A method for preparing bionano lead selenide quantum dots using Bacillus sp HZ3

Abstract

The invention discloses a method for preparing biological nano-lead selenide quantum dots by using Bacillus sp HZ3, and specifically relates to the field of microbial application technology. The Bacillus sp HZ3 selected by the invention can efficiently convert lead nitrate and sodium selenite to produce nano-lead selenide PbSe. The preparation method comprises the following steps: (1) preparing bacterial culture solution; (2) fermentation culture; (3) adding sodium selenite and lead nitrate; (4) adding an inducer; (5) inducing synthesis of biological nano-lead selenide; (6) separating and extracting lead selenide quantum dots. Beneficial effect: According to the characteristics of Bacillus sp HZ3 in synthesizing lead selenide, the invention adds an inducer that helps to enhance the synthesis effect of nano-lead selenide during the culture process, and maximizes the synthesis efficiency of nano-lead selenide by combining high temperature culture-low temperature induction culture-high temperature culture.

Description

Technical Field

[0001] The invention belongs to the technical field of microbial application, and specifically relates to a method of using Bacillus Bacillus .sp HZ3 Method for preparing bio-nano lead selenide quantum dots. Background Art

[0002] With the increasing development of the information society, infrared semiconductor materials have shown extremely important application value in production, life and military fields. However, the regulation range of traditional infrared semiconductor materials in the infrared band is usually narrow, which restricts its application in the entire infrared band. Therefore, the research and development of semiconductor materials with a wide infrared band coverage and simple preparation process has become a research hotspot in the field of infrared semiconductor materials. As a new type of metal compound nanomaterial, lead selenide (PbSe) infrared colloidal semiconductor quantum dots have attracted widespread attention due to their adjustable infrared band spectrum, narrow half-peak width and solution processing. For example, in the optical communication band between 1300 and 1550nm, PbSe quantum dots have the highest fluorescence quantum yield (close to 90%) among all infrared semiconductor materials, and have become a class of materials systems that have attracted much attention.

[0003] However, PbSe quantum dots are extremely sensitive to air. When directly exposed to air, they will undergo oxidation and collision-induced dissociation processes in a short period of time, resulting in the weakening or loss of their optical activity, which greatly restricts the application of PbSe quantum dots.

[0004] In order to effectively passivate PbSe quantum dots and enhance their stability in the air, PbSe quantum dots synthesized by traditional physical and chemical methods will be passivated by shell coating or halogen ion passivation before being used. This not only increases the difficulty of manufacturing PbSe quantum dots, but also increases the production cost. The biological method for synthesizing PbSe quantum dots has mild reaction conditions, low cost, and is environmentally friendly. At the same time, organisms contain many active ingredients with reducing properties and stability. While synthesizing PbSe quantum dots, they can also form a covering and isolating effect on the prepared PbSe quantum dot particles to reduce the agglomeration between particles, making the synthesized PbSe quantum dots more stable than lead selenide synthesized by conventional methods, and no secondary passivation is required. Therefore, it has become a research hotspot for the synthesis of PbSe quantum dots. At present, there are few studies on the microbial synthesis of PbSe quantum dots, which have only been reported in a few fungi such as Trichoderma sp. and Aspergillus terreus. Moreover, these microorganisms synthesize PbSe quantum dots at a slow rate, requiring more than 5 days of culture to convert sodium selenite and lead nitrate into PbSe quantum dots, which greatly limits the large-scale rapid preparation and application of PbSe quantum dots.

