Siderophore compound Fraberin B as well as fermentation strain and fermentation method of siderophore compound Fraberin B

Abstract

The invention relates to a siderophore compound Fraberin B as well as a fermentation strain and a fermentation method thereof. The fermentation strain is a microunit strain 09-2044; the siderophore compound Fraberin B is prepared by fermentation of the fermentation strain, and the siderophore compound Fraberin B is prepared by fermentation of the fermentation strain. The fermentation method comprises the following steps: S1, fermenting a micromonas strain 09-2044 to obtain fermentation liquor; s2, the fermentation liquor is treated through extraction and reversed phase chromatography, and the siderophore compound Fraberin B is obtained. The siderophore compound Fraberin B disclosed by the invention has relatively strong capability of combining iron ions, provides a precursor compound for research and development of novel antibiotics, and has important value for development and utilization of marine drug resources in China.

Description

Technical Field

[0001] This invention relates to the technical field of microbial fermentation, and in particular to a ferphilic compound Fraberin B, its fermentation strain, and fermentation method. Background Technology

[0002] Microbial secondary metabolites are a crucial component of natural products, with a significant number of natural drug products or their lead compounds being produced by microorganisms or through interactions between microorganisms and their hosts. Deep-sea microorganisms, through long-term evolution to adapt to their extreme environments, have developed growth, metabolic regulation, and chemical defense mechanisms distinct from those of terrestrial microorganisms. The unique metabolites synthesized by these microorganisms possess rich chemical structural diversity. Penicillin, which ushered in the antibiotic era, and subsequent macrolide antibiotics like erythromycin, were both produced by microorganisms. However, in recent years, antibiotic resistance has become increasingly serious. Studies have shown that the current rate of antibiotic resistance spread exceeds the rate at which new antibiotics are introduced into clinical practice. Researching antibiotic resistance and developing new antibacterial methods has become an urgent issue for human self-protection. Antibiotics obtained through traditional target and screening methods cannot fundamentally solve the problem of bacterial resistance; finding new ways to treat resistance has become a frontier and hot topic in current scientific research.

[0003] Siderophores prepared under experimental conditions can couple with antibiotics to form antibiotic-siderophore couplers, which can circumvent antibiotic resistance and represent a novel antibacterial agent. Siderophores are small molecule compounds secreted by microorganisms that chelate with iron ions. After chelation, they are recognized by specific outer membrane receptors and transported into the cytoplasm for microbial use. Microorganisms require sufficient iron ions to grow, but Fe3+ is usually present in ferritin, preventing direct utilization. Therefore, siderophore-mediated ferric ion absorption systems are crucial. Furthermore, the deep-sea environment is naturally low in iron ions, suggesting that the ocean, especially the deep sea, may be a major source for obtaining new types of siderophores in the future. Siderophores play a vital regulatory role in metabolic processes. Therefore, research on siderophores has significant theoretical guiding implications. With further research, siderophores will play an important role in many more fields. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the first objective of this invention is to provide a ferrophilic compound Fraberin B, which can be used to prepare the ferrophilic compound Fraberin B by fermentation.

[0005] The second objective of this invention is to provide a fermentation strain of the heptaphilic compound Fraberin B, which has a strong ability to bind iron ions, providing a precursor compound for the research and development of novel antibiotics and having important value for the development and utilization of China's marine drug resources.

[0006] The third objective of this invention is to provide a fermentation method for the heptaphilic compound Fraberin B, which is relatively simple to operate and can stably prepare the heptaphilic compound Fraberin B through clear steps and reasonable condition control.

[0007] To achieve the first objective mentioned above, the present invention provides the following technical solution:

[0008] A fermentation strain of the iron-loving compound Fraberin B, wherein the fermentation strain is Micromonospora sp. 09-2044, and its taxonomic name is Micromonospora sp., was deposited at the Guangdong Provincial Microbial Culture Collection Center on August 12, 2025, with the accession number GDMCC NO.66834.

[0009] To achieve the second objective mentioned above, the present invention provides the following technical solution:

[0010] Fraberin B, a hematophilic compound, is prepared by fermentation using the above-mentioned fermentation strain; and the hematophilic compound Fraberin B is selected from compounds represented by the following formula (I), or from stereoisomers, prodrugs, crystal forms, pharmaceutically acceptable salts, pharmaceutically acceptable esters, or pharmaceutically acceptable solvates of the compound.

