Enzyme-metal-mesoporous covalent organic framework composite catalyst and application thereof in mycotoxin removal
By immobilizing metal particles and enzymes on a mesoporous covalent organic framework, an enzyme-metal-mesoporous covalent organic framework composite catalyst is formed, solving the problem of recycling enzyme-metal cascade catalysts in the degradation of fungal toxins. This achieves efficient and stable catalytic effects and is suitable for food and environmental protection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANCHANG UNIV
- Filing Date
- 2022-12-27
- Publication Date
- 2026-07-24
AI Technical Summary
Existing enzyme-metal cascade catalysts for the degradation of fungal toxins suffer from problems such as difficulty in recycling, high cost, low catalytic efficiency, and unfavorable catalyst preparation conditions. In particular, the small-sized nanoporous supports with high mass transfer resistance lead to poor stability.
Using a mesoporous covalent organic framework as a carrier, metal particles are fixed in situ and enzymes are physically adsorbed to form an enzyme-metal-mesoporous covalent organic framework composite catalyst, which realizes synergistic catalysis of enzymes and metals, and improves catalytic efficiency and stability by adsorbing substrates through the mesoporous covalent organic framework.
It achieves highly efficient catalytic degradation of mycotoxins, the catalyst is easy to recover and can be reused, and has good stability and high specific surface area, making it suitable for food and environmental applications.
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Figure CN115772515B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of biotechnology, specifically relating to an enzyme-metal-mesoporous covalent organic framework composite catalyst and its application in the removal of fungal toxins. Background Technology
[0002] Mycotoxins are highly toxic and chemically stable, commonly found in grains and animal products. They exhibit toxic, carcinogenic, teratogenic, and mutagenic activities in humans and animals. Long-term consumption of food and feed containing excessive levels of mycotoxins can cause serious acute and chronic toxicity, leading to disease and death in both humans and animals. Mycotoxins contaminating grains and food have become a pressing issue. Therefore, developing efficient methods for degrading mycotoxins is of great significance for the safety of grains, feed, and food, as well as the health of humans and animals.
[0003] Among current methods for degrading mycotoxins, enzymatic degradation significantly reduces or even eliminates the toxicity of mycotoxin products, making it an important method due to its high efficiency, environmental friendliness, and mild reaction conditions. It avoids complex operations, specialized equipment, and stringent environmental requirements. However, using free enzymes for catalytic degradation makes enzyme activity susceptible to environmental conditions, resulting in poor stability, difficulty in recovery, increased costs, and limited industrial application. The Fenton reaction, a highly efficient and simple method for generating reactive oxygen species using hydrogen peroxide and nano-ferromagnetic nanoparticles to synthesize hydroxyl radicals, has been widely used in the degradation of various organic pollutants. Currently, there are no reports of applying the Fenton reaction to the degradation of mycotoxins. In the traditional Fenton reaction, hydrogen peroxide is unstable, and excessive addition can easily quench hydroxyl radicals. Furthermore, the Fenton reaction requires an acidic environment to facilitate the stable transformation of iron ions and prevent precipitation; however, excessive addition of acidic reagents can cause environmental pollution.
[0004] Combining the Fenton reaction with enzyme-catalyzed oxidation is an important method to improve the efficiency of hydroxyl radical production. According to literature reports, Huang et al. used a cascade reaction of free glucose oxidase and ferrous ions to generate hydroxyl radicals, catalyzing the degradation of trichloroethylene (concentration 10 mg / L). The degradation reached 78% within 8 hours, a simple operation, but the inability to recycle increased costs (Y. Huang, H. Liu, S. Liu, C. Li, SH Yuan, Chemosphere, 253, 126648. (2020)). Aber et al. immobilized glucose oxidase on magnetite to degrade the dye Acid Yellow 12 (concentration 12 mg / L), achieving a degradation of 62.27% within 2 hours. The magnetism facilitated recovery, but the degradation efficiency was generally low (S. Aber, E. Mahmoudikia, A. Karimi, F. Mahdizadeh, Water Air Soil Pollut, 227, 93. (2016)). Therefore, many problems still exist in the enzyme-metal cascade catalysis of the Fenton reaction, including difficulties in recycling, high cost, low catalytic efficiency, slow catalysis, and unfavorable catalyst preparation conditions. The existing technical bottleneck lies in the small nanopore size and high mass transfer resistance of the currently used immobilized supports.
