CN111925956A - A kind of highland bacillus with functions of producing alkali and passivating heavy metal cadmium and its application - Google Patents

Abstract

The invention discloses a Bacillus altitudinis with the functions of producing alkali and passivating heavy metal cadmium and application thereof, the strain is classified and named as Bacillus altitudinis XT-4, and is delivered to China Center for Type Culture Collection (CCTCC) for preservation in 2019, 5 and 20 months, and the preservation number is CCTCC NO: m2019370. The invention separates and screens the alkali-producing strain which can efficiently prevent and control the cadmium in the environment, and repairs the cadmium pollution in the environment through the application of microorganisms.

Description

A kind of highland bacillus with functions of producing alkali and passivating heavy metal cadmium and its application

technical field

The invention belongs to the field of biotechnology or soil heavy metal bioremediation technology, and in particular relates to a Bacillus highlandi with functions of producing alkali and passivating heavy metal cadmium and its application.

Background technique

Cadmium (Cd) is a heavy metal element with strong biological toxicity. It has strong chemical activity, high mobility and long-lasting toxicity in the environment. Cd ²⁺ is widely present in soil and water, and will enter the human body with the food chain. The accumulation of cadmium in the body will have teratogenic, carcinogenic and mutagenic effects. Studies have shown that pH value can affect the form of heavy metal cadmium in paddy soil. Under normal circumstances, the decrease of pH value in the soil will cause a large amount of heavy metal cadmium to be activated, which will promote the absorption of cadmium by crops, and the increase of pH value will help to enhance the adsorption of cadmium in the soil, resulting in precipitation and a decrease in the exchangeable state. , but too high a pH will promote the dissolution of the carbonate, again "activating" the cadmium. Therefore, reasonable regulation of soil pH will be of great significance to reduce the bioavailability of the heavy metal cadmium. According to a large number of studies, the intensification of farmland acidification in China is due to the unreasonable use of a large amount of nitrogen and phosphorus fertilizers. In the past 30 years, soil pH has decreased. An average drop of 1.2-1.5 units. The acidification of farmland is an important reason for the increase of cadmium bioavailability in soil. Remediation methods for cadmium-contaminated soil include physical remediation, chemical remediation and bioremediation: chemical methods such as precipitation and cementation. Physical methods such as ion exchange, solvent extraction, membrane filtration and activated carbon adsorption. Biological cadmium removal methods mainly include adsorption and precipitation. Biosorption is the chelation of Cd ²⁺ by exopolysaccharides or biological macromolecules such as oxalic acid and malic acid secreted by cells. Biological precipitation means that organisms can precipitate free Cd ²⁺ to form CdS or Cd(OH) ₂ to achieve the purpose of removal. Compared with physical and chemical methods, biological removal method has the advantages of low price and environmental friendliness, which has attracted people's attention. Studies have shown that bioremediation can effectively reduce the bioavailability of heavy metal cadmium, reduce the absorption of crops, and ensure the safety of agricultural products.

Bacillus is widely present in nature and has the characteristics of rapid reproduction, rapid metabolism, strong environmental adaptability and strong stress tolerance. Bacillus can survive and grow in heavy metal-contaminated environments. On the one hand, Bacillus can adsorb heavy metal cadmium in soil particles. On the other hand, it can affect some physical and chemical properties of soil, such as pH, organic matter, etc. Bioavailability, thereby reducing the toxic effect of heavy metal cadmium on plants. Therefore, screening for alkali-producing Bacillus should be used in acidic soil to fine-tune the pH of crop rhizosphere in acidic soil, thereby reducing the bioavailability of cadmium in plant rhizosphere.

In this study, microorganisms with strong resistance to cadmium and alkali production under different fermentation conditions will be screened from cadmium-contaminated soil, in order to fine-tune the pH of crop rhizosphere in acidic soil, reduce the bioavailability of heavy metal cadmium, and improve vegetable rhizosphere pH. and crop yield and quality purposes. Realize the production of safe vegetables on the soil contaminated with light and moderate heavy metal cadmium, and provide theoretical support for the development of microbial remediation technology for soil heavy metal pollution.

Invention content:

In view of the existing technical defects, the purpose of the present invention is to isolate and screen an alkali-producing strain that can effectively inhibit and control cadmium in the environment, and repair the cadmium pollution in the environment through the application of the strain.

