Tobacco leaf extract degrading bacterium YY-2-4-1, screening method and application thereof, and method for treating tobacco leaf extraction wastewater by using tobacco leaf extract degrading bacterium YY-2-4-1

Abstract

The invention discloses a tobacco leaf extract degrading bacterium YY-2-4-1, a screening method and application thereof, and a method for treating tobacco leaf extraction wastewater by using the tobacco leaf extract degrading bacterium YY-2-4-1. The tobacco leaf extract degrading bacterium YY-2-4-1 is acidophilic oligodeoxymonas and is preserved in the China General Microbiological Culture Collection Center (CGMCC), the preservation number is CGMCC NO.36759, the preservation number is CGMCC NO.36759, and the preservation number is CGMCC NO.36759. The pure strain YY2-4-1 is obtained from an original strain obtained from a waste water treatment plant of tobacco leaf extraction waste water by taking a tobacco leaf extract as a raw material through the steps of acclimatization, separation, purification and the like of a culture medium containing a single pollutant of the tobacco leaf extract, and the degradation efficiency of the pure strain YY2-4-1 on the tobacco leaf extraction waste water is 76.6%; pollutants in the tobacco extraction wastewater can be stably and efficiently removed, and the wastewater treatment cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of microbial engineering and environmental protection technology, specifically relating to a tobacco extract degrading bacterium YY-2-4-1, its screening method and application, and a method for treating tobacco extract wastewater using it. Background Technology

[0002] Tobacco leaves contain nicotine, solanine alcohol, chlorogenic acid and other components. The aroma components of tobacco leaves are complex and can be classified into acids, alcohols, ketones, aldehydes, esters, lactones, phenols, nitrogen heterocyclic compounds, furans, amides, ethers and hydrocarbons according to different aroma groups.

[0003] Tobacco extracts are products made from tobacco through extraction, distillation, and other methods to extract specific desired components. Tobacco extracts are frequently used to enhance the aroma of tobacco, enrich tobacco blends, and make the smoke more full-bodied. In tobacco-flavored e-liquid products, tobacco extracts, as the main aroma-producing substances, largely reproduce the original aroma of tobacco.

[0004] Tobacco leaf extraction wastewater is a high-COD, high-color organic wastewater generated during the tobacco leaf extraction process. It contains nicotine, protein, and polyphenol residues. Due to its complex composition, treatment is difficult; biological treatment methods are inadequate, and chemical oxidation methods are too costly. With the expansion of the e-cigarette market, the volume of tobacco leaf extraction wastewater is increasing. Due to its polluting nature, it cannot be discharged indiscriminately. Conventional treatment methods are difficult and costly; therefore, finding a suitable disposal method is an urgent problem to solve. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a tobacco extract degrading bacterium YY-2-4-1, its screening method, and its application. The tobacco extract degrading bacterium YY-2-4-1 can achieve stable and efficient removal of pollutants from tobacco leaf extraction wastewater, thereby reducing wastewater treatment costs.

[0006] This invention also provides a method for treating tobacco leaf extraction wastewater using the tobacco leaf extract degrading bacteria YY-2-4-1. The method involves treating the tobacco leaf extraction wastewater in an SBR biological treatment tank using the tobacco leaf extract degrading bacteria YY-2-4-1. After treatment with the tobacco leaf extract degrading bacteria YY-2-4-1 described in this invention, the COD of the effluent from the sedimentation of the tobacco leaf extraction wastewater ultimately stabilizes below 430 mg / L, and the ammonia nitrogen is maintained below 13 mg / L, meeting the requirement that the effluent COD be below 500 mg / L.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] This invention provides a tobacco extract degrading bacterium, YY-2-4-1, which is an acidophilic oligoanaerobic bacterium, Stenotrophomonas acidaminiphila, deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC NO.36759, located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, on November 25, 2025.