[0005] Therefore, existing technologies still need improvement and development. Developing a novel composite catalyst that is highly efficient, stable, and reusable and applying it to the degradation of mycotoxins is of great significance. Summary of the Invention
[0006] To address the challenges of difficult separation and recovery, and low catalytic efficiency in enzyme-metal cascade Fenton reactions, this invention provides an enzyme-metal-mesoporous covalent organic framework composite catalyst and its preparation method. The catalyst utilizes a mesoporous nanoflower-like covalent organic framework as a support to immobilize metal particles via in-situ reduction, followed by physical adsorption of the enzyme. The composite catalyst prepared by this method efficiently removes fungal toxins through synergistic catalysis by the enzyme and metal, as well as substrate enrichment via adsorption by the mesoporous covalent organic framework. It not only possesses the advantages of cascade catalysis in Fenton reactions but also exhibits easy recovery, good catalytic activity and stability, and reusability, showing promising application prospects in the food and environmental fields.
[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An enzyme-metal-mesoporous covalent organic framework composite catalyst is prepared by using a covalent organic framework as a carrier, reducing metal ions in situ to metal particles and fixing them on the covalent organic framework through coprecipitation, and finally forming the enzyme through physical adsorption.
[0008] Furthermore, the enzyme-metal-mesoporous covalent organic framework composite catalyst is composed of an enzyme, metal nanoparticles, and a nanoflower-like mesoporous covalent organic framework; the metal particles are magnetic iron oxide particles; the enzyme is glucose oxidase; and the covalent organic framework has a nanoflower-like morphology with a pore size of 2-50 nm.
[0009] This invention further provides a method for preparing the above-mentioned enzyme-metal-mesoporous covalent organic framework composite catalyst, the steps of which are as follows: (1) Synthesis of nanoflower-like mesoporous covalent organic framework: Trimethylbenzaldehyde and p-phenylenediamine were dissolved in 1,4-dioxane at a mass ratio of 1~3:1, acetic acid was added and reacted for 0.4~0.6 hours, and the mixture was dried under vacuum to obtain a yellow solid; (2) Synthesis of metal-mesoporous covalent organic frameworks: The covalent organic frameworks were added to the FeCl3 solution and stirred. 3+ Fe is physically adsorbed onto a covalent organic framework, and then centrifuged to remove unadsorbed Fe. 3+ FeCl2 solution and ammonia were added under anaerobic conditions, and the mixture was heated and stirred until the reaction was complete. The product was then recovered under an external magnetic field. (3) Synthesizing enzyme-metal-mesoporous covalent organic framework: The metal-covalent organic framework is added to an aqueous solution containing the enzyme, and the enzyme is synthesized by physical adsorption and binding on the surface of the metal-mesoporous covalent organic framework.
[0010] Furthermore, in step (1), the mass ratio of pyromellitic aldehyde to p-phenylenediamine is 2:1.
[0011] Furthermore, the synthesis conditions in step (1) are 120°C and the incubation time is 3 days.
[0012] Furthermore, in step (1), the centrifugation speed is 3000-8000 rpm and the centrifugation time is 3-8 min.
[0013] Furthermore, in step (1), the drying method is vacuum drying, and the drying temperature is 80°C.
[0014] Furthermore, in step (2), the molar ratio of FeCl3 to FeCl2 is 2:1.
[0015] Furthermore, in step (2), the concentration of FeCl3 is 0.04~0.12 M and the concentration of FeCl2 is 0.02~0.06 M.
[0016] Furthermore, the synthesis conditions in step (2) are a water bath at 50°C and a stirring reaction time of 30-60 minutes.
[0017] Furthermore, the concentration of the enzyme solution in step (3) is 0.01-1 mg / mL.
