Clostridium sp. And application thereof

Abstract

The invention relates to the field of microorganisms, in particular to clostridium and application thereof. The invention provides bacillus fusiformis which is named as WGS3 and has the preservation number of CGMCC (China General Microbiological Culture Collection Center) No.30041. The bacillus fusiformis has good reduction activity on sodium selenite and can be used for generating nano-selenium with high safety and high biological activity. Through determination, the strain can be used for preparing nano-selenium under the high sodium selenite concentration of 150 mmol / L, and the appropriate culture conditions are that the temperature is 35 DEG C and the pH value is 7. After the immobilized clostridium WGS3 microspheres are prepared, the nano-selenium synthesis efficiency can be improved by 7.1% under the concentration of 100 mmol / L.

Description

Technical Field

[0001] The invention relates to the field of microorganisms, and in particular to a clostridium and an application thereof. Background Art

[0002] Selenium is a common trace element in the human body and an important component of human health. Selenium plays an important role in human life activities. It is generally believed that it has the effects of anti-cell oxidation, delaying aging, inhibiting the replication of viral genetic material, and improving vision. At present, supplementing selenium through diet is the most effective and direct way to improve selenium deficiency in the human body. The content of selenium in the earth's crust is only 0.05×10 -6 , and its distribution is extremely dispersed, mostly in the form of heavy metal selenides. How to make rational use of selenium has become an urgent problem to be solved. Among the current methods for synthesizing selenium, biological methods have the advantages of being green and safe, low cost, mild synthesis conditions and environmental protection compared to chemical and physical methods. The synthesized selenium element - nano-selenium, has the advantages of low toxicity, strong biocompatibility and easy absorption compared to inorganic selenium, and is currently one of the safest and most reliable ways to supplement selenium.

[0003] The biosynthetic method for preparing nano-selenium is based on microorganisms (bacteria, fungi, etc.), using selenium-containing compounds as substrates, which are converted into nano-selenium under the action of enzymes and other related metabolites during growth and development. This method is low-cost, mild and safe, and very environmentally friendly. The surface of nano-selenium particles synthesized by microorganisms can be attached with bioorganic molecules such as polysaccharides and proteins, making them have the advantages of high biological activity, small size, uniform particle size, stable structure and easy absorption by organisms. It is the best selenium source additive and fertilizer.

[0004] The topic of preparing nano-selenium by biosynthesis is a hot research field both at home and abroad. With the development of science and technology, more and more microorganisms have been found to have the function of transforming and synthesizing nano-selenium, but there is still a problem of low transformation efficiency in practical applications. Therefore, conducting relevant research and applications on high-concentration tolerance and high-efficiency transformation of microbial synthesized nano-selenium is of great significance to the development of green functional agriculture and the improvement of dietary health. Summary of the invention

[0005] In view of this, the present invention provides a clostridium and application thereof, which has the ability to reduce sodium selenite to nano-selenium.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions.

[0007] The present invention provides Bacillus fusiformis, whose deposit number is CGMCC No.30041.

[0008] The present invention also provides a method for culturing the above-mentioned Bacillus fusiformis, comprising: inoculating the above-mentioned Bacillus fusiformis into a culture medium, adjusting the pH to 6.5, 6.6, 6.7, 6.8, 6.9, 7, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9 or 8, and culturing at 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C or 37°C to obtain a culture.

[0009] In some specific embodiments of the present invention, the culture medium of the above culture method is LB culture medium, which may contain 100 mmol / L, 110 mmol / L, 120 mmol / L, 130 mmol / L, 140 mmol / L or 150 mmol / L sodium selenite.

[0010] The present invention also provides the use of the above-mentioned Bacillus fusiformis in preparing immobilized microbial microspheres.

[0011] In some specific embodiments of the present invention, the preparation of the above application includes: mixing sodium alginate solution, biochar, and the bacterial suspension of Bacillus fusiformis to obtain a mixed solution; dripping the mixed solution into a calcium chloride solution drop by drop, keeping it immersed for 20 min, 25 min, 30 min, 35 min or 40 min, filtering, and washing to obtain the immobilized microbial microspheres.