[0011] .

[0012] Specifically, in the "fraberin B" of the present invention,

[0013] The specific meaning of "stereoisomer" is that when it is specifically designated by chemical name as (R)- or (S)- isomer, it should be understood as having a predominant configuration of (R)- or (S)- isomer, respectively; any asymmetric carbon atom may exist in (R)-, (S)- or (R, S)- configurations, preferably in (R)- or (S)- configuration;

[0014] The specific meaning of "crystal form" refers to the crystal structure of a substance. During crystallization, various factors can affect the bonding patterns within or between molecules, causing molecules or atoms to arrange themselves differently in the crystal lattice, thus forming different crystal structures. The compounds of this invention can exist in one crystal structure or multiple crystal structures, i.e., they have "polymorphism". The compounds of this invention can exist in different crystal forms.

[0015] The term "pharmaceutically acceptable salt" specifically refers to a salt formed by an acidic functional group (e.g., a carboxyl group) present in the compounds provided by the present invention and a suitable inorganic or organic cation (base), or a salt formed by a basic functional group (e.g., an amino group) present in the compounds provided by the present invention and a suitable inorganic or organic anion (acid); non-limiting examples include quaternary ammonium salts, acetates, adipic acid salts, camphorates, alginates, citrates, aspartate salts, benzoates, benzenesulfonates, maleates, and hydrogen sulfates. Butyrate, camphor sulfonate, diglucuronate, glyceryl phosphate, hemisulfate, heptaate, hexanoate, fumarate, hydrochloride, hydrobromide, 2-hydroxyethanesulfonate (isothiosulfate), lactate, methanesulfonate, hydroiodate, nicotinate, 2-naphthalenesulfonate, oxalate, palmitate, pectate, persulfate, picrate, neopentanoate, propionate, succinate, tartrate, thiocyanate, phosphate, 3-phenylpropionate, glutamate, bicarbonate, p-toluenesulfonate, and undecanoate;

[0016] The quaternary ammonium salt is composed of C1-C6 alkyl halides, dialkyl sulfate esters, and C6 alkyl halides. 12 ~C 18 Alkyl halides and C6~C 10 One of the aryl halides is obtained by quaternization; the alkyl group of the C1-C6 alkyl halide is one of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, and isobutyl, and the halide is one of chloride, bromide, and iodide; the dialkyl sulfate is one of dimethyl sulfate, diethyl sulfate, dibutyl sulfate, and dipentyl sulfate; the C 12 ~C 18 The alkyl group of the alkyl halide is one of dodecyl, decyl, tetradecyl, and octadecyl, and the halide is one of chloride, bromide, and iodide; the C6~C 10 The aryl halide is one of benzyl bromide and phenethyl bromide;

[0017] Meanwhile, the acid in the salt is one of hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, oxalic acid, maleic acid, succinic acid, and citric acid;

[0018] The term "pharmaceutically acceptable ester" specifically refers to an ester formed by the carboxyl group present in the compound provided by the present invention and a suitable alcohol; non-limiting examples include formate, acetate, propionate, butyrate, acrylate, ethyl succinate, stearic acid ester, or palmitate; the ester can undergo hydrolysis in the presence of acid or base to produce the corresponding acid or alcohol.

[0019] The specific meaning of "pharmaceutically acceptable solvate" refers to a compound existing in combination with a solvent molecule; the terms "solvent" and "solvent" are used interchangeably. This combination may include a stoichiometric amount of a solvent, such as a monohydrate or dihydrate, or may include any amount of water; for example, methanol or ethanol can form an "alcohol," which may be stoichiometric or non-stoichiometric. As used herein, the term "solvent" refers to a solid form, that is, a compound in solution of a solvent that, while solvable, is not a solvate as used herein.

[0020] To achieve the third objective mentioned above, the present invention provides the following technical solution:

[0021] A fermentation method for the heptaphilic compound Fraberin B includes the following steps:

[0022] S1 fermented micromonospora strain 09-2044 to obtain fermentation broth; wherein, the micromonospora strain 09-2044 is classified as Micromonospora sp., and was deposited at Guangdong Provincial Microbial Culture Collection Center on August 12, 2025, with accession number GDMCC NO.66834.

