Bacillus and application thereof in separation and recovery of heavy rare earth

Abstract

The invention provides bacillus and application thereof in separation and recovery of heavy rare earth, the strain of the bacillus is named as Bacillus sp.DW011 and preserved in Guangdong Microbial Culture Collection Center, and the preservation number is GDMCC No: 65275. The invention belongs to the technical field of biological environmental protection, provides novel bacillus, enriches the prior art, realizes application of the novel bacillus in separation and recovery of heavy rare earth, has extremely strong stress resistance and good adaptability to the external environment, and is beneficial to selective adsorption and recovery of heavy rare earth ions.

Description

Technical Field

[0001] The invention belongs to the technical field of biological environmental protection, and in particular relates to a bacillus and an application thereof in separation and recovery of heavy rare earth. Background Art

[0002] Rare earth metals are a general term for 17 metals in the IIIB group of the periodic table, including scandium, yttrium, and lanthanide. They are widely used in defense, aviation, new energy, and other fields. Rare earths are important national strategic resources and non-renewable resources. In particular, heavy rare earths are more critical in high-tech fields such as chips due to their unique physical and chemical properties. Therefore, heavy rare earths are generally considered to be more scarce and strategically significant than light rare earths. Ionic heavy rare earths in Ganzhou, Jiangxi account for more than 30% of China's ionic rare earth mines, and have a significant influence in the rare earth industry.

[0003] A large number of physical and chemical recovery technologies related to rare earths have been reported at home and abroad. Chinese patent application CN102190325A discloses the use of magnesium sulfate, magnesium chloride, etc. as leaching agents to extract rare earth ions; Chinese patent application CN108726555A discloses the use of hydrophobic ionic liquid precipitants made of solid carboxylic acid compounds to recover rare earth ions. However, the process of this type of chemical recovery process is relatively complicated, and rare earth ions are lost more. In addition, due to the use of a large amount of chemical substances such as inorganic leaching agents and organic extractants, it leads to high energy consumption, secondary pollution caused by waste liquid discharge, and low recovery rate.

[0004] In the biological method of rare earth ion recovery, Bacillus can be used as an adsorbent, using its own special mechanism to adsorb a variety of rare earth ions. Chinese patent application CN110938565A discloses a method for recovering rare earth ions using Bacillus cereus, which has a high removal rate for 17 kinds of rare earth ions. Thanks to the strong resistance of Bacillus to the external environment, it has good adaptability in the application process, but the adsorption capacity for heavy rare earth ions and light rare earth ions is close, which is not conducive to the selective adsorption of heavy rare earth ions.

[0005] Therefore, it is of great significance to provide a new type of Bacillus and its application in separation and recovery of heavy rare earths. Summary of the invention

[0006] In order to solve the problems existing in the prior art, the present invention provides a bacillus and an application thereof in the separation and recovery of heavy rare earths, enriches the prior art, and realizes the application of a new bacillus Bacillus sp.DW011 in the separation and recovery of heavy rare earths. The bacillus has extremely strong stress resistance and good adaptability to the external environment, has a strong selective adsorption capacity for heavy rare earth ions, and the adsorption rate is increased by up to 40% compared with that for light rare earths. The bacillus can be widely used in the recovery of heavy rare earth ions and the separation of rare earth ions.

[0007] The purpose of the present invention will be further illustrated by the following detailed description.

[0008] The invention provides a bacillus, the strain of which is named Bacillus sp.DW011 and is preserved in Guangdong Province Microbiological Culture Collection Center with a preservation number of GDMCC No: 65275.

[0009] Correspondingly, the present invention also provides the use of the Bacillus in separating and recovering heavy rare earths.

[0010] Preferably, the heavy rare earth contains at least one of terbium ions, dysprosium ions, thulium ions and holmium ions.

[0011] More preferably, the heavy rare earth contains at least one of terbium ions and dysprosium ions.

