A dipeptidyl peptidase dpp iii capable of simultaneously degrading aflatoxin b1 and zearalenone, a coding gene and application thereof

Abstract

The application belongs to the technical field of enzyme engineering, and relates to degradation of aflatoxin B1 and zearalenone, in particular to a dipeptidyl peptidase DPP III, a coding gene, an engineering bacterium and an enzyme preparation and application thereof. The dipeptidyl peptidase DPP III has a similarity of more than 70% to the amino acid sequence shown in SEQ ID No. 1. The enzyme can simultaneously degrade AFB1 and ZEN, and the degradation rates of AFB1 and ZEN can reach 98.08% and 98.80% respectively. The enzyme can degrade AFB1 in peanut meal and corn meal contaminated by aspergillus flavus, and the degradation rates can reach 88.2% and 89.9% respectively. The dipeptidyl peptidase DPP III coding gene, the engineering bacterium and the enzyme preparation thereof provide important theoretical and technical support for detoxification of mycotoxins in the field of food and feed.

Description

Technical Field

[0001] This invention belongs to the field of enzyme engineering technology and relates to the degradation of aflatoxin B1 and zearalenone, specifically a dipeptidyl peptidase DPP III, its encoding gene, engineered bacteria, enzyme preparations, and applications. Background Technology

[0002] Fungal toxins are mainly secondary metabolites produced by filamentous fungi such as Fusarium, Aspergillus, and Penicillium. They mainly include deoxynivalenol, zearalenone, aflatoxin, fumonisin, and ochratoxin, among which aflatoxin and zearalenone are the most common.

[0003] Aflatoxin B1 (AFB1) is a toxin produced by Aspergillus flavus (…). Aspergillus flavus ) and parasitic aspergillus ( Aspergillus parasiticus Secondary metabolites produced by AFB1 are widely detected during grain processing, transportation, and storage. AFB1 exhibits high levels of carcinogenicity, teratogenicity, hepatotoxicity, nephrotoxicity, and immunotoxicity. It can cause cytotoxicity through various mechanisms, such as intracellular reactive oxygen species accumulation, oxidative stress, lipid peroxidation, mitochondrial dysfunction, autophagy, and apoptosis. Furthermore, AFB1 can further affect the body's energy supply by disrupting the metabolic pathways of the gut microbiota, thereby leading to certain metabolic diseases. In 1993, the International Agency for Research on Cancer (IARC) classified AFB1 as a Group 1 chemical carcinogen. AFB1 contamination of various food and feed products not only causes enormous economic losses but also poses serious food safety and human health problems.

[0004] Zearalenone (ZEN) is a fungal toxin produced by Fusarium wilt, widely distributed in corn, wheat, barley, sorghum, and other grain feeds and their byproducts. ZEN has a high melting point of 161-163℃ and exhibits excellent chemical stability and temperature resistance, remaining stable even at high temperatures during storage and resisting decomposition. ZEN's structure is similar to natural estrogen, allowing it to bind to estrogen receptors in the body and act as a non-steroidal estrogen, disrupting reproductive hormones regulated by hormone-related genes and the testicular development system. ZEN can also induce genotoxicity, hepatotoxicity, immunotoxicity, and cytotoxicity through oxidative damage, endoplasmic reticulum stress, mitochondrial apoptosis, and autophagy.

[0005] Detoxification of AFB1 and ZEN in food and feed products typically employs three main strategies: physical, chemical, and biological methods. Physical methods include sorting, grinding, washing, microwave heating, cooking, baking, ultraviolet irradiation, gamma irradiation, and photocatalysis, while chemical methods transform AFB1 and ZEN through chemical reactions such as alkaline hydrolysis, ammoniation, ozonation, and peroxidation. Physical and chemical methods have been found to be effective in detoxifying AFB1 and ZEN; however, the toxicity of the final product and food properties, such as nutritional value, sensory characteristics, and palatability, remain questionable. Therefore, biological detoxification methods have become the most promising alternative for the purification of AFB1 and ZEN in feed and food. Biological detoxification via microorganisms can be carried out under mild conditions, minimizing the loss of nutritional value and other food properties. Enzymatic biodegradation alters AFB1 and ZEN into less toxic or non-toxic structures, thereby achieving detoxification.