[0009] The present invention also provides a screening method for the tobacco extract degrading bacterium YY-2-4-1, the screening method comprising the following steps:

[0010] (1) Microbial training: Tobacco leaf extract wastewater was added to an inorganic salt liquid culture medium containing tobacco leaf extract. The COD concentration of the culture medium was gradually increased to 1500 mg / L, 2000 mg / L and 2500 mg / L in 3-day cycles.

[0011] (2) Strain screening: Dilute the trained bacterial solution by 10 -5 The extract was spread onto an inorganic salt solid culture medium containing tobacco leaf extract and incubated at a constant temperature for 60-72 hours.

[0012] (3) Propagation of strain: The strain cultured in step (2) is inoculated into an inorganic salt liquid culture medium containing tobacco extract and cultured at a constant temperature with vibration for 60-72 hours;

[0013] (4) Strain isolation: Dilute the expanded bacterial culture solution by 10 -5 The extract was inoculated into an inorganic salt solid culture medium containing tobacco leaf extract and incubated at a constant temperature for 60-72 hours.

[0014] (5) Strain purification: The rapidly growing single colony from step (4) was streaked into LB solid medium and incubated at a constant temperature for 45-48 h;

[0015] (6) Repeat steps (3)(4)(5) until the colony morphology on the LB solid medium is consistent and there are no second contaminants. The resulting strain is recorded as YY-2.

[0016] (7) Re-screening of strains: Strain YY-2 was inoculated into an inorganic salt liquid culture medium containing tobacco extract. The COD concentration of the culture medium was gradually increased to 3500 mg / L and 5000 mg / L in 3-5 days to further improve the strain’s tolerance and degradation ability.

[0017] (8) Repeat steps (2)(3)(4)(5) to obtain tobacco extract degrading bacteria YY-2-4-1, which is pale yellow in appearance, relatively viscous, easy to pick up, and single colonies are small, raised, transparent and round.

[0018] In step (1), the initial COD of the inorganic salt liquid culture medium containing tobacco extract is 1000-1500 mg / L.

[0019] In step (2), the initial COD of the inorganic salt solid culture medium containing tobacco extract is 2000 mg / L.

[0020] In step (7), the initial COD of the inorganic salt liquid culture medium containing tobacco extract is 2500 mg / L.

[0021] In step (1), the amount of the original bacterial culture is 1-5% of the culture medium volume; in step (2), the inoculation amount is 0.01-0.05 mL; in step (7), the inoculation amount is 1-5% of the culture medium volume.

[0022] The inorganic salt liquid culture medium containing tobacco extract has a pH of 7.5 ± 0.3 and a composition of Na₂HPO₄. 4· 12H2O 1.5-1.6g / L, KH2PO40.3- 0.4g / L, MgSO 4· 7H2O 0.1-0.15g / L, CaCl2 0.05-0.1g / L, trace metal element solution 1ml / L, tobacco extract 1.2g / L;

[0023] The composition of the trace metal element solution is: FeSO₄ 4· 7H2O 0.025g / L, ZnSO 4· 7H2O 0.01g / L, MnCl 2· 4H2O 0.03g / L, H3BO4 0.3g / L, CoCL 2· 6H₂O 0.2g / L, CuCl 2· 2H₂O 0.01g / L, NiCl 2· 6H₂O 0.02 g / L, Na₂MoO 4· 2H2O 0.03g / L.

[0024] The inorganic salt solid culture medium containing tobacco extract is composed of 2g of agar powder added per 100ml of the inorganic salt liquid culture medium containing tobacco extract.

[0025] The LB solid medium consists of: 10 g / L tryptone, 5 g / L yeast extract, 10 g / L sodium chloride, 20 g / L agar powder, and pH 7.5 ± 0.3.

[0026] The temperature for the isothermal incubation and isothermal vibration incubation is 35±3℃; the rotation speed for the isothermal vibration incubation is 150~170 r / min.

[0027] In step (1), the tobacco leaf extraction wastewater is the wastewater generated from the extraction of the tobacco leaf extract; the tobacco leaf extract is the product extract or preparation obtained by crushing, ethanol extraction, sedimentation, centrifugation, concentration, alcohol precipitation, and secondary centrifugation concentration of tobacco leaves.

