An olive-shaped fungus capable of degrading zearalenone and its application

Abstract

The present invention provides an olive-shaped fungus for degrading zearalenone and application thereof; the olive-shaped fungus ( Olivibacter sp.) 16SrDNA nucleotide sequence is shown in SEQ ID NO.1; the present application first discovered that the olive-shaped fungus KP9 can degrade zearalenone under aerobic or microaerobic conditions, and can then be used to degrade zearalenone in grains or feed to reduce the harm of toxins, improve the quality and safety level of agricultural products and feed, and ensure the food safety of humans and animals.

Description

Technical Field

[0001] The invention relates to the field of microorganisms, and in particular to an olive-shaped fungus capable of degrading zearalenone and application thereof. Background Art

[0002] Zearalenone (ZEN) is a fungal toxin isolated by Stob et al. in 1962 from corn contaminated by Fusarium graminearum, also known as F-2 toxin. Pure ZEN is in the form of powder crystals with a molecular formula of C 18 H 22 O5, molecular weight is 318, melting point is 165℃, and has good thermal stability. ZEN is insoluble in water, but its macrolide structure can be opened in alkaline aqueous solution, thereby dissolving, but it can be restored when the pH drops. In addition, ZEN is also easily soluble in organic solvents such as ethyl acetate, acetonitrile, methanol, ether, benzene and chloroform.

[0003] ZEN is a secondary metabolite produced by Fusarium, which is widely present in food and feed. It will cause serious harm to the health of humans and animals after being ingested. The structure of ZEN and its derivatives is similar to estrogen, and they can stably bind to estrogen receptors (ER), causing disorders in the reproductive system of humans and animals and have reproductive toxicity. At the same time, ZEN also has multiple hazards such as cytotoxicity, immunotoxicity, genotoxicity, organ toxicity and carcinogenicity.

[0004] According to statistics from the Food and Agriculture Organization of the United Nations (FAO), about 25% of agricultural products in the world are contaminated with mycotoxins, posing a great safety hazard to livestock and human health. Liu Jiangao et al. conducted ZEN testing on 1,407 feed raw material samples collected from different regions in my country and found that the ZEN excess rate in corn, corn germ meal, corn gluten meal, wheat and DDGS (the ZEN content in the raw materials exceeded my country's feed hygiene limit standard of 500 μg / kg) was significantly higher than that of other types of samples ("Survey on Common Mycotoxin Contamination in Feed Raw Materials in my country in 2021" China Poultry, 2023, 45(10): 70-75). A series of research reports on the contamination status of ZEN have also been conducted abroad. Rodrigues et al. reported that the ZEN contamination rates in corn and wheat samples in the Middle East and Africa were 16% and 25%, respectively, with the highest ZEN content reaching 310 μg / kg and 392 μg / kg, respectively (Degradation of ochratoxin A by brevibacterium species, J Agric Food Chem, 59(19):10755-10760). In Europe, there have also been reports of many cereals such as wheat, corn, soybeans, and rice being contaminated by ZEN, and the ZEN content is more or less distributed in different countries. The Americas also have varying degrees of ZEN contamination, with the ZEN detection rates in corn and DDGS in the United States reaching 42% and 71%, respectively.

[0005] In order to reduce the harm of ZEN, in addition to strengthening the prevention and supervision measures of grain mildew, research on ZEN detoxification is also essential. Any one or more detoxification measures for contaminated feed should follow the following principles: 1) effectively remove and destroy toxins; 2) no toxic residues or carcinogenic or mutagenic residues are produced in the treated products or in the feed after ingestion; 3) do not change the nutritional characteristics and palatability of the feed; 4) are economically and technically feasible and do not significantly increase the cost of the final product.