[0012] In addition, the present invention also provides a method for using the Bacillus to separate and recover heavy rare earths, comprising the following steps: 1) inoculating Bacillus sp. DW011 into LB liquid culture medium, culturing overnight, collecting cell bodies by centrifugation, freeze-drying the cell bodies, and then grinding and sieving to obtain cell powder; 2) incubating the cell powder with a solution containing rare earth ions, centrifuging to obtain cell powder loaded with rare earth ions; 3) eluting the cell powder loaded with rare earth ions with an ethylenediaminetetraacetic acid solution, and the supernatant obtained by centrifugation contains the recovered rare earth ions.

[0013] After the bacterial powder loaded with rare earth ions is eluted 4 to 8 times with ethylenediaminetetraacetic acid solution, the supernatant obtained by centrifugation contains the recovered rare earth ions (mainly heavy rare earth ions), and the precipitate obtained by centrifugation is the bacterial body; the concentration of the ethylenediaminetetraacetic acid solution is preferably 0.25 mol / L; the bacterial body after centrifugation can be reused after washing 3 to 5 times. The bacterial body powder is made by freeze-drying the cell body, which is conducive to long-term storage and is not easy to deteriorate.

[0014] Preferably, the recovered rare earth ions contain at least one of terbium ions, dysprosium ions, thulium ions and holmium ions.

[0015] Preferably, the pH of the solution containing rare earth ions is 5.0-9.0. More preferably, the pH of the solution containing rare earth ions is 6.0-7.4.

[0016] Preferably, the incubation temperature is 30-37° C. and the incubation time is 4-10 min.

[0017] Preferably, the temperature of the overnight culture is 35-38°C.

[0018] Preferably, in step 1), the centrifugal speed is 3000-5000 rpm and the time is 6-12 min; in step 2), the centrifugal speed is 8000-15000 rpm and the time is 1.5-8 min; in step 3), the centrifugal speed is 8000-15000 rpm and the time is 1.5-8 min.

[0019] Compared with the prior art, the beneficial effects of the present invention include:

[0020] (1) The present invention screened out a new type of Bacillus from ionic rare earth mine soil, enriching the existing technology. The strain was named Bacillus sp. DW011 and preserved in Guangdong Microbiological Culture Collection Center (GDMCC) with a preservation number of GDMCC No: 65275.

[0021] (2) The present invention also provides the use of Bacillus in the separation and recovery of heavy rare earths. The provided Bacillus sp. DW011 has extremely strong resistance to external environments and good adaptability, and has a strong selective adsorption capacity for heavy rare earth ions. Compared with the adsorption rate for light rare earths, it is increased by up to 40%, and can be widely used in the recovery of heavy rare earth ions and the separation of rare earth ions. In addition, the method for separating and recovering heavy rare earths provided by the present invention is relatively simple to operate, does not require the use of expensive professional equipment, is relatively simple to operate, and is highly selective for Dy 3+ , Tb 3+ The adsorption and recovery effects of iso-heavy rare earth ions are ideal, and the adsorption and separation effect of heavy rare earth ions in mixed rare earth ions is better, which is beneficial to the recovery and reuse of scarce resources, has a wide range of use conditions, and reduces waste liquid discharge and environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Phylogenetic tree of Bacillus sp.DW011 strain was constructed based on 16S rRNA analysis.

[0023] Figure 2 Growth curve of Bacillus sp.DW011 tolerant to terbium ions.

[0024] Figure 3 Bacillus sp.DW011 to 200mmol / LTb 3+ or Dy 3+ Cell adsorption effect diagram.

[0025] Figure 4 The adsorption effect of Bacillus sp.DW011 on eight mixed rare earths.

[0026] The bacillus provided by the present invention has a strain name of Bacillus sp. DW011, which is preserved in the Guangdong Microbial Culture Collection Center (GDMCC) with a preservation number of GDMCC No 65275: the preservation address is 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou, and the preservation time is October 15, 2024. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0028] In the present invention, the reagents involved are all conventional commercial products, or can be obtained by conventional technical means in the art. The preparation method of LB liquid culture medium comprises the following steps: adding 10g of tryptone, 5g of yeast extract, and 10g of NaCl to 950mL of water, adjusting the pH value to 7.0 with 1mol / L NaOH solution and making the volume to 1L, and sterilizing by high pressure to obtain.

