A strain of Lactobacillus paracasei YM2024 for degrading pesticide residues, its fermentation product, bacterial flora YM-Clean and applications

Abstract

The present invention belongs to the field of microbial technology, and particularly relates to a Lactobacillus paracasei YM2024 for degrading pesticide residues, a bacterial community YM-Clean, and their applications. Lactobacillus paracasei YM2024 was deposited at the China General Microbiological Culture Collection Center on January 25, 2024, with the deposit number CGMCC No. 29770. This strain has an adsorption effect on pesticides and has a high alkaline phosphatase activity, and can degrade a variety of organophosphorus pesticides under in vivo conditions, so as to relieve the damage of pesticides to the intestinal flora and intestinal barrier, and reduce the harm of pesticide residues to the body.

Description

Technical Field

[0001] The present invention belongs to the technical field of microbiology, and particularly relates to a Lactobacillus paracasei YM2024 strain for degrading pesticide residues, a microbial community YM-Clean, and their applications. Background Art

[0002] With the development of agriculture, pesticides are used more and more widely, but pesticide residues have caused serious impacts on the environment and human health. Pesticides usually enter the body along with foods such as unwashed fruits and vegetables, and cause damage to health by destroying the intestinal barrier and entering the human circulation, leading to diseases such as obesity, liver and kidney damage. Therefore, it is of great significance to develop a method that can effectively degrade pesticide residues. As a green and environmental protection technology, microbial degradation technology has become an effective way to solve the problem of pesticide residues. The ways to solve the problem of pesticide residues by microorganisms mainly include adsorption and degradation, but the effects of existing microorganisms in adsorbing and degrading pesticides need to be further improved. Summary of the Invention

[0003] To solve the above technical problems, the present invention provides a Lactobacillus paracasei YM2024 strain for degrading pesticide residues, a microbial community YM-Clean, and their applications. The YM2024 strain of Lactobacillus paracasei can produce a significant adsorption effect on organophosphorus pesticides, and in the complex intestinal environment, this strain can also produce excellent pesticide degradation effects, thereby effectively reducing the harm of organophosphorus pesticides to the human body.

[0004] To achieve the above invention purposes, the present invention adopts the following technical solutions:

[0005] In the first aspect of the present invention, a Lactobacillus paracasei YM2024 strain is provided, and its classification name is Lactobacillus paracasei ( Lacticaseibacillus paracasei ), which was deposited in the China General Microbiological Culture Collection Center on January 25, 2024, and its deposit number is CGMCC No. 29770; the deposit address is the Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing.

[0006] Lactobacillus paracasei is a probiotic widely present in the human intestine, with various physiological functions, capable of regulating the balance of intestinal flora, inhibiting the growth of harmful bacteria, and enhancing the intestinal barrier. The Lactobacillus paracasei YM2024 strain provided by the present invention is obtained by screening from traditional dairy products. In addition to having the common physiological activities of Lactobacillus paracasei, it also has an adsorption effect on pesticides, and at the same time has a high alkaline phosphatase activity, capable of degrading various organophosphorus pesticides under in vivo conditions, thereby alleviating the damage of pesticides to intestinal flora and the intestinal barrier, and reducing the harm of pesticide residues to the body.

[0007] The second aspect of the present invention provides the use of the above-mentioned Lactobacillus paracasei strain YM2024 in reducing the amount of pesticide residues.

[0008] The third aspect of the present invention provides the use of the above-mentioned Lactobacillus paracasei strain YM2024 in adsorbing pesticide residues in a liquid.

[0009] The method of the above use specifically includes the following operations:

[0010] Adding the live cells and / or inactivated cells of the above-mentioned Lactobacillus paracasei strain YM2024 to the liquid to be treated, maintaining at 35-39 °C for at least 4 h, and separating the cells.

[0011] The Lactobacillus paracasei strain YM2024 has a high alkaline phosphatase activity, and after inactivation, it can also produce an adsorption effect similar to that of activated carbon. Therefore, both its live cells and inactivated cells can adsorb pesticides in the liquid and reduce the content of pesticides in the liquid.

[0012] Preferably, the pesticide is an organophosphorus pesticide.

[0013] More preferably, the pesticide includes at least one of dimethoate, chlorpyrifos, and glufosinate.

[0014] Preferably, the concentration of the live cells or inactivated cells in the liquid to be treated is 10 7 cfu / mL~10 9 cfu / mL.