[0006] At present, common ZEN detoxification methods include physical, chemical and biological methods. Physical detoxification methods mainly include heat treatment, irradiation and physical adsorption. In actual production, due to the high energy consumption of various methods or the large demand for adsorbents, the processing cost is high, and there are still disadvantages such as incomplete detoxification, which is difficult to match the actual production needs. The chemical detoxification method mainly uses chemical reagents such as alkali, oxidants, and organic solvents to react chemically with ZEN to change its chemical structure to achieve the purpose of detoxification. The chemical detoxification method can produce a significant detoxification effect on ZEN-contaminated food and feed, and has the characteristics of fast effect and low cost. However, since the chemical reagents themselves may have certain toxicity, the residual chemical reagents in the treated products cannot be completely resolved, and it is easy to cause secondary pollution of the environment. At the same time, it may also have a greater negative impact on the nutrition and quality of food and feed, so it cannot be applied to actual production. The use of biological methods to detoxify mycotoxins is one of the current research hotspots, mainly including microbial adsorption, microbial degradation, and cloning and expressing biological enzymes that have a degrading effect on mycotoxins. Biosorption is the process of using bacterial cell walls to absorb toxins to achieve mycotoxin detoxification, but the toxins are not transformed or disappear. Biodegradation refers to the use of extracellular and intracellular enzymes and some secondary metabolites secreted by microorganisms to decompose mycotoxins into non-toxic and harmless substances. Biodegradation has the advantages of low cost, high efficiency, strong specificity, and non-toxic degradation products. It is currently the most promising method for ZEN detoxification. In view of the toxic effects of ZEN, which seriously affect the health of animals and humans, it is very necessary to find a safe and efficient probiotic strain with a clear genetic background that can be directly applied to degrade ZEN.

[0007] Olivibacter belongs to the Bacteria domain, Bacteroidetes, Sphingobacteriia, Sphingobacteriales, Sphingobacteriaceae. Currently, there are 9 described species of the genus Olivibacter, including O. sitiensis AW-6 isolated from alkaline olive oil milling waste. T , isolated from ginseng field soil 0.soli 0-34 T and 0.ginsengisoli 060 T , isolated from compost 0.domesticus DC186 T 、0.composti CC-KYC063 T , 0.ginsenosidimutans BS18 T and 0.terrae Jip13 T, and O.jilunii 14-2A isolated from DDT-contaminated soil T ,

[0008] 0.oleidegradans TBF2 / 20.2 T Isolated from a water filter contaminated by hydrocarbon compounds. According to literature reports, strains of the genus 0livibacter have a variety of active functions or biological potentials. 0.ginsenosidimutans DC186 T It has β-glucosidase activity and can convert three forms of ginsenosides, Rb, Rc, and Rd, into PPDol-type ginsenosides after incubation at 30°C for 72 hours (Siddiqi MZ, Liu Q, Lee SY, Choi KD, Im WT. Olivabacterginsenosidimutans sp nov., with ginsenoside converting activity isolated from comppost, and reclassification of Pseudosphingobacterium domesticum as Olivabacter domesticus comb.nov. Int J Syst Evol Microbio1. 2018Aug: 68(8): 2509-2514.

[0009] doi:10.1099 / ijsem.0.002819.); to 0. sitiensis DSM17696 T Whole genome DNA sequencing and mining revealed that the strain has the ability to degrade benzoate and 2,4-dichlorobenzoate, and may also have heavy metal resistance and organic solvent degradation potential (Ntougias S, Lapidus A, Han J, Mavromatis K, Pati A, Chen A, Klenk HP, Woyke T, Fasseas C, Kyrpides NC, Zervakis GI. High quality draft genome sequence of 0livibacter sitiensis type strain (AW-6 T), a diphenoldegrader with genes involved in the catechol pathway. Standards in GenomicSciences. 2014June: 9(3): 783-93. doi: 10.4056 / sigs.5088950.). In addition, when potato rhizosphere and phyllosphere microorganisms were isolated and cultured using nitrogen-free medium, it was found that the isolated bacteria contained a large number of strains of the genus Olivibacter, suggesting that strains of the genus Olivibacter may promote the growth and colonization of other microorganisms by playing a nitrogen-fixing role (TurnbullAL, Liu Y, Lazarovits G. Isolation of Bacteria from the Rhizosphere and Rhizoplane of Potato (Solanum tuberosum) Grown in Two Distinct Soils Using Semi Selective Media and Characterization of Their Biological Properties. American Journal of Potato Research, 2012, 89(4): 294-305.). At present, olive-shaped bacteria related to ZEN degradation have not been reported. Summary of the invention

[0010] In response to the problem of widespread zearalenone toxin contamination in the above-mentioned grain production, feed processing and storage processes, the present application provides an olive-shaped fungus that can degrade zearalenone and its application.

