A kind of Schizochytrium with high EPA production and its application

Abstract

The present invention belongs to the field of microbial technology, and specifically relates to a schizochytrium with high EPA production and its application. The present invention obtains a schizochytrium for fermenting and preparing EPA through ultraviolet mutagenesis and selective culture screening, and the strain name is Schizochytrium sp.ALS01. The schizochytrium ALS01 can produce high-yield EPA through fermentation in ordinary culture medium, with an EPA content of up to 10.11%. It can also produce high-yield DHA, with a DHA content of up to 46.02%, and is an ideal microbial resource for producing a variety of ω-3 fatty acids. At the same time, the schizochytrium ALS01 with high EPA and DHA production can not only reduce the production cost of EPA and DHA, but also meet the current growing demand for EPA, which is conducive to promoting the promotion and application of schizochytrium production technology of EPA and DHA.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and particularly relates to a schizochytrium with high EPA production and application thereof. Background Art

[0002] Eicosapentaenoic acid (EPA) is a ω-3 long-chain polyunsaturated fatty acid. 20 H 30 O2, melting point is -54 to -53℃. At room temperature, EPA is a colorless or light yellow transparent liquid with a strong fishy smell. EPA exists in large quantities in the human body's gray matter, nervous system, retinal cell outer segments, myocardium, breast milk, etc. Studies have found that EPA has the effects of anti-coagulation, lowering blood lipids, protecting eyesight, promoting brain development, delaying brain tissue atrophy, inhibiting cancer, enhancing immunity, protecting the heart, reducing inflammatory response, and reducing the risk of diabetes. It plays a key role in the prevention and treatment of human diseases.

[0003] The traditional source of EPA is deep-sea fish, but fish grow slowly, have complex fatty acid compositions, and are difficult to separate, which cannot meet the growing needs of people. In addition, overfishing of deep-sea fish will also cause an imbalance in the ecological environment. Therefore, it is increasingly urgent to find safe, reliable, and sustainable EPA resources. Marine microalgae are considered to be an excellent natural source of EPA. Most marine bacteria, such as Shewanella, Vibrio, and Photobacterium, can produce EPA. However, since most algae grow slowly, their total biomass and oil content are relatively low, the cost of commercially producing EPA from algae is high, and large-scale production of EPA from algae is still considered to be difficult. Schizochytrium is a marine oil-producing fungus that has been used for commercial production of DHA due to its high oil content, easy cultivation, and high biomass. It is also an excellent potential EPA producer.

[0004] Patent document CN108707630A discloses a method and application for increasing the EPA content in Schizochytrium sp. MYA1381. The method is to activate the strain Schizochytrium sp. MYA1381 through a plate and secondary seeds, prepare a seed solution, and then inoculate it into a fermentation medium. Fluridone is added at different stages of the growth of Schizochytrium. By adding fluridone, the EPA content in the oil of Schizochytrium is significantly increased, which is 42.31% higher than that without addition, which provides a basis for using fluridone to increase the EPA content in Schizochytrium.

[0005] Patent document CN114164122A discloses a high-EPA-producing schizochytrium and its application. The high-EPA-producing schizochytrium is obtained by ion beam implantation and ultraviolet-lithium chloride composite mutagenesis, and the schizochytrium has a high EPA-producing performance and grows rapidly. Compared with the existing schizochytrium that needs to be synthesized under low temperature conditions to have a high EPA content, the schizochytrium has a higher EPA yield and efficiency. In addition, a certain amount of squalene is found in the product of the schizochytrium.

[0006] However, although there are reports on the use of Schizochytrium as a method for producing EPA, the EPA content produced is low and cannot meet the growing demand of people. Therefore, researching and developing a method for producing high-yield EPA is still a problem that needs to be solved urgently. Summary of the invention

[0007] In order to overcome the deficiencies in the prior art, the present invention aims to provide a high-yield EPA-producing Schizochytrium and its application. The present invention obtains a Schizochytrium for fermenting and preparing EPA through ultraviolet mutagenesis and selective culture screening. The strain is named Schizochytrium sp.ALS01. The Schizochytrium ALS01 can produce a high yield of EPA through fermentation in ordinary culture medium, with an EPA content of up to 10.11%, and can also produce a high yield of DHA, with a DHA content of up to 46.02%.

