Biological composite material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of materials, and discloses a biological composite material and a preparation method and application thereof.The biological composite material comprises a base membrane, a metal organic framework is evenly dispersed in the base membrane, and glucose oxidase is loaded on the surface of the metal organic framework. The biological composite material obtained by the preparation method disclosed by the invention does not influence the quality of food, and zearalenone in the food can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of material technology, and in particular to a biocomposite material and a preparation method and application thereof. Background Art

[0002] Mycotoxin contamination in the food chain can have significant adverse effects on human health and cause significant socioeconomic losses. Zearalenone (ZEN) is a molecule produced by certain fungi (such as Fusarium species ) is a secondary metabolite produced by ZEN, which is mainly contaminated in corn and its derivatives. It is an endocrine disruptor and may affect the health of animals and humans. ZEN can affect the reproductive system of animals, especially in female animals, which may cause changes in sex hormone levels, thereby affecting fertility and fetal development. Therefore, it has potential safety risks for edible oils and other foods.

[0003] To date, many physical and chemical methods have been designed to reduce the risk of mycotoxin contamination in food. However, simple physical adsorption is not sufficient to achieve complete detoxification, while chemical detoxification may damage the nutritional and flavor components of edible oils. Microbial enzymatic methods can effectively degrade mycotoxins and have been successfully used in the detoxification process of various food matrices. However, certain inherent limitations, such as sensitivity to environmental conditions, complex purification processes, and difficulties in reuse, restrict the large-scale application of natural enzymes. In addition, enzymatic detoxification of mycotoxins in edible oils is very challenging because electron transfer and hydrolysis in enzymatic reactions rarely occur in edible oils, resulting in limited enzyme activity in edible oils.

[0004] Therefore, there is an urgent need for a material that can degrade mycotoxins without affecting food quality. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a biocomposite material and a preparation method and application thereof. The biocomposite material obtained by the present invention not only does not affect the quality of food, but also can reduce the zearalenone in food.

[0006] The invention provides a biocomposite material, which comprises a basement membrane, in which a metal organic framework is uniformly dispersed, and the surface of the metal organic framework is loaded with glucose oxidase.

[0007] Furthermore, the basement membrane is Rhizopus oryzae mycelium.

[0008] Furthermore, the metal organic framework contains Co (cobalt), Mn (manganese), and Fe (iron) metal ions.

[0009] Furthermore, the biocomposite material is positively charged.

[0010] The present invention also provides a method for preparing the biocomposite material, the method comprising: Step 1: Preparation of metal organic framework; Step 2: Loading glucose magnesium oxide on the surface of the metal mailing frame; Step 3: uniformly dispersing the metal organic framework loaded with glucose oxidase in the base film to obtain a biocomposite material; Step 4: Positively charging the biocomposite.

[0011] Furthermore, in step 1, the specific method for preparing the metal organic framework includes: Cobalt nitrate, manganese nitrate and ferrous chloride are added to a solution containing 2-methylimidazole and hexadecyltrimethylammonium bromide. After the solution turns purple, it is stirred at room temperature to separate the solid and liquid. The separated solid is washed and dried.

[0012] Furthermore, the method for preparing the solution containing 2-methylimidazole and hexadecyltrimethylammonium bromide comprises: dispersing 2-methylimidazole and hexadecyltrimethylammonium bromide in ultrapure water.

[0013] Furthermore, in the solution containing 2-methylimidazole and hexadecyltrimethylammonium bromide, the mass concentration of 2-methylimidazole is 32 mg / mL-36 mg / mL.

[0014] Furthermore, in the solution containing 2-methylimidazole and hexadecyltrimethylammonium bromide, the mass concentration of hexadecyltrimethylammonium bromide is 0.02 mg / mL-0.04 mg / mL.

[0015] Furthermore, the mass concentration of the cobalt nitrate in the solution containing 2-methylimidazole and hexadecyltrimethylammonium bromide is 2 mg / mL-3 mg / mL.

[0016] Furthermore, the mass concentration of the manganese nitrate in the solution containing 2-methylimidazole and hexadecyltrimethylammonium bromide is 0.4 mg / mL-0.6 mg / mL.