[0018] Furthermore, the synthesis conditions in step (3) are 0-37℃ and the reaction time is 3-24 h.
[0019] Furthermore, after the synthesis reaction in step (3) is completed, the flower-shaped immobilized enzyme catalyst is obtained by magnetic separation.
[0020] In step (3), the drying method is selected from freeze drying, vacuum drying, and natural air drying.
[0021] This invention further provides an application of removing fungal toxins using an enzyme-metal-mesoporous covalent organic framework, comprising the following steps: (1) Detoxification treatment: Add the enzyme-metal-covalent organic framework composite catalyst prepared above to the aqueous solution of fungal toxin, add glucose, and stir to react; (2) Reuse of enzyme-metal-covalent organic framework composite catalyst: magnetic separation, catalyst precipitate is washed and dried and then reused.
[0022] Furthermore, the concentration of mycotoxins in step (1) is 10-250 ppb.
[0023] Furthermore, the concentration of the enzyme-metal-covalent organic framework composite catalyst in step (1) is 0.1-1 mg / mL.
[0024] Furthermore, the glucose concentration in step (1) is 5-200 mM.
[0025] Furthermore, in step (1), the reaction temperature is 25-55℃, the stirring speed is 100-300 rpm, and the reaction time is 2-24 h.
[0026] Furthermore, the pH value of the solution in step (1) is 3-7.
[0027] Furthermore, the drying method in step (2) is selected from freeze drying, vacuum drying, and natural air drying.
[0028] The present invention has the following advantages:
[0029] The enzyme-metal-mesoporous covalent organic framework composite catalyst of the present invention has the advantages of high specific surface area, high activity and high stability by regionally immobilizing glucose oxidase and magnetic iron oxide nanoparticles on a nanoflower-like mesoporous covalent organic framework. It can efficiently catalyze the degradation and adsorption of fungal toxins. Under an external magnetic field, the catalyst can be recovered and reused multiple times.
[0030] The method for preparing the enzyme-metal-mesoporous covalent organic framework composite catalyst of the present invention is simple and can efficiently degrade and remove fungal toxins, showing great application prospects in the fields of food safety and environmental protection. Attached Figure Description
[0031] Figure 1 This is a scanning electron microscope image of the glucose oxidase-iron tetroxide-covalent organic framework composite catalyst prepared in Example 1.
[0032] Figure 2 This describes the catalytic efficiency of the glucose oxidase-iron tetroxide-covalent organic framework composite catalyst in Example 4 in degrading aflatoxin B1 at different glucose concentrations.
[0033] Figure 3 The removal efficiency of aflatoxin B1 under different concentrations of glucose oxidase-iron tetroxide-covalent organic framework composite catalyst in Example 5 is shown.
[0034] Figure 4 The catalytic activity of the glucose oxidase-iron tetroxide-covalent organic framework composite catalyst in Example 6 in degrading aflatoxin B1 at different pH values was investigated.
[0035] Figure 5 The removal efficiency of aflatoxin B1, ochratoxin and zearalenone by a glucose oxidase-iron tetroxide-covalent organic framework composite catalyst was determined.
[0036] Figure 6 To compare the catalytic efficiency of glucose oxidase-iron tetroxide-covalent organic framework composite catalyst and iron tetroxide-covalent organic framework catalyst in the degradation of aflatoxin B1.
[0037] Figure 7 To improve the reusability of the glucose oxidase-iron tetroxide-covalent organic framework composite catalyst. Detailed Implementation
[0038] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to the following embodiments. Example 1
[0039] Preparation of glucose oxidase-iron tetroxide-mesoporous covalent organic framework composite catalyst.
[0040] 48 mg of pyromellitic aldehyde and 24 mg of p-phenylenediamine were dissolved in 1,4-dioxane, and then acetic acid was added to the mixture. The mixture was stirred for 0.5 hours to obtain a yellow solid, which was then incubated at 120 °C for 3 days. After incubation, the solid was centrifuged at 8000 rpm for 3 minutes and then placed in a vacuum drying oven at 80 °C to obtain a flower-like covalent organic framework.