The object of the present invention can be realized through the following technical solutions:

A strain of Bacillus altitudinis with the functions of producing alkali and passivating heavy metal cadmium. ), the deposit number is CCTCC NO: M2019370; the deposit address: Wuhan University, Wuhan, China. The applicant isolated and screened a microbial strain that can efficiently remove cadmium (Cd). According to the classification of classical microbiological morphological features and bioinformatics, the strain was classified and named.

The application of the above-mentioned Bacillus highlandi strains in passivating soil heavy metal cadmium.

The application of the above-mentioned Bacillus highlandi strains in the preparation of microbial organic fertilizers.

A microbial organic fertilizer, the microbial organic fertilizer contains the above-mentioned Bacillus aureus strains with the functions of producing alkali and passivating heavy metal cadmium.

As a preferred technical solution, the content of the above-mentioned Bacillus aeruginosa strain with the functions of producing alkali and passivating heavy metal cadmium in the microbial organic fertilizer is not less than 1.0×10 ² CFU/g.

Beneficial effects of the present invention:

The invention provides a strain with alkali-producing ability, fast growth rate, strong adaptability to the environment and strong stress tolerance; the strain improves the rhizosphere microecology of crops and decomposes and degrades soil organic matter into small molecules through alkali production, which can be used for crops Therefore, the yield and quality of vegetables and crops can be remarkably improved; the strain is used for preparing the microbial organic fertilizer with the function of fermentation and alkali production, and the effect is remarkable. The present invention separates and selects alkali-producing strains capable of efficiently removing cadmium in the environment, and restores the cadmium pollution in the environment through the application of microorganisms.

Description of drawings

Figure 1: Phylogenetic tree diagram of Bacillus altitudinis XT-4 of the present invention.

Figure 2: Study on the alkali production characteristics of Bacillus highlandi XT-4 of the present invention under different pH conditions.

Fig. 3: Bacillus highlandi XT-4 of the present invention removes cadmium from the medium under different pH conditions, and the graph of pH changes. Description of reference numerals: A and C in Figure 3 show the pH change and cadmium removal curve of XT-4 when the initial Cd concentration is 10 μM and pH=5; B and D in Figure 3 are the initial Cd concentration 10 μM, pH=5.5, pH change and cadmium removal curve of XT-4.

Fig. 4: The graph of soil pH change in the pot experiment of Bacillus highlandi XT-4 of the present invention. Reference number description: In soil (chemical fertilizer + no inoculation, chemical fertilizer + 10 ² cfu/g dw, chemical fertilizer + 10 ⁴ cfu/g dw, organic fertilizer + no inoculation, organic fertilizer + 10 ² cfu/g dw, organic fertilizer The graph of soil pH change in the experimental group of fertilizer + 10 ⁴ cfu/g dw).

Figure 5: Bar graph of the change in effective cadmium in pot experiments by Bacillus highlandi XT-4 of the present invention. Reference number description: In soil (chemical fertilizer + no inoculation, chemical fertilizer + 10 ² cfu/g dw, chemical fertilizer + 10 ⁴ cfu/g dw, organic fertilizer + no inoculation, organic fertilizer + 10 ² cfu/g dw, organic fertilizer Figure of soil available cadmium content in the experimental group of fertilizer + 10 ⁴ cfu/g dw).

Figure 6: A bar graph of changes in total cadmium in the aerial parts of vegetables in a pot experiment with Bacillus highlandi XT-4 of the present invention. Reference number description: In soil (chemical fertilizer + no inoculation, chemical fertilizer + 10 ² cfu/g dw, chemical fertilizer + 10 ⁴ cfu/g dw, organic fertilizer + no inoculation, organic fertilizer + 10 ² cfu/g dw, organic fertilizer Column chart of changes in total cadmium in the aerial parts of vegetables in the fertilizer + 10 ⁴ cfu/g dw) experimental group.

Detailed ways:

Example 1: Isolation and identification of Bacillus highlandi XT-4

(1) Sample collection: The soil collection and separation site was the topsoil of cadmium-contaminated farmland in Xiangtan City, Hunan Province.