[0017] Furthermore, the mass concentration of the ferrous chloride in the solution containing 2-methylimidazole and hexadecyltrimethylammonium bromide is 0.4 mg / mL-0.6 mg / mL.

[0018] Furthermore, the stirring time is 1.5h-2.5h.

[0019] It should be understood by those skilled in the art that solid-liquid separation is to separate the target product. Therefore, those skilled in the art can adopt different methods according to the actual situation to achieve the technical effect. As an example, a centrifugal method is adopted with a rotation speed of 10000 rpm and a centrifugal time of 10 min.

[0020] Furthermore, the specific method of washing includes: washing with ultrapure water at least 3 times.

[0021] Furthermore, the drying temperature is 80° C.-90° C., and the drying time is 5 h-7 h.

[0022] Furthermore, in step 2, the specific method of loading glucose magnesium oxide on the surface of the metal organic framework includes: adding glucose oxidase to the solution containing the metal organic framework, solid-liquid separation, washing, and drying.

[0023] Furthermore, the method for preparing the solution containing the metal organic framework comprises dispersing the metal organic framework in a PBS buffer.

[0024] Furthermore, in the solution containing the metal organic framework, the mass concentration of the metal organic framework is 0.8 mg / mL-1.2 mg / mL.

[0025] Furthermore, the mass concentration of the glucose oxidase in the solution containing the metal organic framework is 30 mg / 100 mL-36 mg / 100 mL.

[0026] It should be understood by those skilled in the art that the purpose of solid-liquid separation is to separate the target from the solution. Therefore, those skilled in the art may filter according to the actual situation. As an example, solid-liquid separation is performed by centrifugation to obtain a solid target.

[0027] Furthermore, the specific method of washing includes: washing with ultrapure water at least three times.

[0028] Furthermore, the drying temperature is 30°C-40°C, and the drying time is 5h-7h.

[0029] Furthermore, in step 3, the specific method of uniformly dispersing the metal organic framework loaded with glucose oxidase in the basement membrane includes: uniformly dispersing the metal organic framework loaded with glucose oxidase in the mycelium of Rhizopus oryzae, and then performing heat treatment to obtain a biocomposite material.

[0030] Furthermore, the ratio of the metal organic framework loaded with glucose oxidase to the Rhizopus oryzae mycelium is 1:1000 by mass.

[0031] Furthermore, the heat treatment temperature is 55°C-65°C, and the heat treatment time is 11h-13h.

[0032] Furthermore, in step 4, the specific method of making the biocomposite material positively charged includes: modifying the biocomposite material.

[0033] Furthermore, the specific method of the modification treatment includes: treating the biocomposite material with a solution containing a modifier, and drying.

[0034] Furthermore, the method for preparing the solution containing the modifier includes: dispersing the modifier in deionized water.

[0035] Furthermore, the mass concentration of the modifier in the solution containing the modifier is 4.5 mg / mL-5.5 mg / mL.

[0036] Furthermore, the modifier includes one of hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, and polyethyleneimine.

[0037] Furthermore, the modifier is polyethyleneimine.

[0038] Furthermore, the treatment method is: by controlling the contact time between the solution containing the modifier and the biocomposite material, the contact time is 9 minutes to 11 minutes.

[0039] In the present invention, those skilled in the art can control the contact time between the solution containing the modifier and the biocomposite material to achieve the purpose of modification. Those skilled in the art can adjust according to actual conditions. For example, soaking or vacuum filtration can be used.

[0040] Furthermore, the drying temperature is 30° C.-40° C., and the drying time is 1.5 h-2.5 h.

[0041] The invention also provides application of the biocomposite material in degrading mycotoxins in food.

[0042] Furthermore, glucose needs to be added during the application process.

[0043] Furthermore, the fungal toxin is zearalenone.

[0044] The embodiments of the present invention have the following technical effects: 1. The biocomposite material obtained by the present invention contains a metal organic framework structure, and the metal organic framework structure is loaded with glucose oxidase. First, the pore structure of the metal organic framework and the porous structure of the Rhizopus oryzae mycelium are conducive to the adsorption of mycotoxins in food, and the mycotoxins are adsorbed in the biocomposite material. By adding glucose, glucose oxidase is prompted to produce hydrogen peroxide, and hydrogen peroxide can activate the peroxidase-like effect of the metal organic framework, thereby degrading the mycotoxins adsorbed in the biocomposite material. In addition, the Rhizopus oryzae mycelium can also fix the metal organic framework structure, thereby preventing the metal organic framework from causing pollution to food.

