Streptomyces gilvosporeus ZY8 as well as fermentation seeds and application thereof

Abstract

The invention relates to the technical field of industrial biology, in particular to streptomyces gilvosporeus ZY8 and a fermentation seed and application thereof, the streptomyces gilvosporeus ZY8 is preserved in the China General Microbiological Culture Collection Center (CGMCC) on November 13, 2024, the preservation number is CGMCC No.32603, and the classification name is streptomyces gilvosporeus. The streptomyces gilvosporeus ZY8 is named as streptomyces gilvosporeus. The streptomyces gilvosporeus ZY8 provided by the invention has a better promoting effect in the aspects of mediating a streptomyces albidosus signal and enhancing the synthesis of natamycin.

Description

Technical Field

[0001] The invention relates to the field of industrial biotechnology, and in particular to Streptomyces chrysoporus ZY8 and fermented seeds and applications thereof. Background Art

[0002] Natamycin is a polyene macrolide antifungal agent synthesized by Streptomyces (such as Streptomyces Chattanooga, Streptomyces chrysosporium, Streptomyces lydicus and Streptomyces natalensis). It can bind to sterol substances on the fungal cell membrane and thus cause the destruction of the membrane structure, thereby inhibiting and killing the fungi. Because it is poorly soluble in water and oil, natamycin is mostly used in food by spraying natamycin suspension for surface preservation. The amount used in food is small, and it cannot enter the human body after consumption. It has high biosafety and has been approved for addition to food processing in my country. At present, the fermentation level of natamycin is low, which makes the production cost high, and the high selling price limits its market application and promotion.

[0003] At present, the strains known to be able to synthesize natamycin mainly include Natal Streptomyces, Chattanooga Streptomyces and Chrysoporus Streptomyces. However, there are differences in the ability to synthesize natamycin between different strains. Among them, the natamycin synthesis yield of Chrysoporus Streptomyces ATCC 13326 is relatively low, which is difficult to meet the needs of large-scale industrial production. Therefore, the development of a high-yield and easy-to-cultivate natamycin synthesis strain has become the focus of current research. Summary of the invention

[0004] In order to explore high-yield strains to increase the yield of synthetic natamycin, the present invention provides a Streptomyces chrysoporus ZY8 and its fermented seeds and applications. The Streptomyces chrysoporus ZY8 provided by the present invention can strongly respond to the signal of Streptomyces parviflorus and increase the synthetic yield of natamycin.

[0005] A Streptomyces gitvosporeus ZY8 was deposited in the General Microbiology Center of China Microorganism Culture Collection Administration on November 13, 2024, with the deposit number CGMCC No.32603, and the classification name was Streptomyces gitvosporeus.

[0006] The Streptomyces chrysoporus ZY8 provided by the present invention is obtained by screening the Streptomyces chrysoporus ATCC 13326 through composite physical and chemical mutagenesis. The Streptomyces chrysoporus ZY8 screened by the present invention can efficiently respond to the signal of Streptomyces parviflorus and strengthen the synthesis of natamycin, and can be effectively applied to the direct addition fermentation of Streptomyces signal or the mixed fermentation of chrysoporus Streptomyces and parviflorus Streptomyces to improve the synthesis yield of natamycin.

[0007] The invention provides fermentation seeds of Streptomyces chrysoporus ZY8, which are obtained by inoculating spores of Streptomyces chrysoporus ZY8 into a natamycin fermentation seed culture medium and culturing at a temperature of 25°C to 31°C and 180rpm to 220rpm for 1d to 3d.

[0008] The invention provides an application of the Streptomyces chrysoporus ZY8 in synthesizing natamycin.

[0009] Furthermore, the Streptomyces chrysoporus ZY8 is used to increase the concentration of natamycin.

[0010] Furthermore, the Streptomyces chrysoporus ZY8 is used to increase the yield of natamycin.

[0011] The present invention also provides a method for synthesizing natamycin by the Streptomyces chrysoporus ZY8, comprising the following steps:

[0012] A natamycin fermentation medium is prepared, sterilized, supplemented with a glucose solution, inoculated with the fermentation seeds of Streptomyces chrysogenum, and fermented under the conditions of an initial pH of 6.0 to 7.5, a temperature of 25 to 33° C., and a dissolved oxygen content of 20% to 40%. The pH is controlled at 6.0 to 7.5 with sterilized NaOH until the fermentation is completed. When the glucose concentration in the fermentation liquid is less than 10 g / L, the concentration in the fermentation liquid is maintained at 10 g / L to 20 g / L, and the fermentation is completed when the natamycin concentration no longer increases.

