Bacillus cereus and application thereof
By isolating and identifying Bacillus cereus YL1, the problem of insufficient degradation ability of pyrethroid insecticides and intermediate degradation products in the prior art is solved, and the effect of efficient degradation of a variety of pyrethroid insecticides is achieved.
Patent Information
- Application Number
- CN202411871085.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-18
- Publication Date
- 2025-03-04
AI Technical Summary
The prior art is difficult to efficiently degrade pyrethroid insecticides and their intermediate degradation products, especially the degradation ability of cyanthroid is limited.
A Bacillus cereus YL1 was isolated and identified, which was able to efficiently degrade a variety of pyrethroid insecticides and intermediate degradation products, including cyanthrin, cyanthrin and aminethrin.
The degradation rate of Bacillus cereus YL1 on cypromethrin is more than 80%, and it can be effectively degraded at different initial concentrations, with a half-life ranging from 1.821d to 4.667d, which significantly improves the degradation ability of pyrethroid insecticides.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of microorganisms, and more specifically, relates to Bacillus cereus and application thereof. Background Art
[0002] Pyrethroids are a new type of industrially synthesized insecticide. Due to their high efficiency, low toxicity and safety, they have been widely used as a substitute for organophosphorus and carbamate insecticides to control agricultural pests and sanitary pests. Its sales reached US$2.8 billion in 2019, accounting for 25% of the global insecticide market. In general, pyrethroids have low water solubility and easily bind to plastics, glass and soil particles. Due to the presence of hydrocarbon rings in its structure, it tends to bind to organic matter, causing minerals to leach into the lower layers of the soil.
[0003] Although pyrethroids are less toxic than organophosphate and organochlorine insecticides, long-term exposure to pyrethroid insecticides may disrupt endocrine secretions, damage lymph nodes and spleen, and cause carcinogenesis. Cypermethrin, the first photostable pyrethroid synthesized, is widely used in agricultural pest control. Because it contains an α-cyano group, cypermethrin is more toxic and persistent, and has a greater potential for environmental pollution and impact on non-target organisms. Therefore, it is of great significance to seek effective strategies to remove the residues of pyrethroid insecticides.
[0004] Biodegradation is one of the most promising methods for removing pyrethroid compounds. Although a large number of pyrethroid-degrading microorganisms have been isolated, most strains do not have a broad spectrum of substrates. In particular, only a few microorganisms such as Acinetobacter baumannii ZH-14, Bacillus sp. DG-02, Brevibacterium aureum DG-12 and Catellibacterium sp. CC-5 can degrade cypermethrin, and the concentration range of their degradation of cypermethrin is 0-100 mg / L. Therefore, it is of great significance to screen new strains that can efficiently degrade cypermethrin. Summary of the invention
[0005] The invention aims to provide a Bacillus cereus and application thereof.
[0006] To achieve the above object, the present invention adopts the following technical solution: The first aspect of the present invention provides a Bacillus cereus, which is named Bacillus cereus YL1, and is deposited in the General Microbiology Center of China National Microbiological Culture Collection Committee on September 11, 2024, with a deposit address of No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, and a deposit number of CGMCC NO.31940.
[0007] The second aspect of the present invention provides the use of the above-mentioned Bacillus cereus in degrading pyrethroid insecticides and intermediate degradation products of pyrethroid insecticides; Furthermore, the pyrethroid insecticides include cypermethrin, beta-cypermethrin, tetramethrin, λ-cyhalothrin, bifenthrin, cypermethrin, permethrin, deltamethrin, and cis-cypermethrin, and the intermediate degradation products of the pyrethroid insecticides include 3-phenoxybenzoic acid, phenol, catechol, and benzoic acid.
[0008] The third aspect of the present invention provides the use of the above-mentioned Bacillus cereus in the preparation of a preparation for degrading pyrethroid insecticides and intermediate degradation products of pyrethroid insecticides; Furthermore, the pyrethroid insecticides include cypermethrin, beta-cypermethrin, tetramethrin, λ-cyhalothrin, bifenthrin, cypermethrin, permethrin, deltamethrin, and cis-cypermethrin, and the intermediate degradation products of the pyrethroid insecticides include 3-phenoxybenzoic acid, phenol, catechol, and benzoic acid.
