Composite micro-ecological preparation for improving black matrix of aquaculture pond and application of composite micro-ecological preparation

Abstract

The invention discloses a compound micro-ecological preparation for improving the black matrix of an aquaculture pond and application of the compound micro-ecological preparation. The compound microecological preparation is prepared from the following components: P.megatherium GBW-PM6, bacillus subtilis S2, bacillus cereus J19, bacillus amyloliquefaciens HFJ-7, a spore germination activator, zeolite powder, attapulgite and red strengthening powder. The composite microecological preparation is prepared into particles with the diameter of 2-3mm through low-temperature particle rolling and fluidized bed drying, the particles are thrown into aquaculture water and fall into the bottom of a pond, the metabolic pathway of sulfur reducing bacteria at the bottom for generating hydrogen sulfide (H2S) by using sulfur-containing substances can be blocked, generation of hydrogen sulfide is reduced, degradation and conversion of residual organic matter at the bottom of the pond in the aquaculture process are promoted, and the yield of the aquaculture water is increased. The problem of blackening and stinking of bottom mud caused by hydrogen sulfide pollution is solved, the self-cleaning capacity of the pond bottom and the water body is improved, ecological breeding is promoted, remarkable economic benefits can be brought, and the method has wide market application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of microbial application, and in particular relates to a composite microecological preparation for improving the black bottom of an aquaculture pond and an application thereof. Background Art

[0002] The protein content of feeds fed to most aquatic animal species is high, and only about 25% of the protein contained in it is converted into fish and shrimp bodies. The rest of the protein is discharged into the water and sinks to the bottom through excretion, residual bait, etc. The sulfur-containing amino acids, mainly including methionine (also known as methionine), cysteine, and cystine, produce sulfates through the desulfurization process of microorganisms. Other sulfur-containing organic substances also include sulfanilic acid, sulfonates, etc., and sulfur-containing inorganic substances include sulfates and sulfites. These sulfates generate hydrogen sulfide (H2S) under the action of sulfate-reducing bacteria (SRB). H2S reacts with iron and manganese elements in the water to generate black sulfide suspended particles / precipitates such as FeS and MnS, causing the bottom of the pond to turn black. The blackening of the bottom mud is mainly caused by sulfate-reducing bacteria, and the black color is also an important sign of the presence of H2S in the pond. When the H2S concentration in water is higher than 0.1~0.2 mg / L, it will cause breathing difficulties for fish, shrimps and crabs, slow growth, weakened vitality and disease resistance, and even cause acute poisoning and death in animals.

[0003] In some aging ponds that have not been cleared for years, the residual bait and feces produced during the breeding process continue to accumulate. If the bottom quality is not improved in time, there will be a thick layer of black and smelly bottom mud, the continuous release of toxic and harmful substances, excessive H2S in the floating water of the pond, and poisoning of farmed animals. Microorganisms are the main driving force for promoting sulfur cycle metabolism, and are closely coupled with the carbon, nitrogen, and phosphorus cycles. Therefore, screening functional strains with H2S control effects and developing microecological preparations with sulfur removal effects have broad application prospects in improving the black bottom of aquaculture ponds. Summary of the invention

[0004] The purpose of the present invention is to provide a composite microecological preparation for improving the black bottom of aquaculture ponds and its application. The present invention uses H2S-producing algae Shewanella XWS as an indicator bacteria, and skillfully uses H2S and Fe 2+ The principle of forming FeS black precipitate is used to screen out functional strains with H2S control effect, and the screened functional strains and functional carriers (auxiliaries) are compounded to make granular composite microecological preparations, which are applied in small amounts and multiple times to aquaculture ponds with deep black and smelly sludge layers and prone to H2S production, which can effectively reduce the thickness of black and smelly sludge and the H2S content in floating water. The technical solution of the present invention solves the problem of difficulty in accurately evaluating the effect of strains during the screening of hydrogen sulfide control functional strains due to the volatility of H2S.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions: The present invention provides a strain of Priesteria gigantea GBW-PM6, which is classified and named Priesteria gigantea ( Priestia megaterium ), deposited in the General Microbiology Center of China Microorganism Culture Collection Administration, with the deposit number: CGMCC No.32334.