[0028] The present invention also provides the application of the tobacco extract degrading bacteria YY-2-4-1 in the treatment of tobacco extract wastewater.

[0029] This invention also provides a method for treating tobacco leaf extraction wastewater using the tobacco leaf extract degrading bacteria YY-2-4-1 described in this invention, characterized in that the method includes the following steps:

[0030] 1) Inoculate the tobacco extract degrading bacteria YY-2-4-1 into LB liquid medium and culture at a constant temperature with shaking for 20-24 hours to obtain the seed culture;

[0031] 2) The seed culture was inoculated into LB liquid medium and cultured for 72 hours before being pumped into the SBR biological treatment tank. The pH of the tobacco leaf extraction wastewater in the SBR biological treatment tank was 7.5±0.3, and the COD was 2500~3500 mg / L. The temperature of the biological treatment tank was controlled at 32~38 ℃, the pH at 7~8, the dissolved oxygen at 2~4 mg / L, the MLSS at 2000-4000 mg / L, and the volumetric loading rate at 0.1-0.3 kg COD / (m³). 3 .d), stay duration 2-5 days.

[0032] In step 2), the inoculation volume of the seed solution is 1-5% of the culture medium volume.

[0033] This invention obtains original bacterial strains from a wastewater treatment plant treating tobacco leaf extraction wastewater. Using tobacco leaf extract as raw material, the strains undergo acclimatization, separation, and purification in a culture medium containing a single pollutant from tobacco leaf extract. Single colonies with different characteristics are selected for rescreening and amplification. After performance verification, a pure strain YY2-4-1 is obtained, which has a degradation efficiency of 76.6% for tobacco leaf extraction wastewater. After scale-up and amplification, it is used for the degradation treatment of tobacco leaf extraction wastewater, improving wastewater treatment efficiency and reducing wastewater treatment costs.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. Highly Targeted Microbial Strains, Significantly Improved Wastewater Degradation Efficiency: Existing technologies for treating tobacco leaf extraction wastewater often employ general-purpose degrading strains or mixed microbial communities that have not undergone targeted acclimatization. These strains have weak affinity for the characteristic pollutants in tobacco leaf extraction wastewater, and their metabolic pathways are mismatched, resulting in low degradation efficiency and long treatment cycles. This invention directly obtains original microbial strains from tobacco leaf extraction wastewater treatment plants. These strains are naturally adapted to the wastewater's water quality environment. Through acclimatization using a culture medium containing a single pollutant from tobacco leaf extract, strains with highly efficient degradation capabilities for characteristic pollutants in tobacco leaves are selectively screened. The final purified strains achieve a wastewater degradation efficiency of up to 76.6%. Compared to existing technologies, targeted microbial strains can significantly increase the pollutant decomposition rate, shorten the wastewater treatment cycle, and improve the effluent quality compliance rate.

[0036] 2. Significantly Reduced Overall Wastewater Treatment Costs: The tobacco extract-degrading bacterium YY-2-4-1 provided by this invention is derived from the target wastewater treatment plant, eliminating the need for additional procurement and directly reducing the cost of obtaining the strain. This invention uses tobacco extract as the sole pollutant source to prepare the acclimatization culture medium, ensuring readily available raw materials and eliminating the need for additional nutrients, thus simplifying the culture medium preparation process and reducing acclimatization costs. The purified strain can be directly scaled up and integrated into existing wastewater treatment systems without requiring large-scale modifications to existing treatment facilities, saving on equipment upgrades and infrastructure investment.

[0037] 3. Strong environmental adaptability and high process stability: The strains screened in this invention originate from the target wastewater ecosystem. After targeted acclimatization, they can tolerate the water quality characteristics of the wastewater and are less prone to maladaptation or loss of activity during actual treatment, maintaining stable degradation capacity over a long period. Simultaneously, the purified single strains have controllable performance, avoiding functional disorders caused by interspecies competition in mixed bacterial communities, further ensuring the continuous and stable operation of the wastewater treatment process. Introducing exogenous strains for treatment is susceptible to the special water quality of tobacco leaf extraction wastewater, leading to problems such as activity decline and bacterial loss, resulting in large fluctuations in the treatment process and unstable effluent quality.