[0011] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0012] First, the present invention provides an olive-shaped bacterium (Olivibacter sp.), which is elliptical to cylindrical, has a capsule, no flagella or pili, has white or slightly yellow colonies, a rough and opaque surface, irregular edges, is Gram-negative, uniformly colored, and is an aerobic bacterium; its phylogenetic evolutionary tree is as follows Figure 2 As shown, the 16SrDNA nucleotide sequence is shown in SEQ ID NO.1.

[0013] The applicant named the strain Olive-shaped bacteria KP9 and deposited it in the General Microbiology Center of China Microorganism Culture Collection Administration (CGMCC), address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, Postal Code: 100101; the deposit date is July 5, 2024, and the deposit number is: CGMCC NO.31185.

[0014] Secondly, the present application provides the use of the olive-shaped fungus KP9 with the above-mentioned preservation number of CGMCC NO.31185 in degrading zearalenone. Preferably, KP9 is used to degrade zearalenone in food or feed; the above-mentioned food includes cereals, such as one or more of corn, wheat, barley, rice, sorghum, and millet. In the present application, the term "feed" generally refers to edible substances that can provide the nutrients required for feeding animals, ensure health, promote growth and production, and do not cause harmful effects under reasonable use (National Standard "General Terms in Feed Industry").

[0015] Specifically, the method for using strain KP9 in degrading zearalenone in grains or feed is as follows: adding a liquid bacterial agent containing olive-shaped bacteria KP9 to the above-mentioned food or feed, and mixing, thereby achieving degradation of zearalenone. The amount of olive-shaped bacteria KP9 used is preferably 10 7-8 Pieces / g (food or feed).

[0016] Third, the present application also provides a liquid bacterial agent for degrading zearalenone, wherein the bacterial agent is preferably a liquid bacterial agent, comprising the olive-shaped bacteria KP9 with the above-mentioned preservation number CGMCC NO.31185. The concentration of olive-shaped bacteria KP9 in the liquid bacterial agent is preferably 10 9-10 In practical applications, the liquid bacterial agent may also include fermentation medium, seed medium and other nutrients required for the growth of olive-shaped bacteria KP9.

[0017] In the present invention, the method for preparing the liquid bacterial agent comprises the following steps:

[0018] a) Activation: Activate the preserved olive-shaped bacteria KP9 stock on LB solid medium;

[0019] b) primary expansion culture: inoculating the olive-shaped fungus KP9 activated in step a) into the seed culture medium and culturing with shaking until the logarithmic phase to obtain the strain;

[0020] c) Secondary expansion culture: inoculating the strain obtained in step b) into a seed tank containing a fermentation medium, with an inoculation amount of 1-3% (v / v), preferably 2% (v / v); culturing to the logarithmic growth phase to obtain a seed solution of olive-shaped fungus KP9;

[0021] Culture conditions: The ventilation volume of sterile air is preferably 0.4-1.5:1 (V / V·m), and more preferably 0.8:1 (V / V·m); the stirring speed is preferably 180-260 rpm, and more preferably 200-220 rpm; the culture temperature is preferably 25-42°C, and more preferably 35-37°C; the culture time is preferably 24-60 hours, and more preferably 24-36 hours.

[0022] d) Tertiary expansion culture: The olive-shaped fungus KP9 seed liquid obtained in step c) is inoculated into a production tank containing a fermentation medium for fermentation culture, with an inoculation amount of 5-10%, preferably 8% (v / v).

