CN116790690A - Method for producing prodigiosin by fermenting sugarcane molasses and beet molasses - Google Patents

Abstract

The invention discloses a method for producing prodigiosin by fermenting cane molasses and beet molasses. Aiming at Serratia marcescens PG-Zeno-001 strain developed in the early stage of the company, on one hand, by optimizing the formula of a fermentation medium, byproducts of sugar cane molasses and beet molasses in the sugar industry are used as carbon sources for prodigiosin production; on the other hand, a method for producing the prodigiosin by using the fermentation medium is also provided, and in the large-scale fermentation of a 100L fermentation tank, the prodigiosin yield of 48 h can reach 16.18 g/L at most. The invention can greatly reduce the cost of prodigiosin fermentation production and is hopeful to construct a new closed loop for sugar industry environment-friendly production.

Description

Method for producing prodigiosin by fermenting sugarcane molasses and beet molasses

Technical Field

The invention relates to the technical field of fermentation engineering, in particular to a method for producing prodigiosin by fermenting cane molasses and beet molasses.

Background

Prodigiosin (Prodigiosin) has a chemical formula of C20H25N3O and a molecular mass of 323.1968 g mol ^-1 The melting point is 151-152 ℃, the methoxy pyrrole skeleton structure with 3 pyrrole rings is provided, 2 pyrrole rings are connected through C-C delta-bond, the other pyrrole ring is connected through methine, and the pyrrole ring has a strong absorption peak at 535nm of ultraviolet visible spectrum, thus the pyrrole ring is a red microbial pigment with green reflection. Prodigiosin was at the earliest isolated from secondary metabolites produced by Serratia marcescens (Serratia marcescens), and researchers have also tried to use new products in recent yearsChassis strains such as Streptomyces (Streptomyces), vibrio (Vibrio), and Pseudomonas (Pseudomonas putida), but are not ideal.

The most widely used prodigiosin is a traditional dyeing agent in textile printing industry at present, and the prodigiosin has the effects of resisting bacteria, malaria, tumors and the like, can induce T, B lymphocyte apoptosis, and is interesting for researchers in medicine, pharmacy and different industries. The anti-cancer drug has antibacterial activity on pathogenic microorganisms, cell movement of synthetic bacteria, transcriptional synthesis regulation and control of products and the like, particularly has a special action mechanism in the aspect of inducing cancer cell apoptosis, and is considered to be an anti-cancer drug with great development potential. The natural prodigiosin has the characteristic of light instability, and the micro-nano encapsulation technology is an effective method for improving the stability of natural pigment. At present, the main encapsulation technologies include spray drying, freeze drying, emulsion, agglomeration, liposome, inclusion complex, nano encapsulation and the like. In addition, in the field of novel functional materials, since prodigiosin has pH response color-changing characteristics, in the field of material science, pH response color-changing performance and biodegradable color-changing films are recently reported to have wide application prospects in the aspects of marking, packaging, base materials and the like. However, wild-type Serratia marcescens has a lower prodigiosin yield and does not have the ability to be produced on a large scale. If prodigiosin is to be truly utilized, breakthrough must be made in the breeding of high-yield strains. It has been reported in the literature that the mutagenesis treatment of S.marcescens jx1 by microwave mutagenesis technique increases the prodigiosin yield of the bacterium from 3.1 g/L to 6.5 g/L. On the other hand, the existing prodigiosin producing strain generally has the characteristic of poor substrate tolerance, and the biological activity of the prodigiosin producing strain at high concentration is drastically reduced, so that the further improvement of the yield is restricted.

In addition, it has been found that ultraviolet radiation affects the stability of prodigiosin, and that this stability is also affected by the pH, the higher the pH, the greater the effect. The pigment is stable at the pH of 3, the pigment content can still be kept about 83% of the original pigment content after 1h of ultraviolet irradiation, and the content is obviously reduced after ultraviolet irradiation under alkaline conditions. In addition, the absorbance of the pigment was found to decrease sharply after the pigment was irradiated with direct outdoor light. The loss rate of the pigment at 7h of irradiation was as high as 92%, which suggests that the pigment is unstable under direct light, probably because the double bonds in the pyrrole ring of the red pigment are destroyed. Serratia marcescens has conditional pathogenicity, genetic operation tools are not mature, the period of gene modification is long, the effect is probably not obvious, and the traditional mutation screening has the advantages of high mutation rate, low cost, high strain stability and the like, and is the most effective mode for screening non-model microorganisms at present.