[0038] 4. Green and environmentally friendly, reducing the risk of secondary pollution: This invention is based on the principle of biodegradation. It uses the tobacco extract degrading bacteria YY-2-4-1 to naturally decompose pollutants in wastewater without the addition of chemical agents. The high efficiency of the tobacco extract degrading bacteria YY-2-4-1 can significantly reduce the residual pollutants in wastewater discharge, reduce the environmental pressure of wastewater discharge on surrounding water bodies and soil, and conform to the development trend of green and environmentally friendly wastewater treatment technology. Attached Figure Description

[0039] Figure 1 This is a flowchart illustrating the screening and application process of tobacco extract-degrading bacteria in this invention. Detailed Implementation

[0040] The present invention will now be described in detail with reference to the embodiments.

[0041] The inorganic salt liquid culture medium containing tobacco leaf extract in the examples had a pH of 7.5 ± 0.3 and a composition of Na₂HPO₄. 4· 12H2O 1.53g / L, KH2PO40.37g / L, MgSO 4· 7H₂O 0.1 g / L, CaCl₂ 0.05 g / L, trace metal element solution 1 ml / L, tobacco extract 1.2 g / L, COD 1500 mg / L; the composition of the trace metal element solution is: FeSO₄ 4· 7H₂O 0.025g / L, ZnSO₄ 4· 7H2O 0.01g / L, MnCl 2· 4H2O 0.03g / L, H3BO4 0.3g / L, CoCL 2· 6H₂O 0.2g / L, CuCl 2· 2H₂O 0.01g / L, NiCl 2· 6H₂O 0.02g / L, Na₂MoO 4· 2H2O 0.03g / L.

[0042] The inorganic salt solid culture medium containing tobacco extract is composed of 2g of agar powder added per 100ml of the inorganic salt liquid culture medium containing tobacco extract.

[0043] The composition of LB liquid medium is: 10 g / L tryptone, 5 g / L yeast extract, 10 g / L sodium chloride, pH 7.5±0.3.

[0044] The composition of LB solid medium is: 10 g / L tryptone, 5 g / L yeast extract, 10 g / L sodium chloride, 20 g / L agar powder, pH 7.5±0.3.

[0045] Example 1

[0046] A tobacco extract-degrading bacterium, YY-2-4-1, is an acidophilic oligoanaerobic bacterium. It is deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC NO.36759, located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, on November 25, 2025.

[0047] The screening method for the tobacco extract degrading bacteria YY-2-4-1 includes the following steps:

[0048] (1) Strain training: Add 5% by weight of tobacco leaf extract wastewater to an inorganic salt liquid culture medium containing tobacco leaf extract with an initial COD of 1500 mg / L. Repeat the cycle for 3 days and gradually increase the COD concentration of the culture medium to 1500 mg / L, 2000 mg / L and 2500 mg / L.

[0049] (2) Strain screening: Dilute the trained bacterial solution by 10 -3 Take 0.05 mL of the inoculated agar and place it in the center of the sterilized plate. Spread the agar evenly using a sterilized triangular slurry. Invert the plate after inoculation and incubate it in a 35°C constant temperature incubator for 72 hours.

[0050] (3) Propagation of strain: The strain cultured in step (2) was inoculated into an inorganic salt liquid culture medium containing tobacco extract and cultured in a constant temperature shaking incubator at 35°C for 72 hours;

[0051] (4) Strain isolation: Dilute the expanded bacterial culture solution by 10 -5 Double the amount of culture medium and streak it with a sterilized inoculation needle. Dip the inoculation needle into the diluted bacterial solution and start streaking in one corner of the sterilized culture medium. Each time the direction is turned, the inoculation needle is burned before streaking the next time. Place the inoculated plate upside down in a 35°C constant temperature incubator and incubate for 72 hours.