[0006] In 1998, Liu et al. first reported the origin of Armillariella tabescens Aflatoxin oxidase (AFO) is an enzyme that degrades AFB1 by oxidizing the furan ring double bond. Laccases from different sources have also been found to degrade AFB1, such as those derived from... Pleurotus pulmonarius Lac2 and Pleurotus eryngii Ery4. (Source: [Original Source Name]) Rhodococcus jostii The dye decolorizing peroxidase Rh_DypB can convert AFB1 to AFQ1. (Source: [Original Source Name]) Mycobacterium smegmatis F 420 H2-dependent reductases reduce α,β-unsaturated esters, leading to instability and eventual cleavage of the lactone ring. (Source: [Original Source Name]) Aeromicrobium sp. The hydrolase ZenH breaks the ester bond of ZEN, forming a low-toxicity degradation product. (Source: [Original Source Name]) Monosporascus sp. The lactonease ZENM of GIB2 can effectively degrade ZEN. To date, most reported degrading enzymes can only degrade specific types of mycotoxins, and this specificity limits their effectiveness in practical applications. Therefore, the search for and identification of new broad-spectrum enzymes for the biodegradation of mycotoxins is urgently needed. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention proposes a dipeptidyl peptidase DPP III, its encoding gene, engineered bacteria, its enzyme preparation, and its applications.

[0008] The technical solution of this invention is implemented as follows:

[0009] A dipeptidyl peptidase DPP III has an amino acid sequence similarity of more than 70% to that shown in SEQ ID No. 1. Amino acid sequences with an amino acid sequence similarity of more than 70% to that of this application can retain the degradation function of the dipeptidyl peptidase DPP III of this application.

[0010] Furthermore, the amino acid sequence of the aforementioned dipeptidyl peptidase DPP Ⅲ is shown in SEQ ID No. 1.

[0011] The gene encoding the dipeptidyl peptidase DPP Ⅲ mentioned above.

[0012] Furthermore, the aforementioned gene has a nucleotide sequence similarity of more than 90% with the nucleotide sequence shown in SEQ ID No. 2. A nucleotide sequence having a nucleotide sequence similarity of more than 90% with the nucleotide sequence of this application can express the amino acid sequence of this application. For example, as shown in SEQ ID No. 3, it is a nucleotide sequence optimized from the E. coli codons, and its sequence has a similarity of more than 90% with the gene sequence shown in SEQ ID No. 2.

[0013] Preferably, the nucleotide sequence of the above-mentioned gene is shown in SEQ ID No. 2 or SEQ ID No. 3.

[0014] Recombinant plasmids containing the genes mentioned above.

[0015] Engineered bacteria containing the aforementioned recombinant plasmids.

[0016] Dipeptidyl peptidase DPP III can be applied to the detoxification of aflatoxin B1 and zearalenone.

[0017] The temperature range for dipeptidyl peptidase (DPP) III to degrade aflatoxin B1 and zearalenone is 20-80℃, and the pH range is 5.0-10.0.

[0018] The optimal temperature for dipeptidyl peptidase DPP III to degrade aflatoxin B1 is 40°C and the optimal pH is 7.0.

[0019] Dipeptidyl peptidase DPP III can maintain a degradation rate of over 80% for aflatoxin B1 within a temperature range of 40-80℃.

[0020] The optimal temperature for dipeptidyl peptidase DPP III to degrade zearalenone in zearalenone is 60℃ and the optimal pH is 8.0.

[0021] Dipeptidyl peptidase DPP III can maintain a degradation rate of over 85% for aflatoxin B1 within a temperature range of 50-80℃.