Through earlier researches, serratia marcescens NRRL B-1481 (purchased from ATCC) is taken as an initial strain, the initial strain is subjected to composite mutagenesis by means of ARTP and ultraviolet mutagenesis, the mutated strain is further screened by improving substrate concentration, culture pH and illumination intensity, a high-yield strain of prodigiosin which is tolerant to high substrate concentration and high light tolerance, namely Serratia marcescens ZN (the preservation name is Serratia marcescens PG-Zeno-001 strain which is preserved in China center for type culture collection, the preservation number is CCTCC M2023361) is obtained, and a fermentation method using the fermentation strain is provided.

It has been reported that most of the prodigiosin production processes use sucrose as a carbon source, which is costly and that the use of sucrose in large quantities during fermentation is prone to competition with the human food chain. For example, CN102002469B discloses a method for producing prodigiosin by fermentation, wherein the carbon source of the fermentation medium is one or more of glycerol, mannitol, sucrose, glucose, fructose, soybean oil and sesame oil, and the optimum yield of prodigiosin is 9.10g/L. CN103436476B discloses a prodigiosin producing strain, its preparation method and application, its fermentation culture medium contains per liter: 0.5 to 1g of sodium chloride, 1g of monopotassium phosphate, 3g of dipotassium phosphate, 1 to 1.2g of ammonium chloride, 1g of magnesium sulfate, 2g of ammonium nitrate, 20 to 50g of fructose or sucrose, 0.1 to 0.5g of yeast powder and the balance of water, and pH7.0 to 8.0; the yield of the prodigiosin can reach 120mg/L after fermentation for 24 hours. CN111548977B discloses a Serratia marcescens engineering bacterium and application thereof in prodigiosin production, wherein the fermentation medium comprises 15-25 g/L sucrose, 10-20 g/L beef extract and 5-15 g/L CaCl ₂ 5-10 g/L proline, 0.1-0.3 g/L MgSO ₄ ·7H ₂ O and 0.04-0.08 g/L FeSO ₄ ·7H ₂ O; the yield of prodigiosin was fermented for 96 hours and was about 5.83 g/L. CN113549643A discloses a method for improving Serratia marcescens to synthesize prodigiosin by overexpressing gene psrB, wherein the fermentation medium comprises 1.5-2.5% of sucrose, 1.0-2.0% of beef extract and CaCl ₂ 0.75-1.25%, L-proline 0.5-1.0% and MgSO ₄ ·7H ₂ 0.0025 to 0.0035 percent of O; the yield of prodigiosin reaches 6.84g/L after 72h fermentation. All of the above patent documents use sucrose or the like as a carbon source, and have high fermentation cost and low prodigiosin yield (for example, not more than 10 g/L), resulting in high prodigiosin production cost. The search of alternative carbon sources to reduce prodigiosin production cost has important significance.

Molasses is one of the byproducts of the sugar industry and can be classified into cane molasses, beet molasses, soybean molasses, etc. according to the sugar raw materials. The nutritional components of different molasses types are different, and the carbohydrate content in the molasses accounts for about 60% of the total solid content, and contains a large amount of fermentable sugar (mainly sucrose). The cost is low, the production cost can be obviously reduced when the fermentation substrate is used, and the fermentation substrate is a good fermentation raw material. Because of the specificity of molasses materials, they are currently sold only as feeds and few reports are available for the production of bulk chemicals, and therefore development and utilization of molasses materials are particularly important.