(2) Isolation and screening of cadmium-resistant strains: Accurately weigh 5g of Xiangtan soil into a 250mL conical flask containing 100mL of sterile water, shake it on a shaker at 30°C and 200rpm for 48h to completely disperse the soil, and after standing for 5min, put it in an ultra-clean Take 1 mL of soil supernatant in Taichung into a 1.5 mL sterile centrifuge tube. Mix 100 μL of soil supernatant with 900 μL of sterile water thoroughly to obtain 10 ^-1 dilutions. Using the same method, obtain 10 ^-2 , 10 ^-3 , 10 ^-4 , 10 ^-5 , 10 ^-6 , 10 ^-7 , ^10-8 serial dilutions for coating plates. Take 100 μL of soil dilution with dilutions of 10 ^-5 , 10 ^-6 , 10 ^-7 , and 10 ^-8 , spread it on the LB medium plate containing 0.15mM Cd, place the plate upside down in a 30 ℃ incubator, and cultivate 5 days. Observe the colony morphology, color, degree of wetness, gloss, etc., pick different colonies into LB liquid test tubes, place the test tubes in a shaker for shaking culture, and then streak the bacterial liquid plate for purification to obtain a single colony. The commonly used LB liquid medium was prepared, and the formula was as follows (1L): tryptone 10g, yeast extract 5g, sodium chloride 10g, supplemented with distilled water to 1L. Sterilize under high pressure steam at 121°C for 20min.

(3) Screening of alkali-producing strains: transfer the cadmium-resistant bacteria monoclonal obtained in step (2) into M9 medium, adjust the pH to 5.0, 5.5 and 7.0, and place the prepared medium at 28°C Shake culture in a shaker, take a sample every 12 hours, measure the pH change of the solution, and screen strains that can efficiently produce alkali. Fig. 2 shows the research results of alkali production characteristics of Bacillus highlandi XT-4 screened by the present invention under different pH conditions. M9 medium: 1.5g _{Na2HPO4 · 12H2O} , 1.5g _KH2PO4 , 1.0g( _NH4 ) _2SO4 , 0.2g _{MgSO4 · 7H2O} , 0.01g _{CaCl2 · 2H2O} , 0.001g FeSO4 _{· 7H2O} , and pH 7.2, water 1000ml.

(4) Classification and identification of alkali-producing strains: genotype identification was performed by amplifying the partial nucleotide sequence of 16S rRNA. PCR was performed using prokaryotic 16S rRNA universal primers 27F (5'-AGAGTTTGATCMTGGCTCAG-3') and 1492R (5'-GGYTACCTTGTTACGACTT-3'). The 16S rRNA of Bacillus XT-4 was amplified and sequenced (as shown in SEQ ID No. 1), and then compared with the NCBI GenBank nucleotide database. The acid sequence homology was 98.96%. The MEGA6.0 software was used to construct a phylogenetic tree, and it was found that the Bacillus XT-4 isolated by the present invention could stably aggregate with the Bacillus strain (see Figure 1), and the strain was identified as Bacillus altitudinis XT-4.

(5) Morphology and physiological and biochemical characteristics of strain XT-4: Bacillus highlandi is a gram-positive bacterium with rod-shaped cells that can produce spores; on LB agar plates, the growth rate is faster, and the colonies are nearly round, yellow, and edged Untidy, dull, opaque colonies, the strains are fermented on LB liquid medium to produce alkali, so that the pH value of the fermentation broth rises to above pH 8.5; Sodium citrate and sodium succinate are the only carbon sources for growth; the pH growth range is wide and can tolerate pH4.0-10.0.

(6) Preservation of Bacillus altitudinis XT-4: Bacillus altitudinis XT-4 can be cultured on LB liquid or solid medium at 37°C, and can be stored at 4°C for short-term after culture. For long-term preservation, it is more suitable to use glycerol cryovials or freeze-drying tubes to preserve strains. The strain was submitted to the China Collection of Type Cultures (CCTCC) for preservation on May 20, 2019, and the preservation number is CCTCC NO: M2019370; the preservation address is Wuhan University, Wuhan, China.

Example 2: pH Change and Cadmium Removal Curve of Bacillus altitudinis XT-4

Pick a single clone of the strain XT-4 and inoculate it into 100 mL of LB liquid medium, shake it in a shaker at 30°C until the OD _600nm is about 0.5, use it as a seed solution, and inoculate it with a 1% (volume) inoculation amount. Fresh 100 mL of M9 liquid medium (starting OD600≈0.01), pH adjusted to 5.0, 5.5 and 7.0, and ₁₀ μM of CdCl2 added to the medium. The prepared culture medium was placed in a shaker at 30°C for shaking culture, and samples were taken every 12 hours to measure the pH change of the solution and the remaining Cd content in the solution at the same time. The concentration of cadmium in the solution can be measured by hydrogen flame atomic absorption spectrometer (AAS). As shown in Figure 3: under the conditions of initial pH of the medium at 5.0 and 5.5, the results showed that the Cd ion concentration in the medium supernatant decreased with the increase of the OD ₆₀₀ of the strain XT-4 in the medium, and the culture The pH of the base increased gradually, and the OH- ions in the medium increased. When the growth of the strain entered the stable phase, the bacterial number was in a balanced state, and the concentration of Cd ions in the medium also tended to be stable. The removal rates of cadmium after 36h were 95.99% and 96.50%, respectively.