[0015] The fourth aspect of the present invention provides the use of the above-mentioned Lactobacillus paracasei strain YM2024 in degrading pesticides.

[0016] Preferably, the above use is for degrading pesticide residues in the intestine.

[0017] Preferably, the pesticide is an organophosphorus pesticide.

[0018] More preferably, the pesticide includes at least one of dimethoate, chlorpyrifos, and glufosinate.

[0019] The fifth aspect of the present invention provides a probiotic powder made from the above-mentioned Lactobacillus paracasei strain YM2024.

[0020] The eighth aspect of the present invention provides a bacterial community YM-Clean with the ability to degrade pesticide residues, including the above-mentioned Lactobacillus paracasei strain YM2024 and at least one other strain with the ability to degrade pesticide residues.

[0021] Preferably, the strain with the ability to degrade pesticide residues includes Bifidobacterium animalis subsp. lactis BAL-28, which was deposited in the China General Microbiological Culture Collection Center on June 26, 2022, with the deposit number CGMCC No. 7.462. This strain has been disclosed in the patent with the application number CN202310956580.0 and the title "Bifidobacterium animalis subsp. lactis BAL-28 with prevention of indigestion and flatulence, promotion of absorption, its fermentation products, flora CW and applications".

[0022] The beneficial effects of the present invention are as follows:

[0023] The Lactobacillus paracasei YM2024 strain provided by the present invention has a high alkaline phosphatase activity and the ability to degrade organophosphorus pesticides. This strain can not only adsorb pesticides under in vitro conditions but also promote pesticide degradation in an in vitro fermentation simulation system of the intestine. Moreover, experiments have proved that the Lactobacillus paracasei YM2024 strain can colonize in the human intestine and survive continuously in the intestinal environment for more than one week, so it has the potential to continuously degrade pesticide residues. At the same time, the Lactobacillus paracasei YM2024 is more in line with the situation where various pesticides may remain on fruits and vegetables in practical applications and has excellent degradation effects on mixed pesticides containing dimethoate, chlorpyrifos, and glufosinate. Therefore, this strain can reduce pesticides in fruits and vegetables by means such as soaking and reduce pesticides in the body by oral administration, thereby reducing the harm of pesticides to the body. Description of the Drawings

[0024] Figure 1 It is the cell morphology of Lactobacillus paracasei YM2024 in Example 1;

[0025] Figure 2 It is the colony morphology of Lactobacillus paracasei YM2024 in Example 1. Detailed Embodiments

[0026] In order to make the objectives, technical solutions and advantages of the present invention clearer, the following further elaborates on the present invention in combination with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the protection scope of the present invention.

[0027] The following illustrates the solutions of the present invention through specific embodiments.

[0028] The components and preparation methods of the culture media used in the following embodiments are as follows:

[0029] Improved MRS liquid medium: Peptone 10.0 g, Beef extract powder 5.0 g, Yeast extract powder 4.0 g, Glucose 20.0 g, Tween-80 1.0 ml, Dipotassium hydrogen phosphate 2.0 g, Sodium acetate 5.0 g, Ammonium citrate 2.0 g, Agar 15.0 g, Magnesium sulfate (MgSO4·7H2O) 0.2 g, Manganese sulfate (MnSO4·4H2O) 0.05 g, Distilled water 1000 mL, pH 6.2 ± 0.2.

[0030] Intestinal model medium (CMGM) (g / L): Starch, 5.0; Pectin, 2.0; Guar gum, 1.0; Mucin (porcine stomach type III), 4.0; Xylan, 2.0; Arabinogalactan, 2.0; Inulin, 1.0; Casein, 3.0; Peptone water, 5.0; Tryptone, 5.0; Bile salts, 0.4; Yeast extract, 4.5; Ferrous sulfate (FeSO4·7H2O), 0.005; Sodium chloride, 4.5; Potassium chloride, 4.5; Potassium dihydrogen phosphate (KH2PO4), 0.5; Magnesium sulfate (MgSO4·7H2O), 1.25; Calcium chloride (CaCl2·6H2O), 0.15; Sodium bicarbonate (NaHCO3), 1.5; Cysteine, 0.8; Heme, 0.05; Tween 80, 1.0.

[0031] Unless otherwise specified, the technical means used in the following examples are conventional means well-known to those skilled in the art; the materials, reagents, etc. used in the following examples can all be obtained through commercial channels.

