Strain of pseudogaurax and method for preparing natural blue-violet pigment therefrom and application thereof

Abstract

The application discloses a strain of Pseudogymnothrichum and a method for preparing natural blue-violet pigment by using the strain and application of the strain. Pseudoduganella sp. The strain can be used for fermentation biosynthesis of blue-violet pigment by using various carbon sources, the fermentation cycle of the strain is short, the yield of the pigment is high, the produced pigment has good thermal stability, and the pigment has biological activities such as antioxidation and antitumor. The strain, fermentation liquor and fermentation liquor extract of the strain can be used as dyes, edible pigments or indicators, and have wide application prospects in the fields of printing and dyeing, food, medicine, chemistry, chemical industry and packaging. The strain is a temperature-sensitive bacterium, and has potential application potential in the fields of environmental monitoring and biochips.

Description

Technical Field

[0001] This invention relates to a microbial strain and a method for preparing microbial pigments, particularly to a pseudodugong strain and a method for preparing natural blue-violet pigments, and its application. Background Technology

[0002] With social development and improved living standards, people are paying more attention to health, and natural pigments are highly favored for their safety, greenness, non-toxicity, and even bioactivity. Currently, there are three main ways to obtain natural pigments: extraction from plants and animals, chemical synthesis, and production using microbial fermentation technology. Among these, the production of natural pigments using microorganisms has advantages such as being unrestricted by seasons and raw materials, having a short production cycle, and relatively simple extraction processes, thus showing promising development prospects. The fermentation production of natural pigments such as red yeast rice pigment and carotenoids using microbial fermentation technology has become a reality, but the microbial fermentation production of natural pigments such as blue-violet pigment and green pigment has not yet been realized. Therefore, selecting and breeding microorganisms with the ability to synthesize natural pigments and developing new natural pigments has broad market prospects.

[0003] No published domestic or international patents or journal articles have reported on the production of blue-violet pigment by *Pseudodugongia* fungi, nor have they provided a *Pseudodugongia* strain capable of producing blue-violet pigment. However, this invention isolated and screened a *Pseudodugongia* strain from soil samples. Pseudoduganella sp.) QHDZ (patent accession number CCTCC NO: M 2021449) This strain can synthesize blue-violet pigment with a wide pH range of adaptability, good stability and antioxidant and anti-tumor biological activities using a variety of carbon sources. It has practical significance for the production of natural blue-violet pigment and its application in multiple fields. Summary of the Invention

[0004] The purpose of this invention is to provide a strain of *Pseudodugong*, a method for preparing natural blue-violet pigment, and its application. This invention isolates and screens a strain of *Pseudodugong* from soil. Pseudoduganella sp. The strain QHDZ (patent accession number CCTCC NO: M 2021449) has advantages such as high pigment synthesis level, short fermentation cycle, and low production cost. The blue-purple pigment QHDZ-P synthesized by this strain has good heat stability, stability under weakly alkaline and acidic conditions, and minimal impact from common food additives and ingredients. In addition, *Pseudoduranus* (… Pseudoduganella sp. The blue-purple pigment produced by QHDZ also possesses antioxidant and antitumor bioactivities, and has potential application value in the fields of food, medicine, printing and dyeing, and chemical industry. Furthermore, this strain can be used in combination with other strains or its fermentation products can be compounded with other compounds.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] False dugong strains, said strains include False dugong fungi ( Pseudoduganella sp. GHDZ CCTCCNO: M 2021449; *Pseudodugong* ( Pseudoduganella sp. Resting cells of QHDZ CCTCC NO: M 2021449; and *Pseudodugong* ( Pseudoduganella sp. Fermentation broth and its cell extract of QHDZ CCTCC NO: M 2021449.