[0023] S2 obtained Fraberin B, a hematophilic compound represented by formula (Ⅰ), by processing the fermentation broth with extraction and reversed-phase chromatography;

[0024] .

[0025] Furthermore, the specific implementation of S1 is as follows:

[0026] S11 Micromonas strain 09-2044 was inoculated onto a plate medium, and after cultivation, Micromonas colonies were obtained. The plate medium was prepared from the following raw materials in weight percentage: tryptone 0.8-1.2 wt%, yeast extract 0.4-0.6 wt%, sodium chloride 0.8-1.2 wt%, agar 1.0-3.0 wt%, and the balance being deionized water, with a pH of 7-8.

[0027] S12 involves inoculating Micromonas colonies onto a fermentation medium and, after shaking culture, obtaining a fermentation broth. The fermentation medium is made from the following raw materials in weight percentage: starch 0.8-1.2 wt%, glycerol 0.8-1.2 wt%, glucose 0.8-1.2 wt%, yeast extract 0.1-0.3 wt%, peptone 0.1-0.3 wt%, sodium chloride 0.05-0.2 wt%, calcium carbonate 0.2-0.4 wt%, corn starch 0.2-0.3 wt%, with the balance being deionized water, and a pH of 7-8.

[0028] Further, in S11, the plate culture medium is made from raw materials comprising the following weight percentages: 0.96 wt% tryptone, 0.48 wt% yeast extract, 0.96 wt% sodium chloride, 1.9 wt% agar, with the balance being deionized water, pH 7-8.

[0029] Furthermore, in step S11, the culture temperature is controlled at 25~35℃, and the culture time is 5~7 days.

[0030] Further, in S12, the fermentation medium is made from raw materials comprising the following weight percentages: starch 0.96 wt%, glycerol 0.96 wt%, glucose 0.96 wt%, yeast extract 0.19 wt%, peptone 0.19 wt%, sodium chloride 0.10 wt%, calcium carbonate 0.29 wt%, corn starch 0.24 wt%, with the balance being deionized water, pH 7-8.

[0031] Furthermore, in S12, the fermentation temperature is controlled at 25~35℃, the rotation speed is 150~200ppm, and the fermentation time is 5~7 days.

[0032] Furthermore, the specific implementation of S2 is as follows:

[0033] S21 The fermentation broth was sequentially subjected to solid-liquid separation, filtrate evaporation under reduced pressure and ethyl acetate extraction. The organic phase was collected and ethyl acetate was removed by reduced pressure distillation to obtain crude extract.

[0034] S22 dissolved the crude extract in methanol, filtered to remove insoluble matter, and then purified it by rapid preparative liquid chromatography, gel column LH-20 and reversed-phase high-performance liquid chromatography, respectively. The eluent was collected and evaporated to dryness under reduced pressure to obtain the heptaphilic compound Fraberin B.

[0035] Furthermore, in S22, the rapid preparation liquid chromatography conditions include a mobile phase of methanol and water, elution with a methanol concentration gradient of 20wt%, 40wt%, 60wt%, 80wt%, and 100wt%, and an ODS reversed-phase column.

[0036] Furthermore, in S22, the gel column LH-20 conditions include a drop rate of 3 s / drop, a fraction of 12 min / tube, for a total of 100 tubes.

[0037] Further, in S22, the reversed-phase high-performance liquid chromatography conditions include: a mobile phase of methanol and water, an elution time of 40-45 min, a flow rate of 2-4 mL / min, a ZORBAX SB-C18 reversed-phase column, an elution process in which the concentration of methanol in the mobile phase increases from 20 v / v% to 48 v / v%, a detection wavelength of 210 nm, and collection of the eluent with a retention time of 19.5 min.

[0038] In summary, the beneficial technical effects of the present invention are as follows:

[0039] 1. The present invention isolates and screens a small single-celled strain 09-2044, which, when cultured in a selected medium, can be used for fermentation to prepare Fraberin B, a compound containing the ironophile class, and has good industrialization potential and application prospects.