[0045] 2. In the present invention, the metal organic framework structure has three metal ions, namely Co, Mn and Fe. The metal ion Mn is the active center of the natural enzyme. The introduction of Fe can adjust the bond strength between the central metal atom and the ligand molecule, showing a synergistic enhancement of substrate affinity and electron transfer ability, thereby improving its ability to degrade fungal toxins by enhancing peroxidase-like activity. Fe and Mn can be successfully doped into the cobalt metal organic framework, so that the final metal organic framework is not only structurally stable, but also has peroxidase-like activity.

[0046] 3. In the present invention, the biocomposite material has a positive charge and the fungal toxin has a negative charge, and the electrostatic effect further promotes the adsorption effect of the biocomposite material on the fungal toxin, thereby facilitating the subsequent degradation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 It is a preparation principle diagram provided in Example 1 of the present invention.

[0049] Figure 2 is a scanning electron microscope image of the metal organic framework obtained in Example 1 and Comparative Examples 1-2 of the present invention, wherein Figure 2 A is the metal organic framework of Example 1, Figure 2 B is the metal organic framework of Example 2, Figure 2 C is the metal organic framework of Example 1.

[0050] Figure 3 is the element distribution diagram of the metal organic framework obtained in Example 1 of the present invention and Comparative Examples 1-2, wherein Figure 3A is the EDS spectrum of comparative example 1, Figure 3 B is the EDS spectrum of comparative example 2, Figure 3 C is the EDS spectrum of Example 1, Figure 3 D is the distribution diagram of the C element in Example 1, Figure 3 E is the distribution diagram of the O element in Example 1, Figure 3 F is the distribution diagram of Mn element in Example 1, Figure 3 G is the distribution diagram of N element in Example 1, Figure 3 H is the distribution diagram of Co element in Example 1, Figure 3 1 is the distribution diagram of Fe element in Example 1.

[0051] Figure 4 is the N of the metal organic framework obtained in Example 1 and Comparative Examples 1-2 of the present invention. 2 Adsorption isotherm and pore size distribution diagram, where Figure 4 A in the figure is the adsorption analysis diagram of Example 1. Figure 4 B is the adsorption analysis diagram of Example 2. Figure 4 C is the adsorption analysis diagram of Example 1, Figure 4 D in the figure is the pore size distribution diagram of comparative example 1, Figure 4 E is the pore size distribution diagram of comparative example 2, Figure 4 F is the pore size distribution diagram of Example 1.

[0052] Figure 5 is a diagram showing the removal effect of ZEN in the embodiments and comparative examples, wherein Figure 5 Where A is the removal rate of ZEN by the metal organic framework of Example 1 and Comparative Examples 1-2, Figure 5 Where B is the removal rate of ZEN by the metal organic framework of Example 1, the biofilms of Examples 1 to 3 and Comparative Example 3, Figure 5 Where C is the amount of ZEN removed by the metal organic framework of Example 1, the biofilms of Examples 1 to 3 and Comparative Example 3, Figure 5 D in the figure is the removal rate of ZEN in the cycling experiment of the biofilm in Example 1. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0054] In a first aspect, some embodiments provide a biocomposite material, the biocomposite material comprising a base film, a metal organic framework is uniformly dispersed in the base film, and glucose oxidase is loaded on the surface of the metal organic framework.

[0055] In some embodiments, the basement membrane is Rhizopus oryzae mycelium.

[0056] In some embodiments, the metal organic framework contains Co (cobalt), Mn (manganese), and Fe (iron) metal ions.

[0057] In some embodiments, the biocomposite material is positively charged.

[0058] In a second aspect, some embodiments of the present invention also provide a method for preparing the biocomposite material, the method comprising: Step 1: Preparation of metal organic framework; Step 2: Loading glucose magnesium oxide on the surface of the metal mailing frame; Step 3: uniformly dispersing the metal organic framework loaded with glucose oxidase in the base film to obtain a biocomposite material; Step 4: Positively charging the biocomposite.