[0006] The present invention also provides a composite microecological preparation for improving the black bottom of an aquaculture pond, wherein the composite microecological preparation contains the following components: a live bacteria content of not less than 1.00×10 10 CFU / g of the Priesteria gigantea GBW-PM6, and the content of live bacteria is not less than 2.00×10 9 CFU / g Bacillus subtilis, live bacteria content not less than 5.00×10 9 CFU / g of Bacillus cereus, and the content of live bacteria is not less than 1.50×10 10 CFU / g of Bacillus amyloliquefaciens and functional carriers.

[0007] Furthermore, the Bacillus subtilis is selected from Bacillus subtilis with a preservation number of CGMCC No.19824 ( Bacillus subtilis ) S2; the Bacillus cereus is selected from Bacillus cereus with a deposit number of CGMCC No.10052 ( Bacillus cereus ) J19; the amyloliquefaciens Bacillus is selected from the amyloliquefaciens Bacillus with a deposit number of CGMCC No. 10011 ( Bacillus amyloliquefaciens )HFJ-7.

[0008] Furthermore, the functional carrier comprises, by weight percentage of the composite microecological preparation, 5% to 10% of a spore germination activator, 30% to 40% of zeolite powder, 15% to 20% of attapulgite, and the remainder is red fusogenic powder.

[0009] Furthermore, in the spore germination activator, L-alanine accounts for 60%, fructose accounts for 40%, the zeolite powder is clinoptilolite powder with a particle size of not less than 150 meshes, and the attapulgite is extremely small granular attapulgite with a diameter of 0.5 to 1.0 mm.

[0010] Furthermore, the composite microecological preparation is a round particle with a diameter of 2-3 mm, which is obtained by mixing the strain and the carrier, adding water, rolling the particles with a granulator, and then drying the particles at a low temperature of 50-60° C. in a fluidized bed.

[0011] The present invention also provides the use of the Priesteria gigantea GBW-PM6 in improving the black bottom of an aquaculture pond.

[0012] The present invention also provides application of the composite microecological preparation in improving the black bottom of an aquaculture pond.

[0013] Furthermore, the composite microecological preparation is applied to the black bottom of the pond, once every three days in the early stage, with 200g to 300g per mu of water surface sprinkled, and once every five days after one month, with 200g to 300g per mu of water surface sprinkled.

[0014] Furthermore, the thickness of the black mud at the black bottom of the pond gradually decreased, and the hydrogen sulfide in the floating water was significantly reduced.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial technical effects: (1) The bacterial strains of the composite microecological agent of the present invention are indigenous bacteria isolated from the aquaculture environment. After primary screening under aerobic conditions using a microplate and secondary screening under microaerobic conditions using a test tube method, the obtained strains can function both in water bodies with good dissolved oxygen conditions and under microaerobic conditions with poor oxygen, and have a wider range of application scenarios.

[0016] (2) The screening of strains and product efficacy evaluation in the composite microecological preparation of the present invention uses Shewanella algae ( Shewanella algae ) indicator method, with H2S-producing algae Shewanella XWS as the indicator bacteria, after adding SIM medium containing ferrous salts to the microplate or test tube, inoculate 1% XWS and add the bacterial solution of the strain to be screened, incubate at 30°C, and it will begin to show light black turbidity after 2h~3h, and observe the black precipitation of the reaction system after 4h~6h. The microplate method is used to screen aerobic / aerobic sulfur-controlling functional bacteria, and the test tube method is used to screen microaerobic / anaerobic sulfur-controlling functional bacteria. This method has the advantages of strong targeting, simple operation, short time consumption and low cost.

[0017] (3) In addition to the functional microorganisms, the present invention also contains ingredients that promote the germination of spores, thereby improving the efficiency of spores. In addition, zeolite powder and attapulgite are both porous carriers, which promote the local adsorption of small molecules such as H2S and increase the contact concentration between probiotics and H2S. Although zeolite powder has strong fluidity and is not conducive to granulation, attapulgite has a certain viscosity, which can overcome this problem. No additional adhesive is required during the granulation process, which facilitates the release after sinking to the bottom of the water. After rolling, the granules are dried at a low temperature of 50-60°C in a fluidized bed to facilitate the retention of live bacteria.