[0009] A fourth aspect of the present invention provides a preparation for degrading pyrethroid insecticides and intermediate degradation products of pyrethroid insecticides, wherein the preparation contains the above-mentioned Bacillus cereus.
[0010] The fifth aspect of the present invention provides the use of the above-mentioned preparation in degrading pyrethroid insecticides and intermediate degradation products of pyrethroid insecticides; Furthermore, the pyrethroid insecticides include cypermethrin, beta-cypermethrin, tetramethrin, λ-cyhalothrin, bifenthrin, cypermethrin, permethrin, deltamethrin, and cis-cypermethrin, and the intermediate degradation products of the pyrethroid insecticides include 3-phenoxybenzoic acid, phenol, catechol, and benzoic acid.
[0011] The significant advantages of the present invention are: The invention provides a Bacillus cereus YL1 having a degradation effect on pyrethroid insecticides such as cypermethrin, the strain still has a certain tolerance to cypermethrin with a concentration of up to 600 mg / L, can degrade 9 pyrethroids of type I and type II and 4 pyrethroid intermediates, and can especially effectively degrade high-efficiency cypermethrin, tetramethrin, λ-cyhalothrin and cypermethrin, with a degradation rate of more than 80%. The strain can also effectively degrade cypermethrin of different initial concentrations (25-600 mg / L), with a half-life ranging from 1.821 d to 4.667 d.
[0012] The separation and identification of Bacillus cereus YL1 of the present invention enriches the resource library of pesticide-degrading bacteria, has great application value for the restoration of water environments polluted by pyrethroid insecticides, and provides a new development approach for the existing pesticide residue pollution control. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 : Colony morphology and bacterial morphology of Bacillus cereus YL1.
[0014] Figure 2 : Phylogenetic tree of Bacillus cereus YL1.
[0015] Figure 3 : Degradation of cypermethrin by Bacillus cereus YL1.
[0016] Figure 4 : Three-dimensional response surface plot. (a) Interactive effect of temperature and pH value on the degradation of cypermethrin by Bacillus cereus YL1, (b) Interactive effect of temperature and inoculum size on the degradation of cypermethrin by Bacillus cereus YL1, (c) Interactive effect of pH value and inoculum size on the degradation of cypermethrin by Bacillus cereus YL1.
[0017] Figure 5 : Contour diagram of the effects of temperature and pH on the degradation of cypermethrin (a) and cubic diagram of cypermethrin degradation (b).
[0018] Figure 6 : Degradation kinetics of cypermethrin with different initial concentrations by Bacillus cereus YL1.
[0019] Figure 7 : Broad-spectrum degradation of different pyrethroid insecticides by Bacillus cereus YL1.
[0020] Figure 8 : Degradation of 3-PBA, catechol, benzoic acid and phenol by Bacillus cereus YL1. DETAILED DESCRIPTION
[0021] In order to make the contents of the present invention easier to understand, the technical solution of the present invention is further described below in conjunction with specific implementation methods, but the present invention is not limited thereto.
[0022] Embodiment 1: 1 Experimental Materials and Methods 1.1 The reagents involved are as follows: High-efficiency cypermethrin, tetramethrin, λ-cyhalothrin, permethrin, deltamethrin, bifenthrin and 3-phenoxybenzoic acid (3-PBA) were purchased from Shanghai Yuanye Biotechnology Co., Ltd. with a purity of >97%. Phenol was purchased from Shanghai Hushi Laboratory Equipment Co., Ltd. with a purity of >99%. Cypermethrin, cis-cypermethrin, benzoic acid and catechol were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. with a purity of >99%. Cyproconazole was purchased from Tanmo Quality Inspection Technology Co., Ltd. with a purity of 97.7%.
[0023] 1.2 The culture media involved are as follows: LB liquid culture medium: NaCl 10g / L, tryptone 10g / L, yeast extract 5g / L, sterilized with high-temperature steam at 121°C for later use.
[0024] LB solid culture medium: NaCl 10 g / L, tryptone 10 g / L, yeast extract 5 g / L, and 1.5 wt% agar powder, sterilized with high-temperature steam at 121°C for later use.