[0013] Furthermore, the fermented seeds of Streptomyces chrysoporus are inoculated at an inoculation rate of 5 g / 100 mL to 10 g / 100 mL.

[0014] Furthermore, the fermentation broth also includes live bacterial liquid of Streptomyces parvum.

[0015] Furthermore, the live bacterial liquid of Streptomyces parvum is inoculated at an inoculation rate of 5 g / L to 20 g / L.

[0016] The culture medium formula used in the present invention is:

[0017] (1) 1 L Betana medium: 10 g glucose, 1 g yeast powder, 2 g peptone, 20 g agar, and the balance is distilled water, pH 7.5.

[0018] (2) 1 L natamycin fermentation seed medium: 20 g glucose, 6 g yeast powder, 6 g soy peptone, 5 g NaCl, and the balance is distilled water, pH 7.5.

[0019] (3) 1 L natamycin fermentation medium: 80 g glucose, 10 g yeast powder, 20 g soy peptone, 5 g NaCl, and the balance is distilled water, pH 7.5.

[0020] (4) 1LYPD liquid medium: 20 g glucose, 10 g yeast extract, 20 g peptone, and the balance distilled water, pH 6.5.

[0021] For all the above cases involving glucose, the sugar-containing substances were prepared separately from other ingredients, sterilized at 121°C for 20 min, and then combined into the same system culture medium.

[0022] The Streptomyces albulus described in the present invention includes one or more species including IFO14147 (Streptomyces albulus IFO14147, CICC11022), etc., and the ε-polylysine synthesis gene cluster exists in the genome of the Streptomyces albulus, which is purchased from the China Industrial Microbiological Culture Collection (CICC); the red yeast is Rhodotorula mucilaginosa CICC 32140 (Rhodotorula mucilaginosa, CICC 32140), which is an indicator of the product synthesis level and is purchased from the China Industrial Microbiological Culture Collection (CICC); Streptomyces gitvosporeus ATCC 13326 (Streptomyces gitvosporeus ATCC 13326) is purchased from the American Type Culture Collection.

[0023] Description of biological material deposit:

[0024] Streptomyces gitvosporeus ZY8, referred to as Streptomyces gitvosporeus ZY8 in the present invention, was deposited in the General Microbiology Center of China National Microbiological Culture Collection Administration on November 13, 2024, with a deposit number of CGMCC No. 32603. The address of the depository is No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, Postal Code: 100101, and is classified and named Streptomyces gitvosporeus.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The Streptomyces chrysanthemus ZY8 provided by the present invention is obtained by composite physical and chemical mutagenesis of Streptomyces chrysanthemus ATCC 13326. The Streptomyces chrysanthemus ZY8 provided by the present invention can directly add fermentation to synthesize natamycin, and its yield is 1.57 times that of Streptomyces chrysanthemus ATCC 13326, and can also efficiently respond to the signal of Streptomyces parviflorus to promote the increase of natamycin yield, and its yield is 2.35 times that of Streptomyces chrysanthemus ATCC 13326; in addition, the yield of natamycin synthesized by the mixed bacterial system of Streptomyces chrysanthemus ZY8 and Streptomyces parviflorus is 3.52 times that of Streptomyces chrysanthemus ATCC 13326. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 This is a colony picture of Streptomyces chrysoporus ZY8.

[0029] Figure 2 This is a fed-batch fermentation process of natamycin based on the mixed bacterial system of Streptomyces chrysoporus ZY8 and Streptomyces parviflorus. In the figure, the arrow indicates the time point when Streptomyces parviflorus IFO14147 is added. DETAILED DESCRIPTION

[0030] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention. The experimental methods described in the embodiments of the present invention are conventional methods unless otherwise specified, and the materials, reagents, etc. used in the following embodiments can be obtained from commercial channels unless otherwise specified.

[0031] Example 1: Breeding method of Streptomyces chrysoporus ZY8

[0032] S1, preparation of a single spore suspension of Streptomyces chlorophyceae ATCC 13326: spores of Streptomyces chlorophyceae ATCC 13326 were spread on Betana medium, cultured at 28°C for 10 days, washed and collected with pre-sterilized 20% glycerol, and after adding glass beads, placed in an oscillating incubator at 200 rpm for 5 hours, and then oscillated in an ultrasonic cleaner for 20 minutes to fully disperse the spores. Finally, the single spore suspension of Streptomyces chlorophyceae ATCC 13326 was filtered 5 times with pre-sterilized absorbent cotton, and the filtered single spore suspension of Streptomyces chlorophyceae ATCC 13326 was aliquoted and stored in a -80°C refrigerator for later use.