CN106754550a discloses a serratia PFMP-5 strain culture and application for controlling vegetable root-knot nematode disease, which is described in claim 3 as "the culture medium is NA culture medium, the formula is molasses 3%, ammonium sulfate 10%, peptone 5%, calcium carbonate 0.5%, and the balance is water" by mass percent; however, in paragraphs 38-45 of the detailed description, "wherein the medium used in steps 1, 2 and 3 is NA medium" is also described. Wherein, the formula of the culture medium used in the step 4 comprises the following components in percentage by mass: 3% of molasses, 10% of ammonium sulfate, 5% of peptone, 0.5% of calcium carbonate and the balance of water. First, the document describes that there is a conflict between the steps 1 to 3 and 4, and it is not possible to determine whether the NA medium is used in the same manner as in step 1 to 3 (according to the claims) or whether the medium is used in a different formulation (according to the examples of the specification). Secondly, the "NA medium" is generally designated in the art as a "Nutrient Agar medium" (i.e., NA) which is usually provided with a nitrogen source in beef extract powder, peptone, and Agar as a coagulant (see standard "Nutrient Agar medium" of YY/T0577-2005 issued by the national food and drug administration), which is obviously unsuitable for liquid seed culture and mixed fermentation culture, whereas the NA medium is used as a medium for liquid seed culture (paragraph 44 of the specification) and fermentation culture (claims 1 to 3), which is reasonably suspected by those skilled in the art to be incapable of achieving the corresponding object of the invention. Again, the feed carbon sources employed in this document are glucose and glycerol (paragraph 46 of the specification) rather than molasses, and it is clear that this document does not give any clear teaching of substituting molasses for glucose or the like as the fermentation carbon source. Finally, molasses is available in a variety of sources, and molasses of different sources also brings about a significant difference in fermentation efficiency, and this document does not disclose the specific source of molasses. It can be seen that based on the disclosure of this document, it is still not clear to the person skilled in the art how to substantially reduce the cost of prodigiosin fermentation production.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a novel fermentation production process of prodigiosin, so as to improve the conversion rate of products and reduce the production cost of prodigiosin.

In a first aspect, the present invention provides a fermentation medium for producing prodigiosin comprising: tryptone 5-7.5 g/L, peanut cake powder 2.5-4 g/L, caCl ₂ 2.5 to 4.0 g/L, 4.8 to 5.2 g/L of sodium chloride, 20 to 25 mL/L of cane molasses or 25 to 30 mL/L of beet molasses, 0.5 to 1 g/L of glycine, 0.5 to 1 g/L of proline and 0.8 to 1.2 mL/L of defoamer. Hydrochloric acid is used for adjusting the pH value of the fermentation medium to 6.0, the fermentation medium is sterilized for 20 minutes by damp heat at 121 ℃, and the fermentation medium is cooled for standby.

Besides sucrose contained in molasses, common carbon sources such as glycerol, mannitol, sucrose, glucose, fructose, vegetable oil, animal oil and the like are not additionally added into the fermentation medium, so that the fermentation cost is reduced.

Molasses is commercially available and is produced by concentrating waste soaking liquid in the process of producing edible sucrose, so that the cost is extremely low. The inventor finds that the fermentation culture medium prepared by taking cane molasses or beet molasses as a carbon source instead of sucrose is most suitable for prodigiosin producing strain PG-Zeno-001 which is self-ground by the company, and determines that the optimal concentration of the prodigiosin producing strain PG-Zeno-001 is 20 mL/L of cane molasses and 25-30 mL/L of beet molasses respectively.

In a second aspect, the present invention provides a fermentation production method of prodigiosin, characterized in that Serratia marcescens is fermented using the medium as described above to produce prodigiosin. Serratia marcescens is Serratia marcescens PG-Zeno-001 strain which is preserved in China Center for Type Culture Collection (CCTCC) with the preservation number of CCTCC M2023361 in the year of 2023 and the month of 20.

Preferably, the prodigiosin fermentation production method comprises the following steps:

(1) Selection of fermentation strains: the strain is Serratia marcescens (Serratia marcescens) PG-Zeno-001;

(2) Preparing a fermentation medium: tryptone 5-7.5 g/L, peanut cake powder 2.5-4 g/L, caCl ₂ 2.5 to 4.0 g g/L, 5.0 g g/L sodium chloride, 20 g mL/L cane molasses or 30 g mL/L beet molasses, 0.5 to 1g g/L glycine, 0.5 to 1g g/L proline, 1g mL/L defoamer, adjusting the pH of the culture medium to 6.0 by using hydrochloric acid, sterilizing for 20 minutes at 121 ℃ by damp heat, and cooling for later use;

(3) Preparing a feed medium: tryptone 300 g/L, peanut cake powder 50 g/L, cane molasses 400 mL/L or beet molasses 600 mL/L, proline 10g/L, pH not adjusted, sterilizing at 121deg.C for 20 min under moist heat, and cooling;

(4) Preparing an inclined plane: inoculating LB inclined plane with the fermentation strain glycerol tube for activation culture, and culturing at constant temperature of 25-30 ℃ for 24-48 h to obtain an inclined plane, and refrigerating the inclined plane for later use;