[0052] (5) Strain purification: Select the fast-growing single colonies from step (4) and streak them. During the streak process, after each rotation, the inoculation needle is burned before the next streak. Place the inoculated plate upside down in a 35°C constant temperature incubator for 48 hours.

[0053] (6) Repeat steps (3)(4)(5) until the colony morphology on the LB solid medium is consistent and there are no other bacteria. The resulting strain is recorded as YY-2. It is pale yellow in appearance, relatively viscous, easy to pick up, and the single colony is small, raised, transparent and round.

[0054] (7) Re-screening of strains: Strain YY-2 was inoculated into inorganic salt liquid medium containing tobacco extract with an initial COD of 2500 mg / L. The inoculation amount was 5% of the weight of the medium. The cycle was 3-5 days. The COD concentration of the medium was gradually increased to 3500 mg / L and 5000 mg / L.

[0055] (8) Repeat steps (2)(3)(4)(5) to finally select a strain YY-2-4-1 with a pale yellow appearance, other characteristics of being relatively viscous, easy to pick up, and small, raised, transparent, and round single colonies.

[0056] The strain YY-2-4-1 was sequenced using the 16S rDNA method. Its nucleotide sequence is shown in SEQ ID NO:1. Its gene sequence has a similarity of 99.79% with that of Oligotrophomonas acidophilus. Finally, it was determined at the molecular level that this strain belongs to Oligotrophomonas acidophilus.

[0057]

[0058] Strains YY-2 and YY-2-4-1 were inoculated into LB liquid medium in a sterile room and cultured in a constant temperature shaking incubator for 45 h. After removing the supernatant, the cells were washed three times with inorganic salt liquid medium. The resulting bacterial cells were then transferred to inorganic salt liquid medium containing tobacco extract at a COD concentration of 2000 mg / L and cultured in a constant temperature shaking incubator for 24 h. COD changes were measured at 8 h, 16 h, and 24 h. Multiple experiments verified that the degradation rate of tobacco extract by strain YY-2 within 24 h was 42.5%, and that of strain YY-2-4-1 was 76.6%.

[0059] Example 2

[0060] A method for treating tobacco leaf extraction wastewater using the tobacco leaf extract-degrading bacteria YY-2-4-1 was employed. The wastewater parameters were as follows: water volume was 15 m³ / min. 3 / d, water quality: COD 35000mg / L, ammonia nitrogen 600mg / L, suspended solids (SS) 4600mg / L, pH 4.6, color 3000, total salinity 6140mg / L;

[0061] The method includes the following steps:

[0062] 1) The tobacco extract degrading bacteria YY-2-4-1 was inoculated into LB liquid medium and cultured at 35℃ with shaking for 24 h to obtain the seed culture;

[0063] 2) Inoculate the seed solution into a 2m 3 In LB liquid medium, the inoculum was 3%, and after culturing at 35℃ for 72 hours, it was pumped into the SBR biological treatment tank. Tobacco leaf extraction wastewater, after being adjusted to pH 7.5 and COD 3000 mg / L in an equalization tank, was pumped into the SBR biological treatment tank. The biological treatment tank temperature was controlled at 35℃, pH 7.5, dissolved oxygen 3 mg / L, MLSS 3000 mg / L, and volumetric loading rate 0.2 kg COD / (m³). 3 .d), stay time 2d.

[0064] The COD of the effluent after sedimentation eventually stabilized at 430 mg / L and ammonia nitrogen at 13 mg / L, meeting the requirement that the COD of the effluent be below 500 mg / L.

[0065] Comparative Example 1

[0066] The rest is the same as in Example 2, except that the tobacco extract degrading bacteria YY-2-4-1 is replaced with strain YY-2.

[0067] The final effluent COD stabilized at 1360 mg / L and ammonia nitrogen at 25 mg / L.