[0008] The specific technical solutions of the present invention are as follows:

[0009] The present invention provides a schizochytrium with high EPA production. The schizochytrium sp. ALS01 was deposited in the China Center for Type Culture Collection on June 17, 2024, with a deposit number of CCTCC No: M 20241235.

[0010] The present invention successfully obtains a mutant Schizochytrium sp. ALS01 with high EPA production through ultraviolet mutagenesis technology and selective culture medium screening. Specifically, the original strain of Schizochytrium sp. is subjected to ultraviolet mutagenesis treatment, and then the Schizochytrium sp. after ultraviolet mutagenesis treatment is inoculated into a selective culture medium designed by the inventor and cultured under specific culture conditions, and finally Schizochytrium sp. ALS01 with high EPA and DHA production is screened out, and its EPA content is significantly increased to 10.11%, and its DHA content is increased to 46.02%, which are much higher than those of unmodified Schizochytrium sp.

[0011] The preferred ultraviolet irradiation intensity of the present invention is 50 to 150 mJ / cm 2 The irradiation time is 1 to 3 minutes.

[0012] The selective culture designed by the inventors: glucose 90g / L, sodium alginate 25-40g / L, sodium glutamate 5g / L, yeast powder 4-6g / L, Na2SO4 12 g / L, MgSO4 2 g / L, KH2PO4 1 g / L, (NH4)2SO4 1 g / L, K2SO4 0.65g / L, KCl 0.5g / L, CaCl2·2H2O 0.17g / L, FeSO4·7H2O 10mg / L, calcium pantothenate 3.2mg / L, MnCl2·4H2O 3mg / L, ZnSO4·7H2O 3mg / L, NiSO4·6H2O 2mg / L, CuSO4·5H2O 2mg / L, CoCl2·6H2O0.04mg / L, Na2MoO4·2H2O 0.04mg / L, VB19.5 mg / L, VB 12 0.1 mg / L, fluridone 50 mg / L, ferulic acid 50-80 mg / L, pH is adjusted to 6.5, and the fluridone and ferulic acid are added 48-72 hours after the start of fermentation.

[0013] The specific culture conditions provided by the present invention are: temperature of 20-28° C., preferably 20° C.; rotation speed of 170-200 rpm; dissolved oxygen content controlled at 2%-10%, preferably 6%.

[0014] Furthermore, the present invention provides a bacterial agent, which comprises the Schizochytrium ALS01 or a fermentation product thereof.

[0015] Furthermore, the present invention provides a method for producing ω-3 polyunsaturated fatty acids, using the Schizochytrium ALS01 or the bacterial agent to ferment and obtain a product containing ω-3 polyunsaturated fatty acids.

[0016] Furthermore, the fermentation temperature is kept constant at 28°C.

[0017] Furthermore, the fermentation rotation speed is 350-450 r / min, the ventilation volume is 1-3 vvm, and the dissolved oxygen content is 30%-100%.

[0018] Furthermore, the culture medium involved in the fermentation process of the product containing ω-3 polyunsaturated fatty acids obtained by fermentation using the Schizochytrium ALS01 or the bacterial agent includes a primary seed culture medium, a secondary seed culture medium and a fermentation culture medium:

[0019] The primary seed culture medium includes: 20 g / L glucose, 1 g / L yeast extract, 5 g / L peptone, and 34 g / L sea crystal.

[0020] The secondary seed culture medium comprises: 30 g / L glucose, 10 g / L yeast powder, 12 g / L Na2SO4, 2 g / L MgSO4, 1 g / L KH2PO4, 1 g / L (NH4)2SO4, 0.65 g / L K2SO4, 0.5 g / L KCl, 0.17 g / L CaCl2·2H2O, and the pH value is adjusted to 6.5.

