.0% soybean oil as the basal medium, and 0.01%, 0.03%, 0.05%, 0.07%, 0.09% glutamic acid were added respectively.

[0085]

[0086] The results showed that the highest fermentation unit of monensin was obtained in the fermentation medium supplemented with 0.07% glutamic acid.

[0087] 2.5 Effects of different amino acid combinations on the fermentation unit of monensin

[0088] Using glucose 2.5%, maltose 2.0%, soybean meal powder 84883.0%, casein 1.0%, sodium sulfate 0.22%, sodium nitrate 0.22%, manganese chloride 0.033%, aluminum sulfate 0.07%, ferrous sulfate 0.01%, L-ascorbic acid 0.0019%, dipotassium hydrogen phosphate 0.0075%, calcium carbonate 0.25%, 0.008% nicotinamide, 0.003% choline chloride and 0.003% biotin, and soybean oil 2.0% as the basal medium, different combinations of leucine, cysteine and glutamic acid were added respectively.

[0089]

[0090] The results showed that the combination of glutamic acid and cysteine had significantly higher fermentation units than other combinations. The addition amounts of glutamic acid and cysteine were 0.05 - 0.07% and 0.07 - 0.09% respectively, and the highest fermentation unit of monensin was obtained in the fermentation medium supplemented with 0.07% glutamic acid and 0.09% cysteine.

[0091] Therefore, the optimal fermentation medium formula is as follows: glucose 2.5%, maltose 2.0%, soybean meal powder 84883.0%, casein 1.0%, sodium sulfate 0.22%, sodium nitrate 0.22%, manganese chloride 0.033%, aluminum sulfate 0.07%, ferrous sulfate 0.01%, L-ascorbic acid 0.0019%, dipotassium hydrogen phosphate 0.0075%, calcium carbonate 0.25%, nicotinamide 0.008%, choline chloride 0.003%, biotin 0.003%, glutamic acid 0.07%, cysteine 0.09%, soybean oil 2.0%, and the balance is water. After detection, the shake flask fermentation unit was 36002 μg / mL, which was 30.21% higher than the shake flask fermentation unit of 27648 μg / mL in the basal medium without adding growth factors and amino acids.

[0092] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A fermentation medium for improving the fermentation production of monensin by Streptomyces cinnamonensis, characterized in that, The fermentation medium contains a carbon source, a nitrogen source, inorganic salts, growth factors, vegetable oil, and water; the nitrogen source contains glutamic acid and cysteine, and the growth factors contain nicotinamide, choline chloride, and biotin; Calculated by the weight - volume percentage concentration of the fermentation medium, the content of glutamic acid is 0.05 - 0.07%, the content of cysteine is 0.07 - 0.09%, the content of nicotinamide is 0.007 - 0.009%, the content of choline chloride is 0.002 - 0.005%, and the content of biotin is 0.003 - 0.005%.

2. The fermentation medium according to claim 1, wherein The carbon source is one or a combination of two or more of glucose, maltose, sucrose, fructose, mannitol, lactose, starch, dextrin, and soluble starch, and the content of the carbon source is 2 - 6%; the nitrogen source also contains one or a combination of two or more of soybean meal powder, casein, cottonseed meal, corn steep liquor, yeast extract, and fish meal, and the content of the nitrogen source is 2 - 6%; the inorganic salts are one or a combination of two or more of sodium sulfate, sodium nitrate, manganese chloride, aluminum sulfate, ferrous sulfate, dipotassium hydrogen phosphate, calcium carbonate, sodium chloride, magnesium chloride, magnesium sulfate, and potassium dihydrogen phosphate, and the content of the inorganic salts is 0.3 - 2%; the growth factors also contain L - ascorbic acid, and the content of L - ascorbic acid is 0.001 - 0.003%; the vegetable oil is any one or a combination of two or more of soybean oil, corn oil, peanut oil, cottonseed oil, linseed oil, sunflower oil, and coconut oil, and the content of the vegetable oil is 1 - 3%.

3. The fermentation medium according to claim 2, wherein The carbon source is glucose and maltose, the nitrogen source is soybean meal powder, casein, glutamic acid, and cysteine, the inorganic salts are sodium sulfate, sodium nitrate, manganese chloride, aluminum sulfate, ferrous sulfate, dipotassium hydrogen phosphate, and calcium carbonate, the growth factors are nicotinamide, choline chloride, biotin, and L - ascorbic acid, and the vegetable oil is soybean oil.

4. The fermentation medium according to claim 3, wherein, The fermentation medium contains the following components in weight - volume percentage concentration: Glucose 1 - 3%, maltose 1 - 3%, soybean meal powder 2 - 4%, casein 0.5 - 2%, glutamic acid 0.05 - 0.07%, cysteine 0.07 - 0.09%, sodium sulfate 0.1 - 0.5%, sodium nitrate 0.1 - 0.5%, manganese chloride 0.01 - 0.05%, aluminum sulfate 0.02 - 0.2%, ferrous sulfate 0.005 - 0.02%, dipotassium hydrogen phosphate 0.005 - 0.02%, calcium carbonate 0.1 - 0.5%, nicotinamide 0.007 - 0.009%, choline chloride 0.002 - 0.005%, biotin 0.003 - 0.005%, L - ascorbic acid 0.001 - 0.003%, soybean oil 1 - 3%, and the balance is water.

5. The fermentation medium according to claim 1, characterized in that, The pH of the fermentation medium is 6.8 ± 0.

2.

6. A method for producing monensin by fermentation of Streptomyces cinnamonensis, characterized in that, The method includes: inoculating the fermentation seed liquid of Streptomyces cinnamonensis into the fermentation medium according to any one of claims 1 - 5 for shake - flask culture to obtain a fermentation broth containing monensin.

7. The method according to claim 6, wherein The temperature of the shake flask culture is 32 ± 1 °C, the time of the shake flask culture is 8 - 12 d, and the shaker rotation speed of the shake flask culture is 220 - 250 rpm.

8. The method according to claim 6, characterized in that, The fermentation seed liquid of the Streptomyces cinnamoneus is prepared by the following method: inoculating the Streptomyces cinnamoneus into a slant medium for primary culture to obtain an activated strain; and inoculating the activated strain into a seed medium for secondary culture to obtain the fermentation seed liquid of the Streptomyces cinnamoneus; The slant medium is composed of components with the following weight - volume percentage concentrations: potassium nitrate 0.05 - 0.15%, sodium chloride 0.025 - 0.075%, dipotassium hydrogen phosphate 0.025 - 0.075%, yeast powder 0.1 - 0.3%, magnesium sulfate 0.025 - 0.075%, ferrous sulfate 0.0005 - 0.0015%, soluble starch 1 - 3%, agar powder 1 - 3%, with the balance being water, and the pH being 6.8 ± 0.2; The seed medium is composed of components with the following weight - volume percentage concentrations: glucose 0.25 - 0.75%, soybean meal powder 1 - 2%, yeast powder 0.2 - 0.3%, corn dextrin 1 - 3%, calcium carbonate 0.05 - 0.15%, with the balance being water, and the pH being 6.8 ± 0.

2.

9. The method according to claim 8, characterized in that The conditions for the primary culture are: the culture temperature is 32 ± 0.2 °C, and the culture time is 5 - 7 days.

10. The method according to claim 8, wherein The conditions for the secondary culture are: the culture temperature is 32 ± 0.2 °C, the shaker rotation speed is 220 - 250 rpm, and the culture time is 20 - 22 h.

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