[0023] Culture conditions: The ventilation volume of sterile air is preferably 0.4-1.5:1 (V / V·m), and more preferably 0.8:1 (V / V·m); the stirring speed is preferably 180-260 rpm, and more preferably 200-220 rpm; the culture temperature is preferably 30-37°C, and more preferably 36-37°C; the culture time is preferably 24-36 hours, and more preferably 24-30 hours.

[0024] After the third-level expansion culture, the olive-shaped fungus KP9 liquid inoculum capable of degrading zearalenone was formed, wherein the concentration of olive-shaped fungus KP9 was 10 9-10 Pieces / mL.

[0025] The advantages of the present invention are as follows: the present invention utilizes the olive-shaped fungus (Olivibacter sp.) KP9 to degrade zearalenone, and in the process of solving toxin pollution, the degradation is thorough and there is no secondary pollution, thereby improving the quality and safety level of agricultural products and feeds, and ensuring the safety of human and animal consumption; the olive-shaped fungus (Olivibacter sp.) KP9 strain is used to produce various preparations for degrading zearalenone, which has the characteristics of low production and use cost and safe use. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the liquid chromatogram of ZEN degradation by strain KP9.

[0027] Figure 2 NJ phylogenetic tree constructed based on the 16S rRNA gene sequence of strain KP9.

[0028] Figure 3 This is a morphological photograph of strain KP9 under transmission electron microscopy. DETAILED DESCRIPTION

[0029] The culture medium formula involved in this application is as follows:

[0030] LB solid medium: composed of the following components in mass volume ratio (g / L): peptone 10.0, yeast extract 5.0, sodium chloride 10.0, agar powder 15.0, pH 7.0.

[0031] Seed culture medium: It is composed of the following components in mass volume ratio (g / L): 20.0% glucose, 10.0% peptone, 10.0% yeast powder, 5.0% beef extract, 5.0% sodium chloride, 0.5% disodium hydrogen phosphate, 1.5% sodium dihydrogen phosphate, pH 6.0, and is sterilized by high pressure wet heat at 121°C, cooled to 37°C, and set aside.

[0032] Fermentation medium: composed of the following components in mass volume ratio (g / L): glucose 50.0, peptone 10.0, yeast powder 0.5, soybean meal powder 10.0, calcium chloride 0.1, magnesium sulfate 0.1, pH 7.0.

[0033] MM liquid culture medium (formula per liter): KH2PO4 1.0 g, Na2HPO4 1.5 g, (NH4)2SO4 0.5 g, CaCl2 0.025 g, MgSO4·7H2O 0.5 g, NaNO3 0.5 g, deionized water is added to 1000 mL, pH 7.0, sterilized at 121°C for 20 min.

[0034] In the present invention, the inoculation amount of the liquid bacterial agent is 5×10 7 In the specific implementation, the inoculation amount is controlled at 10 7-8 Within the range of pcs / g, the purpose of the invention can be achieved.

[0035] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0036] Example 1 Obtaining Olivebacter sp. KP9

[0037] Collect the contents from animal excrement, weigh 2g of the contents and mix them in 20mL pH5.0 MM liquid culture medium, place it in a room temperature shaker at 180rpm for overnight culture, let it stand for 1h, take 0.5mL of the supernatant in 4.5mL pH5.0 MM liquid culture medium, place it in a 30℃, 180rpm shaker for 72h, take 0.5mL and inoculate it in 4.5mL pH5.0 MM liquid culture medium containing 5μg / mL ZEN toxin as the experimental group; set up a blank control (pH5.0 MM liquid culture medium containing 5μg / mL ZEN toxin, no inoculation). After inoculation, place it in a 30℃ incubator for 24h, and use high performance liquid chromatography to detect the content of zearalenone in the culture medium. The specific steps are as follows:

[0038] (1) Sample treatment: Take 300 μL of the sample to be tested, add 700 μL of chromatographic acetonitrile, mix evenly with a vortex shaker, pass through a 0.22 μm organic phase filter, put into a liquid phase bottle, and detect with high performance liquid chromatography.