[0012] In some specific embodiments of the present invention, the preparation of the above application comprises the following steps:

[0013] S1: inoculating the above-mentioned Bacillus fusiformis seed liquid into a culture medium, wherein the culture medium is a sterile culture medium containing sodium selenite, culturing, centrifuging, discarding the supernatant, and resuspending with physiological saline to obtain a bacterial suspension;

[0014] S2: mixing the sodium alginate solution, the biochar and the bacterial suspension to obtain a mixed solution;

[0015] S3: adding the mixed solution dropwise into the calcium chloride solution, soaking for 20 min, 25 min, 30 min, 35 min or 40 min, filtering, washing, and obtaining the immobilized microbial microspheres;

[0016] The sodium alginate solution may be a 3.5%, 4%, 4.5% or 5% sodium alginate solution;

[0017] The content of the biochar in the mixed solution may be 1%, 1.5% or 2%;

[0018] The concentration of the calcium chloride solution may be 0.5%, 1% or 2%.

[0019] The present invention also provides immobilized microbial microspheres, comprising the above-mentioned Bacillus fusiformis.

[0020] In some specific embodiments of the present invention, the immobilized microbial microspheres further comprise sodium alginate and biochar.

[0021] In some specific embodiments of the present invention, the preparation method of the immobilized microbial microspheres includes: mixing sodium alginate solution, biochar, and the bacterial suspension of Bacillus fusiformis to obtain a mixed solution; dripping the mixed solution into a calcium chloride solution dropwise, soaking for 20 min, 25 min, 30 min, 35 min or 40 min, filtering, and washing to obtain the immobilized microbial microspheres.

[0022] In some specific embodiments of the present invention, the method for preparing the above-mentioned immobilized microbial microspheres comprises the following steps:

[0023] S1: inoculating the above-mentioned Bacillus fusiformis seed liquid into a culture medium, wherein the culture medium is a sterile culture medium containing sodium selenite, culturing, centrifuging, discarding the supernatant, and resuspending with physiological saline to obtain a bacterial suspension;

[0024] S2: mixing the sodium alginate solution, the biochar and the bacterial suspension to obtain a mixed solution;

[0025] S3: adding the mixed solution dropwise into the calcium chloride solution, soaking for 20 min, 25 min, 30 min, 35 min or 40 min, filtering, washing, and obtaining the immobilized microbial microspheres;

[0026] The sodium alginate solution may be a 3.5%, 4%, 4.5% or 5% sodium alginate solution;

[0027] The content of the biochar in the mixed solution may be 1%, 1.5% or 2%;

[0028] The concentration of the calcium chloride solution may be 0.5%, 1% or 2%.

[0029] The present invention also provides the use of the above-mentioned Bacillus fusiformis or the above-mentioned immobilized microbial microspheres in reducing sodium selenite.

[0030] In some specific embodiments of the present invention, the reduced sodium selenite in the above application is the reduced sodium selenite in water.

[0031] The present invention also provides the use of the above-mentioned Bacillus fusiformis or the above-mentioned immobilized microbial microspheres in the preparation of nano-selenium.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows.

[0033] The present invention obtains Clostridium WGS3 by enriching, culturing, rescreening and purifying selenium-rich soil. The Clostridium WGS3 screened out by the present invention has a strong reducing ability to sodium selenite and can synthesize nano-selenium. At the same time, the Clostridium WGS3 can tolerate a high concentration of 150 mmol / L sodium selenite under culture conditions; and at a concentration of 50 mmol / L sodium selenite, it can be efficiently synthesized into nano-selenium in 6 hours. The microspheres prepared after calcium alginate immobilization treatment can improve the synthesis efficiency by 7.1% at a sodium selenite concentration of 100 mmol / L, and can shorten the preparation time by 6 hours (reduced from 24 hours to 18 hours). It shows excellent sodium selenite tolerance and high conversion efficiency, and has broad application prospects and industrial value in the treatment of high-selenium environments and the industrial production of nano-selenium.

[0034] Biological Deposit Description

[0035] Biological material: WGS3, classification name: Bacillus fusiformis, deposited on March 15, 2024 in the General Microbiology Center of China Culture Collection Administration. The address of the collection center is: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing; the collection number is CGMCC No. 30041. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0037] Figure 1 4 is a morphological diagram showing the Clostridium WGS3 of the present invention on LB agar medium;

[0038] Figure 2 The growth curve (OD 600 ), wherein A represents a simple LB medium, and B represents an LB medium containing 100 mmol / L sodium selenite;

[0039] Figure 3 Schematic diagram of the phylogenetic tree of Clostridium WGS3 of the present invention;