[0025] 1.3 The screening method for the cypermethrin-degrading strain involved is as follows: Five rounds of gradient enrichment and acclimatization of environmental microorganisms were carried out using cypermethrin as substrate: In the first round of enrichment and acclimatization, 10 g of soil sample from Yulong Snow Mountain in Yunnan Province was weighed and added into 100 mL of 50 mg / L cypermethrin. LB liquid medium, cultured at 30°C, 150rpm in the dark for 5 days; in the second round of enrichment and acclimation, 10mL of the first round enrichment solution was added to 100mL of fresh LB liquid medium containing 100mg / L cypermethrin, and cultured at 30°C, 150rpm in the dark for 5 days; in the third round of enrichment, 10mL of the second round enrichment solution was added to 100mL of fresh LB liquid medium containing 200mg / L cypermethrin, and cultured at 30°C, 150rpm in the dark for 5 days; in the fourth round of enrichment, 10mL of the third round enrichment solution was added to 100mL of fresh LB liquid medium containing 400mg / L cypermethrin, and cultured at 30°C, 150rpm in the dark for 5 days; in the fifth round of enrichment, 10mL of the fourth round enrichment solution was added to 100mL of fresh LB liquid medium containing 600mg / L cypermethrin, and cultured at 30°C, 150rpm in the dark for 5 days. Finally, take 200 μL of the fifth round of enrichment solution and dilute 10 -3The plate was spread on LB solid medium containing 50 mg / L cypermethrin and cultured at 30°C in the dark for 2 days. After a single colony grew on the plate, single colonies of different morphologies were picked and streaked on LB solid medium for at least 3 times for purification.
[0026] The single colony strain was inoculated into 5 mL LB liquid medium and activated overnight to the logarithmic phase, then mixed with 50 vol% glycerol at a volume ratio of 1:1, stored in a 2 mL centrifuge tube, and stored at -80 ° C. Subsequently, 50 μL of the YL1 glycerol-preserved strain was taken out from the -80 ° C refrigerator and inoculated into 5 mL LB liquid medium, and activated and cultured at 30 ° C on a shaker at 150 rpm for 20 hours as the seed liquid.
[0027] The seed liquid was inoculated into 20 mL of LB liquid medium containing 50 mg / L cypermethrin at an inoculum of 4 vol%, and three parallel experimental groups (with no bacteria added as the control group) were set up. After culturing for 7 days at 30°C and 150 rpm, samples were taken for high performance liquid chromatography (HPLC) determination to determine the target strain with cypermethrin degradation activity. Finally, a strain with the highest degradation ability for cypermethrin was obtained and numbered as YL1.
[0028] 1.4 The handling methods of the standards and samples involved are as follows: (1) Preparation of standard samples of cypermethrin, beta-cypermethrin, tetramethrin, λ-cyhalothrin, bifenthrin, cypermethrin, permethrin, deltamethrin, cis-cypermethrin, 3-PBA, phenol, catechol and benzoic acid: Weigh a certain amount of standard powder and dissolve it in chromatographic grade methanol to prepare a mother solution with a final concentration of 10 g / L. The mother solution is diluted in a gradient to obtain standard solutions of 10 mg / L, 20 mg / L, 40 mg / L, 50 mg / L, 80 mg / L, 100 mg / L and 200 mg / L, 400 mg / L, 1000 mg / L. After filtering with a 0.22 μm organic membrane, HPLC detection is performed. The standard curves of the above substances are drawn with the peak area of the standard sample as the abscissa and the corresponding concentration as the ordinate.
[0029] Sample treatment: Add 10mL of ethyl acetate to a conical flask containing culture medium, and ultrasonically treat for 30 minutes to fully dissolve the substrate in the extract; then add the above mixture to a 50mL centrifuge tube, rinse the original conical flask with 10mL of ethyl acetate, and combine it into a 50mL centrifuge tube, shake vigorously for 1min, let stand for 2min, and centrifuge at 3500rpm for 3min. Then take 2mL of the supernatant organic phase of the centrifuge tube and transfer it to a nitrogen blowpipe, blow nitrogen for about 15min until it is blown dry. Redissolve it with 2mL of chromatographic grade methanol, filter it through a 0.22μm filter membrane, and after the sample preparation is completed, place it in a 4℃ refrigerator for HPLC testing. Calculate the degradation rate of pyrethroid insecticides (intermediate degradation products) according to the following formula: Wherein A1 is the residual concentration of pyrethroid insecticide (intermediate degradation product) after treatment with Bacillus cereus YL1, and A0 is the initial concentration of pyrethroid insecticide (intermediate degradation product) of the blank control.