[0059] In some embodiments, in step 1, the specific method of the metal organic framework includes: Cobalt nitrate, manganese nitrate and ferrous chloride are added to a solution containing 2-methylimidazole and hexadecyltrimethylammonium bromide. After the solution turns purple, it is stirred at room temperature to separate the solid and liquid. The separated solid is washed and dried.

[0060] In some embodiments, the method for preparing the solution containing 2-methylimidazole and hexadecyltrimethylammonium bromide comprises: dispersing 2-methylimidazole and hexadecyltrimethylammonium bromide in ultrapure water.

[0061] In some embodiments, in the solution containing 2-methylimidazole and hexadecyltrimethylammonium bromide, the mass concentration of 2-methylimidazole is 32 mg / mL-36 mg / mL.

[0062] In some embodiments, in the solution containing 2-methylimidazole and hexadecyltrimethylammonium bromide, the mass concentration of hexadecyltrimethylammonium bromide is 0.02 mg / mL-0.04 mg / mL.

[0063] In some embodiments, the mass concentration of the cobalt nitrate in the solution containing 2-methylimidazole and hexadecyltrimethylammonium bromide is 2 mg / mL-3 mg / mL.

[0064] In some embodiments, the mass concentration of manganese nitrate in the solution containing 2-methylimidazole and hexadecyltrimethylammonium bromide is 0.4 mg / mL-0.6 mg / mL.

[0065] In some embodiments, the mass concentration of ferrous chloride in the solution containing 2-methylimidazole and hexadecyltrimethylammonium bromide is 0.4 mg / mL-0.6 mg / mL.

[0066] In some embodiments, the stirring time is 1.5h-2.5h.

[0067] In some embodiments, the specific method of washing includes: washing with ultrapure water at least 3 times.

[0068] In some embodiments, the drying temperature is 80° C.-90° C., and the drying time is 5 h-7 h.

[0069] In some embodiments, in step 2, the specific method of loading glucose magnesium oxide on the surface of the metal organic framework includes: adding glucose oxidase to a solution containing the metal organic framework, solid-liquid separation, washing, and drying.

[0070] In some embodiments, the method for preparing a solution containing a metal organic framework comprises dispersing the metal organic framework in a PBS buffer.

[0071] In some embodiments, in the solution containing the metal organic framework, the mass concentration of the metal organic framework is 0.8 mg / mL-1.2 mg / mL.

[0072] In some embodiments, the mass concentration of the glucose oxidase in the solution containing the metal organic framework is 30 mg / 100 mL-36 mg / 100 mL.

[0073] In some embodiments, the specific method of washing includes: washing with ultrapure water at least three times.

[0074] In some embodiments, the drying temperature is 30° C.-40° C., and the drying time is 5 h-7 h.

[0075] In some embodiments, in step 3, the specific method of uniformly dispersing the metal organic framework loaded with glucose oxidase in the basement membrane includes: uniformly dispersing the metal organic framework loaded with glucose oxidase in the mycelium of Rhizopus oryzae, and then performing heat treatment to obtain a biocomposite material.

[0076] In the present invention, Rhizopus oryzae mycelium is used as the basement membrane. First, the safety of Rhizopus oryzae mycelium is good, and the product of the present invention is applied to food; second, the Rhizopus oryzae mycelium has a porous structure, which can achieve the effect of physical adsorption of fungal toxins; finally, the Rhizopus oryzae mycelium can fix metal organic framework materials to prevent food contamination. In addition, the Rhizopus oryzae mycelium has many functional groups such as hydroxyl carboxyl amino groups, and the modifier can react chemically with the functional groups on the surface of the mycelium to form a covalent bond.

[0077] In some embodiments, the ratio of the metal organic framework loaded with glucose oxidase to the Rhizopus oryzae mycelium is 1:1000 by mass.

[0078] In some embodiments, the heat treatment temperature is 55° C.-65° C., and the heat treatment time is 11 h-13 h.

[0079] In some embodiments, in step 4, the specific method of imparting positive charge to the biocomposite material includes: subjecting the biocomposite material to a modification treatment.