[0007] Preparation of microbial-derived blue-violet pigment from *Pseudoduranus* QHDZ includes the following preparation methods:

[0008] Preserved pseudodugong fungus ( Pseudoduganella sp. The strain QHDZ CCTCC NO: M 2021449 was activated using conventional methods. One loopful of the culture was then inoculated into liquid seed culture medium and cultured at 20-30 ℃ and 150-200 r / min for 18-24 h to prepare a liquid seed. The prepared liquid seed was then transferred into fermentation medium (inoculum 4%) and cultured at 20-30 ℃ and 150-200 r / min for 1.5-2 days. The culture medium is as follows:

[0009] Slant culture medium: soluble starch 2%, KNO3 0.1%, K2PO4·3H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, agar 2%, pH 7.0-7.2;

[0010] Seed culture medium: soluble starch 2%, KNO3 0.1%, K2PO4·3H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, agar 2%, pH 7.0-7.2;

[0011] The fermentation medium formula 1 is as follows: sucrose 5%, potassium nitrate 0.2%, K2PO4·3H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, pH 6.0-7.0;

[0012] After centrifuging the fermentation broth obtained according to the above method to collect the bacterial cells, extract the blue-purple pigment. Centrifuge the fermentation broth at 10000 r / min for 10 min to collect the bacterial cells, wash three times with deionized water, and then add anhydrous ethanol at a ratio of 1:40-60 of bacterial cells to anhydrous ethanol solution. Mix well, sonicate at 40℃ and 500W for 30 min, centrifuge at 10000 r / min for 10 min, and collect the supernatant. The obtained supernatant is the blue-purple pigment extract. Concentrate the extract under vacuum at a constant temperature of 60℃, and then freeze-dry under vacuum at -80℃ and 0.01 MPa for 24 h. The obtained dry matter is the blue-purple pigment extract.

[0013] The method for preparing natural blue-purple pigment by the *Pseudodugong* strain, wherein the fermentation medium formula 1 is: sucrose 5%, potassium nitrate 0.2%, K2PO4·3H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, pH 6.0-7.0.

[0014] The method for preparing natural blue-purple pigment by the aforementioned *Pseudodugong* strain, wherein the fermentation medium formula 2 is: soluble starch 4%, beef extract 0.1%, K2PO4·3H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, pH 6.0-7.0.

[0015] The method for preparing natural blue-purple pigment by the *Pseudodugong* strain, wherein the fermentation medium formula 3 is: soluble starch 3%, sucrose 3%, potassium nitrate 0.1%, K2PO4·3H2O 0.05%, MnSO4·H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, pH 6.0-7.0.

[0016] The method for preparing natural blue-purple pigment from *Pseudodugong* strains, wherein the extraction agent is methanol, acetone, ethyl acetate or other organic solvents.

[0017] Applications of *Pseudodugong* strains, including the following:

[0018] 1) *Pseudodugong* fungi ( Pseudoduganella sp. The fermentation broth, bacterial cells, and cell extracts of GHDZ CCTCC NO: M 2021449 are used in pharmaceutical manufacturing.

[0019] 2) *Pseudodugong* fungi ( Pseudoduganella sp. The fermentation broth, bacterial cells, and cell extracts of QHDZ CCTCC NO: M 2021449 are used in the fields of printing and dyeing, food, chemicals, chemical engineering, and packaging.

[0020] 3) Pseudoduran ( Pseudoduganella sp. QHDZ CCTCC NO: M 2021449 Applications of bacterial cells, produced enzymes and their DNA extracts in environmental monitoring and biochip manufacturing;

[0021] 4) *Pseudodugong* fungi ( Pseudoduganella sp. Blue-violet pigment prepared by QHDZ CCTCC NO: M 2021449 and its application;

[0022] 5) Pseudoduran ( Pseudoduganella sp The application of the blue-purple pigment produced by QHDZ CCTCC NO: M 2021449 in the preparation of drugs for treating malignant tumors, wherein the compound is the fermentation broth or cell extract of the strain; malignant tumors include, but are not limited to, human lung cancer cells A549 and human degenerative lung cancer cells Calu-6.

