Rhodopseudomonas palustris strain Dexin-sdu-018 and application thereof

Abstract

The invention provides a rhodopseudomonas palustris strain Dexin-sdu-018 and an application of the rhodopseudomonas palustris strain Dexin-sdu-018, and belongs to the technical field of functional microorganisms. The preservation number of the rhodopseudomonas palustris strain Dexin-sdu-018 is CGMCC (China General Microbiological Culture Collection Center) No.22278. The rhodopseudomonas palustris strain The strain Dexin-sdu-018 provided by the invention not only has a rapid algae-lysing effect on connezothrix algal bloom to realize prevention and treatment of algal bloom, but also has a good purification effect on a water body with algal bloom outbreak, and can remove nitrite, ammonia nitrogen and sulfide in the water body to different degrees to realize protection and restoration of water resources. Therefore, the technical scheme of the invention provides a new way for water algal blooms caused by the connezothrix algal blooms and water resource protection and restoration.

Description

Technical Field

[0001] The invention belongs to the technical field of functional microorganisms, and specifically relates to a Rhodopseudomonas palustris strain Dexin-sdu-018 and an application thereof. Background Art

[0002] Aphanizomenon is one of the common dominant species in freshwater blooms of cyanobacteria. Studies have shown that Aphanizomenon blooms can produce paralytic shellfish poisons (PSPs), which are alkaloid neurotoxins with Na + Channel inhibition has a strong lethal effect on organisms and seriously threatens the ecological environment and human health.

[0003] At present, the common methods for controlling water blooms caused by Aphanizomenon flos-water include physical removal, biological removal and ecological methods. The physical removal method consumes a lot of manpower and material resources, and the removal efficiency is slow. The ecological method includes a means of controlling the growth of algae according to the growth process of Aphanizomenon flos-water and the restrictive ecological factors in the environment, such as controlling the growth of algae by controlling the pH, water temperature, light area and water depth of the water body, as well as the coverage rate of aquatic plants and the concentration of plant allelopathic substances. This method is not applicable to the control of water blooms in large areas of water in the natural environment. The biological removal method mainly uses algae-removing animals to control the growth of algae. For example, some snails, zebra snails, apple snails, etc. can be used for removal. Among them, the snail is powerful and can quickly remove algae, but its movement speed is very slow, and the removal efficiency needs to be further improved. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a Rhodopseudomonas palustris strain Dexin-sdu-018, which can effectively achieve the algae-lyzing effect of Aphanizomenon flos-water, realize microbial algae control and water resource bioremediation.

[0005] The invention provides a Rhodopseudomonas palustris strain Dexin-sdu-018, whose preservation number is CGMCC No.22278.

[0006] The invention provides a fermentation liquid of the Rhodopseudomonas palustris strain Dexin-sdu-018.

[0007] The invention provides an algae-lytic agent, comprising the Rhodopseudomonas palustris strain Dexin-sdu-018 and / or the fermentation broth.

[0008] Preferably, the algicidal agent is in the form of an aqueous solution and / or a freeze-dried powder.

[0009] The present invention provides the use of the Rhodopseudomonas palustris strain Dexin-sdu-018, the fermentation liquid or the algicidal agent in dissolving Aphanizomenon.

[0010] The present invention provides the use of the Rhodopseudomonas palustris strain Dexin-sdu-018, the fermentation liquid or the algae-lytic agent in preventing and / or controlling water blooms caused by Aphanizomenon.

[0011] Preferably, the Aphanizomenon includes Aphanizomenon bloom-aquae.

[0012] The present invention provides the use of the Rhodopseudomonas palustris strain Dexin-sdu-018, the fermentation liquid or the algae-lytic agent in water resource protection and / or restoration.

[0013] Preferably, the water resource protection and / or restoration includes at least one of the following: removing nitrite in water, reducing ammonia nitrogen content in water and reducing sulfide content in water.

[0014] Preferably, the working concentration of live bacteria of the Rhodopseudomonas palustris strain Dexin-sdu-018 is not less than 1×10 7 CFU / ml.