[0005] The Chinese patent with publication number CN103626139A discloses a method for synthesizing lead selenide quantum dots by local supersaturation induced by nanosecond pulse laser. Lead selenide nanocrystals are prepared in oleic acid using lead acetate trihydrate and sulfur powder, and then a 4ml PbSe (OA) solution is prepared using lead selenide raw materials with a concentration of 2.5mM. Nanosecond parallel laser is used to act until clarified, ice bath assisted, laser parameters are 700V, 5Hz, and carried out at room temperature and normal atmospheric pressure. 5ml of ethanol is then added to the obtained product solution, and then centrifugal precipitation is performed. After cyclic cleaning, the obtained final product is dispersed in cyclohexane to obtain lead selenide quantum dots with good dispersion. The lead selenide quantum dots prepared by this method have good crystallinity and a faster synthesis speed. However, this method still has the problems of complex operation steps and low efficiency. At the same time, oleic acid and ammonium oil, which are irritating to the human respiratory tract, are used in this preparation method, so there are health risks and environmental pollution risks. Summary of the invention

[0006] The technical problem to be solved by the present invention is to avoid the problems of complex operation, high production cost, low efficiency, potential health risks and environmental pollution risks in the preparation of PbSe quantum dots by traditional physical and chemical methods.

[0007] The present invention solves the above technical problems through the following technical means:

[0008] Bacillus strains used in the present invention Bacillus .sp HZ3, deposit number: CCTCC NO: M20221472, deposit date: September 21, 2022, deposit unit: China Center for Type Culture Collection (CCTCC), deposit address: Luojia Mountain, Bayi Road, Wuchang District, Wuhan City, Hubei Province.

[0009] The present invention provides a method of using Bacillus Bacillus .sp HZ3 A method for preparing biological nano-lead selenide quantum dots, comprising the following steps:

[0010] (1) Preparation of bacterial culture medium: Pick Bacillus .sp HZ3 single colony was added to YNP medium for cultivation to obtain bacterial culture solution;

[0011] (2) Fermentation culture: Add the bacterial culture solution obtained in step (1) to the fermentation medium and culture until the culture solution is Bacillus .sp HZ3 bacterial colony count reaches 10 7 CFU / mL;

[0012] (3) Adding sodium selenite (Na2SeO3) and lead nitrate (Pb(NO3)2): Add sodium selenite solution to the culture solution obtained in step (2), and then add lead nitrate solution and continue culturing;

[0013] (4) Adding an inducer: adding an inducer to the culture solution obtained in step (3);

[0014] (5) Induced synthesis of biological nano-lead selenide: After adding the inducer, first culture at room temperature, then transfer to low temperature culture, and then transfer to room temperature culture again. Cultivate until the color of the culture medium changes from light yellow to gray-brown and the color no longer darkens, and the nano-lead selenide quantum dots are completely generated;

[0015] (6) Separation and extraction of lead selenide quantum dots: The culture solution obtained in step (5) is placed in a centrifuge tube, subjected to a preliminary centrifugation operation, the bacterial precipitate is discarded, and the supernatant is collected; the supernatant is then placed in a clean centrifuge tube, subjected to a secondary centrifugation operation, and the obtained precipitate is resuspended in double distilled water to obtain the prepared nano-lead selenide quantum dots.

[0016] Beneficial effect: The present invention adopts a special strain of Bacillus Bacillus .sp HZ3, a biological method for synthesizing nanomaterials, has mild reaction conditions, low cost, and simple operation, which improves the efficiency of preparing nano-lead selenide quantum dots.

[0017] Preferably, the YNP medium in step (1) is prepared from 5-10 g of peptone, 3-5 g of beef powder, 5-10 g of yeast powder, 1-3 mg of vitamin B2, 0.1-0.3 g of sodium nitrate, and 1000 mL of pure water.

[0018] Preferably, in step (2), the bacterial culture solution obtained in step (1) is added to the fermentation medium at 1-3% (v / v).

[0019] Preferably, the fermentation medium in step (2) is prepared from 3-5 g of peptone, 3-5 g of beef powder, 3-5 g of yeast powder, 1-3 g of glucose, 1-2 g of ammonium nitrate, 0.01-0.04 g of calcium chloride, 1-3 mg of vitamin B2, and 1000 mL of pure water.

[0020] Preferably, the inducing agent in step (4) is one or more of sodium sulfite, CTAB, and thioredoxin.