[0030] 1.5 The testing methods for the standards and samples involved are as follows: HPLC detection conditions: chromatographic column: Shimadzu C18 column (4.6*150mm; 5μm); column temperature: 30℃; flow rate: 0.5mL / min; injection volume: 10μL. The mobile phase is chromatographic grade methanol: ultrapure water (95:5), testing pyrethroids such as cypermethrin, detection wavelength 254nm, running time 17min; the mobile phase is chromatographic grade methanol: ultrapure water (65:35), testing 3-PBA, detection wavelength 230nm, running time 20min; the mobile phase is chromatographic grade methanol: ultrapure water (45:55), testing benzoic acid, phenol, benzoic acid intermediates, detection wavelength 230nm; running time 17min.
[0031] 1.6 Observation of colony morphology of pyrethroid-degrading bacteria involved Scrape a loop of YL1 bacteria and inoculate it into LB solid medium for streak culture. After culturing at 30°C for 24 hours, observe the colonies.
[0032] 2 Results and analysis 2.1 Observation of colony morphology of strain YL1 After separation, purification and degradation verification, a strain YL1 with cypermethrin degradation activity was obtained. Figure 1 As shown, the YL1 strain formed approximately round, soft, non-pigmented, opaque colonies with a slightly shiny white appearance on the LB agar plate after incubation at 30°C for 24 h.
[0033] 2.2 Scanning electron microscopy observation of strain YL1 like Figure 2As shown, under scanning electron microscopy, the cells of strain YL1 are rod-shaped with square ends in short or long chains, with spores of 1.0 to 1.5 μm. The spores are round or cylindrical and mesial or submesial, without flagella.
[0034] 2.3 16S rRNA molecular biological identification of strain YL1 The accession number of the 16S rRNA gene sequence of strain YL1 in the GenBank database is PQ164389. Based on the 16S rRNA gene sequence of strain YL1, homology comparison was performed using NCBI, and it was found that the coverage rate of strain YL-1 and Bacillus cereus MCCC 1A06185 (Bacillus cereus) was 94% and the consistency was 100%. Then Ez BioCloud was used to compare and construct a phylogenetic tree. YL1 and Bacillus cereus MCCC 1A06185 were in the same branch, with a bootstrap value of 98, and YL1 was preliminarily identified as Bacillus cereus.
[0035] Based on the above identification results, the strain YL1 isolated by the present invention was identified as Bacillus cereus. Bacillus cereus YL1 was deposited in the General Microbiological Center of the China Microbiological Culture Collection Administration on September 11, 2024, with a deposit address of No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, and a deposit number of CGMCC NO.31940.
[0036] 2.4 Degradation of cypermethrin by Bacillus cereus YL1 The preparation method of Bacillus cereus YL1 seed liquid was the same as 1.3. The Bacillus cereus YL1 seed liquid was inoculated into LB liquid medium containing 50 mg / L cypermethrin at a concentration of 4 vol%. Three parallel groups were set up (with no bacteria added as the control group), and cultured at 30°C and 150 rpm for 15 days. Samples were taken regularly at 1, 3, 5, 7, 9, 11, 13, and 15 days, and the cypermethrin pesticide residue was determined by high performance liquid chromatography (HPLC) and the OD was determined by an enzyme marker. 600 Values were used to draw the pesticide degradation curve and bacterial growth curve.
[0037] (2) Experimental results The results of the degradation experiment of cypermethrin by Bacillus cereus YL1 are as follows Figure 3As shown in the figure, cypermethrin was gradually degraded with the extension of degradation time, and its degradation rate was the fastest during 0-7 days. The degradation rates were about 70% and 85% on the 3rd and 7th days, respectively. It was almost completely degraded on the 13th day, with a degradation rate of about 95%. This is the first time that Bacillus cereus was found to have degradation activity on cypermethrin, while cypermethrin in the control group was almost not degraded. OD of Bacillus cereus YL1 and the control group 600 As the degradation time increased, the OD of the control group increased gradually. 600 were significantly higher than those in the experimental group, and on the 5th day, the OD 600 Almost reaching the same level as the control group, the OD of the experimental group after 5 days 600 It is gradually higher than the control group. It is speculated that the strain may be gradually utilizing cypermethrin through cometabolism, thereby growing better.