[0068] Comparative Example 2

[0069] A method for treating tobacco leaf extraction wastewater, wherein the wastewater parameters are as follows: water volume is 15m³. 3 / d, water quality: COD 35000mg / L, ammonia nitrogen 600mg / L, suspended solids (SS) 4600mg / L, pH 4.6, color 3000, total salinity 6140mg / L;

[0070] The treatment method includes the following steps:

[0071] The wastewater from tobacco leaf extraction was adjusted to pH 7.5 and COD 3000 mg / L in an equalization tank before being pumped into the SBR biological treatment tank. The temperature in the biological treatment tank was controlled at 35℃, pH at 7.5, DO at 3 mg / L, MLSS at 3000 mg / L, and the volumetric loading rate was 0.2 kg COD / (m³). 3 With a hydraulic retention time of 2 days, the COD of the effluent stabilized at 2360 mg / L and ammonia nitrogen at 42 mg / L, which is far greater than the requirement that the effluent COD be less than 500 mg / L.

[0072] Comparative Example 3

[0073] The rest is the same as in Example 2, except that the tobacco extract degrading bacteria YY-2-4-1 is replaced with commercially available Oligotrophomonas acidophilus, and the strain is from Ningbo Mingzhou Biotechnology Co., Ltd.

[0074] The final effluent COD stabilized at 2280 mg / L and ammonia nitrogen at 45 mg / L, far exceeding the requirement of less than 500 mg / L for effluent COD.

[0075] As can be seen from Comparative Example 2, the COD removal rate of tobacco leaf extraction wastewater treated directly by the "SBR aerobic biochemical" method was only 21%, and the COD removal rate of Comparative Example 3 was only 24%. The removal rates were low and the effluent did not meet the standards, indicating that general activated sludge and common acidophilus bacteria on the market cannot effectively treat and degrade pollutants in tobacco leaf extraction wastewater.

[0076] In Comparative Example 1, the COD removal rate of the tobacco leaf extraction wastewater treated by the domesticated and screened degrading bacteria strain YY-2 was 55%, which was significantly higher than that of Comparative Examples 2 and 3. This indicates that the domesticated and screened degrading bacteria YY-2 has a degrading effect on pollutants in tobacco leaf extraction wastewater.

[0077] In Example 2, the utilization of the degrading bacterium YY-2-4-1 achieved a COD removal rate of 87%, demonstrating that the degradation effect of the screened strain YY-2-4-1 was further improved compared to YY-2. The influent COD was 3000 mg / L and the effluent COD was 430 mg / L, achieving the discharge requirement of effluent COD below 500 mg / L. This effectively removed various pollutants from the leachate wastewater and has the advantages of stable operation, low cost, and simple and reliable operation.

[0078] The above detailed description of a tobacco extract degrading bacterium YY-2-4-1, its screening method and application, and the method of using it to treat tobacco extract wastewater, is illustrative rather than limiting. Several embodiments can be listed within the defined scope. Therefore, variations and modifications without departing from the overall concept of the present invention should be within the protection scope of the present invention.

Claims

1. A tobacco extract degrading bacterium YY-2-4-1, characterized in that, The tobacco extract degrading bacterium YY-2-4-1 is an acidophilic oligoanaerobic bacterium, deposited at the China General Microbiological Culture Collection Center, with accession number CGMCC NO.36759.

2. A method for screening the tobacco extract degrading bacteria YY-2-4-1 as described in claim 1, characterized in that, The screening method includes the following steps: (1) Microbial training: Tobacco leaf extract wastewater was added to an inorganic salt liquid culture medium containing tobacco leaf extract. The COD concentration of the culture medium was gradually increased to 1500 mg / L, 2000 mg / L and 2500 mg / L in 3-day cycles. (2) Strain screening: Dilute the trained bacterial solution by 10 -5 The extract was spread onto an inorganic salt solid culture medium containing tobacco leaf extract and incubated at a constant temperature for 60-72 hours. (3) Propagation of strain: The strain cultured in step (2) is inoculated into an inorganic salt liquid culture medium containing tobacco extract and cultured at a constant temperature with vibration for 60-72 hours; (4) Strain isolation: Dilute the expanded bacterial culture solution by 10 -5 The extract was inoculated into an inorganic salt solid culture medium containing tobacco leaf extract and incubated at a constant temperature for 60-72 hours. (5) Strain purification: The rapidly growing single colony from step (4) was streaked into LB solid medium and incubated at a constant temperature for 45-48 h; (6) Repeat steps (3)(4)(5) until the colony morphology on the LB solid medium is consistent and there are no second contaminants. The resulting strain is recorded as YY-2. (7) Re-screening of strains: Inoculate strain YY-2 into an inorganic salt liquid culture medium containing tobacco extract, and gradually increase the COD concentration of the culture medium to 3500 mg / L and 5000 mg / L in a cycle of 3-5 days. (8) Repeat steps (2)(3)(4)(5) to obtain tobacco extract degrading bacteria YY-2-4-1.