[0040] 2. Fraberin B, a heptaphilic compound of the present invention, possesses a unique chemical structure and excellent performance, and can be used as a synthetic precursor for the preparation of novel antibiotic drugs. From a chemical structure perspective, the compound structure shown in formula (I) endows it with a special chelating ability with iron ions, enabling it to play a highly efficient role in the heptaphilic-mediated ferric ion absorption system. In terms of performance, the antibiotic-heptaphilic coupling compound formed by its coupling with antibiotics can effectively circumvent the problem of antibiotic resistance, providing a new approach to solving the challenge of bacterial resistance. Verification has shown that Fraberin B has a strong ability to bind iron ions, providing a precursor compound for the research and development of novel antibiotics, and is of significant value for the development and utilization of China's marine drug resources.

[0041] 3. The preparation method of this invention is relatively simple to operate. Through clear steps and reasonable condition control, the ferophile compound Fraberin B can be stably prepared. Moreover, the raw materials of the culture medium used in the fermentation process are widely available and low in cost, which is conducive to large-scale industrial production, reducing production costs and improving production efficiency. In particular, by precisely controlling the composition and ratio of the plate culture medium and the fermentation culture medium, as well as the culture temperature, time, rotation speed and other conditions, a suitable environment is provided for the growth and fermentation of the small monocellular strain 09-2044, which is conducive to the efficient fermentation of the strain to produce the target compound. In the extraction and purification stage, a series of methods such as solid-liquid separation, extraction, vacuum distillation and various chromatographic purifications are used to effectively remove impurities and obtain high-purity ferophile compound Fraberin B. Attached Figure Description

[0042] Figure 1 This is a colony morphology diagram of the Micromonas colonies cultured in Example 2 of the present invention.

[0043] Figure 2 This is the peak elution result diagram of Fraberin B, a heptaphilic compound prepared in Example 2 of this invention.

[0044] Figure 3 This is the 1H-NMR spectrum of Fraberin B, a heptaphilic compound from Example 3 of this invention.

[0045] Figure 4 This is the 13C-NMR spectrum of Fraberin B, a heptaphilic compound from Example 3 of this invention.

[0046] Figure 5 This is a graph showing the detection results of Fraberin B, a hematophilic compound, added to the CAS reagent in Example 3 of the present invention; from left to right, it represents the CAS detection reagent, the compound solution, and the mixture, respectively.

[0047] Figure 6 This is a graph showing the detection results of Fraberin B, a hematophilic compound, added to 2% FeCl3 detection reagent in Example 3 of the present invention; from left to right, it represents 2% FeCl3 detection reagent, compound solution, and mixture, respectively.

[0048] This invention provides micromonospora strain 09-2044, with accession number GDMCC NO.66834, accession date August 12, 2025, accession location Guangdong Provincial Microbial Culture Collection Center (GDMCC), accession address 5th Floor, Experimental Building, No. 100 Xianlie Middle Road, Yuexiu District, Guangzhou, Guangdong Province, postcode: 510075, and classification name micromonospora sp. Detailed Implementation

[0049] To make the technical means, creative features, objectives and effects of this invention clearer and easier to understand, the invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0050] Example 1: This invention discloses a fermentation strain of the heptaphilic compound Fraberin B. The fermentation strain is a micromonospora strain 09-2044. 16S rRNA gene analysis confirmed that it belongs to the marine micromonospora strain. The nucleotide sequence contains the nucleotide sequence shown in SEQ ID No:1. Its classification name is Micromonospora sp., and it was deposited at the Guangdong Provincial Microbial Culture Collection Center on August 12, 2025, with the accession number GDMCC NO.66834.

[0051]

[0052] The original method of obtaining the micromonotrophic strain 09-2044: The strain was obtained from seabed sediments collected by the Fujian Institute of Microbiology, which were then processed and provided to us as the micromonotrophic strain.

[0053] Example 2: A fermentation method for Fraberin B, a heptaphilic compound disclosed in this invention, includes the following steps:

[0054] S1 fermentation of the small single-celled strain 09-2044 from Example 1 yielded the fermentation broth;

[0055] The specific implementation of S1 is as follows:

[0056] S11 First, dissolve 10g tryptone, 5g yeast extract, and 10g sodium chloride in 1L of water, sterilize at 121℃ for 20min, and allow to reach the natural pH to obtain a plate culture medium. Then, streak the Micromonas strain 09-2044 onto the plate culture medium and incubate at 30℃ for 5 days to obtain Micromonas colonies. The colony morphology is shown in the attached figure. Figure 1 As shown;

[0057] S12 First, dissolve 10g starch, 10g glycerol, 10g glucose, 2g yeast extract, 2g peptone, 1g sodium chloride, 3g calcium carbonate and 2.5g corn starch in water and bring the volume to 1L. Sterilize at 121℃ for 20min and allow the pH to return to normal. Then, inoculate Micromonas colonies onto the fermentation medium and shake to culture. After the culture is complete, the fermentation broth is obtained.