[0023] The advantages and positive effects of this invention are:

[0024] (1) The pseudodugong fungus provided by this invention ( Pseudoduganella sp. QHDZ, CCTCC NO: M 2021449, is a typical new strain. Its optimal growth medium is Gao's No. 1, with an optimal growth temperature of 20-25℃, a minimum growth temperature of 0-4℃, a maximum growth temperature of 30℃, and an optimal growth pH of 6.0-8.0. It exhibits the characteristic of producing blue-purple pigment and is characterized by simple culture conditions and rapid reproduction. This strain has been identified as *Pseudoduranus*. Pseudoduganella sp. ).

[0025] (2) The pseudodugong fungus isolated and screened in this invention ( Pseudoduganella sp. QHDZ, CCTCC NO: M2021449, can produce large quantities of blue-violet pigment through fermentation, featuring a short fermentation cycle, simple extraction method, and environmentally friendly production process. Using this strain, the pigment yield can reach 483.95 mg / L. The blue-violet pigment has a maximum absorption peak at 570 nm. It exhibits a DPPH free radical scavenging rate of 20.4%, a hydroxyl free radical scavenging rate of 28.96%, and an ABTS free radical scavenging rate of 31.65%. The pigment has high thermal stability, with a loss rate of only 3.2% at 80℃. The pigment consists of two components in a 1:9 ratio, with the main component QHDZ-P-2 showing significant inhibitory effects on human lung cancer cells A549 and human degenerative lung cancer cells Calu-6. (Note: The last sentence about *Pseudoduranus* appears unrelated and likely refers to a different strain.) Pseudoduganella sp. The blue-purple pigment produced by QHDZ CCTCC NO: M 2021449 can be used as a pigment and dye, and also has potential applications in the food, pharmaceutical, and chemical industries. Attached Figure Description

[0026] Figure 1 It belongs to the genus *Pseudodus* ( Pseudoduganella sp. Colony morphology of strain QHDZ, accession number CCTCC NO: M 2021449;

[0027] Figure 2 It belongs to the genus *Pseudodus* ( Pseudoduganella sp. Fermentation broth of strain QHDZ, preservation number CCTCC NO: M 2021449;

[0028] Figure 3 It belongs to the genus *Pseudodus* ( Pseudoduganella sp. A photograph (1000×) of strain QHDZ, accession number CCTCC NO: M 2021449, under an optical microscope.

[0029] Figure 4 It belongs to the genus *Pseudodus* ( Pseudoduganella sp. Scanning electron microscope image of strain QHDZ, accession number CCTCC NO: M 2021449;

[0030] Figure 5 It belongs to the genus *Pseudodus* ( Pseudoduganella sp Photograph of the crystalline morphology of the blue-purple pigment QHDZ-P produced by strain QHDZ (CCTCC NO: M 2021449);

[0031] Figure 6 It belongs to the genus *Pseudodus* ( Pseudoduganella sp Photograph of the blue-purple pigment QHDZ-P in anhydrous ethanol solution produced by strain QHDZ (CCTCC NO: M 2021449);

[0032] Figure 7 It belongs to the genus *Pseudodus* ( Pseudoduganella sp .) The UV-Vis full-wavelength scanning spectrum of the blue-violet pigment QHDZ-P produced by strain QHDZ (CCTCC NO: M 2021449);

[0033] Figure 8 It belongs to the genus *Pseudodus* ( Pseudoduganella sp .) Mass spectrum of the blue-purple pigment component QHDZ-P-2 produced by strain QHDZ (accession number CCTCC NO: M 2021449);

[0034] Figure 9 It belongs to the genus *Pseudodus* ( Pseudoduganella sp The 1H NMR spectrum of the blue-violet pigment component produced by strain QHDZ (CCTCC NO: M 2021449) is shown in Figure 1.

[0035] Figure 10 It belongs to the genus *Pseudodus* (Pseudoduganella sp .) Carbon NMR spectrum of the blue-violet pigment QHDZ-P-2 produced by strain QHDZ (accession number CCTCC NO: M2021449);

[0036] Figure 11 It belongs to the genus *Pseudodus* ( Pseudoduganella sp. The blue-purple pigment QHDZ-P-2 produced by strain QHDZ (CCTCC NO: M2021449) has an inhibitory effect on human non-small cell lung cancer A549.