[0015] The present invention provides a Rhodopseudomonas palustris strain Dexin-sdu-018, with a deposit number of CGMCC No. 22278. The present invention uses a culture solution of Aphanizomenon bloom-water to screen and obtain bacteria with good algae-dissolving effect, that is, a Rhodopseudomonas palustris strain Dexin-sdu-018. The present invention is tested through small-scale and pilot experiments, and the results show that the strain Dexin-sdu-018 not only has a rapid algae-dissolving effect on Aphanizomenon bloom-water, achieving the prevention and treatment of water blooms, but also has a good purification effect on water bodies where water blooms break out, removes the contents of nitrite, ammonia nitrogen and sulfide in the water body to varying degrees, and achieves the protection and restoration of water resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the morphological picture of Rhodopseudomonas palustris strain under optical microscope;

[0017] Figure 2 The growth of Aphanizomenon flos-aquae on the 2nd and 7th days after adding Rhodopseudomonas palustris inoculant;

[0018] Figure 3 The results show the changes in the algicidal effect of different inoculation amounts of Rhodopseudomonas palustris on Aphanizomenon flos-water, where the ordinate represents the chlorophyll content chla (μg / L);

[0019] Figure 4Effects of inoculum addition of Rhodopseudomonas palustris on aquarium waters with Aphanizomenon blooms;

[0020] Figure 5 The results of the effect of adding Rhodopseudomonas palustris inoculant on the ammonia nitrogen, sulfide and nitrite levels in fish tank water with an outbreak of Aphanizomenon aquaticum.

[0021] Biological deposit information

[0022] Rhodopseudomonas palustris strain Dexin-sdu-018 was deposited on May 6, 2021 at the General Microbiology Center of China Culture Collection Administration, located at No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, with the deposit number CGMCC No. 22278. DETAILED DESCRIPTION

[0023] The invention provides a Rhodopseudomonas palustris strain Dexin-sdu-018, whose preservation number is CGMCC No.22278.

[0024] In the present invention, the strain Dexin-sdu-018 is isolated from the water body of the sea cucumber breeding pond. The strain Dexin-sdu-018 has a typical colony morphology of Rhodopseudomonas palustris, which is round, smooth, with neat edges and brown-red. Molecular identification, the DNA sequence of 16s rRNA of the strain Dexin-sdu-018 is shown in SEQ ID NO: 1. Based on the morphological, physiological and biochemical results and molecular identification results, the strain Dexin-sdu-018 belongs to Rhodopseudomonas palustris.

[0025] The invention provides a fermentation liquid of the Rhodopseudomonas palustris strain Dexin-sdu-018.

[0026] In the present invention, the method for preparing the fermentation broth preferably inoculates the seed liquid of the palustris Rhodopseudomonas strain Dexin-sdu-018 into a fermentation medium for fermentation and culture to obtain the fermentation broth. The method for preparing the seed liquid of the palustris Rhodopseudomonas strain Dexin-sdu-018 preferably inoculates the activated palustris Rhodopseudomonas strain Dexin-sdu-018 into a seed culture medium for culture. The seed culture medium preferably contains 3.5 g / L sodium acetate, 0.5 g / L ammonium chloride, and KH 2 PO 41.0g / L, magnesium sulfate 0.5g / L, glutamic acid 1.5g / L, seawater 1ml / L, calcium chloride 0.01g / L and yeast extract 2g / L, pH value is 7.0. The liquid volume of the seed culture solution is preferably 50%. The inoculation amount of the activated palustris Rhodopseudomonas strain Dexin-sdu-018 is preferably 1.5% to 2.5%, which can be 2%. The culture condition is cultured at 28 to 35°C until the OD value is 0.7. The fermentation medium is preferably sodium acetate 2.0g / L, ammonium chloride 0.5g / L, KH 2 PO 4 1.0g / L, magnesium sulfate 0.5g / L, glutamic acid 1.0g / L, seawater 1ml / L, calcium chloride 0.01 / L, yeast extract 2.0 / L, adjust the pH to 6.8. During the fermentation culture, the inoculation amount is preferably 8% to 12%, and can be 10%. The fermentation culture conditions are preferably: temperature 33°C, tank pressure 0.05mpa, ventilation volume 0.02vvm (only for tank pressure maintenance), stirring speed should not be too high, set to 350rpm (50L). The effective live bacteria concentration of the fermentation liquid is preferably 1×10 8 CFU / ml~100×10 8 CFU / ml, can be 10×10 8 CFU / ml.