(5) Shake flask seed culture: inoculating the slant strain obtained in the step (4) into a shake flask filled with a shake flask LB seed medium to be sterilized, and culturing at 200 rpm at 25-30 ℃ for 8 h;

(6) Primary seed culture: inoculating the shake flask seeds cultured in the step (5) into a sterilized 10L first-stage seed tank filled with 5L LB medium according to a volume ratio of 1%, and starting to culture, wherein the culture conditions are as follows: aeration rate is 0.3-1.5 VVM, tank pressure is 0.1 Mpa, temperature is 25-30 ℃, saturation of dissolved oxygen is 1-80%, and culture time is 10 h;

(7) Fermenting in a fermentation tank: inoculating the first-level seeds cultured in the step (6) into a sterilized 100L fermentation tank filled with 50L fermentation medium according to the volume ratio of 5-10%, and starting to culture; culture conditions: initial ventilation of 0.3 VVM, tank pressure of 0.1 Mpa, temperature of 25-30 ℃ and cultivation time of 48-96 hours; the dissolved oxygen control scheme is as follows: an initial rotation speed of 0-12 h is 200 rpm, the rotation speed is slowly increased to 350 rpm along with the reduction of dissolved oxygen, and then the dissolved oxygen is controlled by 30% in association with the dissolved oxygen through stirring; 12-36 h, controlling 15% of dissolved oxygen by associating the dissolved oxygen with the feed, 36-h, and finally reducing the stirring speed to 200 rpm, and controlling 10% of dissolved oxygen by associating the dissolved oxygen with the feed.

In clear contrast to CN106754550a, glucose and glycerol are not added to the feed medium of the present invention, but instead cane molasses or beet molasses is still used as a source of fermentation carbon, thereby greatly reducing the cost of producing prodigiosin by fermentation.

Based on the technical scheme, the invention can obtain the following beneficial effects:

1. in response to the national double-carbon target, the invention innovatively uses the low-cost cane molasses raw material as a carbon source for the large-scale production of prodigiosin, remodels the novel process for the low-cost large-scale production of prodigiosin, and surprisingly discovers that compared with other carbon sources, cane molasses and beet molasses have better substitution effects on cane sugar, and is hopeful to construct a novel closed loop for the environment-friendly production of the traditional sugar industry.

2. The fermentation medium with optimized components is used for fermenting and producing the prodigiosin, and the prodigiosin yield of 48 h can reach 16.18 g/L in large-scale fermentation of a 100L fermentation tank.

Drawings

FIG. 1 is a bar graph of wet weight of thalli and prodigiosin content for different carbon source species in shake flask fermentation;

FIG. 2 is a bar graph of cell wet weight and prodigiosin content at different concentrations of sugar cane molasses and beet molasses in shake flask fermentation;

FIG. 3 is a fermentation progress curve for 100L fermentation using cane molasses;

FIG. 4 is a fermentation progress curve for a 100L fermentation using beet molasses.

Detailed Description

Example 1 screening of carbon sources produced by fermentation

In order to reduce the carbon source cost of the prodigiosin fermentation and determine the optimal carbon source of the prodigiosin fermentation, 5 g/L sucrose, glycerol, glucose, cane molasses, beet molasses, soybean molasses, corn starch hydrolysate, wheat starch hydrolysate and sweet potato starch hydrolysate are respectively selected as alternative carbon sources for shake flask experiments. The operation steps are as follows:

(1) Sucrose, glycerol, glucose, cane molasses, beet molasses, and soybean molasses are all commercially available, whereas starchy materials such as corn starch hydrolysate, wheat starch hydrolysate, and sweet potato starch hydrolysate are obtained by treatment with starch hydrolyzing enzymes purchased from novelin (china) investment limited;

(2) Preparation of the fermentation strain: the strain is Serratia marcescens (Serratia marcescens) PG-Zeno-001 and is stored in a glycerol pipe;

(3) Preparing an inclined plane: inoculating the fermentation strain from a glycerol tube to an LB inclined plane for activation culture, culturing at a constant temperature of 25-30 ℃ for 24-48 hours to obtain an inclined plane, and refrigerating the inclined plane for later use;

(4) Culturing test tube seeds: inoculating the slant strain obtained in the step (2) into a sterilized test tube filled with 5 mL of LB seed culture medium, and culturing at 25-30 ℃ for about 8 h;