[0021] Preferably, the concentration of the inducer in step (4) is 1-15 mg / L.

[0022] Preferably, in step (3), the concentration of the sodium selenite solution is 1 mol / L, the concentration of the lead nitrate solution is 100 mol / L, the volume ratio of the sodium selenite solution to the culture medium is (1-5):1000; the volume ratio of the lead nitrate solution to the culture medium is (1-5):100.

[0023] Preferably, in step (5), normal temperature refers to 28-37°C, and low temperature refers to 15-20°C.

[0024] Preferably, in step (5), the culture is first cultured at 28-37°C and 150-200 rpm for 8-14 h, then cultured at low temperature, cultured at 15-20°C and 150-200 rpm for 8-14 h, and then cultured at 28-37°C and 150-200 rpm again.

[0025] Preferably, the speed of the preliminary centrifugation in step (6) is 6000-10000 r / min, and the time is 3-8 min.

[0026] Preferably, the rotation speed of the secondary centrifugation in step (6) is 20000-30000 r / min, and the time is 10-20 min.

[0027] Preferably, the culture conditions in step (1), step (2) and step (3) are all 28-37° C. and 150-200 rpm shaking culture.

[0028] Preferably, the culturing time in step (1) is 12-14 h; the culturing time in step (2) is 6-8 h; and the culturing time in step (3) is 1-2 h.

[0029] Experimental results: The obtained lead selenide quantum dot PbSe particles were measured by a nano-laser particle size analyzer, and the particle size range was 10-40 nm. Using a scanning electron microscope and an energy dispersive spectrometer (SEM-EDX), nanoparticles with a particle size of 10-30 nm were observed, and the EDX energy spectrum showed characteristic peaks of Pb and Se, indicating that the prepared nanoparticles were lead selenide quantum dot PbSe particles.

[0030] The advantages of the present invention are:

[0031] (1) The present invention adopts a special strain of Bacillus Bacillus .sp HZ3, a biological method for synthesizing nanomaterials, has mild reaction conditions, low cost, and simple operation, which improves the efficiency of preparing nano-lead selenide quantum dots.

[0032] (2) The lead selenide quantum dot PbSe synthesis strain Bacillus sp. used in the present invention Bacillus.spHZ3 has very strong tolerance and reducing ability to heavy metals (Cu, Pb, Ag, etc.) and selenium (Se). The strain can tolerate 10 mM lead nitrate Pb(NO3)2 and 10 mM sodium selenite, and can continuously synthesize lead selenide quantum dots PbSe during its growth, thereby greatly reducing the production cost of lead selenide quantum dots PbSe.

[0033] (3) The present invention is directed to Bacillus .spHZ3 synthesizes the characteristics of lead selenide quantum dots PbSe. In the synthesis process, a special inducing agent is added, and a combination of high temperature culture-low temperature culture-high temperature culture is adopted, thereby further improving the synthesis efficiency of lead selenide quantum dots PbSe, making Bacillus Bacillus .spHZ3 can convert 4 mM lead nitrate and 4 mM sodium selenite into lead selenide quantum dots PbSe within 48 hours, greatly improving the synthesis efficiency of nano-lead selenide. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Bacillus Bacillus .Comparison of the growth of spHZ3 in medium containing sodium selenite or lead nitrate;

[0035] Figure 2 Bacillus sp. 2 of the present invention Bacillus . Transmission electron microscopy observation and particle size analysis of lead selenide quantum dots synthesized by spHZ3;

[0036] Figure 3 Bacillus sp. 2 of the present invention Bacillus .EDX analysis of the elemental composition of lead selenide quantum dots synthesized by spHZ3;

[0037] Figure 4 Bacillus in different embodiments Bacillus . X-ray diffraction pattern of lead selenide quantum dots synthesized by spHZ3;

[0038] Figure 5 Bacillus in different embodiments Bacillus . Fluorescence spectrum analysis of lead selenide quantum dots synthesized by spHZ3;

[0039] Figure 6 This diagram shows the effect of adding inducers on the synthesis of lead selenide quantum dots by Bacillus spHZ3. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art.