[0041] Two mg of the covalent organic framework was added to 0.06 M FeCl3 solution, and adsorption was allowed to occur for 3 hours. The solid was washed by centrifugation, and 2 mL of deionized water was added. Then, 400 μL of 0.03 M FeCl2 solution was added, nitrogen gas was purged to remove oxygen, and then 800 μL of ammonia solution was slowly added. The reaction was allowed to proceed for 30 minutes. After the reaction was complete, the iron(III) oxide-covalent organic framework was recovered under an external magnetic field.
[0042] 10 mg of iron(III) oxide-covalent organic framework was added to 2 mL of 1 mg / mL glucose oxidase solution and reacted at room temperature for 3 hours. After the reaction was completed, the mixture was magnetically separated and washed, and then freeze-dried to obtain the glucose oxidase-iron(III) oxide-covalent organic framework composite catalyst.
[0043] The enzyme activity in the glucose oxidase-iron tetroxide-covalent organic framework composite catalyst was 32.4 U / mg, and the conversion frequency of aflatoxin B1 catalyzed by the metal catalyst was 16.9 h. -1 The scanning electron microscope (SEM) image of the glucose oxidase-ferric oxide-covalent organic framework composite catalyst prepared in this embodiment is shown below. Figure 1 As shown in the figure, the covalent organic framework has a nanoflower-like morphology, the metal particles have a size of 8.9 nm, and the composite catalyst has an average pore size of 18 nm. Example 2
[0044] Preparation of glucose oxidase-iron tetroxide-mesoporous covalent organic framework composite catalyst.
[0045] 96 mg of trimesaldehyde and 48 mg of p-phenylenediamine were dissolved in 1,4-dioxane, and then acetic acid was added to the mixture. The mixture was stirred for 0.5 hours to obtain a yellow solid, which was then incubated at 120 °C for 3 days. After incubation, the solid was centrifuged at 5000 rpm for 5 minutes and then placed in a vacuum drying oven at 80 °C to obtain a flower-like covalent organic framework.
[0046] Two mg of the covalent organic framework was added to 0.04 M FeCl3 solution, and adsorption was allowed to occur for 3 hours. The solid was washed by centrifugation, and 2 mL of deionized water was added. Then, 400 μL of 0.02 M FeCl2 solution was added, nitrogen gas was purged to remove oxygen, and then 800 μL of ammonia solution was slowly added. The reaction was allowed to proceed for 45 minutes. After the reaction was completed, the iron(III) oxide-covalent organic framework was recovered under an external magnetic field.
[0047] 10 mg of iron(III) oxide-covalent organic framework was added to 2 mL of 0.01 mg / mL glucose oxidase solution, and the reaction was carried out at room temperature for 12 hours. After the reaction was completed, the mixture was magnetically separated and washed, and then freeze-dried to obtain the glucose oxidase-iron(III) oxide-covalent organic framework composite catalyst.
[0048] The enzyme activity in the glucose oxidase-iron tetroxide-covalent organic framework composite catalyst was 35.7 U / mg, and the conversion frequency of aflatoxin B1 catalyzed by the metal catalyst was 19.6 h⁻¹. -1 The metal particles have a size of 6.7 nm, and the composite catalyst has an average pore size of 39 nm. Example 3
[0049] Preparation of glucose oxidase-iron tetroxide-mesoporous covalent organic framework composite catalyst.
[0050] 48 mg of pyromellitic aldehyde and 24 mg of p-phenylenediamine were dissolved in 1,4-dioxane, and then acetic acid was added to the mixture. The mixture was stirred for 0.5 hours to obtain a yellow solid, which was then incubated at 120 °C for 3 days. After incubation, the solid was centrifuged at 3000 rpm for 8 minutes and then placed in a vacuum drying oven at 80 °C to obtain a flower-like covalent organic framework.