[0027] The invention provides an algae-lytic agent, comprising the Rhodopseudomonas palustris strain Dexin-sdu-018 and / or the fermentation broth.

[0028] In the present invention, the algicidal agent is preferably in the form of an aqueous solution and / or a freeze-dried powder.

[0029] The aqueous solution of the algalytic agent is preferably prepared by mixing the fermentation broth of the palustris Rhodopseudomonas strain Dexin-sdu-018 with glycerol to obtain an aqueous solution. The amount of glycerol added accounts for 40% to 90% of the total volume of the algalytic agent. The preparation method of the freeze-dried powder of the algalytic agent is preferably to separate the bacterial cells from the fermentation broth of the palustris Rhodopseudomonas strain Dexin-sdu-018, mix the bacterial cells with a freeze-dried protective agent, and obtain a freeze-dried powder by vacuum freeze drying. The mass ratio of the bacterial cells to the freeze-dried protective agent is preferably 1:1 to 3, and can be 1:2.5. The lyoprotectant preferably comprises the following components: an aqueous solution of 10% to 20% glucose, 0.2% to 5% sucrose and 0.2% to 5% sodium glutamate; it may be an aqueous solution of 12% to 18% glucose, 0.5% to 4% sucrose and 0.4% to 4% sodium glutamate; it may be an aqueous solution of 14% to 17% glucose, 1% to 3% sucrose and 1% to 3% sodium glutamate; it may also be an aqueous solution of 15% glucose, 2% sucrose and 1.5% sodium glutamate.

[0030] In the present invention, the algicidal agent and the live bacteria concentration of the Rhodopseudomonas palustris strain Dexin-sdu-018 are not less than 1×10 7 CFU / ml, which can be 1×10 8 CFU / ml, 1×10 9 CFU / ml, 1×10 10 CFU / ml, 1×10 11 CFU / ml.

[0031] The present invention provides the use of the Rhodopseudomonas palustris strain Dexin-sdu-018, the fermentation liquid or the algicidal agent in dissolving Aphanizomenon.

[0032] In the present invention, the Aphanizomenon preferably includes Aphanizomenon blooms. The performance of dissolving Aphanizomenon is to reduce the content of chlorophyll in water. The working concentration of live bacteria of the Rhodopseudomonas palustris strain Dexin-sdu-018 is preferably not less than 1×10 7 CFU / ml, can be 5×10 7 CFU / ml, 1×10 8 CFU / ml, 1×10 9 CFU / ml, 5×10 10 CFU / ml and 1×10 10 CFU / ml. Small-scale experiments showed that 1×10 9 CFU / ml of the fermentation liquid of the palustris strain Dexin-sdu-018 was inoculated into the water containing Aphanizomenon blooms at 2%, 5% and 10%. The chlorophyll content in the water was significantly reduced compared with the control on the second day after addition, and the water was transparent on the seventh day after addition. The goldfish breeding water body with Aphanizomenon blooms was used as the pilot test object, and the palustris strain Dexin-sdu-018 was inoculated at a 10% inoculation rate. The results showed that the water in the fish tank with the outbreak of Aphanizomenon blooms was dark green, and the activity range of the ornamental fish inside was difficult to observe. The fish tank turned light green or whitish on the second day after adding the fermentation liquid of the strain Dexin-sdu-018. The fish tank could be observed to have an increased spatial activity range by naked eye observation. The influence of algae had been completely eliminated on the fourth and seventh days, and no recurrence was found later.

[0033] In view of the fact that the Rhodopseudomonas palustris strain Dexin-sdu-018 has good algalytic properties of Aphanizomenon, the present invention provides the use of the Rhodopseudomonas palustris strain Dexin-sdu-018, the fermentation broth or the algalytic agent in preventing and / or controlling water blooms caused by Aphanizomenon.

[0034] In the present invention, the Aphanizomenon preferably includes Aphanizomenon flos-aquae.

[0035] The present invention provides the use of the Rhodopseudomonas palustris strain Dexin-sdu-018, the fermentation liquid or the algae-lytic agent in water resource protection and / or restoration.