[0038] 2.5 Response surface experiment to optimize the degradation conditions of cypermethrin by Bacillus cereus YL1 (1) Experimental methods The response surface methodology was used to optimize the three key factors affecting the degradation ability of Bacillus cereus YL1: temperature, pH value and inoculum size. The Box-Behnken model was used for experimental design. Temperature, pH and inoculum size were represented by X1, X2 and X3, respectively, and -1, 0 and 1 represented the levels of these three independent variables, respectively. i =(X i -X0) / △X i Encode the independent variables, where x i is the coded value of the independent variable, X i is the actual experimental level value of the independent variable, X0 is the actual value of the experimental level center point, △X i The statistical software Design-Expert 13 was used for experimental design and analysis. The coding of each factor level is shown in Table 1. The experimental results are the degradation rate of strain YL1 in LB liquid medium containing 50 mg / L cypermethrin on the 7th day.
[0039] Table 1 Response surface methodology experimental design and results Note: The data in the table are the mean ± standard deviation of 3 replicates (2) Experimental results The three-dimensional response surface diagram for optimizing the degradation of cypermethrin is shown in Figure 2. Figure 4As shown in the figure, (a) the interactive effect of temperature and pH value on the degradation of cypermethrin by Bacillus cereus YL1, (b) the interactive effect of temperature and inoculum size on the degradation of cypermethrin by Bacillus cereus YL1, (c) the interactive effect of pH value and inoculum size on the degradation of cypermethrin by Bacillus cereus YL1. The difference analysis of contour slope and response surface color change showed that the interaction between pH value and temperature and inoculum size was more obvious, while the interaction between temperature and inoculum size was slightly weaker.
[0040] The contour map and cubic optimization map of cypermethrin degradation are shown in Figure 2. Figure 5 a and Figure 5 As shown in Figure b, when the temperature is 30-40℃ and the pH is between 7 and 8, the degradation rate of cypermethrin exceeds 85%; the optimal degradation conditions predicted by cubic graph optimization are temperature 40℃, pH 7.97, and inoculation amount 4.27%. Under these conditions, the maximum theoretical value of cypermethrin degradation by Bacillus cereus YL1 is 86.15%. Experimental verification shows that under the above optimal conditions, the degradation rate of cypermethrin by Bacillus cereus YL1 after 7 days is 85.50%, which is close to the maximum degradation rate (86.15%) predicted theoretically, reflecting that the optimized degradation conditions of the model are reliable.
[0041] 2.6 Degradation effect of Bacillus cereus YL1 on different initial concentrations of cypermethrin (1) Experimental methods The preparation method of Bacillus cereus YL1 seed solution is the same as 1.3. The Bacillus cereus YL1 seed solution was inoculated into 20 mL LB liquid culture medium containing 25 mg / L, 50 mg / L, 100 mg / L, 150 mg / L, 200 mg / L, 300 mg / L, 400 mg / L, and 600 mg / L cypermethrin at a 4% inoculum, and cultured at 30°C and 150 rpm for 15 days. Samples were taken regularly at 1, 3, 5, 7, 9, 11, 13, and 15 days, and the degradation rate of cypermethrin by Bacillus cereus YL1 under each concentration condition was determined, and the degradation kinetic curve of cypermethrin was drawn.
[0042] (2) Experimental results The degradation results of cypermethrin at different concentrations are shown in Figure 6As shown, it can be seen that Bacillus cereus YL1 has a degradation effect on all concentrations of cypermethrin. Overall, with the increase of concentration, the degradation ability gradually decreases. Bacillus cereus YL1 degrades 25-100 mg / L cypermethrin quickly, and the degradation rate is greater than 50% on the 3rd day; especially on the 1st day, the degradation rate of 25 mg / L cypermethrin has reached 80%, and it is almost completely degraded on the 7th day; Interestingly, the degradation rate of 150 mg / L cypermethrin by Bacillus cereus YL1 on the 9th day is as high as 85%, which is higher than that of 50 mg / L and 100 mg / L cypermethrin, and the degradation rate of 200-400 mg / L cypermethrin on the 9th day is 40%-60%. In addition, Bacillus cereus YL1 still has a certain tolerance to 600 mg / L cypermethrin, and the degradation efficiency is 25.88% on the 15th day.