[0033] Preparation of Streptomyces parvum signal extract: scrape 3 loops (about 1×10 7) Spores of Streptomyces parviflorus were inoculated into a 500mL Erlenmeyer flask containing 80mL of natamycin fermentation medium and cultured in a constant temperature shaking incubator at 200r / min at 30°C for 2d. Washed with deionized water three times, resuspended with 65% ethanol, the mixture was placed in a mortar and ground with quartz sand for 10min, then centrifuged to obtain the supernatant, dried in a blast drying oven, and re-dissolved with water, and sterilized at 121°C for 15min to obtain the signal extract of Streptomyces parviflorus, and stored at -20°C. The volume ratio of the wet weight of the Streptomyces parviflorus cells used to the re-dissolved water was 1g:3mL.

[0034] S2, 1L strain selection medium: Betana medium containing 0.05g LiCl and 120mL of Streptomyces parvum signal extract.

[0035] Prepare the mixed solution: 2.5 μL of 0.5 mg / mL NTG (nitrosoguanidine), 0.5 mL of 5 g / L (pH = 6) citric acid buffer and 0.5 mL of about 5.0 × 10 7 The three were mixed to obtain a mixture, which was reacted in a 30°C constant temperature shaking incubator at 100 rpm for 60 min and diluted to 10 5 times.

[0036] Spreading culture: dilute to 10 -5 Take 1 mL of the mixed solution and spread it on the strain selection medium prepared in S2, and culture it in a constant temperature incubator at 28°C for 9 days until colonies grow out one after another.

[0037] S3, pre-cultured red yeast: obtained by culturing in YPD liquid medium at 30°C and 180 rpm for 1 day.

[0038] In the clean bench, lift one side of the strain breeding medium and slide it in a circular motion to release the adhesion between the strain breeding medium and the culture dish, lift the strain breeding medium, inject 1 mL of pre-cultured red yeast into the gap between the strain breeding medium and the culture dish, rotate the strain breeding medium so that the red yeast is evenly distributed in the gap between the strain breeding medium and the culture dish, and place the system in a 28°C incubator for 1 day to obtain the first round of mutagenesis strains.

[0039] The size of the red yeast inhibition zone under the colonies grown by the first round of mutagenic strains on the strain selection medium was observed and compared with the inhibition zone of the first round starting strain Streptomyces chrysoporus ATCC 13326, and the high-yield strains with larger inhibition zones than the starting strains were selected for streaking purification and expanded culture to obtain several spores of the first round high-yield strains.

[0040] S4, using an inoculation loop to scrape two loops of the first round of high-yield bacterial strain spores, inoculated into a 250mL conical flask containing 30mL of natamycin fermentation seed medium, and cultured in a constant temperature shaking incubator at 28°C, 200rpm for 2d; inoculated with 8% (v / v) high-yield bacterial spores into a 250mL conical flask containing 30mL of natamycin fermentation medium, and cultured in a constant temperature shaking incubator at 28°C, 200rpm for 3d. Finally, the fermentation was terminated, and the natamycin yield was determined to obtain the highest yield strain of Streptomyces chrysospora ZY1 in the first round of mutagenesis.

[0041] S5, using Streptomyces chrysoporus ZY1 as the second round starting strain, a single spore suspension of Streptomyces chrysoporus ZY1 was prepared according to the method described in S1.

[0042] S6, about 1.0×10 7 Spores of Streptomyces chrysoporus ZY1 strain at a concentration of 100 / mL were spread on the strain selection medium, and the above plate was irradiated at 30 cm under an 8W ultraviolet lamp in a clean bench for 2 minutes, and then placed in a constant temperature incubator at 28°C for 9 days until colonies grew out one after another.

[0043] S7, according to S3, screen and obtain a strain having an inhibition zone larger than that of the second round starting strain Streptomyces chrysoporus ZY1, and according to the steps in S4, screen and obtain the Streptomyces chrysoporus ZY2 strain with the highest yield.

[0044] S8, the chrysosporium streptomyces ZY2 was repeatedly subjected to nitrosoguanidine and ultraviolet mutagenesis according to the above method, and the plate with mold signal added was used as the screening condition and the yeast inhibition zone was used as the screening method to select strains that efficiently responded to the streptomyces signal and promoted the synthesis of natamycin. After repeated 4 rounds of mutagenesis, the high-yield strain chrysosporium streptomyces ZY8 was obtained, such as Figure 1 shown.