[0040] Figure 4 The effect of Clostridium WGS3 of the present invention on the synthesis of nano-selenium at different initial sodium selenite concentrations is shown;

[0041] Figure 5 The effect of the Clostridium WGS3 of the present invention on the synthesis of nano-selenium at different pH values ​​is shown;

[0042] Figure 6 The effect of the Clostridium WGS3 of the present invention on the synthesis of nano-selenium at different temperatures is shown;

[0043] Figure 7 shows the immobilized Clostridium WGS3 microspheres;

[0044] Figure 8 The synthesis of nano-selenium by immobilized Clostridium WGS3 microspheres at a concentration of 100 mmol / L sodium selenite is shown. DETAILED DESCRIPTION

[0045] The present invention discloses a Clostridium and its application. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve it. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The method and application of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0046] The clostridium of the present invention is named WGS3, and has the ability to reduce sodium selenite to nano-selenium.

[0047] Furthermore, the optimal growth pH of the Clostridium WGS3 of the present invention is 7.

[0048] Furthermore, the optimum growth temperature of the Clostridium WGS3 of the present invention is 35°C.

[0049] The present invention discloses a method for obtaining the above-mentioned Clostridium WGS3:

[0050] (1) collecting selenium-rich soil in Hailun City, Heilongjiang Province as the microbial source of the Clostridium;

[0051] (2) enriching and culturing the microbial source with a liquid LB medium containing sodium selenite to obtain an enriched mixed bacterial liquid;

[0052] (3) diluting the bacterial solution obtained above with sterile water to form bacterial solutions with different concentration gradients, and applying the diluted bacterial solutions with different concentration gradients to LB agar medium containing sodium selenite concentrations for culturing;

[0053] (4) Pick a single colony from the above culture medium and streak it onto fresh LB agar medium containing sodium selenite. Repeat this operation several times until pure bacteria are obtained.

[0054] The pure bacterial colonies were streaked on LB agar medium at 35°C. The morphological characteristics of the strain were as follows: the colonies were white, nearly round, opaque, smooth, flat, and with neat edges. The pure bacterial colonies were streaked on agar medium containing sodium selenite at 35°C. The colonies were red with light red edges.

[0055] Furthermore, the LB agar medium comprises the following components by mass concentration: 5% tryptone, 10% yeast extract, 5% NaCl, 2% agar powder, and a pH of 7.2.

[0056] Furthermore, the concentration of sodium selenite in the liquid LB medium is 10-100 mmol / L.

[0057] It should be understood that the expression "one or more of..." includes each of the items recited after the expression individually and in various different combinations of two or more of the recited items, unless otherwise understood from the context and usage. The expression "and / or" in combination with three or more recited items should be understood to have the same meaning, unless otherwise understood from the context.

[0058] The use of the terms "comprising", "having" or "containing", including their grammatical synonyms, should generally be understood as open and non-restrictive, for example not excluding other unrecited elements or steps, unless otherwise specifically stated or otherwise understood from the context.

[0059] It should be understood that the order of steps or the order in which certain actions are performed is not important as long as the application is still operable. In addition, two or more steps or actions can be performed simultaneously.

[0060] The use of any and all examples or exemplary language such as "for example" or "including" herein is intended only to better illustrate the present application and is not intended to limit the scope of the present application. No language in this specification should be construed as indicating that any unclaimed element is essential to the practice of the present application.

[0061] In addition, the numerical ranges and parameters used to define the present application are approximate values, and the relevant values ​​in the specific embodiments have been presented as accurately as possible. However, any numerical value inherently inevitably contains standard deviations due to individual test methods. Therefore, unless otherwise expressly stated, it should be understood that all ranges, quantities, values ​​and percentages used in this disclosure are modified by "about". Here, "about" generally refers to the actual value within plus or minus 10%, 5%, 1% or 0.5% of a specific value or range.

[0062] Unless otherwise specified, the raw materials, reagents, consumables and instruments involved in the present invention are all common commercial products and can be purchased from the market.

[0063] The present invention will be further described below in conjunction with the embodiments.

[0064] Example 1: Isolation of bacterial strains

[0065] This implementation case provides a method for obtaining Bacillus fusiformis WGS3, which specifically includes the following steps:

[0066] (1) Selenium-rich soil was collected from Hailun City, Heilongjiang Province and used as a microbial source for Clostridium WGS3.