[0029] Example 1 Isolation and Identification of Bacillus sp. DW011

[0030] 1. Isolation of strains

[0031] The rare earth ion adsorption strain Bacillus sp.DW011 provided by the present invention is isolated from the soil of the ionic rare earth mining area in Ganzhou, Jiangxi Province. The isolation steps of the strain specifically include: 1) Collection of soil samples: Collect soil samples from rare earth mines and place them in an ice box at 2°C for standby use; 2) Isolation of Bacillus strains: Add 10g of soil sample to a triangular flask with glass beads and 90mL of sterile water, place it in a shaker for 10min, and the conditions for the shaker culture are: 37°C, 150rpm, stand for 10min, take 1mL of supernatant in an EP tube, place it in an 85°C water bath for 10min, then ice bath for 15min, draw 100μL of bacterial solution and place it in a gradient of 10 -1 ~10 -5 The mixture was diluted and spread on LB solid medium containing 1000 mg / L thulium ion, and cultured overnight in a 37°C constant temperature incubator. Single colonies were picked and streaked on LB solid medium for purification three times to obtain single Bacillus colonies. 3) Screening of Bacillus strains: The single Bacillus colonies isolated in step 2) were transferred to a medium containing TbCl 3 The tolerance of the strain to rare earth ions was observed in LB liquid culture medium with concentrations of 0, 400, 600, 700, 800 and 1000 mg / L, and Bacillus resistant to high concentrations of rare earth ions was screened.

[0032] 2. Identification of strains

[0033] The rare earth ion-resistant Bacillus screened above was cultured in LB liquid medium to the logarithmic growth phase, the bacteria were collected by centrifugation, and the bacterial genomic DNA was extracted. The 16S rRNA gene fragment in the bacterial genomic DNA was amplified using universal primers, wherein the universal primers included a forward primer AGAGTTTGATCCTGGCTCAG (SEQ ID NO: 1) and a reverse primer GGTTACCTTGTTACGACTT (SEQ ID NO: 2); the amplified product was sent to Shanghai Bioengineering Co., Ltd. for sequencing, and the measured sequence was input into NCBI for comparison, and a phylogenetic tree was constructed using MEGA software as shown in FIG. Figure 1 As shown, the strain was determined to be Bacillus sp. DW011.

[0034] Molecular identification results: 16S rDNA sequence is as follows:

[0035] GTGCAGGGGCGGCGTGCTATACATGCAAGTCGAGCGGACAGAAGGGAGCTTGCTCCCG

[0036] GATGTTAGCGGCGGACGGGTGAGTAACACGTGGGTAACCTGCCTGTAAGACTGGGATAA

[0037] CTCCGGGAAACCGGAGCTAATACCGGATAGTTCCTTGAACCGCATGGTTCAAGGATGAA

[0038] AGACGGTTTCGGCTGTCACTTACAGATGGACCCGCGGCGCATTAGCTAGTTGGTGAGGT

[0039] AACGGCTCACCAAGGCGACGATGCGTAGCCGACCTGAGAGGGTGATCGGCCACACTGG

[0040] GACTGAGACACGGCCCAGACTCCTACGGGAGGCAGCAGTAGGGAATCTTCCGCAATGG

[0041] ACGAAAGTCTGACGGAGCAACGCCGCGTGAGTGATGAAGGTTTTCGGATCGTAAAGCT

[0042] CTGTTGTTAGGGAAGAACAAGTGCAAGAGTAACTGCTTGCACCTTGACGGTACCTAACC

[0043] AGAAAGCCACGGCTAACTACGTGCCAGCAGCCGCGGTAATACGTAGGTGGCAAGCGTT

[0044] GTCCGGAATTATTGGGCGTAAAGGGCTCGCAGGCGGTTTCTTAAGTCTGATGTGAAAGC

[0045] CCCCGGCTCAACCGGGGAGGGTCATTGGAAACTGGGAAACTTGAGTGCAGAAGAGGA

[0046] GAGTGGAATTCCACGTGTAGCGGTGAAATGCGTAGAGATGTGGAGGAACACCAGTGGC

[0047] GAAGGCGACTCTCTGGTCTGTAACTGACGCTGAGGAGCGAAAGCGTGGGGAGCGAACA

[0048] GGATTAGATACCCTGGTAGTCCACGCCGTAAACGATGAGTGCTAAGTGTTAGGGGGTTTC

[0049] CGCCCCTTAGTGCTGCAGCTAACGCATTAAGCACTCCGCCTGGGGAGTACGGTCGCAAG

[0050] ACTGAAACTCAAAGGAATTGACGGGGGCCCGCACAAGCGGTGGAGCATGTGGTTTAAT

[0051] TCGAAGCAACGCGAAGAACCTTACCAGGTCTTGACATCCTCTGACAACCCTAGAGATAG

[0052] GGCTTTCCCTTCGGGGACAGAGTGACAGGTGGTGCATGGTTGTCGTCAGCTCGTGTCGT

[0053] GAGATGTTGGGTTAAGTCCCGCAACGAGCGCAACCCTTGATCTTAGTTGCCAGCATTCA

[0054] GTTGGGCACTCTAAGGTGACTGCCGGTGACAAACCGGAGGAAGGTGGGGATGACGTCA

[0055] AATCATCATGCCCCTTATGACCTGGGCTACACACGTGCTACAATGGACAGAACAAAGGG

[0056] CTGCGAGACCGCAAGGTTTAGCCAATCCCACAAATCTGTTTCTCAGTTCGGATCGCAGTC

[0057] TGCAACTCGACTGCGTGAAGCTGGAATCGCTAGTAATCGCGGATCAGCATGCCGCGGTG

[0058] AATACGTTCCCGGGCCTTGTACACACCGCCCGTCACACCACGAGAGTTTGCAACACCCGAAGTCGGTGAGGTAACCTTTATGGAGCCAGCCGCCGAAGTGACAGAGTT (SEQ ID NO: 3)

[0059] Morphological characteristics of the colony: white, candle-like, round, flat, large in size, with a smooth and shiny surface, and easy to pick up.

[0060] Microscopic morphological characteristics: The bacteria are rod-shaped.

[0061] Rare earth ion tolerance identification: The growth curve of Bacillus sp.DW011 resistant to rare earth terbium ions is as follows Figure 2 As shown, the initial pH value was 7.0.

[0062] 3. Preservation of strains

[0063] Through the above identification results, it was confirmed that DW011 belonged to the Bacillus sp. species, and it was named Bacillus sp. DW011, preserved in the Guangdong Microbiological Culture Collection Center with the preservation number GDMCC No: 65275, and was found to be alive after detection.

[0064] Example 2 Method for Separating and Recovering Heavy Rare Earth Using Bacillus sp. DW011

[0065] 1. Bacillus sp.DW011 adsorption recovery of Tb 3+ / Dy 3+

[0066] The method for separating and recovering heavy rare earth by adsorption of Bacillus sp. DW011 comprises the following steps: inoculating Bacillus sp. DW011 into LB liquid culture medium, culturing at 37°C overnight, collecting cell bodies by centrifugation, the centrifugation speed is 3500 rpm, the time is 10 min; 600 1.5) and pH 7.0 containing rare earth ions Tb 3+ or Dy 3+ The solution was incubated for 5 min, Tb 3+ or Dy 3+ The initial concentration of the solution was 200mmol / L, and the solution was centrifuged at a speed of 12000rmp for 2min to obtain cells loaded with rare earth ions. The rare earth ion concentration in the supernatant was determined after centrifugation, and the calculation was: the removal rate of rare earth ions % = (initial ion concentration - supernatant ion concentration) / initial ion concentration × 100%. The results are as follows Figure 3 As shown. Figure 3 It can be seen that the Bacillus DW011 provided by the present invention has a high affinity for rare earth ions Tb 3 + 、Dy 3+ The adsorption removal and recovery effects of Tb 3+ The adsorption removal rate was 90.46%, Dy 3+ The adsorption removal efficiency was 94.21%.