[0032] Example 1

[0033] The embodiment of the present invention provides the Lactobacillus paracasei strain YM2024, its obtaining process and identification process.

[0034] 1. Obtaining process

[0035] On September 12, 2019, local traditional yogurt was obtained at Taxkorgan Tajik Autonomous County (altitude 4000 meters, latitude 35°37′ - 38°40′, longitude 71°20′ - 77°01′), and the Lactobacillus paracasei strain YM2024 was obtained from the local traditional yogurt.

[0036] 2. Identification

[0037] 2.1 Colony morphology observation

[0038] Cell morphology: Polymorphic bacilli (as Figure 1 shown); Colony morphology observation: Smooth and shiny surface (as Figure 2 shown); Gram staining: Positive.

[0039] 2.2 16S rDNA sequence sequencing

[0040] 16S rDNA sequence of Lactobacillus paracasei YM2024 (shown as SEQ ID No.1):

[0041]

[0042] By performing BLAST sequence alignment in the NCBI database, the identity between Lactobacillus paracasei YM2024 and Lactobacillus paracasei ( Limosilactobacillus reuteri ) is 99.93%.

[0043] Through cell morphology observation, colony morphology observation, Gram staining, and 16S rDNA sequence comparison, this strain is consistent with Lactobacillus paracasei ( Limosilactobacillus reuteri ). Lactobacillus paracasei YM2024 was deposited in the China General Microbiological Culture Collection Center (Address: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Beichen West Road, Chaoyang District, Beijing 100101), and the deposit number is CGMCC No. 29770.

[0044] Example 2

[0045] This example provides a bacterial suspension of Lactobacillus paracasei YM2024 strain, and its preparation method is as follows:

[0046] Inoculate the seed liquid of Lactobacillus paracasei YM2024 into the modified MRS liquid medium, and activate it continuously for 3 generations. Adjust the cell concentration of the obtained cells with PBS to obtain the bacterial suspension.

[0047] Example 3

[0048] This example provides a YM2024 probiotic powder, and its preparation method is as follows: Add Lactobacillus paracasei YM2024 into the medium at an inoculation amount of 3% for fermentation culture. The culture conditions are: 37 °C, 12 hours; after fermentation is completed, centrifuge at 6000 r / min for 30 min to obtain the bacterial sludge. Mix the bacterial sludge evenly with the freeze-drying protectant, then perform freeze-drying and pulverize to obtain the YM2024 probiotic powder (the viable count is 1.1×10 11 CFU / g).

[0049] Preparation method of the medium: Mix 40 g of glucose, 4 g of soy peptone, 3 g of yeast extract powder, 2 g of diammonium hydrogen citrate, 6 g of anhydrous sodium acetate, 3 g of dipotassium hydrogen phosphate, 1 g of isomaltooligosaccharide, 3 g of starch and other food-grade materials, then add 1000 g of pure water and mix until there are no visible particles to the naked eye. After melting the materials, adjust the pH to 5.0 - 6.8, and sterilize at 117.5 - 118.5 °C for 20 min to obtain the medium.

[0050] Preparation method of cryoprotectant: Mix 100 g of starch, 20 g of glucose, 60 g of maltodextrin, 30 g of sucrose, 10 g of lactose, 50 g of skim milk powder and other food raw materials evenly, add 1000 g of pure water and dissolve until there are no visible particles to the naked eye. After melting the materials, adjust the pH to 5.0 - 6.8, sterilize at 117.5 - 118.5 °C for 20 min, and adjust the pH to 6.0 - 7.3 after sterilization to obtain the cryoprotectant.

[0051] Example 4

[0052] This example provides the alkaline phosphatase activity of Lactobacillus paracasei YM2024 strain, as well as the adsorption effect and degradation effect of organophosphorus pesticides.

[0053] 1. Determination of alkaline phosphatase activity of Lactobacillus paracasei YM2024

[0054] 1.1 Treatment of Lactobacillus paracasei YM2024

[0055] Lactobacillus paracasei YM2024 is cultured in modified MRS medium at 37 °C, activated for three generations, centrifuged (12000 rpm / min) for 3 min to obtain the bacterial sludge. Resuspend with 50 mM PBS, lyse with an ultrasonic cell disruptor, and centrifuge (12000 rpm / min) at 4 °C for 10 min to take the supernatant for standby.