[0043] The degradation kinetic parameters of different concentrations of cypermethrin by Bacillus cereus YL1 are shown in Table 2. Overall, except for 100 mg / L, the degradation rate constant k gradually decreased with the increase of cypermethrin concentration, while t 1 / 2 The half-life was continuously prolonged, among which Bacillus cereus YL1 had the fastest degradation efficiency for 25 mg / L cypermethrin, with a half-life of only 1.821 days, while Bacillus cereus YL1 took longer to degrade 300 mg / L and above cypermethrin, with a half-life of more than 3 days. The above results showed that Bacillus cereus YL1 showed efficient degradation ability for cypermethrin.
[0044] Table 2 First-order degradation kinetic parameters of cypermethrin at different concentrations 2.7 Broad-spectrum degradation of Bacillus cereus YL1 (1) Experimental methods The preparation method of Bacillus cereus YL1 seed solution is the same as 1.3. The seed solution of Bacillus cereus YL1 was inoculated into 20 mL LB liquid medium containing 50 mg / L cypermethrin, beta-cypermethrin, tetramethrin, λ-cyhalothrin, bifenthrin, cypermethrin, permethrin, deltamethrin, and cis-cypermethrin at a 4% inoculation rate, and cultured at 30°C and 150 rpm for 7 days to determine the degradation effect of Bacillus cereus YL1 on different pyrethroids.
[0045] (2) Experimental results The broad-spectrum degradation of Bacillus cereus YL1 Figure 7As shown in the figure, Bacillus cereus YL1 has degradation effects on all nine pyrethroids, among which the degradation effect on type II high-efficiency cypermethrin is the best, and it can be almost completely degraded on the 7th day; the degradation effect on type I permethrin and tetramethrin, as well as type II cypermethrin and λ-cyhalothrin is good, and their degradation rates are about 80% on the 7th day. The degradation efficiency of type I bifenthrin and type II cypermethrin is also more than 50% on the 7th day. The degradation effect on type II deltamethrin is the worst, and its degradation rate is less than 10%.
[0046] 2.8 Degradation kinetics of four pyrethroids by Bacillus cereus YL1 (1) Experimental methods The preparation method of Bacillus cereus YL1 seed solution is the same as 1.3. In order to study the degradation characteristics of Bacillus cereus YL1 on cypermethrin, bifenthrin, cypermethrin and cypermethrin, the above pyrethroid mother solution was added to make the final mass concentration of 20mL conical flask 50mg / L, and cultured at 30℃, pH 7.0, 150r / min shaking for 15d, and samples were taken every other day to measure OD 600 The pyrethroid pesticide residues were determined by HPLC, and the pesticide degradation curve and bacterial growth curve were drawn.
[0047] (2) Experimental results The degradation kinetic parameters of four pyrethroid pesticides by Bacillus cereus YL1 are shown in Table 3. The degradation rates of four pyrethroid pesticides by Bacillus cereus YL1 are cypermethrin > cypermethrin > fenvalerate > bifenthrin, among which cypermethrin has the fastest degradation efficiency and the shortest half-life of only 0.6268d.
[0048] Table 3 First-order degradation kinetic parameters of different pyrethroids 2.9 Degradation of intermediate degradation products of cypermethrin by Bacillus cereus YL1 (1) Experimental methods The preparation method of Bacillus cereus YL1 seed solution is the same as 1.3. Inoculate the Bacillus cereus YL1 seed solution with a 4% inoculum into 20 mL LB liquid medium containing 50 mg / L 3-PBA, catechol, benzoic acid, and phenol, respectively, and culture at 30°C and 150 rpm for about 15 days. Take samples every other day to measure the residual amount of intermediate degradation products and OD 600 The recovery method of intermediate degradation products refers to 1.4.