[0080] In some embodiments, the specific method of the modification treatment includes: treating the biocomposite material with a solution containing a modifier, and drying.

[0081] In some embodiments, the method for preparing the solution containing the modifier includes: dispersing the modifier in deionized water.

[0082] In some embodiments, the mass concentration of the modifier in the solution containing the modifier is 4.5 mg / mL-5.5 mg / mL.

[0083] In some embodiments, the modifier includes one or more of hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, and polyethyleneimine.

[0084] In the present invention, the modifier can form a covalent bond by chemically reacting with the functional groups on the surface of the mycelium through the functional groups of the mycelium, such as hydroxyl, carboxyl, and amino groups, so that the biocomposite material can carry a positive charge.

[0085] In some embodiments, the modifier is polyethyleneimine.

[0086] In the present invention, the functional groups of the mycelium of Rhizopus oryzae can undergo nucleophilic reaction with the nitrogen atoms in polyethyleneimine to form bonds. In addition, polyethyleneimine can achieve a better improvement in the positive potential of the biocomposite material, thereby being more conducive to the adsorption of fungal toxins.

[0087] In some embodiments, the treatment method is: by controlling the contact time between the solution containing the modifier and the biocomposite material, the contact time is 9 min-11 min.

[0088] In some embodiments, the drying temperature is 30° C.-40° C., and the drying time is 1.5 h-2.5 h.

[0089] In a third aspect, some embodiments of the present invention also provide use of the biocomposite material in degrading fungal toxins.

[0090] In some embodiments, the fungal toxin is zearalenone.

[0091] The following is a detailed description of the embodiments and comparative examples: Embodiment 1: 2-Methylimidazole (2.74 g) and 3 mg CTAB (cetyltrimethylammonium bromide) were dissolved in 80 mL ultrapure water, and then Co(NO 3 ) 2 (0.174 g), Mn(NO 3 ) 2 (0.04 g), FeCl 2 (0.04 g). The color of the solution quickly turned purple. After stirring the reaction solution with a magnetic stirrer at room temperature for 2 hours, the solution was centrifuged at 10,000 rpm for 10 minutes to collect the precipitate. Finally, the product was rinsed with ultrapure water three times and dried at 85 ° C for 6 hours to obtain the metal organic framework Fe / Mn-ZIF67; The metal organic framework (100 mg) was dissolved in 100 mL of PBS buffer, 33 mg of glucose oxidase was added, the precipitate was centrifuged and filtered, washed with ultrapure water three times, and then the obtained solid was dried at 35 °C for 6 hours to obtain the product Fe / Mn-ZIF67@GOx; The obtained Fe / Mn-ZIF67@GOx (10 mg) powder was dispersed in 10 g of washed Rhizopus oryzae mycelium by suction filtration to obtain a biofilm mixture. The biofilm mixture was then placed in a petri dish and transferred to an oven (60 ° C) for 12 hours to obtain a biocomposite Fe / Mn-ZIF67@GOx / biofilm.

[0092] The obtained Fe / Mn-ZIF67@GOx / biofilm composite material was positively charged modified using polyethyleneimine (PEI) CTAB (cetyltrimethylammonium bromide). The modifier (5 mg / mL) was dissolved in water, and the biocomposite was treated with 10 mL of the modifier solution by vacuum filtration for 10 min, and then vacuum dried at 35 °C for 2 h. It was recorded as BTGP.

[0093] Embodiment 2: The preparation method of Example 2 is the same as that of Example 1, but the modifier used in Example 2 is CTAB (cetyltrimethylammonium bromide), and other parameters are the same as those of Example 1, which are denoted as BTGB.

[0094] Embodiment 3: The preparation method of Example 3 is the same as that of Example 1, but the modifier used in Example 3 is hexadecyltrimethylammonium chloride (CTAC), and other parameters are the same as those in Example 1, which are recorded as: BTGC.