[0037] Figure 12 It belongs to the genus *Pseudodus* ( Pseudoduganella sp. The blue-purple pigment QHDZ-P-2 produced by strain QHDZ (CCTCC NO: M2021449) has an inhibitory effect on human degenerative lung cancer Calu-6.

[0038] Figure 13 It belongs to the genus *Pseudodus* ( Pseudoduganella sp The effect of the blue-purple pigment QHDZ-P-2 produced by strain QHDZ (CCTCC NO: M2021449) on apoptosis in non-small cell lung cancer A549 cells. Detailed Implementation

[0039] The following is a specific example of a pseudodugong fungus in conjunction with the present invention. Pseudoduganella sp. QHDZ, deposited on April 25, 2021 at the China Center for Type Culture Collection (CCTCC NO. M), accession number: CCTCC NO: M 2021449. This study investigated the extraction and screening of a strain of *Pseudoduranus* isolated from soil. Pseudoduganella sp. The blue-purple pigment QHDZ-P can be obtained by fermenting QHDZ cells and then extracting the cells with organic solvents. This pigment exhibits a maximum absorption peak at 570 nm. It demonstrates high thermal stability; temperatures below 80℃ have no effect on its stability, and after treatment at 100℃ for 9 hours, the pigment's color value retention rate remains above 86%. At concentrations of 0.01 mg / mL to 0.05 mg / mL, QHDZ-P exhibits scavenging abilities of 20.4% and 28.96% against DPPH and hydroxyl radicals, respectively, both showing a positive dose-response relationship. The pigment's scavenging rate against DPPH radicals is higher than that of vitamin E at the same concentration, while its scavenging ability against hydroxyl radicals is lower. Within the concentration range of 0.05 mg / mL to 0.25 mg / mL, QHDZ-P achieves a scavenging ability of 31.65% against ABTS radicals, and at 0.25 mg / mL, its scavenging rate is approximately three times that of vitamin E at the same concentration.

[0040] The blue-purple pigment QHDZ-P produced by this strain consists of two components: purple QHDZ-P-1 and blue QHDZ-P-2, with a mass ratio of approximately 1:9. QHDZ-P-2 exhibits significant inhibitory effects on both non-small cell lung cancer (NSCLC) A549 cells and human degenerative lung cancer (Calu-6) cells. Testing showed that pigment QHDZ-P-2, at concentrations between 6.25 μmol / mL and 100 μmol / mL, inhibited the proliferation of NSCLC A549 cells, and this inhibition was positively correlated with the administered concentration. At concentrations between 50 μmol / mL and 200 μmol / mL, pigment QHDZ-P-2 significantly induced apoptosis in NSCLC A549 cells, with the apoptosis rate increasing with increasing concentration.

[0041] Therefore, using pseudodugong fungus ( Pseudoduganella sp In addition to its use as a pigment and dye, the blue-violet pigment produced by QHDZ is also a potential bioactive substance with antioxidant and antitumor activities, and has broad application prospects.

[0042] A method for preparing blue-violet pigment from the pseudodugong strain QHDZ, the method comprising the following steps:

[0043] Preserved pseudodugong fungus ( Pseudoduganella sp. After activation using conventional methods, strain QHDZ CCTCC NO: M 2021449 was inoculated into a liquid seed culture medium and cultured at 20-30 ℃ and 180 r / min for 18-24 h to prepare a liquid seed. The prepared liquid seed was then transferred into a fermentation medium (inoculation amount 4%) and cultured at 20-30 ℃ and 180 r / min for 48 h. To extract the blue-purple pigment, the fermentation broth was centrifuged at 10000 r / min for 10 min to collect the bacterial cells. Then, it was mixed with anhydrous ethanol at a material-to-liquid ratio of 1:60 and sonicated at 40 ℃ for 30 min. The supernatant was then collected by centrifugation at 10000 r / min for 10 min. The obtained supernatant was the blue-purple pigment extract. The pigment extract was concentrated under vacuum at a constant temperature of 60 ℃ and then freeze-dried under vacuum at -80 ℃ and 0.01 MPa for 24 h to obtain the blue-purple pigment extract.