[0056] 1.2 Detection of alkaline phosphatase activity

[0057] (1) Set up blank control wells, standard product wells and sample wells using a 96-well plate according to Table 1. The dosages of the standard product working solution are 4, 8, 16, 24, 32 and 40 µL respectively, and 50 µL of the sample is added directly.

[0058] Table 1 Group setting

[0059]

[0060] (2) Gently pipette and mix well. Incubate at 37 °C for 10 min.

[0061] (3) Add 100 µL of the reaction termination solution in the Beyotime Alkaline Phosphatase Assay Kit (P0321S) to each well to terminate the reaction.

[0062] (4) Measure the absorbance at 405 nm.

[0063] After detection, the alkaline phosphatase activity of Lactobacillus paracasei YM2024 is 0.235 ± 0.002 U / mL.

[0064] 2. Adsorption effect of Lactobacillus paracasei YM2024 on organophosphorus pesticides

[0065] Inoculate 3% of the bacterial suspension into 10 mL of modified MRS liquid medium, and activate it continuously for 3 generations. Centrifuge (12,000 rpm / min) for 3 min to collect the bacterial cells, wash them 3 times with 50 mM PBS, and adjust the concentration of the bacterial suspension with 50 mM PBS to prepare a bacterial suspension of viable bacteria with a concentration of 10 7 cfu / mL and 10 9 cfu / mL for standby; Take the bacterial suspension of viable bacteria and prepare an inactivated bacterial suspension by heating in a water bath at 80°C for 30 min. Use commercially available Lactobacillus paracasei LPC12 as a control, and the treatment methods for its bacterial cells and inactivated bacterial cells are the same as those for YM2024. Add the bacterial suspension of viable bacteria and the inactivated bacterial suspension to the solutions of dimethoate (3 mg / L), chlorpyrifos (3 mg / L), and glufosinate (3 mg / L) respectively, culture at 37°C for 4 h, centrifuge (12,000 rpm / min) for 3 min, collect the supernatant, and detect it by gas chromatography. Chromatographic conditions: The carrier gas is high-purity nitrogen with a flow rate of 10 mL / min; the fuel gas is high-purity H2 with a flow rate of 75 mL / min; the combustion-supporting gas is air with a flow rate of 100 mL / min. The inlet temperature is 200°C, the detector temperature is 250°C, the initial temperature of the column oven is 90°C, hold for 1 min, then increase to 260°C at a rate of 10°C / min, and hold for 3 min. The injection method is splitless injection, and the septum purge is 3 mL / min. Use a DB-1701 medium-polarity capillary column and an FPD detector, with an injection volume of 1.0 μL. Qualitative analysis is based on the retention time, and quantitative analysis is based on the peak area. The experiment uses a dimethoate solution without Lactobacillus as a blank control, and performs the same treatment. Each sample has 3 parallel groups, and the experiment is repeated 3 times.

[0066] The results are shown in Table 2.

[0067] Table 2 Adsorption effect

[0068]

[0069] Calculation formula for adsorption rate:

[0070] Adsorption rate (%) = (pesticide concentration before adding the bacterial suspension - pesticide concentration after adding the bacterial suspension) ÷ pesticide concentration before adding the bacterial suspension × 100%.

[0071] The degradation of pesticides by bacterial cells requires a long time, while the contact time between bacterial cells and pesticides in this experiment is short. Therefore, the decrease in pesticide concentration is mainly due to the adsorption effect that takes effect in the short term. Therefore, the change in pesticide concentration caused by pesticide degradation is ignored in the calculation of the adsorption rate.

[0072] As can be seen from Table 2, the viable and inactivated cells of Lactobacillus paracasei YM2024 have good adsorption effects on dimethoate, chlorpyrifos, and glufosinate. And at a relatively high concentration (1.0x10 9 cfu / mL), the adsorption effects of the viable and inactivated cells of Lactobacillus paracasei YM2024 on dimethoate and glufosinate are significantly better than those of the commercially available viable and inactivated cells of Lactobacillus paracasei. The adsorption effect of the viable cells of Lactobacillus paracasei YM2024 on chlorpyrifos is better than that of the commercially available viable cells of Lactobacillus paracasei; at a relatively low concentration (1.0x10 7 cfu / mL), the adsorption effect of the viable and inactivated cells of Lactobacillus paracasei YM2024 on chlorpyrifos is significantly better than that of the commercially available Lactobacillus paracasei.