[0018] In summary, the composite microecological preparation provided by the present invention can generate huge economic benefits and has broad application prospects and promotion value in the purification and repair of black bottoms in aging aquaculture ponds. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is the separation and purification of pond pathogenic bacteria during the screening process of H2S-producing indicator bacteria in Example 1; Figure 2 is the initial TCBS plate for screening Shewanella algae XWS in Example 1; Figure 3 This is the process in which the culture system turns black after the indicator bacteria XWS is inoculated in Example 1; Figure 4 The microplate method was used in Example 1 to evaluate the sulfur control effect of different strains; Figure 5 The test tube method was used in Example 2 to evaluate the sulfur control effect of different strains; Figure 6 is the 16s rDNA phylogenetic tree of GBW-PM6 in Example 3; Figure 7 The colony and bacterial cell (crystal violet staining) morphology of GBW-PM6 in Example 3; Figure 8 It is a comparison of H2S content between the control group and the zeolite powder group in Example 5; Fig. 9 This is the appearance of the composite microecological preparation particles in Example 6; Fig.10 The black bottom mud of the shrimp pond in Example 6; Fig.11 This is a side view of the changes in black mud after using the composite microecological preparation once in Example 6; Fig.12 This is the front view of the black mud changes after using the composite microecological preparation once in Example 6; Fig.13 This is the H2S situation of the floating water after using the composite microecological preparation once in Example 6; Fig.14 This is the color of black mud after using the composite probiotic preparation three times in Example 6. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described in detail with reference to the following specific examples.

[0021] In the following examples, unless otherwise specified, the experimental methods used are conventional methods, and the materials and reagents used can be purchased from biological or chemical reagent companies.

[0022] The Bacillus subtilis of the present invention ( Bacillus subtilis )S2 is derived from aquaculture pond sludge in Jiaozhou, Qingdao, and was deposited in the General Microbiological Center of China Microbiological Culture Collection (CGMCC) on May 15, 2020, with the deposit number CGMCC No. 19824. It has the effects of improving algae phase, flocculating organic matter and inhibiting Vibrio.

[0023] The Bacillus cereus ( Bacillus cereus )J19 originated from the sediment of sea cucumber aquaculture area and was deposited in the General Microbiological Center of China Microbiological Culture Collection (CGMCC) on November 25, 2014, with the deposit number CGMCC No. 10052. It has the ability to inhibit Vibrio parahaemolyticus and decompose organic matter in aquaculture water and improve water transparency.

[0024] The Bacillus amyloliquefaciens ( Bacillus amyloliquefaciens HFJ-7 is derived from plant rhizosphere soil and was deposited in the General Microbiology Center of China Microorganism Culture Collection Administration (CGMCC) on November 19, 2014. The deposit number is CGMCC No.10011. It has the function of killing fecal coliform bacteria, reducing ammonia nitrogen in feces, and producing surfactants to reduce the surface tension of water.

[0025] The ingredients of the improved SIM medium are: tryptone 20.0 g / L, polyvalent peptone 6.0 g / L, ammonium ferric sulfate 1.0 g / L, sodium thiosulfate 1.0 g / L, solid culture medium supplemented with agar 3.5 g / L, pH 7.2 ± 0.2 (25°C).

[0026] Example 1: Establishment of a screening and evaluation method for hydrogen sulfide functional bacteria and preliminary screening of sulfur control functional strains In order to study the formation process of pond black mud, the present invention uses indicator bacteria that can produce H2S, which show black colonies on TCBS plates ( Figure 1~Figure 2 ), after purification, sequencing and identification, it was determined to be Shewanella algae through sequence comparison, and numbered as indicator bacteria XWS (other known H2S-producing indicator bacteria can also be used to screen strains). The indicator bacteria XWS was cultured in LB liquid culture medium for 12 hours, and as seed liquid, 100μL of XWS seed liquid was inoculated in a test tube containing 10 mL of modified SIM culture medium, and cultured statically in a 30°C incubator. The color change was observed every half an hour, and it was found that with the reproduction of the indicator bacteria XWS, the culture system began to gradually turn black after 2 hours, and the color became darker after 4 hours, and it was already very black after 8 hours. This shows that Shewanella algae is a sulfate-reducing bacteria, which reproduces very rapidly under suitable nutritional conditions and can produce a high amount of H2S in a very short time ( Figure 3 ). It can be used to screen hydrogen sulfide-controlling bacteria.