[0044] The method for preparing blue-violet pigment by the aforementioned pseudodugong strain, wherein the fermentation medium formula 1 is: sucrose 5%, potassium nitrate 0.2%, K2PO4·3H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, pH 6.0-7.0.

[0045] The method for preparing blue-purple pigment by the aforementioned pseudodugong strain, wherein the fermentation medium formula 2 is: soluble starch 4%, beef extract 0.1%, K2PO4·3H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, pH 6.0-7.0.

[0046] The method for preparing blue-violet pigment by the aforementioned *Pseudodugong* strain, wherein the fermentation medium formula 3 is: soluble starch 3%, sucrose 3%, potassium nitrate 0.1%, K2PO4·3H2O 0.05%, MnSO4·H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, pH 6.0-7.0.

[0047] The present invention will be further described in detail below with reference to the embodiments shown in the accompanying drawings. Specific Implementation Example 1:

[0049] Preserved pseudodugong fungus ( Pseudoduganella sp. The strain CCTCC NO: M 2021449 was activated using conventional methods. One loopful of the culture was then inoculated into liquid seed medium and cultured at 20-30 ℃ and 180 r / min for 18-24 h to prepare liquid seed. The prepared liquid seed was then transferred into fermentation medium (inoculation amount 4%) and cultured at 20-30 ℃ and 180 r / min for 1.5-2 days. The cell count in the fermentation broth of this strain can reach 22-25 g / L.

[0050] Slant culture medium: soluble starch 2%, KNO3 0.1%, K2PO4·3H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, agar 2%, pH 7.0-7.2.

[0051] Seed culture medium: soluble starch 2%, KNO3 0.1%, K2PO4·3H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, agar 2%, pH 7.0-7.2.

[0052] The fermentation medium formula 1 is as follows: sucrose 5%, potassium nitrate 0.2%, K2PO4·3H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, pH 6.0-7.0.

[0053] After centrifuging the fermentation broth obtained according to the above method to collect the bacterial cells, the blue-purple pigment was extracted. The fermentation broth was centrifuged at 10000 r / min for 10 min to collect the bacterial cells, which were then washed three times with deionized water. Anhydrous ethanol was then added at a ratio of 1:30-60 (bacterial cells to anhydrous ethanol solution), mixed thoroughly, and ultrasonicated at 40℃ and 500W for 30 min, followed by centrifugation at 10000 r / min for 10 min. The supernatant obtained was the blue-purple pigment extract. This extract was concentrated under vacuum at a constant temperature of 60℃, and then freeze-dried under vacuum at -80℃ and 0.01 MPa for 24 h. The resulting dry matter was the blue-purple pigment extract. Specific Implementation Example 2:

[0055] Preserved pseudodugong fungus ( Pseudoduganella sp. The strain CCTCC NO: M 2021449 was activated using conventional methods. One loop of the culture was then inoculated into liquid seed medium and cultured at 20-30℃ and 180 r / min for 18-24 h to prepare liquid seed. The prepared liquid seed was then transferred into fermentation medium (inoculation amount 4%) and cultured at 20-30℃ and 180 r / min for 1.5-2 days. The cell count in the fermentation broth of this strain can reach 22-25 g / L.

[0056] Slant culture medium: soluble starch 2%, KNO3 0.1%, K2PO4·3H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, agar 2%, pH 7.0-7.2.

[0057] Seed culture medium: soluble starch 2%, KNO3 0.1%, K2PO4·3H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, agar 2%, pH 7.0-7.2.

[0058] The fermentation medium formula 2 is as follows: soluble starch 4%, beef extract 0.1%, K2PO4·3H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, pH 6.0-7.0.