[0073] 3. Degradation effect of Lactobacillus paracasei YM2024 on pesticides in an in vitro fermentation simulation system of the intestine

[0074] The experiment was divided into four groups: a positive control group, a blank group, a commercially available Lactobacillus paracasei group (Lactobacillus paracasei LPC12), and an experimental group (Lactobacillus paracasei YM2024 of the present invention). The pre-treatment conditions of the four groups were the same. A three-stage continuous culture intestinal model system was used. The human colon three-stage continuous culture model consisted of three fermenters, simulating the proximal (V1, 280 mL), transverse (V2, 300 mL), and distal colon (V3, 320 mL). The three serially connected fermenters were maintained at 37 °C, and the pH values were maintained at 5.5 (V1), 6.2 (V2), and 6.8 (V3), and anaerobic conditions were introduced by continuous N2 introduction. V1 was connected to the intestinal model medium (CMGM) by a peristaltic pump. Fresh and healthy human fecal samples were collected and stored in an anaerobic cabinet (10% H2, 10% CO2, 80% N2). After collection, a 1:5 (w / w) fecal dilution in anaerobic PBS (0.1 mol / L PBS, pH 7.4) was prepared within at most 15 min. Each stage of the colon model was inoculated with 100 mL of fecal slurry. According to the average retention time of healthy individuals, the total system throughput time was set to 48 h. After inoculation, the colon model was run as a batch culture for 24 h to stabilize the bacterial population before the start of medium infusion. After 24 h, the system was run through 8 full-volume turnovers to achieve a steady state. After the systems of the positive control group, the commercially available Lactobacillus paracasei group, and the experimental group were stabilized, CMGM medium added with pesticides (dimethoate 80 mg / L, chlorpyrifos 100 mg / L, glufosinate 50 mg / L) was pumped in through a peristaltic pump. The blank group was pumped with CMGM medium without dimethoate, chlorpyrifos, and glufosinate, and continued to be cultured for 24 h to reach a steady state for 2 h. Considering the operating volume (900 mL) and retention time (48 h) of the colon model system, the viable freeze-dried powder of Lactobacillus paracasei LPC12 and the viable freeze-dried powder of Lactobacillus paracasei YM2024 were respectively added to V1 at 1% (w / v) per day in the experimental group and the commercially available Lactobacillus paracasei group (the preparation methods of the viable freeze-dried powders of the two groups were the same as in Example 3, and the viable bacteria counts were both 1.1×10 11CFU / g), and then perform eight volume turnovers to reach a steady state for 3 h. Then, sample and detect the contents of dimethoate, chlorpyrifos, and glufosinate-ammonium in the system after inoculation for three consecutive days. The pesticide content is detected by gas chromatography. Chromatographic conditions: The carrier gas is high-purity nitrogen with a flow rate of 10 mL / min; the fuel gas is high-purity H2 with a flow rate of 75 mL / min; the combustion-supporting gas is air with a flow rate of 100 mL / min. The inlet temperature is 200 °C, the detector temperature is 250 °C, the initial temperature of the column oven is 90 °C, hold for 1 min, increase to 260 °C at a rate of 10 °C / min, and hold for 3 min. The injection method is splitless injection, and the septum purge is 3 mL / min. A DB-1701 medium-polarity capillary column and an FPD detector are used, the injection volume is 1.0 μL, qualitative analysis is based on retention time, and quantitative analysis is based on peak area.

[0075] The average value and variance of the samples taken and detected for three consecutive days are shown in Table 3.

[0076] Table 3 Degradation effect ( ±s)

[0077]

[0078] In addition, the colonization ability was judged by detecting the change in the viable count of Lactobacillus paracasei in the effluents of the experimental group and the control group by PMA-qPCR method. The results showed that the strain could still be detected after stopping adding the strain in the system, indirectly indicating that Lactobacillus paracasei strain YM2024 could colonize in the intestinal environment. At the same time, the detection results showed that Lactobacillus paracasei strain YM2024 could survive continuously in the intestinal environment for more than one week.