[0045] The spores of Streptomyces chrysosporium ZY8 were continuously subcultured and the natamycin synthesis ability was identified in the following manner: spores of Streptomyces chrysosporium ATCC 13326 and Streptomyces chrysosporium ZY8 (about 1×10 7 The mixture was inoculated into a 500 mL Erlenmeyer flask containing 60 mL of natamycin fermentation seed culture medium, and cultured in a constant temperature shaking incubator at 28°C and 200 rpm for 2 days until a large number of granular mycelial balls were formed; the mature fermentation seed liquid was added to a 250 mL Erlenmeyer flask containing 30 mL of natamycin fermentation culture medium at an inoculation rate of 8%, and the flask was placed in a constant temperature shaking incubator and cultured at 28°C and 200 rpm for 3 days. After the culture was completed, the natamycin concentration in the fermentation liquid was detected.

[0046] Detection of natamycin concentration in fermentation broth: 1 mL of fermentation broth was mixed with 9 mL of methanol, and extracted by shaking in an ultrasonic cleaner for 20 min. The system was placed on a shaker for 3 h, and then centrifuged at 4,500 × g for 10 min. After the supernatant was filtered through a 0.45 μm organic filter, the concentration was detected by HPLC. A C18 column (Acclaim 120, 250 × 4.6 mm, Thermoscientific, USA) was used, the mobile phase was set to a methanol-water mixture (60% methanol, 40% water), the column temperature was controlled at 25 ° C, and the injection volume was 10 μL.

[0047] The natamycin shake flask fermentation levels of Streptomyces chrysosporium ZY8 after 10 consecutive passages are as follows:

[0048] Table 1 Natamycin shake flask fermentation level (g / L) of Streptomyces chrysospora ZY8 after 10 consecutive passages

[0049]

[0050]

[0051] NOTE: The "added signal" for S6 will be approximately 1.0 × 10 7 Spores of Streptomyces chrysogenum were spread on the strain selection medium; “no signal added” means: about 1.0×10 7 Spores of Streptomyces chrysogenum at a concentration of 100 / mL were spread on a strain selection medium.

[0052] Example 2: Synthesis of Natamycin in a 5L Fermentation Tank Based on Streptomyces chrysoporus ZY8

[0053] S1, culturing natamycin fermentation seeds: scrape 3 rings of spores of Streptomyces chrysoporus ZY8 (about 1×10 6 ) were inoculated into a 500 mL Erlenmeyer flask filled with 60 mL of natamycin fermentation seed medium, and cultured in a constant temperature shaking incubator at 28°C and 180 rpm to 220 rpm for 2 days to obtain fermentation seeds of Streptomyces chrysospora ZY8;

[0054] S2, prepare 3L natamycin fermentation medium, add it to a 5L liquid fermentation tank, sterilize it at 121℃ for 20min, and add 500mL solution of 240g glucose dissolved in it separately sterilized (sterilized at 121℃ for 20min) by peristaltic pump, set the temperature to 28℃, the stirring paddle speed to 200rmp and the ventilation volume to 1vvm as the initial parameters. Inoculate the obtained fermentation seeds of Streptomyces chrysosporus ZY8 with an inoculum of 8%, adjust the pH to 7.5 with pre-sterilized NaOH to start fermentation. When the pH naturally drops to 6.0, dynamically add pre-sterilized NaOH to maintain pH=6.0, and use the speed and dissolved oxygen coupling setting to control the dissolved oxygen at 33% until the fermentation ends at 156h. When the glucose concentration in the fermentation broth is lower than 10g / L, add 600g / L of pre-sterilized glucose solution by peristaltic pump exogenous flow to maintain the concentration of the fermentation broth to the range of 15g / L. During the fermentation process, the fermentation broth was sampled every 12 hours to determine the concentration of natamycin, dry weight of bacteria, and residual glucose in the fermentation broth. The detection method is as follows:

[0055] Detection of natamycin concentration in fermentation broth: 1 mL of fermentation broth was mixed with 9 mL of methanol, and extracted by shaking in an ultrasonic cleaner for 20 min. The system was placed on a shaker for 3 h, and then centrifuged at 4,500 × g for 10 min. After the supernatant was filtered through a 0.45 μm organic filter, the concentration was detected by HPLC. A C18 column (Acclaim 120, 250 × 4.6 mm, Thermoscientific, USA) was used, the mobile phase was set to a methanol-water mixture (60% methanol, 40% water), the column temperature was controlled at 25 ° C, and the injection volume was 10 μL.