[0042] Embodiment 1:

[0043] A method using Bacillus Bacillus .sp HZ3 A method for preparing biological nano-lead selenide quantum dots, comprising the following steps:

[0044] (1) Preparation of bacterial culture medium: Pick Bacillus .sp HZ3 single colony was added to YNP medium and cultured at 28℃ and 150 rpm for 14 h to obtain bacterial culture solution; YNP medium was made of 5 g peptone, 3 g beef powder, 5 g yeast powder, 1 mg vitamin B2, 0.1 g sodium nitrate, and 1000 mL pure water;

[0045] (2) Fermentation culture: Add the culture fluid of the bacterial strain obtained in step (1) to the fermentation medium at a rate of 1% (v / v), and culture at 28°C and 150 rpm for 8 h until the culture fluid is Bacillus .sp HZ3 bacterial colony count reaches 10 7 CFU / mL; the fermentation medium was made of 5 g peptone, 5 g beef powder, 5 g yeast powder, 3 g glucose, 2 g ammonium nitrate, 0.04 g calcium chloride, 3 mg vitamin B2, and 1000 mL pure water;

[0046] (3) Adding sodium selenite (Na2SeO3) and lead nitrate (Pb(NO3)2): Add 0.1 mL of 1 mol / L sodium selenite solution to the culture solution obtained in step (2), shake culture at 28°C and 150 rpm for 2 h, then add 1 mL of 100 mol / L lead nitrate solution, and continue shaking culture at 28°C and 150 rpm;

[0047] (4) Adding an inducer: Add an inducer (sodium sulfite) to the culture solution obtained in step (3) so that the final concentration of the inducer is 1 mg / L;

[0048] (5) Induced synthesis of biological nano-lead selenide: After adding the inducer, first adopt 28°C, 150 rpm shaking culture for 14 hours, then transfer to low temperature culture, 15°C, 150 rpm shaking culture for another 14 hours, then transfer to 28°C, 150 rpm shaking culture again, and culture until the color of the culture medium changes from light yellow to gray brown and the color no longer darkens, the nano-lead selenide quantum dots are completely generated;

[0049] (6) Separation and extraction of lead selenide quantum dots: The culture medium obtained in step (5) is placed in a centrifuge tube and subjected to a preliminary centrifugation at 6000 r / min for 8 min. The bacterial precipitate is discarded and the supernatant is collected. The supernatant is then placed in a clean centrifuge tube and subjected to a secondary centrifugation at 20000 r / min for 20 min. The obtained precipitate is resuspended in double distilled water to obtain the obtained nano-lead selenide quantum dots.

[0050] Experimental results: The ICP-AES results show that 47.5% of the added Pb (NO3)2 and Na2SeO3 are converted into lead selenide quantum dots PbSe. The obtained nano PbSe particles are measured by a nano laser particle size analyzer, and the particle size range is 10-40nm. Using a scanning electron microscope and an energy dispersive spectrometer (SEM-EDX), nanoparticles with a particle size of 10-30 nm are observed. The EDX energy spectrum shows the characteristic peaks of Pb and Se, indicating that the prepared nanoparticles are nano lead selenide quantum dots.

[0051] Embodiment 2:

[0052] A method using Bacillus Bacillus .sp HZ3 A method for preparing biological nano-lead selenide quantum dots, comprising the following steps:

[0053] (1) Preparation of bacterial culture medium: Pick Bacillus .sp HZ3 single colony was added to YNP medium and cultured at 32℃ and 180 rpm for 13h to obtain bacterial culture solution; YNP medium was made of 8 g peptone, 4 g beef powder, 8 g yeast powder, 2 mg vitamin B2, 0.2 g sodium nitrate, and 1000 mL pure water;