[0079] From the above experimental results, it can be seen that Lactobacillus paracasei YM2024 can not only adsorb pesticides under in vitro conditions, but also promote pesticide degradation in the in vitro fermentation simulation system of the intestine, and has the potential to colonize, survive for a long time and continuously degrade pesticide residues in the human intestine. At the same time, Lactobacillus paracasei YM2024 has excellent adsorption and degradation effects on the mixed pesticides containing dimethoate, chlorpyrifos, and glufosinate-ammonium, which is more in line with the situation that various pesticides may remain on fruits and vegetables in actual applications.

[0080] Example 5

[0081] This embodiment provides a YM-Clean probiotic powder of a flora with the ability to degrade pesticide residues. The preparation method is as follows: The seed solutions of Lactobacillus paracasei YM2024 strain and Bifidobacterium animalis subsp. lactis BAL-28 strain are mixed at a volume ratio of 3:2, and then added to a culture medium for fermentation culture at an inoculation amount of 3%. The culture conditions are: 37 °C, 12 hours; after fermentation is completed, centrifuged at 6000 r / min for 30 min to obtain bacterial sludge. The bacterial sludge is mixed evenly with a lyophilization protectant and then freeze-dried, and then pulverized to obtain YM-Clean probiotic powder (the viable count is 1.1×10 11 CFU / g).

[0082] Preparation method of the culture medium: Mix 40 g of glucose, 4 g of soy peptone, 3 g of yeast extract powder, 2 g of diammonium hydrogen citrate, 6 g of anhydrous sodium acetate, 3 g of dipotassium hydrogen phosphate, 1 g of isomaltooligosaccharide, 3 g of starch and other food-grade materials, add 1000 g of pure water and mix well until there are no visible particles to the naked eye. After melting the materials, adjust the pH to 5.0 - 6.8, and sterilize at 117.5 - 118.5 °C for 20 min to obtain the culture medium.

[0083] Preparation method of the lyophilization protectant: Mix 100 g of starch, 20 g of glucose, 60 g of maltodextrin, 30 g of sucrose, 10 g of lactose, 50 g of skim milk powder and other food raw materials evenly, add 1000 g of pure water and dissolve until there are no visible particles to the naked eye. After melting the materials, adjust the pH to 5.0 - 6.8, and sterilize at 117.5 - 118.5 °C for 20 min. After sterilization, adjust the pH to 6.0 - 7.3 to obtain the lyophilization protectant.

[0084] Example 6

[0085] This embodiment provides the adsorption effect and degradation effect of the YM-Clean probiotic powder prepared in Example 5 on organophosphorus pesticides. This experiment is carried out simultaneously with the adsorption effect and degradation effect experiments in Example 4, and the blank control and positive control are the same as those in Example 4.

[0086] 1. Adsorption effect of YM-Clean probiotic powder on organophosphorus pesticides

[0087] The YM-Clean probiotic powder is prepared into 10 7 cfu / mL and 10 9A bacterial suspension of viable bacteria at cfu / mL. Take the bacterial suspension of viable bacteria and prepare an inactivated bacterial suspension by heating in a water bath at 80 °C for 30 min. Add the bacterial suspension of viable bacteria and the inactivated bacterial suspension to solutions of dimethoate (3 mg / L), chlorpyrifos (3 mg / L), and glufosinate-ammonium (3 mg / L) respectively, incubate at 37 °C for 4 h, centrifuge (12,000 rpm / min) for 3 min, collect the supernatant, and detect it by gas chromatography. The chromatographic conditions are the same as in Example 4. Repeat the experiment 3 times.

[0088] The results are shown in Table 4.

[0089] Table 4 Adsorption effect of YM-Clean probiotic powder on organophosphorus pesticides

[0090]

[0091] Calculation formula for adsorption rate:

[0092] Adsorption rate (%) = (Pesticide concentration before adding bacterial suspension - Pesticide concentration after adding bacterial suspension) ÷ Pesticide concentration before adding bacterial suspension × 100%.