[0022] Dipeptidyl peptidase DPP III is an enzyme preparation.

[0023] Preferably, the addition amounts of dipeptidyl peptidase DPP III for peanut meal and corn flour contaminated with Aspergillus flavus are 200 µg / mL and 400 µg / mL, respectively.

[0024] This enzyme preparation can effectively degrade AFB1 in peanut meal and corn flour contaminated with Aspergillus flavus.

[0025] Preferably,

[0026] The application of biomaterials in the degradation of fungal toxins is characterized by degradation rates of 98.08% and 98.80% for aflatoxin B1 and zearalenone, respectively.

[0027] The present invention has the following beneficial effects:

[0028] 1. This application discloses an AFB1 degrading enzyme—dipeptidyl peptidase DPP III—with an optimal temperature of 40°C and pH of 7.0 for AFB1 degradation. This enzyme achieves a degradation rate of up to 98.08% for AFB1. Furthermore, dipeptidyl peptidase DPP III can maintain a degradation rate of over 80% for aflatoxin B1 within a temperature range of 40-80°C, making it an AFB1 degrading enzyme capable of withstanding a certain degree of high temperature. This invention provides a promising candidate for AFB1 detoxification in the food and feed industries.

[0029] 2. Grains are often easily contaminated with AFB1, especially peanut meal and corn flour. Dipeptidyl peptidase DPP III has a degradation rate of 88.2% and 89.9% for AFB1 in peanut meal and corn flour contaminated with Aspergillus flavus, respectively. Dipeptidyl peptidase DPP III offers a promising application prospect for the purification of AFB1 in food or feed.

[0030] 3. This enzyme can also effectively degrade ZEN, with a degradation rate of up to 98.80%. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 The plasmid map is for pET-28a(+).

[0033] Figure 2 The image shows the recombinant plasmid map of pET-28a(+)-DPP Ⅲ.

[0034] Figure 3This is an SDS-PAGE validation image of dipeptidyl peptidase DPP Ⅲ, where M: standard protein marker; P: purified protein.

[0035] Figure 4 The degradation rates of AFB1 and ZEN by dipeptidyl peptidase DPP Ⅲ under different metal ion conditions are shown.

[0036] Figure 5 The degradation rates of AFB1 and ZEN by dipeptidyl peptidase DPP Ⅲ under different pH conditions are shown.

[0037] Figure 6 The degradation rates of AFB1 and ZEN by dipeptidyl peptidase DPP Ⅲ under different temperature conditions are shown.

[0038] Figure 7 The degradation rates of AFB1 and ZEN were measured by different amounts of dipeptidyl peptidase DPP Ⅲ.

[0039] Figure 8 The degradation rates of AFB1 and ZEN by dipeptidyl peptidase DPP Ⅲ at different reaction times are shown.

[0040] Figure 9 The HPLC analysis results show the degradation of AFB1 in peanut meal contaminated with Aspergillus flavus by dipeptidyl peptidase DPP III (A is the control group without the addition of dipeptidyl peptidase DPP III, B is the treatment group with the addition of dipeptidyl peptidase DPP III at 200 µg / mL, and C is the treatment group with the addition of dipeptidyl peptidase DPP III at 400 µg / mL).

[0041] Figure 10 The HPLC analysis results show the degradation of AFB1 in corn flour contaminated with Aspergillus flavus by dipeptidyl peptidase DPP III (A is the control group without the addition of dipeptidyl peptidase DPP III, B is the treatment group with the addition of dipeptidyl peptidase DPP III at 200 µg / mL, and C is the treatment group with the addition of dipeptidyl peptidase DPP III at 400 µg / mL).

[0042] Figure 11 The retention time of the degradation products of AFB1 by dipeptidyl peptidase DPP Ⅲ is given.