[0027] Select 14 candidate probiotic strains from the strain library, culture them in LB liquid culture medium for 24 hours, add 125μL of improved SIM culture medium, 150μL of candidate probiotic solution and 25μL of XWS solution to a 96-well microplate, pipette and swirl evenly, fill the microwells with improved SIM culture solution (if the liquid surface is too shallow, H2S will easily evaporate and dissipate), place in a 30℃ incubator for static incubation, and observe the color change every two hours.

[0028] Figure 4 The experimental results showed that 9 strains of 14 candidate probiotics were co-cultured with the indicator bacteria XWS for 3 h to 6 h, and they had a significant inhibitory effect on the production of H2S. The liquid in the microplate was colorless, the control group with only the modified SIM medium and the indicator bacteria XWS was black, and the candidate probiotic group without effect was also black. This shows that the 9 strains without color can inhibit the production of H2S by XWS. These 9 strains are J19, HFJ-7, GBW-PM6, S2, YZB, LKJ, HSD, GBW-PM1, and GBW-PM2.

[0029] Example 2: Rescreening of sulfur-controlling functional strains At the bottom of the aquaculture pond, due to a certain water depth, the bottom mud cannot be in direct contact with the air, and when the sediment is thick, there are more oxygen-consuming factors such as organic matter in the bottom mud, so the dissolved oxygen conditions at the bottom of the pond are generally not good. Therefore, the screened sulfur-controlling functional strains must have a good sulfur-controlling effect under oxygen conditions, and also need to have a sulfur-controlling effect under microaerobic conditions with poor oxygen. Therefore, the test tube method is further used to verify the sulfur-controlling effect of the 9 probiotics screened in Example 1 that have a sulfur-controlling effect under aerobic conditions under microaerobic conditions.

[0030] Inoculate 9 candidate bacteria into LB liquid medium at 1% inoculation rate, place in a shaking incubator at 37℃ and 200 r / min for 18 h, and set aside. Inoculate XWS into LB liquid medium at 1% inoculation rate, and culture at 30℃ and 200 r / min for 12 h, and set aside. Take 5 mL of candidate bacteria liquid and add it to a test tube containing 10 mL of modified SIM liquid medium, inoculate 150 μL of indicator bacteria XWS liquid (for strict anaerobic bacteria, cover the surface of the liquid with a layer of vegetable oil), and place it in a 30℃ incubator for 3h~6h, and observe the color change every two hours.

[0031] Figure 5 The experimental results show that under the condition of micro-oxygen at a high liquid level in the test tube, J19, HFJ-7, GBW-PM6 and S2 have the function of inhibiting the production of H2S.

[0032] Example 3: Identification and preservation of GBW-PM6 The DNA of strain GBW-PM6 was used as template, 16S rDNA universal primers were used for amplification, and the amplified fragments were sequenced. The 16S rDNA sequencing results were compared and analyzed, and the results showed that strain GBW-PM6 and Priestia megaterium The highest homology was found in GBW-PM6, so the strain was identified as Priesteria gigantea. The 16s rDNA phylogenetic tree of GBW-PM6 is shown in Figure 6The nucleotide sequence is shown in SEQ ID No. 1, and the colony and bacterial morphology are shown in Figure 7 shown.

[0033] The Priesteria gigantea GBW-PM6 was deposited in the General Microbiology Center of China Microbiological Culture Collection Administration (CGMCC), address: No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences; the deposit date is: October 24, 2024, Priesteria gigantea Priestia megaterium The deposit number is: CGMCC No.32334.

[0034] Example 4: Verification of the mechanism of action of sulfur-controlling functional bacteria Four sulfur-controlling functional bacteria J19, HFJ-7, GBW-PM6 and S2 were inoculated into LB liquid medium at a 1% inoculation rate, cultured overnight (14-16 h) at 30°C and 200 r / min shaking, and centrifuged at 1000 r / min for 5 min to obtain the supernatant containing metabolites but not bacteria. 5 mL of fermentation broth or supernatant was added to a test tube containing 10 mL of LB liquid medium, inoculated with 1% or 150 μL of indicator bacteria XWS seed liquid, and left to stand in a 30°C incubator overnight. At the same time, a blank control group without inoculation of XWS and functional bacteria, a negative control group with inoculation of XWS but not functional bacteria, and a common bacteria control group with inoculation of XWS and common bacteria were made. The H2S concentration of the fermentation broth was detected every 12 h using a sulfide detection kit. The results showed (Table 1) that the fermentation supernatant of strains J19, HFJ-7, GBW-PM6 and S2 could reduce the production of H2S, with J19 being the best.