[0054] (2) Fermentation culture: Add the culture fluid of the bacterial strain obtained in step (1) to the fermentation medium at a rate of 2% (v / v), and culture at 32°C and 180 rpm for 7 h until the culture fluid is Bacillus .sp HZ3 bacterial colony count reaches 10 7 CFU / mL; the fermentation medium was made of 4 g peptone, 4 g beef powder, 4 g yeast powder, 2 g glucose, 1.5 g ammonium nitrate, 0.03 g calcium chloride, 2 mg vitamin B2, and 1000 mL pure water;

[0055] (3) Adding sodium selenite (Na2SeO3) and lead nitrate (Pb(NO3)2): Add 0.3 mL of 1 mol / L sodium selenite solution to the culture solution obtained in step (2), shake culture at 32°C and 180 rpm for 1.5 h, then add 3 mL of 100 mol / L lead nitrate solution, and continue shaking culture at 32°C and 180 rpm;

[0056] (4) Adding inducer: Add inducer (sodium sulfite, CTAB, thioredoxin, mass ratio 1:2:2) to the culture solution obtained in step (3) so that the final concentration of the inducer is 10 mg / L;

[0057] (5) Induced synthesis of biological nano-lead selenide: After adding the inducer, first adopt 32°C, 180 rpm shaking culture for 12 hours, then transfer to low temperature culture, 18°C, 180 rpm shaking culture for another 12 hours, then transfer to 32°C, 180 rpm shaking culture again, and culture until the color of the culture medium changes from light yellow to gray brown and the color no longer darkens, the nano-lead selenide quantum dots are completely generated;

[0058] (6) Separation and extraction of lead selenide quantum dots: The culture medium obtained in step (5) is placed in a centrifuge tube and subjected to a preliminary centrifugation at 8000 r / min for 5 min. The bacterial precipitate is discarded and the supernatant is collected. The supernatant is then placed in a clean centrifuge tube and subjected to a secondary centrifugation at 25000 r / min for 15 min. The obtained precipitate is resuspended in double distilled water to obtain the obtained nano-lead selenide quantum dots.

[0059] Experimental results: The ICP-AES results show that the added Pb(NO3)2 and sodium selenite Na2SeO3 are completely (100%) converted into lead selenide quantum dots PbSe. The obtained nano-lead selenide particles are measured by a nano-laser particle size analyzer, and the particle size range is 10-40nm. Using a scanning electron microscope and an energy dispersive spectrometer (SEM-EDX), nanoparticles with a particle size of 10-30 nm were observed. The EDX energy spectrum shows the characteristic peaks of Pb and Se, indicating that the prepared nanoparticles are nano-lead selenide particles.

[0060] Embodiment 3:

[0061] A method using Bacillus Bacillus .sp HZ3 A method for preparing biological nano-lead selenide quantum dots, comprising the following steps:

[0062] (1) Preparation of bacterial culture medium: Pick Bacillus.sp HZ3 single colony was added to YNP medium and cultured at 37℃ and 200 rpm for 12 h to obtain bacterial culture solution; YNP medium was made of 10 g peptone, 5 g beef powder, 10 g yeast powder, 3 mg vitamin B2, 0.3 g sodium nitrate, and 1000 mL pure water;

[0063] (2) Fermentation culture: Add 3% (v / v) of the bacterial culture solution obtained in step (1) to the fermentation medium and culture at 37°C and 200 rpm for 6 h until the culture medium Bacillus .sp HZ3 bacterial colony count reaches 10 7 CFU / mL; the fermentation medium was made of 3 g peptone, 3 g beef powder, 3 g yeast powder, 1 g glucose, 1 g ammonium nitrate, 0.01 g calcium chloride, 1 mg vitamin B2, and 1000 mL pure water;

[0064] (3) Adding sodium selenite (Na2SeO3) and lead nitrate (Pb(NO3)2): Add 0.5 mL of 1 mol / L sodium selenite solution to the culture solution obtained in step (2), shake culture at 37°C and 200 rpm for 1 h, then add 5 mL of 100 mol / L lead nitrate solution, and continue shaking culture at 37°C and 200 rpm;