[0067] (2) Take 1 g of soil sample, put it into a 250 mL conical flask, add 100 mL of sterile saline, place it in a shaking incubator, shake and mix at 120 r / min for 3 h, take it out and let it stand for 2 h. Aspirate the supernatant and inoculate it into LB liquid culture medium containing 10 mmol / L sodium selenite at a 5% inoculum. Place it in a constant temperature shaking incubator at 35℃ and 180 r / min for 36 h. After observing the turbidity of the culture medium, take it out and place it in a 4℃ refrigerator for use to obtain the initial mixed bacterial solution.

[0068] (3) Take 9 test tubes, numbered 1 to 9, and add 9 mL of sterile saline to each tube. Pipette 1 mL of the initial mixed solution into test tube 1 and mix well. Pipette 1 mL of the solution into test tube 2 and mix well. Repeat this process from test tube 2 to test tube 3. Repeat this process until all 9 test tubes are filled and mixed well to obtain 10% of the original sample solution. -1 , 10 -2 ,……10 -7 Concentration of diluted mixed bacterial solution.

[0069] (4) Move the container of LB dissolved solid culture medium containing 10 mmol / L sodium selenite to the clean bench and sterilize it under ultraviolet irradiation for 30 min. When the temperature drops to 40-50°C, pour an appropriate amount into several sterile culture dishes. After cooling and solidification, the coating operation can be carried out.

[0070] (5) Pipette 100 μL of the diluted mixed bacterial solution and drop it onto the surface of the solid culture medium. Use a cooled applicator to evenly spread it. Then seal it with a sealing film and place it in a constant temperature incubator for inversion at 35°C. Correspondingly, make three parallel groups for each diluted mixed bacterial solution concentration.

[0071] (6) Check the growth of the strain in the culture dish at all times within 48 hours, pick out the colonies according to their morphology and color, and streak them on LB solid medium containing 10 mmol / L sodium selenite. Then, streak the single colonies with good growth several times until a single colony is isolated and the purified strain Clostridium WGS3 is obtained. The streak culture diagram of Clostridium WGS3 is shown in the figure below. Figure 1 shown.

[0072] Take the seed liquid and inoculate it into fresh LB liquid medium and LB liquid medium containing 100 mmol / L sodium selenite at a 2% inoculum, respectively. Culture in an oscillating incubator at 35°C and 180 r / min. Sampling is performed every 2 hours, and the light absorption value at 600 nm is measured using a spectrophotometer until the end of the decay period (about 32 hours). The results are as follows: Figure 2 shown.

[0073] It should be noted that the above-mentioned LB agar medium includes the following components by mass concentration: 5% tryptone, 10% yeast extract, 5% NaCl, and a pH of 7.2. The sterilization method is moist heat sterilization: temperature 121°C, time 20 min. When preparing LB solid medium, first dissolve tryptone, yeast extract and NaCl in water according to the above mass concentration, then adjust the pH to 7.2, and then add agar powder to it at a mass concentration of 2%, mix well and sterilize to obtain LB solid medium.

[0074] In addition, the preparation method of LB medium containing sodium selenite is as follows: 17.294 g of anhydrous sodium selenite solid is dissolved in 100 mL of sterile deionized water to prepare a 1 mol / L sodium selenite mother solution. In an ultra-clean workbench, 1 mL of sodium selenite mother solution is added to 99 mL of LB liquid medium and mixed to obtain a 10 mmol / L sodium selenite LB liquid medium.

[0075] Example 2: Identification of bacterial species

[0076] This implementation case is to identify the obtained Clostridium WGS3 strain. Specifically, after the strain is expanded in culture, DNA extraction is carried out, and then the general primer PCR amplification technology of bacteria is used to amplify DNA, and 16S rDNA sequencing is carried out by Jilin Wenyu Technology Co., Ltd. The sequencing results are as follows:

[0077]

[0078] The BLAST program in NCBI was used to perform homology comparison and search with the 16S rDNA gene sequence in the GenBank database. The comparison results showed that the gene sequence of the WGS3 strain had a high homology with the 16S rDNA gene sequences of multiple strains of bacteria in the Bacilli class. The 16S rDNA gene sequences of 12 bacterial strains were selected, and the 16S rDNA gene sequence of a bacterial strain in the Methanobacterium genus was selected as the outgroup. The phylogenetic tree was analyzed using the MEGA software and the Neighbor-Joining tool to construct a phylogenetic tree, as shown in the figure. Figure 3 As shown. Combined with the morphological characteristics of Clostridium, it was preliminarily identified as Clostridium and named Clostridium WGS3. In addition, after the expansion culture, a part of Clostridium WGS3 can be mixed with glycerol and stored in a -80°C refrigerator, and a part can be streaked on the bevel of a test tube and stored in a 4°C refrigerator. The Clostridium (Bacillus fusiformis) WGS3 in this implementation case has been deposited in the China General Microbiological Culture Collection Center, and the deposit number is CGMCC No. 30041.