[0067] 2. Bacillus sp.DW011 adsorption and separation of mixed rare earth

[0068] The method of using Bacillus sp.DW011 to separate mixed rare earth ions by adsorption comprises the following steps: inoculating Bacillus sp.DW011 into LB liquid culture medium, culturing overnight at 37°C, collecting cell bodies by centrifugation, the centrifugation speed is 3500rmp, and the time is 10min; precooling the cell bodies in -20°C and -80°C refrigerators for 7h, freeze-drying in a freeze dryer for 24h, grinding and screening through a 200-mesh sieve to obtain cell powder; incubating the cell powder with a solution containing mixed rare earth ions (pH 7.0) for 5min, the mixed rare earth ions include terbium, dysprosium, neodymium, lanthanum, thulium, cerium, yttrium, and holmium, and the initial concentration of each rare earth is 100mmol / L, centrifuging to obtain cell powder loaded with rare earth ions. After centrifugation, the rare earth ion concentration in the supernatant is determined, and the calculation is the same as above. The result is as follows: Figure 4 As shown. Figure 4It can be seen that the adsorption rate of the Bacillus sp. DW011 provided by the present invention for terbium ions, dysprosium ions, thulium ions, and holmium ions is very high, which is significantly higher than the adsorption rate for light rare earth ions such as lanthanum ions.

[0069] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A Bacillus, characterized in that: The strain was named Bacillus sp.DW011 and deposited in Guangdong Microbiological Culture Collection Center with the deposit number of GDMCC No: 65275.

2. Use of the bacillus according to claim 1 in separation and recovery of heavy rare earth.

3. The use of the bacillus according to claim 2 in separation and recovery of heavy rare earth, characterized in that: The heavy rare earth contains at least one of terbium ions, dysprosium ions, thulium ions, and holmium ions.

4. The use of the bacillus according to claim 2 in separation and recovery of heavy rare earth, characterized in that: The heavy rare earth contains at least one of terbium ions and dysprosium ions.

5. The method for separating and recovering heavy rare earth using Bacillus according to claim 1, characterized in that: The method comprises the following steps: 1) inoculating Bacillus sp. DW011 into LB liquid culture medium, culturing overnight, collecting cell bodies by centrifugation, freeze-drying the cell bodies, grinding and sieving to obtain cell powder; 2) incubating the cell powder with a solution containing rare earth ions, centrifuging to obtain cell powder loaded with rare earth ions; 3) eluting the cell powder loaded with rare earth ions with an ethylenediaminetetraacetic acid solution, and centrifuging to obtain a supernatant containing the recovered rare earth ions.

6. The method for separating and recovering heavy rare earth using Bacillus according to claim 5, characterized in that: The recovered rare earth ions contain at least one of terbium ions, dysprosium ions, thulium ions and holmium ions.

7. The method for separating and recovering heavy rare earth using Bacillus according to claim 5, characterized in that: The pH of the solution containing rare earth ions is 5.0-9.

0.

8. The method for separating and recovering heavy rare earth using Bacillus according to claim 5, characterized in that: The incubation temperature is 30-37° C. and the incubation time is 4-10 min.

9. The method for separating and recovering heavy rare earth using Bacillus according to claim 5, characterized in that: The temperature of the overnight culture is 35-38°C.

10. The method for separating and recovering heavy rare earth using Bacillus according to claim 5, characterized in that: In the step 1), the centrifugal speed is 3000-5000 rpm and the time is 6-12 min; in the step 2), the centrifugal speed is 8000-15000 rpm and the time is 1.5-8 min; in the step 3), the centrifugal speed is 8000-15000 rpm and the time is 1.5-8 min.

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