[0051] Two mg of the covalent organic framework was added to 0.12 M FeCl3 solution, and adsorption was allowed to occur for 3 hours. The solid was washed by centrifugation, and 2 mL of deionized water was added. Then, 400 μL of 0.06 M FeCl2 solution was added, nitrogen gas was purged to remove oxygen, and then 800 μL of ammonia solution was slowly added. The reaction was allowed to proceed for 60 minutes. After the reaction was completed, the iron(III) oxide-covalent organic framework was recovered under an external magnetic field.
[0052] 10 mg of iron(III) oxide-covalent organic framework was added to 2 mL of 0.5 mg / mL glucose oxidase solution, and the reaction was carried out at room temperature for 24 hours. After the reaction was completed, the mixture was magnetically separated and washed, and then freeze-dried to obtain the glucose oxidase-iron(III) oxide-covalent organic framework composite catalyst.
[0053] The enzyme activity in the glucose oxidase-iron tetroxide-covalent organic framework composite catalyst was 28.2 U / mg, and the conversion frequency of aflatoxin B1 catalyzed by the metal catalyst was 22.3 h. -1 The metal particles have a size of 12 nm, and the composite catalyst has an average pore size of 11 nm. Example 4
[0054] The catalytic efficiency of glucose oxidase-iron tetroxide-mesoporous covalent organic framework composite catalyst in degrading aflatoxin B1 under different glucose concentrations was investigated.
[0055] The specific steps are as follows: The reaction solution consisted of 200 ng / mL aflatoxin B1, 0.5 mg / mL glucose oxidase-ferric oxide-covalent organic framework composite catalyst prepared in Example 1, and different concentrations of glucose (1 mM, 10 mM, 50 mM, 100 mM, and 200 mM). The initial pH was adjusted to 5, and the reaction was carried out at room temperature with stirring at 200 rpm for 2 h. After the reaction was completed, the catalyst was separated by magnetic adsorption, washed with ultrapure water, and resuspended in the original volume of ultrapure water for reuse.
[0056] The catalytic efficiency of glucose oxidase-iron tetroxide-covalent organic framework composite catalyst in degrading aflatoxin B1 at different glucose concentrations is as follows: Figure 2 As shown in the figure, when the glucose concentration is 50 mM, 38% of aflatoxin B1 can be degraded, which is higher than the degradation efficiency of other glucose concentrations. Example 5
[0057] Removal efficiency of aflatoxin B1 at different concentrations of glucose oxidase-ferric oxide-mesoporous covalent organic framework composite catalyst.
[0058] The specific steps are as follows: The reaction solution consisted of 100 ng / mL aflatoxin B1, 100 mM glucose, and different concentrations of the glucose oxidase-ferric oxide-covalent organic framework composite catalyst prepared in Example 1 (0.1 mg / mL, 0.25 mg / mL, 0.5 mg / mL, 0.75 mg / mL, and 1 mg / mL). The initial pH was adjusted to 5, and the reaction was carried out at 200 rpm for 12 h at room temperature. After the reaction was completed, the catalyst was separated by magnetic adsorption, washed with ultrapure water, and resuspended in the original volume of ultrapure water for reuse.
[0059] The removal efficiency of aflatoxin B1 at different concentrations of glucose oxidase-ferric oxide-covalent organic framework composite catalysts is as follows: Figure 3 As shown in the figure, the removal efficiency of the catalyst with a concentration of 0.5 mg / mL for aflatoxin B1 is 97%, while the removal efficiencies of the catalysts with concentrations of 0.75 mg / mL and 1 mg / mL for aflatoxin B1 are 100%. Example 6
[0060] The catalytic activity of glucose oxidase-iron tetroxide-mesoporous covalent organic framework composite catalyst in degrading aflatoxin B1 at different pH values was investigated.
[0061] The specific steps are as follows: The reaction solution consisted of 100 ng / mL aflatoxin B1, 50 mM glucose, and 0.5 mg / mL of the glucose oxidase-iron tetroxide-covalent organic framework composite catalyst prepared in Example 1. The initial pH values were adjusted to 3, 4, 5, 6, and 7, respectively, and the reaction was carried out at 200 rpm for 2 h at room temperature.