[0065] (4) Adding inducer: Add inducer (sodium sulfite and CTAB, mass ratio 1:2) to the culture solution obtained in step (3) so that the final concentration of the inducer is 15 mg / L;

[0066] (5) Induced synthesis of biological nano-lead selenide: After adding the inducer, first adopt 37°C, 200 rpm shaking culture for 8 hours, then transfer to low temperature culture, 20°C, 200 rpm shaking culture for another 8 hours, then transfer to 37°C, 200 rpm shaking culture again, and culture until the color of the culture medium changes from light yellow to gray brown and the color no longer darkens, the nano-lead selenide quantum dots are completely generated;

[0067] (6) Separation and extraction of lead selenide quantum dots: The culture solution obtained in step (5) was placed in a centrifuge tube and subjected to preliminary centrifugation at 10,000 r / min for 3 min. The bacterial precipitate was discarded and the supernatant was collected. The supernatant was then placed in a clean centrifuge tube and subjected to a second centrifugation at 30,000 r / min for 10 min. The obtained precipitate was resuspended in double distilled water to obtain the prepared nano-lead selenide quantum dots.

[0068] Experimental results: The ICP-AES results show that 76.5% of the added Pb(NO3)2 and Na2SeO3 are converted into lead selenide PbSe. The obtained nano-particles of lead selenide are measured by a nano-laser particle size analyzer, and the particle size range is 10-40 nm. Using a scanning electron microscope and an energy dispersive spectrometer (SEM-EDX), nanoparticles with a particle size of 10-30 nm were observed, and the EDX energy spectrum showed characteristic peaks of Pb and Se, indicating that the prepared nanoparticles are nano-particles of lead selenide.

[0069] Figure 1 Bacillus Bacillus .Comparison of the growth of spHZ3 in culture medium containing sodium selenite or lead nitrate; As can be seen from the figure, when sodium selenite and lead nitrate are added at the same time, the culture medium turns brown, indicating the generation of lead selenide quantum dots;

[0070] Figure 2 Bacillus sp. 2 of the present invention Bacillus .spHZ3 Transmission electron microscopy observation and particle size analysis of the synthesized lead selenide quantum dots. It can be seen from the figure that the particle size distribution of the synthesized lead selenide quantum dots is between 15-30nm;

[0071] Figure 3 Bacillus sp. 2 of the present invention Bacillus .EDX analysis of the elemental composition of lead selenide quantum dots synthesized by spHZ3;

[0072] Figure 4 Bacillus in different embodiments Bacillus . X-ray diffraction pattern of lead selenide quantum dots synthesized by spHZ3;

[0073] Figure 5 Bacillus in different embodiments Bacillus . Fluorescence spectrum analysis of lead selenide quantum dots synthesized by spHZ3;

[0074] Figure 6 Adding inducers to Bacillus Bacillus .spHZ3 influence diagram on the synthesis of lead selenide quantum dots, (1: no inducer added, 2: sodium sulfite and CTAB added, 3: sodium sulfite, CTAB and thioredoxin added). It can be seen from the figure that different inducers have different effects on the synthesis efficiency of lead selenide quantum dots.