[0056] Detection of glucose concentration in fermentation broth: 300 μL of fermentation broth and 700 μL of anhydrous ethanol were mixed, and the mixture was centrifuged after standing for 1 hour to obtain the supernatant, and then filtered through a 0.45 μm filter membrane for HPLC detection. An organic acid test column (Aminex HPX-87H, 300×7.8 mm; Hercules, USA) was used, the mobile phase was set to 5 mM sulfuric acid, the column temperature was controlled at 60°C, and the injection volume was 10 μL.

[0057] Detection of cell dry weight: The cell dry weight (DCW) was detected by filter paper differential gravimetry. 10 mL of fermentation broth was taken out from a 5L fermenter, centrifuged at 4,500 × g for 10 min, the precipitate was washed twice with distilled water, and filtered with filter paper (Φ7 cm, medium speed, SCRC) that had been previously dried at 105°C and weighed. The filter paper was then dried at 105°C to a constant weight and weighed. The weight difference before and after was calculated, and the cell dry weight in the fermentation broth was calculated based on the volume of 10 mL of the original fermentation broth.

[0058] Test results: After the final fermentation, the concentration of natamycin produced by Streptomyces chrysosporium ZY8 was 3.3 g / L, and the dry weight of the bacteria was 25.3 g / L. The starting strain Streptomyces chrysosporium ATCC 13326 was cultured in the same fermentation process, and its final natamycin concentration was 2.1 g / L, and the dry weight of the bacteria was 20.6 g / L. The natamycin yield of the high-yield strain ZY8 was 1.57 times that of Streptomyces chrysosporium ATCC 13326.

[0059] Example 3: Synthesis of Natamycin in a 5L Fermentation Tank Based on the Signals of Streptomyces chrysosporium ZY8 and Streptomyces parviflorus

[0060] Prepare 3L of natamycin fermentation medium, add it to a 5L liquid fermentation tank, sterilize it at 121℃ for 20min, and add all 500mL of a solution containing 240g of glucose that has been sterilized separately (sterilized at 121℃ for 20min) with a peristaltic pump, set the temperature to 28℃, the stirring paddle speed to 200rmp and the ventilation volume to 1vvm as initial parameters. Inoculate the fermentation seeds of Streptomyces chrysosporus ZY8 obtained in S1 in Example 2 with an inoculum of 8%, and start fermentation by adjusting the pH to 7.5 with pre-sterilized NaOH. When the fermentation is 48h, add 500mL of the signal extract of Streptomyces parviflorus described in S1 in Example 1 from the feed bottle to the fermentation tank at one time, and when the pH naturally drops to 6.0, add pre-sterilized NaOH to maintain the pH to 6.0 dynamically, and adjust the dissolved oxygen to 30% by the speed and dissolved oxygen coupling setting until the fermentation is completed at 156h. When the glucose concentration in the fermentation broth was lower than 10 g / L, 600 g / L of pre-sterilized glucose solution was added via a peristaltic pump to maintain the fermentation broth concentration within the range of 15 g / L. During the fermentation process, the fermentation broth was sampled every 12 h to measure the natamycin concentration, bacterial dry weight, and residual glucose in the fermentation broth.

[0061] The natamycin concentration, cell dry weight and residual glucose in the fermentation broth were determined according to the determination method in Example 2. After the final fermentation, the natamycin concentration produced by Streptomyces chrysosporium ZY8 was 8.7 g / L and the cell dry weight was 29.7 g / L. The starting strain Streptomyces chrysosporium ATCC 13326 was cultured in the same fermentation process, and its final natamycin concentration was 3.7 g / L and the cell dry weight was 24.8 g / L. The natamycin yield of the high-yield strain ZY8 was 2.35 times that of Streptomyces chrysosporium ATCC 13326.

[0062] Example 4: Synthesis of Natamycin in a 5L Fermentation Tank Based on a Mixed Bacterial System of Streptomyces chrysoporus ZY8 and Streptomyces parviflorus

[0063] Preparation of live Streptomyces parvum bacterial suspension: scrape 3 loops (about 1×10 7) S. parvum spores were inoculated into a 500 mL Erlenmeyer flask containing 80 mL of natamycin fermentation medium and cultured in a constant temperature shaking incubator at 200 rpm at 30° C. for 2 days.