Example 3: Pakchoi pot experiment

The potted test soil was taken from the cadmium-contaminated vegetable soil in Xiangtan, which was naturally air-dried and passed through a 2mm sieve. Each pot (specification: diameter 9cm, height 7cm) was divided into 0.5kg soil samples. The experiment was divided into 4 treatment groups (ie: treatment group 1: adding organic fertilizer to the soil, and adding a combined bacterial solution with a final concentration of 1 × 10 ² CFU/g; treatment group 2: adding 2% (mass) to the soil. ) organic fertilizer, and the combined bacterial solution with a final concentration of 1×10 ⁴ CFU/g was added; treatment group 3: chemical fertilizers equivalent to those of organic fertilizers N, P and K were added to the soil, and the final concentration was 1×10 ² CFU/g bacterial solution; treatment group 4: chemical fertilizer was added to the soil, and the bacterial solution with a final concentration of 1 × 10 ⁴ CFU/g was added; each group was set up with 4 replicates. The vegetable variety used in the experiment was Chinese cabbage "Shanghai cabbage". Qing" (Brassica rapassp.chinensis, cv.Shanghaiqing), take the cabbage with a seedling height of 7-10cm two weeks after sowing and transplant it. The four treatment groups are transplanted, and one plant is transplanted in each pot. Planting After 4 weeks, the plants and rhizosphere soil (soil within 5 mm of the root system) were harvested, and the pH of the rhizosphere soil, the available Cd content of the rhizosphere soil, the dry weight of the plant, the fresh weight and the Cd content of the shoot were determined.

After the plants were grown in pots for 5 weeks, the difference ΔpH between the pH value of the rhizosphere soil at harvest and the pH value of the soil at sowing was shown in Figure 4. Under the condition of no inoculation, chemical fertilizers and organic fertilizers were added. The pH of the soil was 5.18 and 5.31, respectively. In the experimental group added with chemical fertilizer, compared with the control group, in the experimental group added with 1*10 ² cfu/g dw, the pH increased from 5.18 to 5.43, an increase of 2.9%. In the test group added with 1*10 ⁴ cfu/g dw, the pH increased from 5.18 to 5.52, an increase of 4.5%. In the experimental group added with organic fertilizer, compared with the control group, in the experimental group added with 1*10 ² cfu/g dw, the pH increased from 5.31 to 5.56, an increase of 5.3%. In the test group added with 1*10 ⁴ cfu/g dw, the pH increased from 5.31 to 5.64, an increase of 6.8%. The results showed that the addition of strain XT-4+ organic fertilizer could increase the pH in the soil.

Example 4: Column chart of changes in available cadmium in pot experiment

The available cadmium in soil was extracted by calcium chloride leaching method. The specific steps are as follows: weigh about 1.5g of the slurry into a 50ml centrifuge tube with an analytical balance, add 25ml of 0.1M CaCl ₂ , and extract the centrifuge tube in a shaker at 25°C and 200rpm for 24h, then rotate at 3000rpm/min. , centrifuged for 5 min, took the supernatant to pass through a 0.22 μm filter membrane, and measured the Cd concentration in the supernatant by ICP-MS. Finally, the extracted cadmium content was determined by air-acetylene flame atomic absorption spectrometry.

After the plants were grown in pots for 5 weeks, the pH value in the rhizosphere soil at harvest and the effective cadmium content in the soil at sowing are shown in Figure 5. Under the condition of no inoculation, chemical fertilizers and organic fertilizers were added to the soil. The contents of available cadmium were 0.57 and 0.52 mg/kg, respectively. In the experimental group added with chemical fertilizer, compared with the control group, in the experimental group added with 1*10 ² cfu/g dw, the effective cadmium content decreased from 0.57 to 0.55, a decrease of 3.8%. In the experimental group added with 1*10 ⁴ cfu/g dw, the effective cadmium content decreased from 0.57 to 0.51, a decrease of 12%. In the experimental group added with organic fertilizer, compared with the control group, in the experimental group added with 1*10 ² cfu/g dw, the effective cadmium content decreased from 0.52 to 0.51, a decrease of 1.0%. In the experimental group added with 1*10 ⁴ cfu/g dw, the effective cadmium content decreased from 0.52 to 0.45, a decrease of 10.8%. The results showed that the addition of strain XT-4+ organic fertilizer could reduce the effective cadmium concentration in the soil, so as to achieve the effect of passivating cadmium.