[0075] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method using Bacillus Bacillus .sp HZ3 A method for preparing biological nano-lead selenide quantum dots, comprising the following steps: (1) Preparation of bacterial culture medium: Pick Bacillus .sp HZ3 single colony was added to YNP medium to obtain bacterial culture solution; (2) Fermentation culture: Add the bacterial culture solution obtained in step (1) to the fermentation medium and culture until the culture solution is Bacillus .sp HZ3 bacterial colony count reaches 10 7 CFU / mL; (3) Adding sodium selenite and lead nitrate: adding sodium selenite solution to the culture solution obtained in step (2), and then adding lead nitrate solution, and continuing the culture; (4) Adding an inducer: adding an inducer to the culture solution obtained in step (3); the inducer is one or more of sodium sulfite, CTAB, and thioredoxin; (5) Induced synthesis of biological nano-lead selenide: After adding the inducer, first adopt room temperature 28-37℃, 150-200 rpm shaking culture for 8-14h, then transfer to low temperature 15-20℃, 150-200 rpm and continue shaking culture for 8-14h, then transfer to room temperature 28-37℃, 150-200 rpm and shake culture again, and culture until the color of the culture medium changes from light yellow to gray brown and the color no longer darkens, the nano-lead selenide quantum dots are completely generated; (6) Separation and extraction of lead selenide quantum dots: The culture solution obtained in step (5) is placed in a centrifuge tube, subjected to a preliminary centrifugation operation, the bacterial precipitate is discarded, and the supernatant is collected; the supernatant is then placed in a clean centrifuge tube, subjected to a secondary centrifugation operation, and the obtained precipitate is resuspended in double distilled water to obtain the prepared nano-lead selenide quantum dots; The Bacillus Bacillus The accession number of .sp HZ3 is CCTCC NO: M 20221472.

2. The method of using Bacillus according to claim 1 Bacillus .sp HZ3 A method for preparing biological nano-lead selenide quantum dots, characterized in that: The YNP medium in step (1) is prepared from 5-10 g of peptone, 3-5 g of beef powder, 5-10 g of yeast powder, 1-3 mg of vitamin B2, 0.1-0.3 g of sodium nitrate, and 1000 mL of pure water.

3. The method of using Bacillus according to claim 1 or 2 Bacillus .sp HZ3 A method for preparing biological nano-lead selenide quantum dots, characterized in that: In the step (2), the bacterial culture solution obtained in the step (1) is added to the fermentation medium at 1-3% (v / v).

4. The method of utilizing Bacillus according to claim 3 Bacillus .sp HZ3 A method for preparing biological nano-lead selenide quantum dots, characterized in that: In step (2), the fermentation medium is prepared from 3-5 g of peptone, 3-5 g of beef powder, 3-5 g of yeast powder, 1-3 g of glucose, 1-2 g of ammonium nitrate, 0.01-0.04 g of calcium chloride, 1-3 mg of vitamin B2, and 1000 mL of pure water.

5. The method of utilizing Bacillus according to claim 4 Bacillus .sp HZ3 A method for preparing biological nano-lead selenide quantum dots, characterized in that: The concentration of the inducer in step (4) is 1-15 mg / L.

6. The method of claim 1 using Bacillus Bacillus .sp HZ3 A method for preparing biological nano-lead selenide quantum dots, characterized in that: In the step (3), the concentration of the sodium selenite solution is 1 mol / L, the concentration of the lead nitrate solution is 100 mol / L, the volume ratio of the sodium selenite solution to the culture medium is (1-5):1000; the volume ratio of the lead nitrate solution to the culture medium is (1-5):

100.

7. The method of utilizing Bacillus according to claim 1 Bacillus .sp HZ3 A method for preparing biological nano-lead selenide quantum dots, characterized in that: In the step (5), normal temperature refers to 28°C, and low temperature refers to 15°C.

8. The method of claim 1 using Bacillus Bacillus .sp HZ3 A method for preparing biological nano-lead selenide quantum dots, characterized in that: In step (6), the speed of the initial centrifugation is 6000-10000 r / min, and the time is 3-8 min; the speed of the secondary centrifugation is 20000-30000 r / min, and the time is 10-20 min.

9. The method of claim 1 using Bacillus Bacillus .sp HZ3 A method for preparing biological nano-lead selenide quantum dots, characterized in that: The culture conditions in step (1), step (2) and step (3) are all 28-37° C. and 150-200 rpm shaking culture.

10. The method of utilizing Bacillus sp. according to claim 1 Bacillus .sp HZ3 A method for preparing biological nano-lead selenide quantum dots, characterized in that: The culture time in step (1) is 12-14 hours; the culture time in step (2) is 6-8 hours; and the culture time in step (3) is 1-2 hours.

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