[0035] Table 1 Effect of the supernatant of sulfur-controlling functional bacteria on the H2S concentration produced by indicator bacteria XWS (mg / L)

[0036] Furthermore, LB solid medium was used to coat and test the bacterial count of XWS in the experimental group with the added amount of candidate bacteria supernatant. The results showed (Table 2) that the supernatants of strains HFJ-7, GBW-PM6 and S2 significantly inhibited the proliferation of XWS, while J19 had no significant effect on the bacterial count of XWS.

[0037] Table 2 Effects of supernatants of different candidate bacteria on Shewanella algae (×10 8 CFU / mL)

[0038] In summary, the action mechanism of the four screened sulfur-controlling functional bacteria is that J19 inhibits the H2S production of XWS through its metabolites, but does not affect the proliferation activity of XWS; HFJ-7, GBW-PM6 and S2 mainly control the production of H2S by inhibiting the proliferation of XWS.

[0039] Example 5: Test of adsorption of H2S and Shewanella algae by clinoptilolite powder XWS was inoculated into LB liquid medium at a 1% inoculation rate, and cultured at 30°C and 200 r / min for 12 h to obtain XWS seed solution for later use. 1% indicator bacteria XWS seed solution was inoculated into two LB liquid media containing and not containing 1% clinoptilolite powder (150 mesh), respectively, and cultured at 30°C and 200 r / min for 24 h, and then the XWS bacterial count was detected by coating on solid LB medium plates.

[0040] The results showed that the number of XWS bacteria in the control group without clinoptilolite was (1.20±0.27)×10 8 CFU / mL, while the XWS bacterial count in the experimental group with 1% clinoptilolite powder was (1.67±0.25)×10 7 CFU / mL, which was reduced by 86.1% compared with the control group.

[0041] After culturing the indicator bacteria XWS in a test tube containing LB liquid medium, 1:1 volume of water was added to 50% of the test tubes, and 1:1 volume of 2% clinoptilolite powder solution was added to 50% of the test tubes. After standing for 1 hour, the supernatant was aspirated and the H2S concentration was measured using a sulfide test kit. The results showed that the H2S content in the group with clinoptilolite powder was significantly reduced ( Figure 8 ).

[0042] After adding clinoptilolite powder in the above test, the number of indicator bacteria XWS and the H2S content decreased, indicating that it was related to the adsorption characteristics of zeolite powder.

[0043] Example 6: Preparation of sulfur-controlling composite microecological preparation and post-treatment effect experiment of black mud The sulfur control compound microecological preparation powder package contains 5.00×10 9 CFU / g Bacillus cereus J19, 1.50×10 10 CFU / g Bacillus amyloliquefaciens HFJ-7, 1.00×10 10 CFU / g Priesteria gigantea GBW-PM6 and 2.00×10 9CFU / g Bacillus subtilis S2, 5% spore germination activator (L-alanine accounts for 60%, fructose accounts for 40%), 30% zeolite powder, 15% attapulgite, and red fusogenic powder is used to fill it to 100%. Using granular attapulgite with a micro-particle size (0.5 ~ 1.0mm) as the original carrier, add water to the sulfur-controlling composite microecological preparation powder bag according to its mass, gradually transfer it to the granulator, the speed is 60r / min, roll it into particles with a diameter of 2~3mm, polish it for 10min, and dry it at a low temperature of 50~60℃ in a fluidized bed to a moisture content of 5~7%, and obtain brick-red composite microecological preparation particles ( Fig. 9 ).

[0044] Black and smelly bottom mud collected from the Rudong shrimp farming pond after shrimp harvesting and draining the pond water on July 6, 2024 ( Fig.10 ), Test 1: Spread a layer of black bottom mud with a thickness of about 1 cm on the bottom of a transparent glass wide-mouth bottle, add 1g of compound microecological preparation particles, gently inject tap water along the wall to make the water layer height about 4 cm, and then seal it with plastic wrap. After 3 days, observe the appearance color of the bottom mud, take the floating water at the junction of mud and water, and use the H2S test kit to determine its H2S situation. At the same time, make a control group without adding compound microecological preparations.