[0058] S2 was obtained by extracting and processing the fermentation broth with reversed-phase chromatography to obtain the heptaphilic compound Fraberin B;

[0059] The specific implementation of S2 is as follows:

[0060] S21 The fermentation broth was centrifuged at 4000 rpm for 12 min, the supernatant was collected, the filtrate was evaporated under reduced pressure and dried, and then fully extracted with ethyl acetate solution. The ethyl acetate solution fraction was collected, and the ethyl acetate solution was removed by reduced pressure distillation to obtain the crude extract.

[0061] S22 dissolved the crude extract in methanol, filtered to remove insoluble matter, and then purified it by rapid preparative liquid chromatography, gel column LH-20 and reversed-phase high performance liquid chromatography, respectively. The eluent was collected and evaporated to dryness under reduced pressure to obtain the heptaphilic compound Fraberin B.

[0062] The rapid preparative liquid chromatography conditions include a mobile phase of methanol and water, elution with a methanol concentration gradient of 20wt%, 40wt%, 60wt%, 80wt%, and 100wt%, and an ODS reversed-phase column.

[0063] The LH-20 gel column conditions included a drop rate of 3 s / drop, a fraction of 12 min / tube, for a total of 100 tubes;

[0064] The reversed-phase high-performance liquid chromatography (RP-HPLC) conditions included a mobile phase of methanol and water, an elution time of 40–45 min, a flow rate of 2–4 mL / min, a ZORBAX SB-C18 reversed-phase column, and during elution, the concentration of methanol in the mobile phase increased from 20 v / v% to 48 v / v%. The detection wavelength was 210 nm. The peak values ​​are shown in the attached figure. Figure 2 As shown, the eluent of the peak with a retention time of 19.5 min was collected;

[0065] After being evaporated to dryness under reduced pressure, 7.6 mg of the target compound was obtained and recorded as Fraberin B, a hematophilic compound. The compound was tested for its properties and was found to be a pale yellow solid and soluble in DMSO solvent.

[0066] Example 3: Fraberin B, a heparinoid compound disclosed in this invention, was dissolved in d6-DMSO. The 1H-NMR spectrum of Fraberin B prepared in Example 3 is shown below. Figure 3 As shown, the 13C-NMR spectrum dissolved in d6-DMSO is as follows: Figure 4 As shown in Table 1, the classification of the heptaphilic compound Fraberin B is as follows.

[0067] Table 1

[0068] Position δC, Type δH (J in Hz) 1 <![CDATA[22.6, CH3]]> 1.8(s) 2 168.9, C - 3 <![CDATA[38.4, CH2]]> 3.0 (m, J = 6.6 Hz) 4 <![CDATA[28.8, CH2]]> 1.4 (m, J = 7.3 Hz) 5 <![CDATA[23.5, CH2]]> 1.2(m) 6 <![CDATA[26.0, CH2]]> 1.5 (m, J=7.2Hz) 7 <![CDATA[47.0, CH2]]> 3.5 (t, J = 7.0 Hz) 8 173.4, C - 9 <![CDATA[25.0, CH2]]> 2.3 (m, J=7.6Hz) 10 <![CDATA[8.9, CH3]]> 1.0 (t, J = 7.5 Hz)

[0069] As shown in Table 1, the structure of Fraberin B, a heptaphilic compound of the present invention, is as follows:

[0070] .

[0071] The obtained ferrophilic compound Fraberin B was added to the CAS detection reagent for detection, and the results are as follows: Figure 5 As shown in the figure. The results showed that the reagent changed from blue-purple to red, indicating that the compound has ferrophilic binding activity.