[0062] The catalytic activity of glucose oxidase-ferric oxide-covalent organic framework composite catalyst in decomposing aflatoxin B1 at different pH values is as follows: Figure 4 As shown in the figure, the glucose oxidase-iron tetroxide-covalent organic framework composite catalyst has stable catalytic activity in the pH range of 3-7, with the highest catalytic activity at pH 5. Example 7
[0063] A glucose oxidase-ferric oxide-mesoporotic covalent organic framework composite catalyst for the removal of ochratoxin.
[0064] The reaction solution consisted of 1 μg / mL ochratoxin, 50 mM glucose, and 0.5 mg / mL of the glucose oxidase-ferric oxide-covalent organic framework composite catalyst prepared in Example 1. The initial pH was adjusted to 5, and the reaction was carried out at room temperature with stirring at 200 rpm for 24 h. After the reaction, the catalyst was separated magnetically, washed with ultrapure water, and resuspended in the original volume of ultrapure water for reuse.
[0065] The glucose oxidase-iron tetroxide-covalent organic framework composite catalyst achieved a removal efficiency of 92% for ochratoxin. Example 8
[0066] A glucose oxidase-iron tetroxide-mesoporotic covalent organic framework composite catalyst was used to degrade and remove zearalenone from zearalenone.
[0067] The reaction solution consisted of 1 μg / mL zearalenone, 50 mM glucose, and 0.5 mg / mL of the glucose oxidase-ferric oxide-covalent organic framework composite catalyst prepared in Example 1. The initial pH was adjusted to 5, and the reaction was carried out at room temperature with stirring at 200 rpm for 2 h. After the reaction, the catalyst was separated magnetically, washed with ultrapure water, and resuspended in the original volume of ultrapure water for reuse.
[0068] The glucose oxidase-iron oxide-covalent organic framework composite catalyst achieved a removal efficiency of 86% for zearalenone.
[0069] The removal efficiencies of glucose oxidase-ferric oxide-covalent organic framework composite catalyst in treating aflatoxin B1 (AFB1), ochratoxin (OTA), and zearalenone (ZEN) are as follows: Figure 5 As shown.
[0070] Comparative Example 1 The degradation and removal of aflatoxin B1 by traditional iron oxide-mesoporous covalent organic framework catalysts was used as a comparison.
[0071] The Fenton reaction system of traditional iron(III) oxide-covalent organic framework catalysts differs from the cascade reaction system of glucose oxidase-iron(III) oxide-covalent organic framework composite catalysts, particularly in the hydrogen peroxide generation mechanism and pH adjustment mechanism, thus affecting catalytic efficiency. This comparative example explores the impact of the cascade reaction system on the catalytic degradation of mycotoxins.
[0072] The specific steps are as follows: First, take two centrifuge tubes containing the same catalytic activity, iron(III) oxide-covalent organic framework and glucose oxidase-iron(III) oxide-covalent organic framework prepared in Example 1. Add 0.15 mg / mL glucose oxidase-iron(III) oxide-covalent organic framework, 50 mM glucose, and 100 ng / mL aflatoxin B1 to centrifuge tube 1. Add an equal amount of iron(III) oxide-covalent organic framework, an equal amount of hydrogen peroxide, and 100 ng / mL aflatoxin B1 to centrifuge tube 2, and mix well. Adjust the initial pH to 5, and stir the mixture at 200 rpm for 4 hours at room temperature. After the reaction, separate the solutions magnetically. The difference in aflatoxin B1 content between the two experimental solutions represents the difference in the catalyst's efficiency in degrading the toxin.