[0045] The results showed that the surface of the black mud in the composite microecological preparation group turned into earthy yellow, the floating water was clear, and the H2S content was less than 0.2mg / L. The black mud in the control group was still completely black, and the floating water was like a layer of mist, making it difficult to see the bottom through the water layer, and the H2S content was greater than 0.5mg / L ( Figures 11 to 13 ).

[0046] Experiment 2: A layer of 2-3 cm thick black bottom mud was laid on the bottom of a transparent glass jar. On the first day, 1 g of compound microecological preparation particles were added. Tap water was gently injected along the wall to make the water layer about 6-7 cm high. Then the bottle was sealed with plastic wrap and left to stand. After 2 days, i.e. on the 4th day, 1 g of compound microecological preparation particles was added again and the bottle was left to stand. This was repeated once more. The compound microecological preparation was added 3 times in 10 days. The results showed that the color of the black mud changed to earthy yellow ( Fig.14 ).

[0047] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for a person skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to replace some of the technical features therein by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions claimed to be protected by the present invention.

Claims

1. A strain of Priesteria gigantea GBW-PM6, characterized in that Its taxonomic name is Priesteria gigantea. Priestia megaterium ), deposited in the General Microbiology Center of China Microorganism Culture Collection Administration, with the deposit number: CGMCC No.32334.

2. A composite microecological preparation for improving the black bottom of an aquaculture pond, characterized in that: The composite microecological system contains the following components: the content of live bacteria is not less than 1.00×10 10 CFU / g of the Priesteria gigantea GBW-PM6 of claim 1, and the content of live bacteria is not less than 2.00×10 9 CFU / g Bacillus subtilis, live bacteria content not less than 5.00×10 9 CFU / g of Bacillus cereus, and the content of live bacteria is not less than 1.50×10 10 CFU / g of Bacillus amyloliquefaciens and functional carriers.

3. The composite microecological preparation for improving the black bottom of aquaculture ponds according to claim 2, characterized in that: The Bacillus subtilis is selected from Bacillus subtilis with a preservation number of CGMCC No.19824 ( Bacillus subtilis ) S2; the Bacillus cereus is selected from Bacillus cereus with a deposit number of CGMCC No.10052 ( Bacillus cereus ) J19; the amyloliquefaciens Bacillus is selected from the amyloliquefaciens Bacillus with a preservation number of CGMCC No. 10011 ( Bacillus amyloliquefaciens )HFJ-7.

4. The composite microecological preparation for improving the black bottom of aquaculture ponds according to claim 2, characterized in that: The functional carrier comprises, by weight percentage of the composite microecological preparation, 5% to 10% of a spore germination activator, 30% to 40% of zeolite powder, 15% to 20% of attapulgite, and the remainder is red fusogenic powder.

5. The composite microecological preparation for improving the black bottom of aquaculture ponds according to claim 4, characterized in that: The spore germination activator comprises 60% L-alanine and 40% fructose, the zeolite powder is clinoptilolite powder with a particle size of not less than 150 meshes, and the attapulgite is extremely small granular attapulgite with a diameter of 0.5 to 1.0 mm.

6. The composite microecological preparation for improving the black bottom of aquaculture ponds according to claim 2, characterized in that: The composite microecological preparation is a round particle with a diameter of 2-3 mm, which is obtained by mixing the strain with a carrier, adding water, rolling the particles with a rolling machine, and then drying the particles at a low temperature of 50-60° C. on a fluidized bed.

7. Use of Priesteria gigantea GBW-PM6 according to claim 1 in improving the black bottom of aquaculture ponds.

8. Use of the composite microecological preparation according to any one of claims 2 to 7 in improving the black bottom of an aquaculture pond.

9. The use according to claim 8, characterized in that: The composite microecological preparation is applied to the black bottom of the pond, once every three days in the early stage, 200g-300g per mu of water surface is sprinkled, and once every five days after one month, 200g-300g per mu of water surface is sprinkled.

10. The use according to claim 8, characterized in that: The thickness of the black mud at the black bottom of the pond gradually decreased, and the hydrogen sulfide in the floating water decreased significantly.

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