[0064] Prepare 3L of natamycin fermentation medium, add it to a 5L liquid fermentation tank, sterilize it at 121℃ for 20min, and use a peristaltic pump to add all the 500mL solution of 240g glucose that has been sterilized separately (sterilized at 121℃ for 20min), set the temperature to 28℃, the stirring paddle speed to 200rmp and the ventilation volume to 1vvm as initial parameters. Inoculate the fermentation seeds of Streptomyces chrysosporium ZY8 obtained in S1 in Example 2 with an inoculum of 8%, adjust the pH to 7.5 with pre-sterilized NaOH to start fermentation. At 48h of fermentation, add 500mL of live Streptomyces parviflorus bacterial liquid into the tank from the inoculation port of the fermentation tank under the protection of the fire ring. When the pH naturally drops to 6.0, dynamically add pre-sterilized NaOH to maintain pH=6.0, and use the rotation speed and dissolved oxygen coupling setting to regulate the dissolved oxygen at 30% until the fermentation ends after 156h. Figure 2 When the glucose concentration in the fermentation broth was lower than 10 g / L, 600 g / L of pre-sterilized glucose solution was added through a peristaltic pump to maintain the fermentation broth concentration within the range of 15 g / L. During the fermentation process, the fermentation broth was sampled every 12 hours to measure the natamycin concentration, bacterial dry weight, and residual glucose in the fermentation broth.

[0065] The natamycin concentration, cell dry weight and residual glucose in the fermentation broth were determined according to the process described in Example 2. After the final fermentation, the natamycin concentration produced by Streptomyces chrysosporium ZY8 was 14.8 g / L and the cell dry weight was 34.2 g / L. The starting strain Streptomyces chrysosporium ATCC 13326 was cultured in the same fermentation process, and its final natamycin concentration was 4.2 g / L and the cell dry weight was 27.2 g / L. The natamycin yield of the high-yield strain ZY8 was 3.52 times that of Streptomyces chrysosporium ATCC 13326.

[0066] Although preferred embodiments of the present invention have been described, additional changes and modifications may occur to these embodiments once those skilled in the art are aware of the basic inventive concepts.

[0067] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A Streptomyces gitvosporeus ZY8, characterized in that: It was deposited in the General Microbiology Center of China Microorganism Culture Collection Administration on November 13, 2024, with the deposit number CGMCC No.32603 and the classification name Streptomyces gitvosporeus.

2. A fermented seed of Streptomyces chrysoporus ZY8 according to claim 1, characterized in that: The fermentation seeds are obtained by inoculating spores of Streptomyces chrysoporus ZY8 into a natamycin fermentation seed culture medium and culturing at a temperature of 25° C. to 31° C. and 180 rpm to 220 rpm for 1 to 3 days.

3. Use of the Streptomyces chrysoporus ZY8 according to claim 1 in synthesizing natamycin.

4. The use according to claim 3, wherein the Streptomyces chrysoporus ZY8 is used to increase the concentration of natamycin.

5. The use according to claim 3, wherein the Streptomyces chrysoporus ZY8 is used to increase the yield of natamycin.

6. A method for synthesizing natamycin by Streptomyces chrysoporus ZY8 according to claim 3, characterized in that: The steps include: A natamycin fermentation medium is prepared, sterilized, supplemented with a glucose solution, inoculated with the fermentation seeds of Streptomyces chrysogenum, and fermented under the conditions of an initial pH of 6.0 to 7.5, a temperature of 25 to 33° C., and a dissolved oxygen content of 20% to 40%. The pH is controlled at 6.0 to 7.5 with sterilized NaOH until the fermentation is completed; when the glucose concentration in the fermentation liquid is less than 10 g / L, the concentration in the fermentation liquid is maintained at 10 g / L to 20 g / L, and the fermentation is completed when the natamycin concentration no longer increases.

7. The method for synthesizing natamycin by Streptomyces chrysoporus ZY8 according to claim 6, characterized in that: The fermented seeds of Streptomyces chrysoporus are inoculated at an inoculation rate of 5 g / 100 mL to 10 g / 100 mL.

8. The method for synthesizing natamycin by Streptomyces chrysoporus ZY8 according to claim 6, characterized in that: The fermentation liquid also includes live bacterial liquid of Streptomyces parvum.

9. The method for synthesizing natamycin by Streptomyces chrysoporus ZY8 according to claim 8, characterized in that: The live bacterial liquid of Streptomyces parvum is inoculated at an inoculation rate of 5 g / L to 20 g / L.

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