[0095] Comparative Example 1: The preparation method of Comparative Example 1 is the same as that of Example 1, except that the preparation of the metal organic framework of Comparative Example 1 is as follows: 2-Methylimidazole (2.74 g) and 3 mg CTAB (cetyltrimethylammonium bromide) were dissolved in 80 mL ultrapure water, and then Co(NO 3 ) 2 (0.174 g). The color of the solution quickly turned purple. After stirring the reaction solution at room temperature for 2 hours with a magnetic stirrer, the solution was centrifuged at 10,000 rpm for 10 minutes to collect the precipitate. Finally, the product was rinsed with ultrapure water three times and dried at 85°C for 6 hours to obtain the metal organic framework ZIF67.

[0096] Comparative Example 2: The preparation method of Comparative Example 2 is the same as that of Example 1, except that the preparation of the metal organic framework of Comparative Example 2 is as follows: 2-Methylimidazole (2.74 g) and 3 mg CTAB (cetyltrimethylammonium bromide) were dissolved in 80 mL ultrapure water, and then Co(NO 3 ) 2 (0.174 g), Mn(NO 3 ) 2 (0.04 g). The color of the solution quickly turned purple. After stirring the reaction solution at room temperature for 2 hours with a magnetic stirrer, the solution was centrifuged at 10,000 rpm for 10 minutes to collect the precipitate. Finally, the product was rinsed with ultrapure water three times and dried at 85°C for 6 hours to obtain the metal organic framework Mn-ZIF67.

[0097] Comparative Example 3: The preparation method of Comparative Example 3 is the same as that of Example 1, but no modifier is used in Comparative Example 3, and other methods are the same as those of Example 1, which is denoted as BTG.

[0098] The obtained embodiments and comparative examples were tested: (1) Peroxidase activity test: The behavior of peroxidase mimics (PODs) of metal-organic frameworks is revealed by their H 2 O 2 The ability to catalyze the oxidation of TMB colorimetric solution (3,3',5,5'-tetramethylbenzidine colorimetric solution) to produce blue oxTMB (oxidized 3,3',5,5'-tetramethylbenzidine) in the presence of 20 μL of MOF was evaluated. The steps were as follows: TMB (1-200 μM, 20 μL), MOF (1 mg / mL, 20 μL), and 50 μL of H 2 O 2 (1mM) solution. Use a microplate reader to measure the absorbance at 650nm at different time points. Substitute into the Michaelis-Menten equation: ; Where V is the reaction rate; V max is the maximum reaction rate; [S] is the substrate concentration; K m is the Michaelis-Menten constant. According to the Lineweaver-Burk method, the Michaelis-Menten equation can be rearranged into a double reciprocal plot to obtain Km and Vmax.

[0099] (2) Degradability test: 1 mg of the MOF material prepared in Example 1 and Comparative Examples 1-2, and 10 mg of the biofilm prepared in Example 2 were added to 2 µg / mL of ZEN (zearalenone), and 100 mM of glucose solution was added. After incubation for 60 minutes, the MOFs or biofilms were separated by centrifugation at a relative centrifugal force (RCF) of 12,000 g for 1 minute in a microcentrifuge. Then, 0.2 mL of the liquid supernatant was filtered through a 0.22 μm filter and stored at 4 ° C for HPLC analysis.

[0100] The ZEN concentration was then analyzed by HPLC. The excitation and emission wavelengths were 274 nm and 440 nm, respectively. The analysis was performed under isocratic conditions at a flow rate of 1.0 mL / min, with ultrapure water and acetonitrile (50:50, v / v) as mobile phase A and methanol as mobile phase B, and the flow rate was set to 1 mL / min.

[0101] Results and analysis: The biocomposite material was successfully prepared according to the method of the present invention. The preparation process is as follows: Figure 1 As shown. In the present invention, glucose oxidase is loaded on the metal organic framework structure. First, the pore structure of the metal organic framework and the porous structure of the Rhizopus oryzae mycelium are conducive to the adsorption of mycotoxins in food, and the mycotoxins are adsorbed into the biocomposite material. Figure 2The morphological characteristics of the metal organic frameworks of Example 1 and Comparative Examples 1-2 were characterized by scanning electron microscopy. Figure 2 The metal organic frameworks obtained in the examples and comparative examples are both dodecahedral structures with an average size of about 1 μm. Compared with comparative example 1, examples 1 and comparative example 2 have rougher surfaces, which increases the specific surface area of ​​the metal organic framework material obtained in example 1, thereby facilitating the expansion of the contact surface between the metal organic framework and the fungal toxins and improving the adsorption and degradation performance.