[0021] The fermentation medium comprises: 90 g / L glucose, 5 g / L sodium glutamate, 5 g / L corn steep liquor, 12 g / L Na2SO4, 2 g / L MgSO4, 1 g / L KH2PO4, 1 g / L (NH4)2SO4, 0.65 g / L K2SO4, 0.5 g / L KCl, 0.17 g / L CaCl2·2H2O, 1 mL / L trace element solution, 1 mL / L vitamin solution, and the pH value is adjusted to 6.5; the trace element solution comprises 10 mg / L FeSO4·7H2O, 3.2 mg / L calcium pantothenate, 3 mg / L MnCl2·4H2O, 3 mg / L ZnSO4·7H2O, 2 mg / L NiSO4·6H2O, 2 mg / L CuSO4·5H2O, 0.04 mg / L CoCl2·6H2O, and 0.17 g / L Na2MoO4·2H2O. 0.04 mg / L; the vitamin solution contains VB19.5 mg / L, VB 12 0.1 mg / L.

[0022] In addition, the present invention also claims to protect the use of Schizochytrium ALS01 in the preparation of ω-3 polyunsaturated fatty acids.

[0023] Furthermore, the ω-3 polyunsaturated fatty acids are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

[0024] Furthermore, the present invention also provides a product containing ω-3 polyunsaturated fatty acids, wherein the raw material of the product comprises at least one of the Schizochytrium ALS01, the bacterial agent or the product obtained by the method for producing ω-3 polyunsaturated fatty acids.

[0025] In addition, the product containing ω-3 polyunsaturated fatty acids is at least one of food, medicine or feed.

[0026] Compared with the prior art, the Schizochytrium ALS01 provided by the present invention can simultaneously ferment and produce high-yield EPA and DHA. After the Schizochytrium ALS01 is fermented in a common culture medium, it is found that the biomass can reach 76.48 g / L, the oil can reach 50.03 g / L, the average content of DHA is 46.02%, the average content of EPA is 10.11%, the average yield of DHA can reach 23.03 g / L, and the average yield of EPA can reach 5.06 g / L, which is an ideal microbial resource for producing a variety of ω-3 fatty acids. At the same time, the Schizochytrium ALS01 with high yields of EPA and DHA can not only reduce the production cost of EPA and DHA, but also meet the current growing demand for EPA, which is conducive to promoting the promotion and application of Schizochytrium production technology of EPA and DHA.

[0027] The microbial information of Schizochytrium ALS01 provided by the present invention: The Schizochytrium ALS01 (Schizochytrium sp. ALS01) was deposited in the China Center for Type Culture Collection on June 17, 2024, with the deposit number: CCTCC No: M 20241235, and the deposit address: Wuhan University, Wuhan, China, Postal Code: 430072. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a trend chart of biomass, lipid content and EPA content (percentage of lipids) of the original strain of Schizochytrium.

[0029] Figure 2 This is a trend chart of biomass, lipid content and EPA content (percentage of lipids) of Schizochytrium mutant strains. DETAILED DESCRIPTION

[0030] The present invention is further illustrated below through the description of specific implementation modes, but this is not a limitation of the present invention. Those skilled in the art can make various modifications or improvements based on the basic idea of ​​the present invention, but as long as they do not deviate from the basic idea of ​​the present invention, they are all within the scope of the present invention.