[0039] (2) HPLC conditions:

[0040] Chromatographic column: Agilent ZORBAX SB-C18 (250×4.6nm, 5μm)

[0041] Mobile phase: methanol: water = 4:1 (v / v);

[0042] Flow rate: 0.8 mL / min;

[0043] Injection volume: 10 μL;

[0044] Detection wavelength: 236nm. The selected bacterial liquid with the effect of degrading ZEN was diluted and spread on LB solid culture medium. After constant temperature culture at 30℃ for 120h, different single colonies were picked and inoculated into pH5.0 MM culture medium containing 5μg / mL ZEN toxin as the experimental group; pH5.0 MM culture medium containing the same concentration of ZEN toxin was used as the control group. After culture at 30℃ for 24h, the ZEN content was detected. Finally, a single strain with the ability to degrade ZEN efficiently was screened and obtained. The applicant named it KP9. The liquid chromatography spectrum of KP9's degradation of ZEN is shown in Figure 1 , Figure 1 Shown in the figure is a comparison of the absorption peaks of zearalenone formed by putting together the liquid chromatograms of zearalenone in the control group and the degradation treatment group. It can be seen that KP9 has the ability to degrade ZEN toxin.

[0045] Example 2 Identification of the strain of Olivebacter sp. KP9

[0046] The colony and bacterial morphology of strain KP9 obtained in Example 1 were identified, and the physiological and biochemical identification results were as follows: Gram-negative rod-shaped bacteria, no spores were formed during the growth process, and flaky, irregular-edged, shiny colonies could be formed on LB medium. Physiological and biochemical characteristics showed that indicators such as β-xylosidase, leucine arylaminease, phenylalanine arylaminease, L-pyrrolidone arylaminease, α-galactosidase, inositol, ELLMAN, β-glucosidase, α-glucoside, D-trehalose, and D-ribose were positive. At the same time, the bacteria could grow in 6.5% NaCl, could hydrolyze esculin, and had a certain resistance to oleandomycin, red tetrazole, and polymyxin B.

[0047] The 16S rDNA sequence of KP9 was cloned and sequenced using 16S universal primers (27F-AGAGTTTGATCCTGGCTCAG; 1492R-GGTTACCTTGTTACGA CTT). The sequencing results were entered into Genbank for BLAST comparison. Sequences closely related to the 16S rDNA of KP9 were selected for phylogenetic tree construction, and the phylogenetic status of KP9 was determined. The phylogenetic tree is shown in Figure 2 .

[0048] Combined with the strain morphological characteristics, KP9 was finally identified as Olivebacter sp. The morphology of KP9 strain under transmission electron microscopy is shown in Figure 3 .

[0049] The applicant deposited the KP9 strain at the General Microbiology Center of the China Microbiological Culture Collection Administration, address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, Postal Code: 100101; the deposit date is July 5, 2024, and the deposit number is: CGMCC NO.31185.

[0050] Example 3 Preparation of Olive Bacteria KP9 Liquid Inoculant

[0051] The olive-shaped fungus KP9 strain preserved in Example 1 was activated on LB solid culture medium, and the activated olive-shaped fungus KP9 was inoculated into a culture bottle containing a seed culture medium, and the culture conditions were controlled as follows: sterile air was introduced at a ventilation ratio of 0.8:1 (V / V·m), the stirring speed was controlled to be 220 rpm, the culture temperature was 37°C, the culture time was 24 hours, and the culture was shaken to the logarithmic phase to obtain the strain; the strain was inoculated into a seed tank containing a seed culture medium at an inoculation rate of 6% (v / v), and cultured to the logarithmic growth phase to obtain the olive-shaped fungus KP9 seed liquid; the obtained olive-shaped fungus KP9 seed liquid was inoculated into a production tank containing a fermentation culture medium at an inoculation rate of 8% (v / v) for fermentation culture, and the culture conditions were consistent with the culture conditions for preparing the olive-shaped fungus KP9 seed liquid, and the concentration of olive-shaped fungus KP9 in the fermentation liquid was detected to be 10 9-10 When the concentration of each nutrient element was 0.1447 W / ml, the liquid bacterial agent of Olive-shaped bacteria KP9 was obtained.