(5) Preparing a fermentation medium: tryptone 5-7.5 g/L, peanut cake powder 2.5-4 g/L, caCl ₂ 2.5 to 4.0 g/L, 5.0 g/L sodium chloride, and the concentration of the carbon source to be selected is regulated to be basically the same as the concentration of sucrose or glucose,Glycine 0.5-1 g/L, proline 0.5-1 g/L, defoamer 1 mL/L; the pH of the medium was adjusted to 6.0 using hydrochloric acid; sterilizing at 121deg.C for 20 min, and cooling to room temperature; according to the experimental requirements, the concentration of the carbon source mother liquor is changed, and the carbon source mother liquor of an experimental group is shown in table 1 (groups 1 to 9);

(6) Fermentation culture: inoculating the test tube seeds cultured in the step (3) into a sterilized 500 mL shake flask containing 100 mL fermentation medium according to a volume ratio of 1%, and starting culturing, wherein the culturing conditions are as follows: after culturing at 25 to 130℃and 200 rpm for 48 hours, the final fermentation broth was examined for wet weight of cells and prodigiosin unit yield, and the results of each group are shown in Table 1.

Table 1: shaking flask experiment results of different carbon sources

Firstly, different types of single carbon sources, namely sucrose, glycerol, glucose, cane molasses, beet molasses, soybean molasses, corn starch hydrolysate, wheat starch hydrolysate and sweet potato starch hydrolysate are compared as alternative carbon sources, and shake flask fermentation screening is carried out. As shown in Table 1, among the three analytical grade carbon sources (sucrose, glycerol and glucose), sucrose was found to have the best fermentation effect, and the wet weight of the cells was 20.4. 20.4 g/L, and the final prodigiosin fermentation yield was 3.5. 3.5 g/L, which was similar to the results reported in the literature. It is remarkable that the fermentation effect of glucose is the worst, the biomass of the bacteria is only 44.1% of that of the experimental group using sucrose, and the final prodigiosin yield is only 0.4 g/L. The above results indicate that sucrose is the most favorable carbon source for Serratia marcescens to produce and accumulate pigments. In the experimental group using molasses as raw materials, both cane molasses and beet molasses showed very good substitution effect on sucrose, the final cell wet weight was up to 25.6 g/L, the prodigiosin content was up to 4.9 g/L, and 58% more than the control group using sucrose, probably because molasses as a composite carbon source was rich in many nutrients other than sucrose, such as amino nitrogen, biotin and a part of crude protein substances, had positive regulation effect on Serratia marcescens production and pigment accumulation, and thus high prodigiosin yield could be obtained. The growth limitation of experimental strains compared with those using starch hydrolysates is probably due to the fact that the incomplete hydrolysates of starch are starch, glucose and partial oligosaccharides, and the associated pathway of glucose metabolism in Serratia marcescens PG-Zeno-001 is weaker, leading to a growth retardation and thus a smaller pigment accumulation.

Based on the results of example 1, the optimal carbon source for large-scale prodigiosin production using 25 mL/L of sugar cane molasses and beet molasses was finally determined and used for subsequent optimization and fermentation production.

Example 2 determination of optimal concentrations of sugar and beet molasses

Based on the results of example 1, we found that 25 mL/L sugar cane molasses and beet molasses both gave good results, so we further optimized the fermentation concentration.

According to the shake flask fermentation results of different concentrations, it is determined that when the concentration of cane molasses in a culture medium is increased from 5 mL/L to 20 mL/L, the wet weight of thalli and the content of prodigiosin reach peak values, and as the concentration is continuously increased, the wet weight of thalli and the content of prodigiosin in a fermentation broth are reduced to a small extent, so that the optimal concentration of cane molasses in the culture medium is determined to be 20 mL/L, and the concentration is used for subsequent large-scale fermentation of prodigiosin. Similar results also finally confirm that the optimum concentration of beet molasses is 30 mL/L.

Table 2: shaking flask fermentation experimental results of different carbon source concentrations

Example 3 detection method of prodigiosin content in fermentation liquor

Taking Serratia marcescens fermentation liquor of which the concentration is 1 mL, adding 4 mL acid methanol mother liquor, performing ultrasonic cell disruption for 15-20 min, centrifuging at low temperature to remove precipitate, diluting supernatant by 5 times, then diluting the supernatant by different times according to gradient, and respectively taking 200 mu L of the diluted supernatant and adding the diluted supernatant into a 96-well plate to measure 535nm absorbance; the pH of the acidic methanol was about 3.0.