[0031] Example 1. Mutagenesis and screening methods of Schizochytrium

[0032] Step S1: Activation of strains: The Schizochytrium strains stored at -80°C were transferred to activation medium, cultured in a constant temperature incubator at 28°C for 3 days, a loop was scraped with an inoculation loop and placed in a seed culture medium, and cultured at 28°C and 200 r / min for 48 hours until the logarithmic growth phase;

[0033] The activation medium comprises: 20 g / L glucose, 5 g / L yeast extract, 12 g / L Na2SO4, 2 g / L MgSO4, 1 g / L KH2PO4, 1 g / L (NH4)2SO4, 0.65 g / L K2SO4, 0.5 g / L KCl, 0.17 g / L CaCl2·2H2O, and the pH is adjusted to 6.5;

[0034] The seed culture medium comprises: 30 g / L glucose, 10 g / L yeast powder, 12 g / L Na2SO4, 2 g / L MgSO4, 1 g / L KH2PO4, 1 g / L (NH4)2SO4, 0.65 g / L K2SO4, 0.5 g / L KCl, 0.17 g / L CaCl2·2H2O, and the pH value is adjusted to 6.5.

[0035] Step S2: UV mutagenesis: Select the Schizochytrium strain in the early logarithmic growth stage for UV mutagenesis. Spread the bacterial solution of Schizochytrium in the early logarithmic growth stage in step S1 evenly on the surface of a sterile solid culture medium and expose it to an irradiation intensity of 150 mJ / cm 2 Irradiate with ultraviolet light for 3 minutes; after irradiation, culture at 28°C for 48 hours in a dark environment to avoid the influence of light on mutagenesis, so that the cells can recover and form single colonies;

[0036] The solid culture medium comprises: 30 g / L glucose, 10 g / L yeast powder, 15 g / L agar, 12 g / L Na2SO4, 2 g / L MgSO4, 1 g / L KH2PO4, 1 g / L (NH4)2SO4, 0.65 g / L K2SO4, 0.5 g / L KCl, 0.17 g / L CaCl2·2H2O, and the pH value is adjusted to 6.5.

[0037] Step S3 strain screening: The single colony induced by ultraviolet in step S2 was inoculated into 200 mL of selective culture medium for further purification and amplification. After 48 hours of culture in the selective culture medium, the culture conditions in the selective culture medium were as follows: temperature of 20°C, rotation speed of 200 rpm, dissolved oxygen content controlled at 6%. After 48 hours of culture, sampling and testing began, and sampling and testing were performed every 12 hours until 120 hours of culture. Each time, 10 mL of samples were sampled for biomass, oil content, DHA and EPA content testing, and the test results were recorded. Finally, the mutant Schizochytrium sp. ALS01 was screened and obtained, which has been deposited in the China Center for Type Culture Collection with the deposit number of CCTCC M 20241235. The test results of the culture process of the Schizochytrium sp. ALS01 mutant are shown in Table 2 and Table 3. Figure 2 shown.

[0038] The solid culture medium comprises: 30 g / L glucose, 10 g / L yeast powder, 15 g / L agar, 12 g / L Na2SO4, 2 g / L MgSO4, 1 g / L KH2PO4, 1 g / L (NH4)2SO4, 0.65 g / L K2SO4, 0.5 g / L KCl, 0.17 g / L CaCl2·2H2O, and the pH value is adjusted to 6.5;

[0039] The selective culture medium includes: glucose 90 g / L, sodium alginate 35 g / L, sodium glutamate 5 g / L, yeast powder 5 g / L, Na2SO4 12 g / L, MgSO4 2 g / L, KH2PO4 1 g / L, (NH4)2SO4 1 g / L, K2SO4 0.65 g / L, KCl 0.5 g / L, CaCl2·2H2O 0.17 g / L, FeSO4·7H2O 10 mg / L, calcium pantothenate 3.2 mg / L, MnCl2·4H2O 3 mg / L, ZnSO4·7H2O 3 mg / L, NiSO4·6H2O 2 mg / L, CuSO4·5H2O 2 mg / L, CoCl2·6H2O 0.04 mg / L, Na2MoO4·2H2O 0.04 mg / L, VB19.5 mg / L, VB 12 0.1 mg / L, fluridone 50 mg / L, ferulic acid 80 mg / L, pH was adjusted to 6.5, and the fluridone and ferulic acid were added 48 to 72 hours after the start of fermentation.