[0052] Example 4 Degradation of ZEN in corn flour by liquid inoculum of Olivaceous bacteria KP9

[0053] Corn contaminated with ZEN toxins harvested from the Liuhe test base (Jiangsu) was baked at 70°C for 24 hours and then crushed and divided into two groups (one group for control and one group for test), with three replicates in each group, each 10 g portion, and divided into 100 mL sterile conical flasks, 10 mL of sterile water was added to each bottle, and after mixing, 0.5 mL of KP9 (prepared in Example 3) was added to the bottle of the treated sample, and 0.5 mL of sterile water was added to the remaining three control conical flasks respectively, and the samples were placed in a 37°C shaking incubator for 24 h. 2.0 g of each treated sample was weighed into a 50 mL centrifuge tube, 20 mL of extract (80% acetonitrile-0.1% formic acid water) was added, and the tubes were placed in an oscillator for 30 min, and a salt bag (FeSO4 2.0 g, NaCl 1.0 g, Na3C6H5O7·2H2O 1.0g), shake for 2min, 10000r / min, centrifuge for 5min, take 2mL of supernatant in a test tube, blow dry with a nitrogen blower, add 1mL of 50% acetonitrile water to dissolve, pass through a 0.22μm filter membrane, put into a liquid phase vial, and use the liquid chromatography-mass spectrometry method (NY / T2071-2011) to detect the content of ZEN in the sample. The test results are shown in Table 1. It can be seen from the results that KP9 liquid bacterial agent can well degrade ZEN in corn flour, and the degradation rate can reach 60.91%.

[0054] Degradation rate % = (average ZEN concentration in the control group - average ZEN concentration in the test group) / average ZEN concentration in the control group * 100%).

[0055] Table 1 Degradation effect of KP9 liquid microbial agent on ZEN in corn flour

[0056] deal with Control (ZEN concentration ug / kg) Test (ZEN concentration ug / kg) Degradation rate (%) 1 2357.45 885.6 – 2 2157.63 982.56 – 3 2489.12 869.45 – average value 2334.73 912.54 60.91

[0057] Example 5 Degradation of ZEN in wheat flour by liquid inoculum of Olivaceous bacteria KP9

[0058] The wheat samples contaminated with ZEN collected in the laboratory were baked at 70°C for 24h and then crushed, divided into two groups (one group for control and one group for test), with three replicates in each group, each 10g, and divided into 50mL conical flasks, 10mL of sterile water was added to each bottle, and after mixing, 0.5mL of KP9 (prepared in Example 3) was added to the bottle of the treated sample, and 0.5mL of sterile water was added to the other three control conical flasks respectively, and placed in a 30°C shaking incubator for 24h, 2.0g of each treated sample was weighed into a 50mL centrifuge tube, 20mL of extract (80% acetonitrile-0.1% formic acid water) was added, and the tube was placed on an oscillator for 30min, and a salt bag (FeSO4 2.0g, NaCl 1.0g, Na3C6H5O7·2H2O 1.0g), shake for 2min, 10000r / min, centrifuge for 5min, take 2mL of supernatant in a test tube, blow dry with a nitrogen blower, add 1mL of 50% acetonitrile water to dissolve, pass through a 0.22μm filter membrane, put into a liquid phase vial, and use the liquid chromatography-mass spectrometry method to detect the content of ZEN in the sample. The test results are shown in Table 2. It can be seen from the results that KP9 liquid bacterial agent can well degrade ZEN in wheat flour, and the degradation rate can reach 78.89%.