[0079] Example 3: Reduction ability of Clostridium WGS3 on sodium selenite under the influence of different factors

[0080] In practical applications, the factors affecting the natural environment are complex and changeable, which directly affect the growth and function of microorganisms. Therefore, in order to explore their tolerance and selenium production efficiency, the experiment used sodium selenite concentration, pH, and temperature as variables for determination, as follows.

[0081] (1) Effect of sodium selenite concentration on the synthesis of nano-selenium by Clostridium WGS3.

[0082] a) Take out the preserved bacteria from the -80℃ refrigerator, thaw at room temperature and inoculate into LB liquid culture medium, culture in a shaking incubator at 35℃ 180 r / min for 24 h, take out and store in a 4℃ refrigerator. This bacterial liquid is the seed liquid.

[0083] b) LB liquid culture medium with sodium selenite concentrations of 50, 100, 120, and 150 mmol / L and a pH of 7 was prepared (the preparation method is as described in Example 1). After wet heat sterilization at 121°C for 20 min, 98 mL of each culture medium was taken from the clean bench and placed in a 250 mL conical flask, and 2 mL of seed solution was added. The culture was cultured in an oscillating incubator at 35°C and 180 r / min to determine the selenium production efficiency under the corresponding conditions. Each treatment was repeated in triplicate and samples were taken every 24 h.

[0084] c) The following method was used to determine nano-selenium: 2 mL of fermentation broth was placed in a centrifuge tube (three groups of repeated samples were taken); centrifuged at 8000 r / min for 10 min, the supernatant was discarded, and the precipitate was taken; 1 mol / L Na 2 1 mL of S solution was shaken to dissolve; after standing for 1 hour, centrifuged and the supernatant was collected. The absorbance at 500 nm was measured to determine the reduction efficiency under the corresponding conditions. Each concentration was repeated three times.

[0085] The results are as follows Figure 4 As shown. At a concentration of 50 mmol / L, it can be completely converted into nano-selenium in 6 hours, and as the concentration increases, the time required for conversion is extended. 100 mmol / L requires 24 hours, 120 mmol / L requires 30 hours, and 150 mmol / L requires 36 hours. As the concentration increases, the toxic stress on the bacteria in the early stage increases, the hysteresis time is extended, and the reduction time is also extended accordingly.

[0086] (2) Effect of pH on the synthesis of nano-selenium by Clostridium WGS3

[0087] LB liquid culture medium with a sodium selenite concentration of 100 mmol / L and pH values ​​of 5, 6, 7, 8, and 9 was prepared. The rest of the operations were the same as above. The selenium production efficiency under the corresponding conditions was determined. Three groups were repeated for each pH value, and samples were taken every 24 hours. Figure 5 At pH 7-8, all of them can be converted into nano-selenium, while excessive acidity or alkalinity is not suitable for bacterial growth and enzyme synthesis.

[0088] (3) Effect of temperature on the synthesis of nano-selenium by Clostridium WGS3

[0089] Prepare LB liquid medium with a sodium selenite concentration of 100 mmol / L and a pH of 7. The rest of the operations are the same as above to determine the selenium production efficiency under the corresponding conditions. Three groups were repeated for each temperature. The results are shown in Figure 6 As shown. At a concentration of 100 mmol / L, the lower the temperature, the lower the conversion efficiency, indicating that the enzyme activity is low at this time. As the temperature rises, the conversion rate increases, and the metabolism of the bacteria and the activity of the enzyme increase. At 35°C, 100 mmol / L of nano-selenium can be synthesized in 24 hours, and the efficiency is in the first echelon of research on bacterial synthesis of nano-selenium.

[0090] Example 4: Immobilized microorganisms enhance the synthesis of nano-selenium by Clostridium WGS3

[0091] This embodiment provides an immobilized microbial microsphere preparation, which contains the above-mentioned Clostridium WGS3 and straw biochar with excellent adsorption and biocompatibility, and can improve the synthesis rate of nano-selenium under the same conditions. The preparation steps are as follows.