3. The screening method according to claim 2, characterized in that, The inorganic salt liquid culture medium containing tobacco extract has a pH of 7.5 ± 0.3 and consists of: Na₂HPO₄·12H₂O 1.5-1.6 g / L, KH₂PO₄ 0.3-0.4 g / L, MgSO₄·7H₂O 0.1-0.15 g / L, CaCl₂ 0.05-0.1 g / L, trace metal element solution 1 mL / L, and tobacco extract 1.2 g / L; the trace metal element solution consists of: FeSO₄... 4· 7H2O 0.025g / L, ZnSO 4· 7H2O 0.01g / L, MnCl 2· 4H2O 0.03g / L, H3BO4 0.3g / L, CoCL 2· 6H₂O 0.2g / L, CuCl 2· 2H₂O 0.01g / L, NiCl 2· 6H₂O 0.02g / L, Na₂MoO 4· 2H2O 0.03g / L.

4. The screening method according to claim 2, characterized in that, The inorganic salt solid culture medium containing tobacco extract is composed of 20 g / L of agar powder added to the inorganic salt liquid culture medium containing tobacco extract.

5. The screening method according to claim 2, characterized in that, The LB solid culture medium consisted of: 10 g / L tryptone, 5 g / L yeast extract, 10 g / L sodium chloride, and pH 7.5 ± 0.

3.

6. The screening method according to claim 2, characterized in that, The temperature for the isothermal incubation and isothermal vibration incubation is 35±3℃; the rotation speed for the isothermal vibration incubation is 150~170 r / min.

7. The screening method according to claim 2, characterized in that, In step (1), the amount of the original bacterial culture is 1-5% of the mass of the culture medium; in step (2), the inoculation amount is 0.01-0.05 mL; in step (7), the inoculation amount is 1-5% of the mass of the culture medium.

8. The screening method according to claim 2, characterized in that, In step (1), the tobacco leaf extraction wastewater is the wastewater generated from the extraction of the tobacco leaf extract; the tobacco leaf extract is an extract or preparation obtained by crushing, ethanol extraction, sedimentation, centrifugation, concentration, alcohol precipitation, secondary centrifugation concentration, and drying of tobacco leaves.

9. The application of the tobacco extract degrading bacteria YY-2-4-1 as described in claim 1 in the treatment of tobacco extract wastewater.

10. A method for treating tobacco leaf extraction wastewater using the tobacco leaf extract degrading bacteria YY-2-4-1 as described in claim 1, characterized in that, The method includes the following steps: 1) Inoculate the tobacco extract degrading bacteria YY-2-4-1 into LB liquid medium and culture at a constant temperature with shaking for 20-24 hours to obtain the seed culture; 2) The seed culture was inoculated into LB liquid medium and cultured for 72 hours before being pumped into the SBR biological treatment tank. The influent of the tobacco leaf extraction wastewater to the SBR biological treatment tank had a pH of 7.5±0.3 and a COD of 2500~3500 mg / L. The temperature of the biological treatment tank was controlled at 32~38 ℃, pH at 7~8, dissolved oxygen at 2~4 mg / L, MLSS at 2000-4000 mg / L, and volumetric loading at 0.1-0.3 kg COD / (m³). 3 .d), stay duration 2-5 days.

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