[0059] After centrifuging the fermentation broth obtained according to the above method to collect the bacterial cells, the blue-purple pigment was extracted. The fermentation broth was centrifuged at 10000 r / min for 10 min to collect the bacterial cells, washed three times with deionized water, and then methanol was added at a ratio of 1:30-60 (bacterial cells to methanol solution) and mixed thoroughly. The mixture was then sonicated at 40℃ and 500W for 30 min, followed by centrifugation at 10000 r / min for 10 min. The supernatant obtained was the blue-purple pigment extract. This extract was concentrated under vacuum at a constant temperature of 60℃, and then freeze-dried under vacuum at -80℃ and 0.01 MPa for 24 h to obtain the blue-purple pigment extract. Specific Implementation Example 3:

[0061] Preserved pseudodugong fungus ( Pseudoduganella sp. The strain CCTCC NO: M 2021449 was activated using conventional methods. One loop of the culture was then inoculated into liquid seed medium and cultured at 20-30℃ and 180 r / min for 18-24 h to prepare liquid seed. The prepared liquid seed was then transferred into fermentation medium (inoculation amount 4%) and cultured at 20-30℃ and 180 r / min for 1.5-2 days. The cell count in the fermentation broth of this strain can reach 22-25 g / L.

[0062] Slant culture medium: soluble starch 2%, KNO3 0.1%, K2PO4·3H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, agar 2%, pH 7.0-7.2.

[0063] Seed culture medium: soluble starch 2%, KNO3 0.1%, K2PO4·3H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, agar 2%, pH 7.0-7.2.

[0064] The fermentation medium formula 3 is as follows: soluble starch 3%, sucrose 3%, potassium nitrate 0.1%, K2PO4·3H2O 0.05%, MnSO4·H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, pH 6.0-7.0.

[0065] After centrifuging the fermentation broth obtained according to the above method to collect the bacterial cells, the blue-purple pigment was extracted. The fermentation broth was centrifuged at 10000 r / min for 10 min to collect the bacterial cells, washed three times with deionized water, and then acetone was added at a ratio of bacterial cell volume to acetone solution of 1:30-60. The mixture was then sonicated at 40℃ and 500W for 30 min, followed by centrifugation at 10000 r / min for 10 min to collect the supernatant. The supernatant obtained was the blue-purple pigment extract. This extract was concentrated under vacuum at a constant temperature of 60℃, and then freeze-dried under vacuum at -80℃ and 0.01 MPa for 24 h to obtain the blue-purple pigment extract. Specific Implementation Example 4:

[0067] Pseudoduran ( Pseudoduganella sp The blue-purple pigment produced by CCTCC NO: M 2021449 is used as a multifunctional pigment in food and pharmaceutical production. Specific Implementation Example 5:

[0069] Pseudoduran ( Pseudoduganella sp The blue-purple pigment produced by CCTCC NO: M 2021449 is used as an anti-tumor drug or in combination with other anti-tumor drugs for the treatment of tumors. Specific Implementation Example 6:

[0071] Pseudoduran ( Pseudoduganella sp The blue-violet pigment produced by CCTCC NO: M 2021449 is used as a dye for fabric dyeing. Specific Implementation Example 7:

[0073] Pseudoduran ( Pseudoduganella sp The blue-purple pigment produced by CCTCC NO: M 2021449 is used as a colorant in the production of plastic products. Specific Implementation Example 8:

[0075] Pseudoduganella sp. (CCTCC NO: M 2021449) bacterial cells, the enzymes they produce, and their DNA extracts are used in environmental monitoring, biochip manufacturing, etc.