[0073] A comparison of the catalytic efficiencies of glucose oxidase-ferric oxide-covalent organic framework composite catalyst (tube 1) and ferric oxide-covalent organic framework catalyst (tube 2) in the degradation of aflatoxin B1 is shown below. Figure 6 As shown, the degradation efficiency of glucose oxidase-iron tetroxide-covalent organic framework composite catalyst for aflatoxin B1 is 3.5 times that of traditional iron tetroxide-covalent organic framework catalyst. Example 9
[0074] After each catalytic degradation reaction, the glucose oxidase-ferric oxide-mesoporotic covalent organic framework composite catalyst was magnetically separated, washed, and dried before being used again in mycotoxin degradation experiments. Aflatoxin B1 solution was repeatedly degraded using the glucose oxidase-ferric oxide-mesoporotic covalent framework composite catalyst at a concentration of 0.75 mg / mL for 10 consecutive cycles to verify its stability and reusability. Figure 7 As shown, the catalytic effect of the catalyst decreased only slightly after multiple cycles. After 7 cycles, its catalytic effect could still reach more than 90%, and after 8 cycles, it still maintained about 80% of the initial activity, indicating that the prepared composite catalyst has good stability and recyclability.
[0075] The above detailed description is a specific description of one of the feasible embodiments of the present invention. This embodiment is not intended to limit the patent scope of the present invention. All equivalent implementations or modifications that do not depart from the present invention should be included within the scope of the technical solution of the present invention.
Claims
1. The application of an enzyme-metal-mesoporous covalent organic framework composite catalyst in the removal of fungal toxins, characterized in that, The composite catalyst comprises an enzyme, metal nanoparticles, and a nanoflower-like mesoporous covalent organic framework; the metal particles are magnetic iron oxide particles; the enzyme is glucose oxidase; the mesoporous covalent organic framework has a nanoflower-like morphology with a pore size of 2-50 nm; the glucose oxidase and magnetic iron oxide nanoparticles are co-immobilized on the nanoflower-like mesoporous covalent organic framework; the preparation method of the composite catalyst includes the following steps: (1) Synthesis of nanoflower-like mesoporous covalent organic framework: Trimethylbenzaldehyde and p-phenylenediamine were dissolved in 1,4-dioxane at a mass ratio of 1~3:1, acetic acid was added and reacted for 0.4~0.6 hours. The resulting yellow solid was incubated for a period of time, and then centrifuged and vacuum dried to obtain nanoflower-like covalent organic framework. (2) Synthesis of metal-mesoporous covalent organic frameworks: Nanoflower-like mesoporous covalent organic frameworks were added to FeCl3 solution, Fe 3+ The metal-mesoporous covalent organic framework was obtained by physical adsorption onto a covalent organic framework, followed by the addition of FeCl2 solution and ammonia water, followed by heating and stirring. After the reaction was completed, the metal-mesoporous covalent organic framework was recovered under an external magnetic field. (3) Synthesizing enzyme-metal-mesoporous covalent organic framework: The metal-mesoporous covalent organic framework is added to an aqueous solution containing glucose oxidase. The glucose oxidase is physically adsorbed and bound to the surface of the metal-mesoporous covalent organic framework. After the reaction is completed, the flower-like immobilized enzyme-metal-nano flower-like mesoporous covalent organic framework is obtained by magnetic separation.
2. The application according to claim 1, characterized in that, In step (2), the molar ratio of FeCl3 to FeCl2 is 2:1, the concentration of FeCl3 is 0.04~0.12 mM, and the concentration of FeCl2 is 0.02~0.06 mM.
3. The application according to claim 1, characterized in that, The specific application method is as follows: the enzyme-metal-mesoporous covalent organic framework composite catalyst is added to an aqueous solution containing mycotoxins, glucose is added, the reaction is stirred, and the degradation of mycotoxins is catalyzed.
4. The application according to claim 3, characterized in that: The pH of the aqueous solution containing fungal toxins is adjusted to 3-7.
5. The application according to claim 3, characterized in that, The fungal toxin is at least one of aflatoxin, ochratoxin, vomitoxin, and zearalenone.
6. The application according to any one of claims 3 to 5, characterized in that, The catalyst can be recycled and reused after the degradation reaction. The specific steps are as follows: the products after the mycotoxin degradation reaction are magnetically separated to obtain an aqueous solution and catalyst precipitate that do not contain mycotoxins. The catalyst precipitate is washed, dried and reused.