[0040] Example 2: Cultivation method of mutant strain Schizochytrium ALS01

[0041] Step A seed culture: The mutant strain Schizochytrium sp. ALS01 obtained by screening in Example 1 was transferred for 3 generations at an inoculation rate of 1:10 (v / v) as a primary seed solution, 200 mL of the primary seed culture medium was placed in a 500 mL conical flask, and fermented for 48 hours at 28° C. and 200 r / min to obtain a seed solution; then, the seed solution was inoculated into a secondary seed culture medium at an inoculation rate of 1:10 (v / v), and fermented for 120 hours at 28° C. and 200 r / min to obtain a pre-cultured seed solution;

[0042] The primary seed culture medium includes: 20 g / L glucose, 1 g / L yeast extract, 5 g / L peptone, and 34 g / L sea crystal.

[0043] The secondary seed culture medium comprises: 30 g / L glucose, 10 g / L yeast powder, 12 g / L Na2SO4, 2 g / L MgSO4, 1 g / L KH2PO4, 1 g / L (NH4)2SO4, 0.65 g / L K2SO4, 0.5 g / L KCl, 0.17 g / L CaCl2·2H2O, and the pH value is adjusted to 6.5.

[0044] Step B: fermentation tank culture: a 5L stirred fermentation tank is used, the pre-cultured seed solution prepared in step A is inoculated into the fermentation medium at an inoculation rate of 1:10 (v / v), the temperature is automatically controlled to be constant at 28°C, the stirring speed is 400r / min, the ventilation volume is 1-3 / min (relative to the liquid volume), the dissolved oxygen content is controlled to be 60%, and after fermentation for 48h, the dissolved oxygen content is set to 100%, and the fermentation culture is continued for 120h;

[0045] The fermentation medium comprises: 90 g / L glucose, 5 g / L sodium glutamate, 5 g / L corn steep liquor, 12 g / L Na2SO4, 2 g / L MgSO4, 1 g / L KH2PO4, 1 g / L (NH4)2SO4, 0.65 g / L K2SO4, 0.5 g / L KCl, 0.17 g / L CaCl2·2H2O, 1 mL / L trace element solution, 1 mL / L vitamin solution, and the pH value is adjusted to 6.5; the trace element solution comprises 10 mg / L FeSO4·7H2O, 3.2 mg / L calcium pantothenate, 3 mg / L MnCl2·4H2O, 3 mg / L ZnSO4·7H2O, 2 mg / L NiSO4·6H2O, 2 mg / L CuSO4·5H2O, 0.04 mg / L CoCl2·6H2O, and 0.17 g / L Na2MoO4·2H2O. 0.04 mg / L; the vitamin solution contains VB19.5 mg / L, VB 12 0.1 mg / L.

[0046] Experimental Example 1: Comparison of biomass, lipid content, DHA and EPA content between the original strain and mutant strain of Schizochytrium

[0047] 1. Experimental methods:

[0048] The original strain of Schizochytrium was fermented and cultured according to the method of Example 2 after the strain activation step in step S1 of Example 1, and the fermentation culture was continued for 120 hours. The original strain of Schizochytrium and the Schizochytrium ALS01 mutant strain of Example 1 were sampled and tested after 48 hours of culture, and samples were taken every 12 hours for biomass, oil content, DHA and EPA content detection.

[0049] in:

[0050] 1.1. The method for extracting oil is as follows: weigh 10g of Schizochytrium dry powder, add 200mL of chloroform-methanol mixture (2:1), ultrasonicate for 30min, and extract for 24h; after filtering, the filtrate is shaken and washed with 50mL of 0.9% sodium chloride solution, poured into a separating funnel and allowed to stand for stratification; collect the chloroform in the lower layer, dry it with anhydrous sodium sulfate, and concentrate it under reduced pressure to obtain Schizochytrium oil.