[0043] Figure 12 This is a secondary mass spectrum of the degradation products of AFB1 by dipeptidyl peptidase DPP Ⅲ. Detailed Implementation

[0044] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0045] Biomaterials:

[0046] Strains: Escherichia coli DH5α, Escherichia coli BL21(DE3), purchased from Sangon Biotech (Shanghai) Co., Ltd.

[0047] Culture medium:

[0048] LB medium: 10 g·L -1 Tryptone, 5 g·L -1 Yeast extract, 10 g·L -1 Sodium chloride, pH 7.0-7.2.

[0049] Experimental reagents: AFB1 standard sample was purchased from Sigma-Aldrich; other reagents were domestically produced analytical grade.

[0050] Example 1: Preparation of recombinant Escherichia coli BL21(DE3)

[0051] The dipeptidyl peptidase DPP Ⅲ encoding gene, as shown in SEQ ID No. 2, was synthesized by Sangon Biotech (Shanghai) Co., Ltd., and codon optimization was performed based on the preference of Escherichia coli BL21(DE3). The optimized sequence is shown in SEQ ID No. 3. A restriction enzyme site Sac I was introduced at the 5' end of the encoding gene, and a restriction enzyme site Not I was introduced at the 3' end.

[0052] The amino acid sequence of this gene is shown in SEQ ID No. 1. The gene with the nucleotide sequence shown in SEQ ID No. 3 was ligated into the *E. coli* expression vector pET-28a(+). Figure 1 At the corresponding site, the recombinant plasmid pET-28a(+)-DPP Ⅲ was obtained (e.g. Figure 2 (As shown). The obtained recombinant plasmid was added to E. coli DH5α competent cells, heat-shocked in a 42℃ water bath for 45 seconds, and then immediately placed on ice to cool for 2-3 minutes. The recombinant product was then transformed. For the correctly transformed strains, the plasmid was extracted and introduced into the E. coli expression strain BL21(DE3) using the heat shock method. Positive clones were screened using LB agar plates containing kanamycin and verified by bacterial PCR to obtain recombinant E. coli that successfully expressed dipeptidyl peptidase DPP Ⅲ.

[0053] The PCR amplification system and amplification procedure are shown in Tables 1 and 2.

[0054] Table 1 PCR amplification system

[0055]

[0056] Table 2 PCR amplification program

[0057]

[0058] Example 2: Induction and purification of dipeptidyl peptidase DPPⅢ

[0059] 1. Inducible expression of dipeptidyl peptidase DPP-III

[0060] Escherichia coli BL21(DE3) / pET-28a(+)-DPP Ⅲ was inoculated into 25 mL of LB medium and cultured at 37°C with shaking at 200 rpm for 12 h. Then, it was inoculated into 200 mL of LB liquid medium at a 2% inoculation rate and cultured at 37°C with shaking at 200 rpm until OD600 = 0.6~0.8. Finally, IPTG was added to a final concentration of 0.1 mM and induced at 16°C for 20 h.

[0061] 2. Purification of dipeptidyl peptidase DPP-III

[0062] Collect the induced bacterial culture, centrifuge at 8000 rpm for 10 min at 4℃, and discard the supernatant. Resuspend the bacterial cells in 10 mL of equilibration buffer, sonicate for 30 min under ice bath conditions (sonication power 300 W, sonication on for 4 s, sonication off for 4 s), centrifuge at 12000 rpm for 10 min at 4℃, collect the supernatant and filter it through a 0.45 µm aqueous filter membrane. Then, purify the protein using a nickel-NTA column with a prepared 200 mM imidazole elution buffer, collect the eluent, and ultrafilter the eluent through a 10 kDa ultrafiltration tube at 4000 rpm for 30 min at 4℃ to remove imidazole, obtaining the purified protein. The purification effect of the purified protein was detected by SDS-PAGE gel electrophoresis, and the results are shown below. Figure 3 As shown.