[0036] In the present invention, the water resource protection and / or restoration preferably includes at least one of the following: removing nitrite in water, reducing ammonia nitrogen content in water and reducing sulfide content in water.

[0037] Preferably, the working concentration of live bacteria of the Rhodopseudomonas palustris strain Dexin-sdu-018 is preferably not less than 1×10 7 CFU / ml, can be 5×10 7 CFU / ml, 1×10 8 CFU / ml, 1×10 9 CFU / ml, 5×10 10 CFU / ml and 1×10 10 CFU / ml.

[0038] The following is a detailed description of a Rhodopseudomonas palustris strain Dexin-sdu-018 and its application provided by the present invention in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0039] Example 1

[0040] Screening of algicidal bacteria against Aphanizomenon flos-aquae

[0041] 1. Materials

[0042] Culture medium for bacterial isolation and culture: 0.2% glycerol, 1% peptone, 0.5% sodium chloride, 0.5% yeast extract, pH 7.

[0043] Aphanizomenon bloom-water was purchased from the freshwater algae seed bank of the Institute of Hydrobiology, Chinese Academy of Sciences. After the algae were activated, they were inoculated into BG11 culture medium, and the culture conditions were: temperature 35°C, light intensity 2000lx, and light-dark cycle 12h:12h. Before the experiment, the purchased pure algae species of Aphanizomenon bloom-water were first cultured in a light incubator under 2000Lx and 35°C, and manually shaken once every 24h (all under sterile conditions), and pre-cultured for one week, and the growth of miscellaneous algae and algae was examined under a microscope. If good synchronous growth was achieved, it could be used as the algae seed liquid for the experiment.

[0044] 100 mL of water sample collected from the aquaculture water body was added to 400 mL of Aphanizomenon culture solution that had been cultured for 5 days, mixed evenly, and cultured for 15 days according to the culture conditions of Aphanizomenon aquaculture activation. The yellowed algae solution was used as the material for algicidal bacteria. The yellowed algae solution was taken and heated for 10 -1 , 10 -2 , 10 -3 , 10-4 , 10 -5 , 10 -6 Gradient dilution, plate coating, streak separation, culture at 35℃ for 24h to obtain a single colony. Inoculate a single colony into the culture medium for bacterial culture, shake culture at 35℃ for 24h, take 10mL of bacterial solution and add it to 100mL of Aphanizomenon liquid, culture it for 3 days according to the culture conditions for Aphanizomenon activation, dilute the sample with obvious yellowing of algae liquid and the best algae lysing effect, plate coating, streak separation, obtain a single colony, repeat the operation once to confirm the bacteriolysis effect.

[0045] Three strains were screened, among which Dexin-sdu-018 showed obvious yellowing phenomenon, which was determined to be an algae-lysing bacterium with the best algae-lysing effect. Dexin-sdu-018 was identified by PCR identification based on 16S rRNA. The universal primers for 16S rRNA are as follows:

[0046] 27f: 5′-AGAGTTTGATCCTGGCTCAG-3′ (SEQ ID NO: 2);

[0047] 1492r: 5'-CTACGGCTACCTTGTTACGA-3' (SEQ ID NO: 3).

[0048]

[0049] The selected strain Dexin-sdu-018 was analyzed for morphological characteristics. Microscopic examination showed that the bacteria were thin rod-shaped with some bends; the size was 1.49×0.15 μm, and the Gram staining was negative. – , the liquid culture is pink after three days, and the edges of the colonies on the plate are neat and round.

[0050] The comparison of physiological and biochemical characteristics between strain Dexin-sdu-018 and the model strain (Rhodopseudomonas palustris ATCC 17001T) is shown in Table 1.

[0051] Table 1 Comparison of physiological and biochemical characteristics of strain Dexin-sdu-018 and model strains

[0052]

[0053]

[0054] Note: +: growth; -: no growth; ±: weak.

[0055] After identification, the strain Dexin-sdu-018 is a strain of Rhodopseudomonas palustris, which presents a typical colony morphology of Rhodopseudomonas palustris, with a round colony morphology, a smooth surface, neat edges, and a brown-red color. Its nature is a photosynthetic bacterium that inhibits the growth of algae. It has been deposited in the General Microbiological Center of the China Microbiological Culture Collection Administration, with a strain deposit number of CGMCC No. 22278, and is classified and named: Rhodopseudomonas palustris, with an address of No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences.