[0102] The element distribution and EDS spectra of Example 1 and Comparative Example 1-Comparative Example 2 are as follows Figure 3 As shown. The C, O, N, and Co elements in the product were observed and evenly distributed in the material, confirming the successful preparation of the metal organic framework. In addition, Fe and Mn elements were observed in the Fe / Mn-ZIF67 material, further confirming the successful synthesis of the metal organic framework material in Example 1.

[0103] Figure 4 It was observed that the metal organic frameworks in the examples and comparative examples had typical IV type N2 adsorption isotherms, and when the relative pressure was greater than 0.4, an H3 type hysteresis loop began to appear, indicating the presence of mesopores, and the mesopore distribution was relatively wide. When the relative pressure was close to 1, the adsorption amount had a large jump, which may be due to the presence of macropores. The specific surface area of ​​Example 1 was 834.72 m 2 / g and an average pore volume of 0.38 cm 3 / g, the specific surface area of ​​comparative example 1 is 400.79m 2 / g and an average pore volume of 0.23 cm 3 / g, the specific surface area of ​​comparative example 2 is 269.14m 2 / g and an average pore volume of 0.20cm 3 / g, it can be seen that the metal organic framework obtained in Example 1 can provide sufficient adsorption sites.

[0104] exist Figure 5 In A, the ZEN removal efficiencies of the metal organic framework treated systems obtained in Example 1 and Comparative Examples 1-2 were 57.5%, 48.4%, and 51.6%, respectively. It can be found that the removal rate of Example 1 is significantly higher than that of Comparative Examples 1 and 2. This is because the metal ion Mn is the active center of the natural enzyme, and the introduction of Fe can adjust the bond strength between the central metal atom and the ligand molecule, showing a synergistic enhancement of substrate affinity and electron transfer ability, thereby improving its ability to degrade fungal toxins by enhancing the peroxidase-like activity. Figure 5In B, the removal efficiency of ZEN of the system treated with the metal organic framework obtained in Example 1, Examples 1 to 3 and Comparative Example 3 was 57.5%, 96.9%, 82.8%, 85.9% and 75%, respectively. First, the glucose oxidase loaded on the surface of the metal organic framework produces hydrogen peroxide due to the addition of glucose, thereby activating the peroxidase-like effect of the metal organic framework, thereby degrading the fungal toxins adsorbed in the biocomposite material; secondly, the pore structure of the metal organic framework and the porous structure of the Rhizopus oryzae mycelium are conducive to the adsorption of fungal toxins in food, and the fungal toxins are adsorbed in the biocomposite material, which is conducive to degradation; finally, the addition of the modifier is because the modifier can realize the positive charge of the biocomposite film, so that the biocomposite film can adsorb more fungal toxins, which is conducive to the degradation in the later stage. Figure 5 A and Figure 5 B further compared and found that the design of the product of the present invention can successfully activate the peroxidase-like effect of the metal organic framework, thereby reducing fungal toxins. Figure 5 It was further found in B that different modifiers have different improvement effects, among which the composite biofilm BTGP modified with PEI is the best because it has a higher positive charge, which is more conducive to the adsorption of more fungal toxins. Therefore, PEI is further preferred as the modifier. Figure 5 C shows the removal amount of ZEN by the metal organic framework obtained in Example 1, Examples 1 to 3 and Comparative Example 3. After 60 minutes of degradation, BTGP can achieve a removal amount of 2 mg / g. It can be seen that the composite biofilm obtained by the present invention has the effect of degrading fungal toxins.

[0105] The BTGP biofilm recovered above was rinsed several times with ultrapure water, dried at 35°C for 12 hours, and then subjected to the next cycle test. The results showed that after 6 consecutive cycles, the degradation rate of OTA remained above 89% ( Figure 5 D). The slight decrease in degradation efficiency may be due to the adsorption of the matrix on the biofilm surface and the natural decomposition of the biofilm during the cleaning process. It can be seen that the biocomposite membrane of the present invention can be reused and still maintains a good degradation effect after 6 cycles.