Example 4 Large Scale production of prodigiosin on 100L fermentors

The final fermentation medium ratio for prodigiosin production, as determined in example 1, was used to verify the prodigiosin yield in a 100L scale fermentor.

(1) Selection of fermentation strains: the strain is Serratia marcescens (Serratia marcescens) PG-Zeno-001;

(2) Preparing a fermentation medium: tryptone 5-7.5 g/L, peanut cake powder 2.5-4 g/L, caCl ₂ 2.5 to 4.0 g/L, 5.0 g/L sodium chloride, 20 mL/L cane molasses or 30 mL/L beet molasses, 0.5 to 1 g/L glycine, 0.5 to 1 g/L proline and 1 mL/L defoamer; the pH of the medium was adjusted to 6.0 using hydrochloric acid; sterilizing at 121deg.C for 20 min, and cooling to room temperature;

(3) Preparing a feed medium: tryptone 300 g/L, peanut cake powder 50 g/L, cane molasses 400 mL/L or beet molasses 600 mL/L, proline 10g/L, without adjusting pH, sterilizing at 121deg.C for 20 min under moist heat, and cooling to room temperature for use;

(4) Preparing an inclined plane: inoculating LB inclined plane with the fermentation strain glycerol tube for activation culture, and culturing at constant temperature of 25-30 ℃ for 24-48 h to obtain an inclined plane, and refrigerating the inclined plane for later use;

(5) Shake flask seed culture: inoculating the slant strain obtained in the step (4) into a shake flask filled with a shake flask LB seed culture medium to be sterilized, and culturing at 200 rpm and 25-30 ℃ for about 8 h;

(6) Primary seed culture: inoculating the shake flask seeds cultured in the step (5) into a sterilized 10L first-stage seed tank filled with 5L LB medium according to a volume ratio of 1%, and starting to culture, wherein the culture conditions are as follows: aeration rate is 0.3-1.5 VVM, tank pressure is 0.1 Mpa, temperature is 25-30 ℃, saturation of dissolved oxygen is 1-80%, and culture time is 10 h;

(7) Fermenting in a fermentation tank: inoculating the first-level seeds cultured in the step (6) into a sterilized 100L fermentation tank filled with 50L fermentation medium according to the volume ratio of 5-10%, and starting to culture; culture conditions: the initial ventilation is 0.3 VVM, the tank pressure is 0.1 Mpa, the temperature is 25-30 ℃, and the culture time is 48-96 hours. The dissolved oxygen control scheme is as follows: an initial rotation speed of 0-12 h is 200 rpm, the rotation speed is slowly increased to 350 rpm along with the reduction of dissolved oxygen, and then the dissolved oxygen is controlled by 30% in association with the dissolved oxygen through stirring; 12-36 h, controlling 15% of dissolved oxygen by associating the dissolved oxygen with the feed, 36-h, and finally reducing the stirring rotation speed to 200 rpm for fermentation, and controlling 10% of dissolved oxygen by associating the dissolved oxygen with the feed;

(8) Samples of fermentation broth were taken every 4 hours and the prodigiosin concentration was determined as in example 2 and the results are shown in figure 1. The prodigiosin yield of 48 h can reach 15.45 g/L by fermenting the cane molasses; whereas the prodigiosin yield of 48 h can reach 16.18 g/L by fermentation with beet molasses.

The above detailed description of the embodiments should not be construed as limiting the scope of the invention, but it will be apparent to those skilled in the art from this disclosure that many insubstantial modifications and adaptations of the invention are possible within the scope of the invention.

Claims (7)

1. A prodigiosin fermentation production method, which uses fermentation medium to ferment serratia marcescens to produce prodigiosin, is characterized in that:

the Serratia marcescens is Serratia marcescens PG-Zeno-001 strain which is preserved in China Center for Type Culture Collection (CCTCC) with the preservation number of CCTCC M2023361 in the year of 2023 and the month of 20;

the fermentation medium comprises: tryptone 5-7.5 g/L, peanut cake powder 2.5-4 g/L, caCl ₂ 2.5 to 4.0 g/L, 4.8 to 5.2 g/L of sodium chloride, 20 to 25 mL/L of cane molasses or 25 to 30 mL/L of beet molasses, 0.5 to 1 g/L of glycine, 0.5 to 1 g/L of proline and 0.8 to 1.2 mL/L of defoamer.