[0093] As can be seen from Table 4, both the viable bacteria and inactivated bacteria of YM-Clean probiotic powder have good adsorption effects on dimethoate, chlorpyrifos, and glufosinate-ammonium. And at a relatively high concentration (1.0x10 9 cfu / mL), the adsorption effects of the viable bacteria of YM-Clean probiotic powder on dimethoate, chlorpyrifos, and glufosinate-ammonium are significantly better than those of Lactobacillus paracasei YM2024 and commercially available Lactobacillus paracasei. The adsorption effect of the inactivated bacteria on dimethoate is significantly better than that of the commercially available Lactobacillus paracasei, and the adsorption effects on chlorpyrifos and glufosinate-ammonium are better than those of Lactobacillus paracasei YM2024 and commercially available Lactobacillus paracasei; at a relatively low concentration (1.0x10 7 cfu / mL), the adsorption effects of both the viable bacteria and inactivated bacteria of YM-Clean probiotic powder on dimethoate, chlorpyrifos, and glufosinate-ammonium are significantly better than those of Lactobacillus paracasei YM2024 and commercially available Lactobacillus paracasei.

[0094] 2. Degradation effect of YM-Clean probiotic powder on organophosphorus pesticides

[0095] Add the YM-Clean probiotic powder prepared in Example 5 to V1 of the three-stage continuous culture intestinal model system at 1% (w / v) every day, and investigate the degradation effect of organophosphorus pesticides according to the method of Example 4. Samples are taken continuously for three days to detect the contents of dimethoate, chlorpyrifos, and glufosinate-ammonium in the system after inoculation. The average values and variances of the samples taken continuously for three days are shown in Table 5.

[0096] Table 5 Degradation effect of YM-Clean probiotic powder on organophosphorus pesticides ( ±s)

[0097]

[0098] In addition, the colonization ability was judged by detecting the changes in the viable counts of Lactobacillus paracasei YM2024 strain and Bifidobacterium animalis subsp. lactis BAL-28 in the experimental group by PMA-qPCR method. The results showed that the strains could still be detected after stopping the addition of YM-Clean probiotic powder in the system, indirectly indicating that the strains of YM-Clean probiotic powder could colonize in the intestinal environment. At the same time, the detection results showed that the strains of YM-Clean probiotic powder could survive continuously in the intestinal environment for more than one week.

[0099] From the above experimental results, it can be seen that YM-Clean probiotic powder can also adsorb pesticides under in vitro conditions, promote pesticide degradation in the in vitro fermentation simulation system of the intestine, and has the potential to colonize, survive for a long time and continuously degrade pesticide residues in the human intestine. Compared with Lactobacillus paracasei YM2024 strain, YM-Clean probiotic powder has better adsorption and degradation effects on the mixed pesticides containing dimethoate, chlorpyrifos and glufosinate, and is more suitable for treating fruits and vegetables with multiple pesticide residues.

[0100] The above description is only the preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement or improvement made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A strain of Lactobacillus paracasei YM2024, characterized in that, Its classification name is Lactobacillus paracasei ( Lacticaseibacillus paracasei ), which was deposited at the China General Microbiological Culture Collection Center on April 22, 2024, with the deposit number of CGMCC No. 29770; the deposit address is Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing.

2. Use of the Lacticaseibacillus paracasei strain YM2024 as claimed in claim 1 in reducing the amount of pesticide residues.

3. Use of the Lacticaseibacillus paracasei strain YM2024 as claimed in claim 1 in adsorbing pesticide residues in a liquid.

4. The application according to claim 3, wherein The method of the use specifically comprises the following operations: adding viable cells and / or inactivated cells of the Lacticaseibacillus paracasei strain YM2024 to the liquid to be treated, maintaining at 35-39 °C for at least 4 h, and separating the cells; and / or The pesticide is an organophosphorus pesticide; and / or The concentration of the viable bacteria cells or inactivated bacteria cells in the liquid to be treated is 10 7 cfu / mL to 10 9 cfu / mL.

5. The application according to claim 3 or 4, characterized in that, The pesticide comprises at least one of dimethoate, chlorpyrifos and glufosinate.

6. Use of the Lacticaseibacillus paracasei strain YM2024 as claimed in claim 1 in degrading pesticides.

7. The application according to claim 6, wherein The use is for degrading pesticide residues in the intestine; and / or The pesticide is an organophosphorus pesticide.

8. The application according to claim 6 or 7, characterized in that, The pesticide comprises at least one of dimethoate, chlorpyrifos and glufosinate.

9. A probiotic powder, characterized in that, Made from the Lacticaseibacillus paracasei strain YM2024 as claimed in claim 1.

10. A bacterial community YM-Clean with the ability to degrade pesticide residues, characterized in that, Comprising the Lacticaseibacillus paracasei strain YM2024 as claimed in claim 1 and at least one other strain having the ability to degrade pesticide residues.

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