[0106] In summary, the biocomposite membrane of the present invention can degrade fungal toxins in edible oil.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A biocomposite material, characterized in that: The biocomposite material comprises a base film, a metal organic framework is uniformly dispersed in the base film, and glucose oxidase is loaded on the surface of the metal organic framework.

2. The biocomposite material according to claim 1, characterized in that The basement membrane is the mycelium of Rhizopus oryzae; The metal organic framework has Co, Mn, and Fe metal ions; The biocomposite material is positively charged.

3. The method for preparing the biocomposite material according to any one of claims 1 to 2, characterized in that: The preparation method comprises: Step 1: Preparation of metal organic framework; Step 2: Loading glucose magnesium oxide on the surface of the metal mailing frame; Step 3: uniformly dispersing the metal organic framework loaded with glucose oxidase in the base film to obtain a biocomposite material; Step 4: Positively charging the biocomposite.

4. The preparation method according to claim 3, characterized in that: In step 1, the specific method for preparing the metal organic framework includes: Cobalt nitrate, manganese nitrate and ferrous chloride are added to a solution containing 2-methylimidazole and hexadecyltrimethylammonium bromide. After the solution turns purple, it is stirred at room temperature to separate the solid and liquid. The separated solid is washed and dried.

5. The preparation method according to claim 4, characterized in that: In a solution containing 2-methylimidazole and hexadecyltrimethylammonium bromide, the mass concentration of 2-methylimidazole is 32 mg / mL-36 mg / mL; In a solution containing 2-methylimidazole and hexadecyltrimethylammonium bromide, the mass concentration of hexadecyltrimethylammonium bromide is 0.02 mg / mL-0.04 mg / mL; The mass concentration of the cobalt nitrate in the solution containing 2-methylimidazole and hexadecyltrimethylammonium bromide is 2 mg / mL-3 mg / mL; The mass concentration of the manganese nitrate in the solution containing 2-methylimidazole and hexadecyltrimethylammonium bromide is 0.4 mg / mL-0.6 mg / mL; The mass concentration of ferrous chloride in the solution containing 2-methylimidazole and hexadecyltrimethylammonium bromide is 0.4 mg / mL-0.6 mg / mL; The stirring time is 1.5h-2.5h; The drying temperature is 80°C-90°C, and the drying time is 5h-7h.

6. The preparation method according to claim 3, characterized in that: In step 2, the specific method of loading glucose magnesium oxide on the surface of the metal organic framework includes: adding glucose oxidase to a solution containing the metal organic framework, filtering, washing, and drying.

7. The preparation method according to claim 6, characterized in that: In the solution containing the metal organic framework, the mass concentration of the metal organic framework is 0.8 mg / mL-1.2 mg / mL; The mass concentration of the glucose oxidase in the solution containing the metal organic framework is 30 mg / 100 mL-36 mg / 100 mL; The ratio of the glucose oxidase-loaded metal-organic framework to the R. oryzae mycelium was 1:1000 by mass; The drying temperature is 30°C-40°C, and the drying time is 5h-7h.

8. The preparation method according to claim 3, characterized in that: In the step 3, the specific method of uniformly dispersing the metal organic framework loaded with glucose oxidase in the basement membrane includes: uniformly dispersing the metal organic framework loaded with glucose oxidase in the mycelium of Rhizopus oryzae, and then performing heat treatment to obtain a biocomposite material; The temperature of the heat treatment is 55° C.-65° C., and the time of the heat treatment is 11 h-13 h.

9. The preparation method according to claim 3, characterized in that: In step 4, the specific method of making the biocomposite material positively charged includes: modifying the biocomposite material; The specific method of the modification treatment includes: treating the biocomposite material with a solution containing a modifier, and drying; The mass concentration of the modifier in the solution containing the modifier is 4.5 mg / mL-5.5 mg / mL; The modifier includes one or more of hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, and polyethyleneimine; The treatment method is as follows: by controlling the contact time between the solution containing the modifier and the biocomposite material, the contact time is 9 minutes to 11 minutes; The drying temperature is 30°C-40°C, and the drying time is 1.5h-2.5h.

10. Use of the biocomposite material according to any one of claims 1 to 2 or the biocomposite material obtained by the preparation method according to any one of claims 3 to 9 in degrading mycotoxins in food.

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