[0059] Table 2 Degradation effect of KP9 liquid inoculant on ZEN in wheat flour

[0060] deal with Control (ZEN concentration ug / kg) Test (ZEN concentration ug / kg) Degradation rate (%) 1 4853.26 1095.49 – 2 4901.75 964.13 – 3 4633.52 976.98 – average value 4796.18 1012.20 78.89

[0061] Example 6 Degradation of ZEN in DDGS feed by Olivaceous bacteria KP9 liquid inoculant

[0062] DDGS feed produced in Taohuawu, Yichun City, Jiangsu Province was baked at 70°C for 24 hours and then crushed. ZEN standard solution was added to make the ZEN content in DDGS about 1000ug / kg. After fully mixing, it was divided into two groups (one group for control and one group for test), with three replicates in each group, each 10g, and divided into 100mL conical flasks. 10mL sterile water was added to each bottle. After mixing, 0.5mL KP9 (prepared by Example 3) was added to the bottle of the treated sample, and 0.5mL sterile water was added to the remaining 3 control conical flasks. The pH value was measured and adjusted to 6.0, and placed in a 30°C shaking table for incubation for 24h. 2.0g of each treated sample was weighed into a 50mL centrifuge tube, 20mL of extract (80% acetonitrile-0.1% formic acid water) was added, and it was placed on an oscillator for 30min. A salt bag (FeSO42.0g, NaCl 1.0g, Na3C6H5O7·2H2O 1.0g), shake for 2min, 10000r / min, centrifuge for 5min, take 2mL supernatant into a test tube, blow dry with a nitrogen blower, add 1mL 50% acetonitrile water to dissolve, filter through a 0.22μm filter membrane, put into a liquid phase vial, and use liquid chromatography-mass spectrometry to detect the content of ZEN in the sample. The test results are shown in Table 3. It can be seen from the results that KP9 liquid bacterial agent can degrade ZEN in DDGS, and the degradation rate can reach 65.66%.

[0063] Table 3 Degradation of ZEN in feed by KP9 liquid microbial agent

[0064] deal with Control (ZEN concentration ug / kg) Test (ZEN concentration ug / kg) Degradation rate (%) 1 1052.97 362.37 – 2 1012.81 332.55 – 3 964.34 343.68 – average value 1010.04 346.87 65.66

[0065] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A strain of olive-shaped fungus ( Olivibacter sp.), the strain deposit number is: CGMCC NO.31185.

2. Use of the olive-shaped fungus as claimed in claim 1 in degrading zearalenone.

3. The use according to claim 2, characterized in that The application refers to the application of the olive-shaped fungus in degrading zearalenone in food or feed.

4. The use according to claim 3, characterized in that The food comprises at least one of corn, wheat, barley, rice, sorghum and millet.

5. The use according to claim 3, characterized in that The application refers to adding the bacterial agent containing the olive-shaped fungus to food or feed to degrade zearalenone, and the addition amount of the olive-shaped fungus is 10 7 -10 8 Pieces / g food or feed.

6. A liquid bacterial agent for degrading zearalenone, characterized in that: The liquid bacterial agent contains olive-shaped bacteria with a preservation number of CGMCC NO.31185.

7. The method for preparing the liquid bacterial agent according to claim 6, characterized in that: The specific steps are as follows: 1) Inoculate the activated olive-shaped bacteria into the seed culture medium and culture them under shaking until the logarithmic phase to obtain the strain; Each liter of seed culture medium includes: 20.0g glucose, 10.0g peptone, 10.0g yeast powder, 5.0g beef extract, 5.0g sodium chloride, 0.5g disodium hydrogen phosphate, 1.5g sodium dihydrogen phosphate, pH 6.0, deionized water is added to 1L pH 6.0, and sterilized by high pressure wet heat at 121℃; 2) Inoculate the strain into a seed tank containing a fermentation medium at a volume percentage of 1-3%, and culture until the logarithmic growth phase to obtain a seed solution; Each liter of fermentation medium includes: 50.0g glucose, 10.0g peptone, 0.5g yeast powder, 10.0g soybean meal powder, 0.1g calcium chloride, 0.1g magnesium sulfate, pH 7.0, deionized water to 1L, pH 6.0, 121℃ high pressure wet heat sterilization; 3) Inoculate the seed liquid into a production tank containing fermentation medium for fermentation culture at a volume percentage of 5-10% until the concentration of olive-shaped bacteria in the culture liquid reaches 10 9 -10 10 / mL, and the liquid bacterial agent is obtained.

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