[0056] Example 2

[0057] Preparation method of fermentation liquid of Rhodopseudomonas palustris strain Dexin-sdu-018

[0058] 1. Culture medium

[0059] Submerged liquid culture medium for producing Rhodopseudomonas palustris (1L): 3.5 g sodium acetate, 0.5 g ammonium chloride, KH 2 PO 4 1.0g, magnesium sulfate 0.5g, glutamic acid 1.5g, sea water 1ml, calcium chloride 0.01g, yeast extract 2g, adjust pH to 7.0.

[0060] Small tank fermentation medium (1L): sodium acetate 2.0g, ammonium chloride 0.5g, KH 2 PO 41.0g, magnesium sulfate 0.5g, glutamic acid 1.0g, sea water 1ml, calcium chloride 0.01, yeast extract 2.0, adjust pH to 6.8.

[0061] 1. Preparation of primary seed solution

[0062] The activated Rhodopseudomonas palustris strain Dexin-sdu-018 was inoculated into the culture medium at an inoculation rate of 10% to obtain a primary seed solution. The culture results are shown in Table 2.

[0063] Table 2 Preparation parameters of primary seed solution

[0064]

[0065]

[0066] 2. Fermentation tank culture

[0067] The first-grade seed solution prepared above was inoculated into the fermentation tank medium for cultivation. Cultivation parameters: temperature 33°C, tank pressure 0.05 MPa, ventilation volume 0.02 vvm (only for tank pressure maintenance), stirring speed should not be too high, set at 350 rpm (50 L).

[0068] Regularly check the OD of the culture medium 600 The culture results are shown in Table 3.

[0069] Table 3 Fermentation tank culture results

[0070]

[0071] After 27 hours of culture in the fermenter, the samples were observed under a 100x objective lens. Figure 1 The bacterial cell morphology is long and narrow, indicating that the mitosis process is interrupted and multiple bacterial cells are connected together. 600 Stay at around 0.6, no bacteria contamination, the bacteria grow slowly after 24 hours, and basically no longer grow at a high speed on the tank, the highest bacteria count is 10×10 8 CFU / ml or so.

[0072] Example 3

[0073] Experimental study on the algicidal effect of strain Dexin-sdu-018 on Aphanizomenon flos-aquae

[0074] 20 ml, 10 ml and 2 ml of fermentation liquid were added to 200 ml of Aphanizomenon flos-aquae liquid at inoculation amounts of 10%, 5% and 1% respectively, and the changes in chlorophyll content were monitored after 7 days. Aphanizomenon flos-aquae liquid without any fermentation liquid was set as a control.

[0075] The steps of the chlorophyll content determination method are as follows: 3 ml of algae solution is placed in a 10 mL centrifuge tube, centrifuged at 6000 rpm for 5 minutes, the supernatant is discarded, and 5 mL of 90% ethanol solution is added. The test tube is placed in a 75°C water bath for extraction for 5 minutes, and the extract is taken for determination. The absorbance values ​​at 665 nm and 750 nm are read using a spectrophotometer, and 1 mol / L hydrochloric acid is added to it for 8 minutes and then the absorbance values ​​at 665 nm and 750 nm are read again. The chlorophyll content is calculated using formula I:

[0076] C(chla)=27.3×(Ea-Eb)×Ve / VFormula I.

[0077] Among them, C(chla) is the content of chlorophyll a in the water sample in μg / L; Ea is the difference in optical density at wavelengths of 665nm and 750nm before the extract is acidified; Eb is the difference in optical density at wavelengths of 665nm and 750nm after the extract is acidified; Ve is the total volume of the extract (5mL); V is the volume of the filtered water sample (3mL).