[0072] The obtained ferrophilic compound Fraberin B was added to a 2% FeCl3 detection reagent for testing, and the results are as follows: Figure 6 As shown in the figure. The results showed that the reagent changed from yellow to brown, indicating that the compound can bind with iron ions.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A fermentation strain of the heptaphilic compound Fraberin B, characterized in that: The fermentation strain is Micromonospora strain 09-2044, classified as Micromonospora sp., and was deposited at Guangdong Provincial Microbial Culture Collection Center on August 12, 2025, with accession number GDMCC NO.66834.

2. A ferrophilic compound, Fraberin B, characterized in that: It is prepared by fermentation using the fermentation strain according to claim 1; and the iron-loving compound Fraberin B is selected from the compound shown in formula (I), or from the stereoisomer, prodrug, crystal form, pharmaceutically acceptable salt, pharmaceutically acceptable ester or pharmaceutically acceptable solvate of the compound; 。 3. A fermentation method for a hematophilic compound, Fraberin B, characterized in that: Includes the following steps, S1 fermentation, according to the fermentation strain described in claim 1, yields a fermentation broth; S2 obtained Fraberin B, a hematophilic compound represented by formula (Ⅰ), by processing the fermentation broth with extraction and reversed-phase chromatography; 。 4. The fermentation method for the iron-loving compound Fraberin B according to claim 3, characterized in that: The specific implementation of S1 is as follows: S11 Micromonas strain 09-2044 was inoculated onto a plate medium, and after cultivation, Micromonas colonies were obtained. The plate medium was prepared from the following raw materials in weight percentage: tryptone 0.8-1.2 wt%, yeast extract 0.4-0.6 wt%, sodium chloride 0.8-1.2 wt%, agar 1.0-3.0 wt%, and the balance being deionized water, with a pH of 7-8. S12 involves inoculating Micromonas colonies onto a fermentation medium and, after shaking culture, obtaining a fermentation broth. The fermentation medium is made from the following raw materials in weight percentage: starch 0.8-1.2 wt%, glycerol 0.8-1.2 wt%, glucose 0.8-1.2 wt%, yeast extract 0.1-0.3 wt%, peptone 0.1-0.3 wt%, sodium chloride 0.05-0.2 wt%, calcium carbonate 0.2-0.4 wt%, corn starch 0.2-0.3 wt%, with the balance being deionized water, and a pH of 7-8.

5. The fermentation method for the heptaphilic compound Fraberin B according to claim 4, characterized in that: In S11, the culture temperature is controlled at 25~35℃ and the culture time is 5~7 days.

6. The fermentation method for the iron-loving compound Fraberin B according to claim 4, characterized in that: In S12, the fermentation temperature is controlled at 25~35℃, the rotation speed is 150~200ppm, and the fermentation time is 5~7 days.

7. The fermentation method for the iron-loving compound Fraberin B according to claim 3, characterized in that: The specific implementation of S2 is as follows: S21 The fermentation broth was sequentially subjected to solid-liquid separation, filtrate evaporation under reduced pressure and ethyl acetate extraction. The organic phase was collected and ethyl acetate was removed by reduced pressure distillation to obtain crude extract. S22 dissolved the crude extract in methanol, filtered to remove insoluble matter, and then purified it by rapid preparative liquid chromatography, gel column LH-20 and reversed-phase high-performance liquid chromatography, respectively. The eluent was collected and evaporated to dryness under reduced pressure to obtain the heptaphilic compound Fraberin B.

8. The fermentation method for the iron-loving compound Fraberin B according to claim 7, characterized in that: In S22, the rapid preparation liquid chromatography conditions include a mobile phase of methanol and water, elution with a methanol concentration gradient of 20wt%, 40wt%, 60wt%, 80wt%, and 100wt%, and an ODS reversed-phase column.

9. The fermentation method for the heptaphilic compound Fraberin B according to claim 7, characterized in that: In S22, the gel column LH-20 conditions include a drop rate of 3 s / drop, a fraction of 12 min / tube, for a total of 100 tubes.

10. The fermentation method for the heptaphilic compound Fraberin B according to claim 7, characterized in that: In S22, the reversed-phase high-performance liquid chromatography (RP-HPLC) conditions include: a mobile phase of methanol and water; an elution time of 40-45 min; a flow rate of 2-4 mL / min; a ZORBAX SB-C18 reversed-phase column; an increase in the concentration of methanol in the mobile phase from 20 v / v% to 48 v / v% during elution; a detection wavelength of 210 nm; and collection of the eluent with a retention time of 19.5 min.

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