[0049] (2) Experimental results The degradation of pyrethroid intermediate degradation products 3-PBA, catechol, benzoic acid and phenol by Bacillus cereus YL1 is shown in Figure 2. Figure 8 As shown in the figure, overall, the degradation rate of the four intermediate degradation products by Bacillus cereus YL1 gradually increased with the extension of degradation time. Among them, the degradation rates of 3-PBA and benzoic acid were 68.29% and 60% at 15 days, respectively. Bacillus cereus YL1 rapidly degraded catechol and phenol from 0 to 5 days, and the degradation rate was relatively slow after 5 days, and it was completely degraded on the 11th and 13th days, respectively. The OD values of the experimental group containing these four intermediate degradation products were 0.1% and 0.2%, respectively. 600 Overall, the degradation of 3-PBA by Bacillus cereus YL1 is shown in Figure 2. Figure 8 As shown in a, from the third day on, the bacterial mass of Bacillus cereus YL1 was greater than that of the blank control, and 3-PBA was continuously consumed as the bacterial mass increased. After the final 15 days of culture, the degradation efficiency of 3-PBA reached 68.29%. Figure 8 As shown in Figure b, Bacillus cereus YL1 grew rapidly from 0 to 5 days. At 5 days, Bacillus cereus YL1 degraded 91.64% of 50 mg / L catechol, with a significant degradation effect. However, Bacillus cereus YL1 may have entered the decline period and grew slowly in LB liquid medium. It took until 11 days to completely degrade catechol. The degradation of benzoic acid by Bacillus cereus YL1 is shown in Figure b. Figure 8 As shown in Figure c, Bacillus cereus YL1 did not degrade benzoic acid in 0-1d, which is speculated to be the initial adaptation of Bacillus cereus YL1 to the environment where benzoic acid exists; then in 1-9d, Bacillus cereus YL1 used benzoic acid and nutrients in LB liquid culture medium to grow rapidly, and the degradation rate of benzoic acid continued to increase, but it stagnated at 11d; then the amount of bacteria decreased, and the degradation of benzoic acid was slow in 9-15d. Finally, about 60% of benzoic acid was removed after 15d, and benzoic acid could not be completely degraded. The degradation of phenol by Bacillus cereus YL1 is shown in Figure 2. Figure 8 As shown in Figure d, Bacillus cereus YL1 basically did not degrade phenol in the initial stage of 0-1d, which may be due to the gradual adaptation of Bacillus cereus YL1 to the environment where phenol exists; in 1-7d, the rate of phenol utilization by the strain accelerated, and the degradation rate was about 80% at 7d; then the bacteria grew slowly, and the residual amount of phenol gradually decreased, and finally phenol was completely removed at 13d. The above results show that Bacillus cereus YL1 can effectively degrade 3-PBA, catechol, benzoic acid and phenol, four intermediate degradation products of pyrethroids.
[0050] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.
Claims
1. A Bacillus cereus, characterized in that: The Bacillus cereus is named Bacillus cereus ( Bacillus cereus )YL1, deposited on September 11, 2024 in the General Microbiology Center of China Microorganism Culture Collection Administration, the deposit address is No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCC NO. 31940.
2. Use of the Bacillus cereus as claimed in claim 1 in degrading pyrethroid insecticides and intermediate degradation products of pyrethroid insecticides.
3. The use according to claim 2, characterized in that: The pyrethroid insecticides include cypermethrin, beta-cypermethrin, tetramethrin, λ-cyhalothrin, bifenthrin, cypermethrin, permethrin, deltamethrin, and cis-cypermethrin. The intermediate degradation products of the pyrethroid insecticides include 3-phenoxybenzoic acid, phenol, catechol, and benzoic acid.
4. Use of the Bacillus cereus according to claim 1 in the preparation of a preparation for degrading pyrethroid insecticides and intermediate degradation products of pyrethroid insecticides.
5. The use according to claim 4, characterized in that: The pyrethroid insecticides include cypermethrin, beta-cypermethrin, tetramethrin, λ-cyhalothrin, bifenthrin, cypermethrin, permethrin, deltamethrin, and cis-cypermethrin. The intermediate degradation products of the pyrethroid insecticides include 3-phenoxybenzoic acid, phenol, catechol, and benzoic acid.
6. A preparation for degrading pyrethroid insecticides and intermediate degradation products of pyrethroid insecticides, characterized in that: The preparation contains the Bacillus cereus according to claim 1.
7. Use of the preparation according to claim 6 in degrading pyrethroid insecticides and intermediate degradation products of pyrethroid insecticides.
8. The use according to claim 7, characterized in that: The pyrethroid insecticides include cypermethrin, beta-cypermethrin, tetramethrin, λ-cyhalothrin, bifenthrin, cypermethrin, permethrin, deltamethrin, and cis-cypermethrin. The intermediate degradation products of the pyrethroid insecticides include 3-phenoxybenzoic acid, phenol, catechol, and benzoic acid.