[0076] The pseudodugong fungus provided through the above series of embodiments ( Pseudoduganella sp CCTCC NO: M2021449 is a typical new strain. The optimal growth temperature for this strain is 20℃-30℃, and the pH value is 6.0-7.0. This strain has a good ability to produce blue-violet pigment and is characterized by simple culture conditions and rapid reproduction. (The text then abruptly shifts to a seemingly unrelated topic about *Pseudoduranus*.) Pseudoduganella spThe blue-violet pigment produced through fermentation exhibits a maximum absorption peak at 570 nm and demonstrates superior overall scavenging efficacy against DPPH, hydroxyl, and ABTS free radicals compared to vitamin E at the same concentration. This pigment exhibits high thermal stability; temperatures below 80℃ have no effect on the blue-violet pigment, and after heating at 100℃ for 9 hours, the pigment's color value retention rate remains above 86%. The main components of this pigment show significant inhibitory effects on human lung cancer cells A549 and human degenerative lung cancer cells Calu-6. These characteristics demonstrate the clear application value of this strain.

[0077] The above embodiments are merely examples to clearly illustrate the present invention and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

[0078] Preservation information:

[0079] Strain name: Pseudoduran ( Pseudoduganellasp.QHDZ )

[0080] Deposit date: April 25, 2021

[0081] Preservation Institution: China Center for Type Culture Collection (CCTCC NO. M)

[0082] Location of collection: Wuhan University, Wuhan, China

[0083] Accession number: CCTCC NO: M 2021449

[0084] sequence list

[0085] Shenyang University of Chemical Technology

[0086] False dugong strains, their methods for preparing natural blue-violet pigment, and their applications

[0087] SEQ ID NO.1

[0088] 1460bp

[0089] DNA

[0090] Pseudoduganella sp

[0091] .

Claims

1. False dugong Pseudoduganella sp. A method for preparing natural blue-violet pigment from strain GHDZ, characterized in that, The preparation steps include the following: The preserved *Pseudoduranus* GHDZ strain was activated using conventional methods. One loopful of the culture was then inoculated into liquid seed culture medium and cultured at 20-30℃ and 150-200 r / min for 18-24 h to prepare liquid seed. The prepared liquid seed was then transferred into fermentation medium at an inoculum rate of 4% and cultured at 20-30℃ and 150-200 r / min for 1.5-2 days. After centrifuging the fermentation broth obtained according to the above method to collect the bacterial cells, the blue-purple pigment was extracted: the fermentation broth was centrifuged at 10000 r / min for 10 min to collect the bacterial cells, washed 3 times with deionized water, and then anhydrous ethanol was added at a ratio of bacterial cell volume to anhydrous ethanol solution of 1:40-60 and mixed well. The mixture was ultrasonically treated at 40℃ and 500W for 30 min, and then centrifuged at 10000 r / min for 10 min to collect the supernatant. The supernatant obtained was the blue-purple pigment extract. The extract was concentrated under vacuum at a constant temperature of 60℃, and then freeze-dried under vacuum at -80℃ and 0.01 MPa for 24 h. The resulting dry matter was the blue-purple pigment extract. The conventional activation method involves activation using an agar slant culture medium; the composition of the agar slant culture medium is: 2% soluble starch, 0.1% KNO3, 0.05% K2PO4·3H2O, 0.05% MgSO4·7H2O, 0.05% NaCl, 0.001% FeSO4·7H2O, 2% agar, pH 7.0-7.2; Seed culture medium: soluble starch 2%, KNO3 0.1%, K2PO4·3H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, agar 2%, pH 7.0-7.2; There are three fermentation medium formulations, specifically: Fermentation medium formulation 1: sucrose 5%, potassium nitrate 0.2%, K2PO4·3H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, pH 6.0-7.0; Fermentation medium formula 2: soluble starch 4%, beef extract 0.1%, K2PO4·3H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, pH 6.0-7.0; Fermentation medium formula 3: soluble starch 3%, sucrose 3%, potassium nitrate 0.1%, K2PO4·3H2O 0.05%, MnSO4·H2O 0.05%, MgSO4·7H2O 0.05%, NaCl 0.05%, FeSO4·7H2O 0.001%, pH 6.0-7.0; The GHDZ accession number for the pseudodugong fungus is: CCTCC NO: M 2021449.

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