[0051] 1.2. The detection methods for oil, DHA and EPA are as follows:

[0052] (1) Preparation of standard solution:

[0053] Accurately weigh appropriate amounts of DHA methyl ester and EPA methyl ester standards and add n-hexane to prepare a series of standard working solutions.

[0054] (2) Sample pretreatment:

[0055] Weigh 50 mg of algae oil sample, dissolve it in 5 mL of n-hexane, add 2 mol / L KOH methanol solution, reflux in a 70°C water bath for 5 min, centrifuge, take the upper n-hexane phase and filter it through a 0.22 μm microporous filter membrane. The filtrate is the sample solution to be tested.

[0056] (3) Chromatographic conditions:

[0057] Chromatographic column: HP-5 (30mx0.250mmx0.10μm); carrier gas: nitrogen; split ratio: 50:1; injection volume: 1μL; vaporizer temperature: 250℃; FID detector temperature: 300℃; programmed temperature: starting temperature is 50℃, increase the temperature to 120℃ at 20℃ / min, keep for 5min; increase the temperature to 180℃ at 6℃ / min, keep for 10min; increase the temperature to 210℃ at 5℃ / min, keep for 20min; increase the temperature to 250℃ at 10℃ / min, keep for 1min.

[0058] 2. Experimental results:

[0059] 2.1. The test results of the original strain culture process of Schizochytrium are shown in Tables 1 and Figure 1 As shown:

[0060] Table 1 Detection results of the original strain culture process of Schizochytrium

[0061]

[0062] Figure 1 This is a trend chart of biomass, lipid content and EPA content (percentage of lipids) of the original strain of Schizochytrium.

[0063] 2.2. The results of the culture process of Schizochytrium ALS01 mutant are shown in Tables 2 and Figure 2 As shown:

[0064] Table 2 Detection results of Schizochytrium mutant culture process

[0065]

[0066] Figure 2 This is a trend chart of biomass, lipid content and EPA content (percentage of lipids) of Schizochytrium mutant strains.

[0067] From Table 1 and Table 2, Figure 1 and Figure 2 By comparison, during the 120h fermentation process, the DHA and EPA contents produced by the Schizochytrium mutant strain were higher than those of the Schizochytrium original strain. At 120h, the EPA content produced by the Schizochytrium mutant strain was 15.88%, and the yield was 4.21g / L. Compared with the Schizochytrium original strain, the EPA yield was increased by more than 8 times, and the EPA content of the Schizochytrium mutant strain showed an upward trend during the fermentation process, while the Schizochytrium original strain showed a downward trend in the late fermentation period, indicating that the Schizochytrium ALS01 provided by the present invention is an ideal high-yield EPA Schizochytrium, which can effectively increase the yield of EPA. However, it is worth noting that the biomass of Schizochytrium ALS01 was suppressed in the selective culture medium and its culture conditions. After 120h of culture, only 52.61% of the biomass of the original strain under the fermentation culture conditions of Example 2 was obtained, which affected the total yield of EPA, and the cost of the fermentation culture scheme was relatively high.

[0068] Experimental Example 2: Large-scale culture experiment of Schizochytrium ALS01

[0069] 1. Experimental methods:

[0070] In order to increase the biomass of Schizochytrium ALS01, the mutant strain Schizochytrium ALS01 screened in Example 1 was used as the fermentation strain, and 6 sets of repeated experiments were carried out using the culture method of Example 2. First, the strain was amplified in a suitable culture medium through seed culture, and then transferred to a fermenter for large-scale culture.

[0071] After 120 hours of cultivation, the six groups of fermentation broths were centrifuged to remove impurities in the culture medium, and then the residual substances were removed by washing. Then, the precipitated bacteria were freeze-dried for long-term storage and subsequent biomass determination. Finally, each group of freeze-dried Schizochytrium bacteria was weighed to accurately calculate the biomass of each experimental group at the end of fermentation, and to detect the amount of fat, DHA and EPA content of each experimental group. The detection method is shown in Experimental Example 1.