Example 5: Column chart of changes in total cadmium content of Chinese cabbage in pot experiment

Take the mature pakchoi samples on the 30th day of the pot experiment, remove the pakchoi from the flowerpot, rinse the plant surface repeatedly with deionized water, and rinse off the soil. The fresh weight of the whole plant, the fresh weight of the roots and the shoots were measured respectively. The determination of cadmium content in Chinese cabbage refers to the determination method recommended by the National Standard of the People's Republic of China (No. G B5009.15-2014) "Determination of Cadmium in Food".

As shown in Figure 6, in the soil supplemented with chemical fertilizers, the cadmium content of the edible part of the shoots of the cabbage treated with 1*10 ² cfu/g dw and 1*10 ⁴ cfu/g dw was compared with the control without bacteria From 8.07mg/kg to 5.08mg/kg and 4.79mg/kg, a decrease of 37% and 41%. In the soil supplemented with organic fertilizers, the cadmium content of the edible parts of the shoots increased from 6.15 mg/kg to 1*10 ² cfu/g dw and 1*10 ⁴ cfu/gdw compared with the control without inoculation, respectively. dropped to 4.43mg/kg and 3.65mg/kg, a decrease of 28% and 41%.

>MK371783.1Bacillus altitudinis XT-4 16S ribosomal RNAgene

TTCATCGGGCTATAATGCAGTCGAGCGGACAGAAGGGAGCTTGCTCCCGGATGTTAGCGGCGGACGGGTGAGTAACACGTGGGTAACCTGCCTGTAAGACTGGGATAACTCCGGGAAACCGGAGCTAATACCGGATAGTTCCTTGAACCGCATGGTTCAAGGATGAAAGACGGTTTCGGCTGTCACTTACAGATGGACCCGCGGCGCATTAGCTAGTTGGTGAGGTAACGGCTCACCAAGGCGACGATGCGTAGCCGACCTGAGAGGGTGATCGGCCACACTGGGACTGAGACACGGCCCAGACTCCTACGGGAGGCAGCAGTAGGGAATCTTCCGCAATGGACGAAAGTCTGACGGAGCAACGCCGCGTGAGTGATGAAGGTTTTCGGATCGTAAAGCTCTGTTGTTAGGGAAGAACAAGTGCAAGAGTAACTGCTTGCACCTTGACGGTACCTAACCAGAAAGCCACGGCTAACTACGTGCCAGCAGCCGCGGTAATACGTAGGTGGCAAGCGTTGTCCGGAATTATTGGGCGTAAAGGGCTCGCAGGCGGTTTCTTAAGTCTGATGTGAAAGCCCCCGGCTCAACCGGGGAGGGTCATTGGAAACTGGGAAACTTGAGTGCAGAAGAGGAGAGTGGAATTCCACGTGTAGCGGTGAAATGCGTAGAGATGTGGAGGAACACCAGTGGCGAAGGCGACTCTCTGGTCTGTAACTGACGCTGAGGAGCGAAAGCGTGGGGAGCGAACAGGATTAGATACCCTGGTAGTCCACGCCGTAAACGATGAGTGCTAAGTGTTAGGGGGTTTCCGCCCCTTAGTGCTGCAGCTAACGCATTAAGCACTCCGCCTGGGGAGTACGGTCGCAAGACTGAAACTCAAAGGAATTGACGGGGGCCCGCACAAGCGGTGGAGCATGTGGTTTAATTCGAAGCAACGCGAAGAACCTTACCAGGTCTTGACATCCTCTGACAACCCTAGAGATAGGGCTTTCCCTTCGGG GACAGAGTGACAGGTGGTGCATGGTTGTCGTCAGCTCGTGTCGTGAGATGTTGGGTTAAGTCCCGCAACGAGCGCAACCCTTGATCTTAGTTGCCAGCATTCAGTTGGGCACTCTAAGGTGACTGCCGGTGACAAACCGGAGGAAGGTGGGGATGACGTCAAATCATCATGCCCCTTATGACCTGGGCTACACACGTGCTACAATGGACAGAACAAAGGGCTGCGAGACCGCAAGGTTTAGCCAATCCCACAAATCTGTTCTCAGTTCGGATCGCAGTCTGCAACTCGACTGCGTGAAGCTGGAATCGCTAGTAATCGCGGATCAGCATGCCGCGGTGAATACGTTCCCGGGCCTTGTACACACCGCCCGTCACACCACGAGAGTTTGCAACACCCGAAGTCGGTGAGGTAACCTTTATGGAGCCAGCCGCCGAAGTGCGAGTA

sequence listing

<110> Nanjing Agricultural University

<120> A kind of Bacillus highlandi with functions of producing alkali and passivating heavy metal cadmium and its application