[0092] (1) Take out the preserved bacteria from the -80℃ refrigerator, thaw at room temperature and inoculate into LB liquid culture medium, culture in a shaking incubator at 35℃ and 180 r / min for 24 h, take out and store in a 4℃ refrigerator. This bacterial liquid is the seed liquid;

[0093] (2) Prepare LB liquid medium with a sodium selenite concentration of 150 mmol / L and a pH of 7 (the preparation method is as described in Example 1), sterilize it with wet heat at 121°C for 20 min, take 98 mL from the clean bench and put it into a 250 mL conical flask, add 2 mL of seed liquid, and culture it in a shaking incubator at 35°C and 180 r / min for 24 h. After taking it out, centrifuge it at 8000 rpm / min, resuspend the bacteria in physiological saline to prepare a bacterial suspension, and dilute it until its OD 600 =1.0±0.02, this operation was performed under a sterile environment;

[0094] (3) Prepare a sodium alginate solution with a mass concentration of 4% (4 g / 100 mL), mix the bacterial suspension and straw biochar into it, and prepare a 4% sodium alginate-bacteria-biochar mixed solution, in which the biomass carbon content is 2% (2 g / 100 mL);

[0095] (4) Use a syringe to draw the sodium alginate-bacteria-biochar solution drop by drop into the 1% calcium chloride solution and keep it immersed for 30 min;

[0096] (5) After filtering, the microspheres were washed with sterile water to obtain immobilized Clostridium WGS3 microspheres (such as Figure 7 and stored in 0.9% saline.

[0097] Weigh 2 g of immobilized microspheres with the surface water wiped off by filter paper after washing, put them into 100 mL of LB liquid culture medium with a sodium selenite concentration of 100 mmol / L and a pH of 7, and culture them in an oscillating incubator at 35°C and 180 r / min for 24 h. Set up three groups of replicates and perform nano-selenium concentration detection every 2 h. Figure 8 As shown in the figure, at a sodium selenite concentration of 100 mmol / L, the hysteresis period was shortened to 4 h and the total conversion time was shortened to 18 h. Compared with the synthesis of nano-selenium by free bacteria in Example 3, the conversion efficiency was increased by 7.1%. This shows that calcium alginate microspheres ensure the survival of bacteria and the activity of enzymes, reduce the toxic stress of sodium selenite on bacteria to a certain extent, and shorten the adaptation time of bacteria. The addition of straw biochar can reduce the sodium selenite concentration of the overall solution by virtue of its excellent adsorption properties, and can also reduce the toxic stress so that Clostridium WGS3 can survive in a relatively safer environment.

[0098] 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. Bacillus fusiformis, characterized in that The deposit number is CGMCC No. 30041.

2. The method for culturing Bacillus fusiformis according to claim 1, wherein: include: The Bacillus fusiformis according to claim 1 is inoculated into a culture medium, the pH is adjusted to 7-8, and the culture is carried out at 34-36° C. to obtain a culture.

3. Use of the Bacillus fusiformis according to claim 1 in preparing immobilized microbial microspheres.

4. The use according to claim 3, characterized in that The preparation comprises: mixing a sodium alginate solution, biochar, and the bacterial suspension of Bacillus fusiformis according to claim 1 to obtain a mixed solution; dripping the mixed solution into a calcium chloride solution drop by drop, keeping it immersed for 20 to 40 minutes, filtering, and washing to obtain the immobilized microbial microspheres.

5. Immobilized microbial microspheres, characterized in that: The method comprises the Bacillus fusiformis according to claim 1.

6. The immobilized microbial microspheres according to claim 5, characterized in that: Also contains sodium alginate and biochar.

7. The immobilized microbial microspheres according to claim 5 or 6, characterized in that: The preparation method comprises: mixing sodium alginate solution, biochar and the bacterial suspension of Bacillus fusiformis according to claim 1 to prepare a mixed solution; dripping the mixed solution into a calcium chloride solution drop by drop, keeping it immersed for 20 to 40 minutes, filtering, washing, and obtaining the immobilized microbial microspheres.

8. Use of the Bacillus fusiformis according to claim 1 or the immobilized microbial microspheres according to any one of claims 5 to 7 in reducing sodium selenite.

9. Use of the Bacillus fusiformis according to claim 1 or the immobilized microbial microspheres according to any one of claims 5 to 7 in the preparation of nano-selenium.

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