[0072] 2. Experimental results:

[0073] The experimental results are shown in Table 3:

[0074] Table 3 Various test results of large-scale culture of Schizochytrium ALS01

[0075]

[0076] As shown in Table 3, the average amount of biomass of the Schizochytrium ALS01 provided by the present invention after fermentation reaches 76.48 g / L, the average amount of oil reaches 50.03 g / L, the average yield of DHA reaches 23.03 g / L, and the average yield of EPA reaches 5.06 g / L. Among them, the EPA content of 10.11% is significantly lower than that of 15.88% in Example 1, but it still belongs to a higher level content in the prior art, and the biomass is significantly increased, even 16.39% higher than the biomass of the original strain. In this way, under the conditions of a low-cost ordinary fermentation culture scheme, the EPA yield of Schizochytrium ALS01 is increased by 20.19%, which is more conducive to large-scale production.

[0077] The Schizochytrium ALS01 provided by the present invention can not only produce high-yield EPA, but also simultaneously produce high-content DHA, and is an ideal microbial resource for producing a variety of ω-3 fatty acids.

Claims

1. A Schizochytrium that produces high EPA, characterized in that: The Schizochytrium sp. ALS01 was deposited in the China Center for Type Culture Collection on June 17, 2024, with the deposit number: CCTCC No: M20241235.

2. The EPA-producing Schizochytrium according to claim 1, characterized in that The Schizochytrium ALS01 is obtained by ultraviolet mutagenesis technology and selective culture medium screening, wherein the ultraviolet irradiation intensity is 50-150 mJ / cm² and the irradiation time is 1-3 min.

3. The EPA-producing Schizochytrium according to claim 2, characterized in that The selective culture medium is composed of: glucose 90 g / L, sodium alginate 25-40 g / L, sodium glutamate 5 g / L, yeast powder 4-6 g / L, Na2SO4 12 g / L, MgSO4 2 g / L, KH2PO4 1 g / L, (NH4)2SO4 1 g / L, K2SO4 0.65 g / L, KCl 0.5 g / L, CaCl2·2H2O0.17 g / L, FeSO4·7H2O 10 mg / L, calcium pantothenate 3.2 mg / L, MnCl2·4H2O 3 mg / L, ZnSO4·7H2O 3mg / L, NiSO4·6H2O 2 mg / L, CuSO4·5H2O 2 mg / L, CoCl2·6H2O 0.04 mg / L, Na2MoO4·2H2O0.04 mg / L,VB1 9.5 mg / L,VB 12 0.1 mg / L, fluridone 50 mg / L, ferulic acid 50~80 mg / L, pH adjusted to 6.5, fluridone and ferulic acid were added 48~72 hours after the start of fermentation.

4. The EPA-producing Schizochytrium according to claim 3, characterized in that The culture conditions of the Schizochytrium ALS01 in the selective culture medium are: temperature of 20-28° C., rotation speed of 170-200 rpm, and dissolved oxygen content controlled at 2%-10%.

5. A bacterial agent, characterized in that: The bacterial agent comprises the Schizochytrium ALS01 or a fermentation product thereof according to claim 1.

6. A method for producing ω-3 polyunsaturated fatty acids, characterized in that A product containing ω-3 polyunsaturated fatty acids obtained by fermentation using the Schizochytrium ALS01 described in any one of claims 1 to 4 or the bacterial agent described in claim 5.

7. The method for producing ω-3 polyunsaturated fatty acids according to claim 6, characterized in that The fermentation temperature is constant at 28°C, the rotation speed is 350-450 r / min, the ventilation volume is 1-3 vvm, and the dissolved oxygen content is 30%-100%.

8. Use of the Schizochytrium ALS01 according to any one of claims 1 to 4 or the bacterial agent according to claim 5 in the preparation of ω-3 polyunsaturated fatty acids.

9. The use according to claim 8, characterized in that The ω-3 polyunsaturated fatty acids are EPA and DHA.

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