<160> 1

<170> SIPOSequenceListing 1.0

<210> 1

<211> 1444

<212> DNA

<213> Bacillus altitudinis XT-4

<400> 1

ttcatcgggc tataatgcag tcgagcggac agaagggagc ttgctcccgg atgttagcgg 60

cggacgggtg agtaacacgt gggtaacctg cctgtaagac tgggataact ccgggaaacc 120

ggagctaata ccggatagtt ccttgaaccg catggttcaa ggatgaaaga cggtttcggc 180

tgtcacttac agatggaccc gcggcgcatt agctagttgg tgaggtaacg gctcaccaag 240

gcgacgatgc gtagccgacc tgagagggtg atcggccaca ctgggactga gacacggccc 300

agactcctac gggaggcagc agtagggaat cttccgcaat ggacgaaagt ctgacggagc 360

aacgccgcgt gagtgatgaa ggttttcgga tcgtaaagct ctgttgttag ggaagaacaa 420

gtgcaagagt aactgcttgc accttgacgg tacctaacca gaaagccacg gctaactacg 480

tgccagcagc cgcggtaata cgtaggtggc aagcgttgtc cggaattatt gggcgtaaag 540

ggctcgcagg cggtttctta agtctgatgt gaaagccccc ggctcaaccg gggagggtca 600

ttggaaactg ggaaacttga gtgcagaaga ggagagtgga attccacgtg tagcggtgaa 660

atgcgtagag atgtggagga acaccagtgg cgaaggcgac tctctggtct gtaactgacg 720

ctgaggagcg aaagcgtggg gagcgaacag gattagatac cctggtagtc cacgccgtaa 780

acgatgagtg ctaagtgtta gggggtttcc gccccttagt gctgcagcta acgcattaag 840

cactccgcct ggggagtacg gtcgcaagac tgaaactcaa aggaattgac gggggcccgc 900

acaagcggtg gagcatgtgg tttaattcga agcaacgcga agaaccttac caggtcttga 960

catcctctga caaccctaga gatagggctt tcccttcggg gacagagtga caggtggtgc 1020

atggttgtcg tcagctcgtg tcgtgagatg ttgggttaag tcccgcaacg agcgcaaccc 1080

ttgatcttag ttgccagcat tcagttgggc actctaaggt gactgccggt gacaaaccgg 1140

aggaaggtgg ggatgacgtc aaatcatcat gccccttatg acctgggcta cacacgtgct 1200

acaatggaca gaacaaaggg ctgcgagacc gcaaggttta gccaatccca caaatctgtt 1260

ctcagttcgg atcgcagtct gcaactcgac tgcgtgaagc tggaatcgct agtaatcgcg 1320

gatcagcatg ccgcggtgaa tacgttcccg ggccttgtac acaccgcccg tcacaccacg 1380

agagtttgca acacccgaag tcggtgaggt aacctttatg gagccagccg ccgaagtgcg 1440

agta 1444

Claims (5)

1. A strain of Bacillus altitudinis with the functions of alkali production and passivation of heavy metal cadmium, the strain is classified and named Bacillus altitudinis XT-4, and it was sent to the China Center for Type Culture Collection on May 20, 2019 (CCTCC) deposit, the deposit number is CCTCC NO: M2019370. 2. the application of the Bacillus highlandi strain of claim 1 in passivating soil heavy metal cadmium. 3. the application of the Bacillus highlandi strain described in claim 1 in the preparation of microbial organic fertilizer. 4. A microbial organic fertilizer, characterized in that, the microbial organic fertilizer comprises the Bacillus highlandi strain of claim 1 with the functions of producing alkali and passivating heavy metal cadmium. 5. The microbial organic fertilizer according to claim 3, wherein the content of the Bacillus highlandi strain with the functions of producing alkali and passivating heavy metal cadmium according to claim 1 in the microbial organic fertilizer is not less than 1.0×10 ² CFU/g.

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