2. The prodigiosin fermentation production method according to claim 1, characterized in that: the fermentation medium is not added with any one of glycerol, mannitol, sucrose, glucose, fructose, vegetable oil and animal oil.

3. The prodigiosin fermentation production method according to claim 1, characterized in that: and (3) adjusting the pH value of the fermentation culture medium to 6.0 by using hydrochloric acid, carrying out damp-heat sterilization on the fermentation culture medium at 121 ℃ for 20 minutes, and cooling for later use.

4. The prodigiosin fermentation production method according to claim 1, characterized in that: adding a feed medium during fermentation, the feed medium comprising: tryptone 300 g/L, peanut cake meal 50 g/L, cane molasses 400 mL/L or beet molasses 600 mL/L, proline 10g/L.

5. The prodigiosin fermentation production method according to claim 4, characterized in that: the feed medium is not added with any one of glycerol, mannitol, sucrose, glucose, fructose, vegetable oil and animal oil.

6. The prodigiosin fermentation production method according to claim 5, characterized in that: the pH value of the feed supplement culture medium is not regulated after the feed supplement culture medium is prepared, the feed supplement culture medium is directly subjected to damp-heat sterilization at 121 ℃ for 20 minutes, and the feed supplement culture medium is cooled for standby.

7. The prodigiosin fermentation production method according to any one of claims 1 to 6, characterized by comprising the steps of:

(1) Selection of fermentation strains: the strain is Serratia marcescens (Serratia marcescens) PG-Zeno-001;

(2) Preparing a fermentation medium: tryptone 5-7.5 g/L, peanut cake powder 2.5-4 g/L, caCl ₂ 2.5 to 4.0 g/L, 4.8 to 5.2 g/L of sodium chloride, 20 to 25 mL/L of cane molasses or 25 to 30 mL/L of beet molasses, 0.5 to 1 g/L of glycine, 0.5 to 1 g/L of proline and 0.8 to 1.2 mL/L of defoamer, adjusting the pH value of a fermentation medium to 6.0 by using hydrochloric acid, sterilizing for 20 minutes at 121 ℃ in a wet heat mode, and cooling for later use;

(3) Preparing a feed medium: tryptone 300 g/L, peanut cake powder 50 g/L, cane molasses 400 mL/L or beet molasses 600 mL/L, proline 10g/L, pH not adjusted, sterilizing at 121deg.C for 20 min under moist heat, and cooling;

(4) Preparing an inclined plane: inoculating LB inclined plane with the fermentation strain glycerol tube for activation culture, and culturing at constant temperature of 25-30 ℃ for 24-48 h to obtain an inclined plane, and refrigerating the inclined plane for later use;

(5) Shake flask seed culture: inoculating the slant strain obtained in the step (4) into a shake flask filled with a shake flask LB seed medium to be sterilized, and culturing at 200 rpm at 25-30 ℃ for 8 h;

(6) Primary seed culture: inoculating the shake flask seeds cultured in the step (5) into a sterilized 10L first-stage seed tank filled with 5L LB medium according to a volume ratio of 1%, and starting to culture, wherein the culture conditions are as follows: aeration rate is 0.3-1.5 VVM, tank pressure is 0.1 Mpa, temperature is 25-30 ℃, saturation of dissolved oxygen is 1-80%, and culture time is 10 h;

(7) Fermenting in a fermentation tank: inoculating the first-level seeds cultured in the step (6) into a sterilized 100L fermentation tank filled with 50L fermentation medium according to the volume ratio of 5-10%, and starting to culture; culture conditions: initial ventilation of 0.3 VVM, tank pressure of 0.1 Mpa, temperature of 25-30 ℃ and cultivation time of 48-96 hours; the dissolved oxygen control scheme is as follows: an initial rotation speed of 0-12 h is 200 rpm, the rotation speed is slowly increased to 350 rpm along with the reduction of dissolved oxygen, and then the dissolved oxygen is controlled by 30% in association with the dissolved oxygen through stirring; 12-36 h, controlling 15% of dissolved oxygen by associating the dissolved oxygen with the feed, 36-h, and finally reducing the stirring speed to 200 rpm, and controlling 10% of dissolved oxygen by associating the dissolved oxygen with the feed.