[0078] Results Figure 2 and Figure 3 .Depend on Figure 2 It can be seen that compared with the control group, the 10% inoculation amount of dexin-sdu-018 bacterial solution can reduce the color of the algae solution of Aphanizomenon flos-aquae from the second day, and the algae solution of Aphanizomenon flos-aquae becomes clear and green-free on the seventh day. Figure 3 It can be seen that compared with the control group, different inoculation amounts of dexin-sdu-018 bacterial solution can effectively reduce the chlorophyll content in the algae solution of Aphanizomenon flos-aquae, achieving different degrees of algae-lysis effect, and the degree of algae-lysis increases with the extension of treatment time, and is positively correlated with the inoculation amount of dexin-sdu-018 bacterial solution.

[0079] Example 4

[0080] Strain Dexin-sdu-018 algae lysing 50L pilot scale application

[0081] A landscape fish tank (50 L water body) with an outbreak of Aphanizomenon was selected, and Dexin-sdu-018 fermentation liquid with a bacterial content of 500 million CFU / ml was added at a dosage of 2%, and the algae-lysing effect was recorded on the second day, fourth day and one week respectively.

[0082] Results Figure 4 It can be seen that the water in the fish tank initially showed dark green when the bloom of Aphanizomenon bloomed, and it was difficult to observe the range of activities of the ornamental fish in it. On the second day after the addition of the bacterial agent, the fish tank turned light green or whitish, and the fish's spatial activity range increased when observed with the naked eye. The influence of the algae was completely eliminated on the fourth and seventh days, and no recurrence was found later.

[0083] Example 5

[0084] Effects of Dexin-sdu-018 bacterial agent on algae dissolution on water quality

[0085] The algae bodies of Aphanizomenon obtained by BG11 culture were inactivated at 121℃ and divided into 3 conical bottles, each bottle containing 500mL of 2% inactivated Aphanizomenon algae liquid, and 1% of the cultured liquid dexin-sdu-018 bacterial liquid was inoculated into the inactivated algae liquid. The water samples were cultured at 35℃ for one week, and the water samples were taken out every 24 hours. The water samples were tested with a water quality meter, and the contents of ammonia nitrogen, sulfide and nitrite in the water samples were tested with a commercially available water quality analysis test kit (brand: Liancheng Animal Health), and the water purification effect of the isolated strains was observed.

[0086] Results Figure 5 From the results, we can see that the nitrite content began to decrease significantly on the third day, while ammonia nitrogen showed a slow and continuous change process, and sulfide decreased slightly, but not significantly. This shows that the Dexin-sdu-018 bacterial agent has little effect on water quality by dissolving Aphanizomenon aquatica.

[0087] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A Rhodopseudomonas palustris strain Dexin-sdu-018, characterized in that: The deposit number is CGMCC No.22278.

2. A fermentation broth of the Rhodopseudomonas palustris strain Dexin-sdu-018 according to claim 1.

3. An algae-lysing agent, characterized in that: It comprises the Rhodopseudomonas palustris strain Dexin-sdu-018 described in claim 1 and / or the fermentation broth described in claim 2.

4. The algicidal agent according to claim 3, characterized in that: The algicidal agent is in the form of an aqueous solution and / or a freeze-dried powder.

5. Use of the Rhodopseudomonas palustris strain Dexin-sdu-018 according to claim 1, the fermentation liquid according to claim 2, or the algicidal agent according to claim 3 or 4 in dissolving Aphanizomenon.

6. Use of the Rhodopseudomonas palustris strain Dexin-sdu-018 according to claim 1, the fermentation liquid according to claim 2, or the algae-lytic agent according to claim 3 or 4 in preventing and / or controlling algal blooms caused by Aphanizomenon.

7. The use according to claim 5 or 6, characterized in that: The Aphanizomenon includes Aphanizomenon bloom-aquae.

8. Use of the Rhodopseudomonas palustris strain Dexin-sdu-018 according to claim 1, the fermentation liquid according to claim 2, or the algae-lytic agent according to claim 3 or 4 in water resource protection and / or restoration.

9. The use according to claim 8, characterized in that: The water resource protection and / or restoration includes at least one of the following: removing nitrite in water, reducing ammonia nitrogen content in water and reducing sulfide content in water.

10. The use according to any one of claims 5 to 9, characterized in that: The working concentration of live bacteria of the Rhodopseudomonas palustris strain Dexin-sdu-018 is not less than 1×10 7 CFU / ml.

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