[0063] Analysis of implementation effect: The degradation of AFB1 by the purified dipeptidyl peptidase DPPⅢ prepared in Example 2

[0064] The protein purified in Example 2 was analyzed for protein concentration using a Bradford protein assay kit and stored at 4°C for later use. The degradation of AFB1 by dipeptidyl peptidase DPP III was carried out in a 500 µL system containing 5.0 μg / mL AFB1, 20 µg dipeptidyl peptidase DPP III protein, and 50 mM Tris-HCl buffer (containing 0.5 mM metal ions, pH 7.0). After co-incubation for 24 h, the reaction was terminated by adding 500 µL of methanol. The system was thoroughly mixed and filtered through a 0.22 μm organic filter membrane. The AFB1 content was determined by high-performance liquid chromatography (HPLC).

[0065] The chromatographic conditions for detecting AFB1 using high performance liquid chromatography were as follows: column: Proshell 120-C18 column (150 × 4.6 mm, 4 μm); UV detector: detection wavelength 365 nm; flow rate: 1 mL / min; injection volume: 10 µL; acquisition time: 10 min; column temperature: 35℃; mobile phase: methanol:acetonitrile:water = 1:1:3 (v / v / v).

[0066] The AFB1 degradation rate is calculated using the following formula:

[0067] Degradation rate = ×100%.

[0068] The pH of the reaction system was adjusted to 7.0, the temperature was controlled at 40℃, and 0.5 mM Zn was added. 2+ , Mn 2+ Mg 2+ Co 2+ Cu 2+ ,Depend on Figure 4 A indicates that in Cu 2+ In its presence, dipeptidyl peptidase DPP Ⅲ degrades AFB1.

[0069] In enzymatic reactions, the pH and temperature of the reaction system have a significant impact on enzyme activity. In this example, the pH and temperature of the reaction system were varied to detect the effect of dipeptidyl peptidase DPP III on the degradation rate of AFB1. After determining the optimal pH and reaction temperature, the amount of dipeptidyl peptidase DPP III added was optimized accordingly. The specific steps are as follows:

[0070] Adjust the pH of the reaction system to 5.0-10.0 and control the temperature at 40℃. Figure 5 As shown in A, the degradation rate of AFB1 was highest at pH 7.0, with a degradation rate of 97.11% after 24 hours.

[0071] The reaction temperature was adjusted to 20-90℃ at pH=7.0. Figure 6 As shown in A, the degradation rate of AFB1 reaches its highest at 40℃, and maintains a degradation rate of over 80% within the range of 40-80℃.

[0072] The pH of the reaction system was adjusted to 7.0, and the temperature was controlled at 40℃. The amounts of dipeptidyl peptidase (DPPⅢ) added were 10, 20, 30, 40, 50, and 60 µg, respectively. The results are as follows: Figure 7 As shown in Figure A, the degradation rate of AFB1 by dipeptidyl peptidase DPP III increases with the increase of the amount of dipeptidyl peptidase DPP III, but the increasing trend gradually slows down. From an economic point of view, the optimal enzyme amount is 20 µg.

[0073] The degradation rate of AFB1 at different reaction times was investigated under the conditions of pH 7.0, temperature 40℃, and enzyme addition of 20 µg. The results are as follows: Figure 8 As shown in Figure A, the degradation rate of AFB1 increases with time, reaching 98.08% at 30 h.

[0074] Analysis of Implementation Results: The degradation of ZEN by the purified dipeptidyl peptidase DPPⅢ prepared in Example 2

[0075] The degradation of ZEN by dipeptidyl peptidase (DPP) III was carried out in a 500 µL system containing 10 μg / mL ZEN, 20 µg DPP III protein, and 50 mM Tris-HCl buffer (containing 0.5 mM metal ions, pH 7.0). After co-incubation for 24 h, the reaction was terminated by adding 500 µL of methanol. The system was thoroughly mixed and filtered through a 0.22 μm organic filter membrane. The ZEN content was determined by high-performance liquid chromatography (HPLC).

[0076] The chromatographic conditions for detecting AFB1 using high performance liquid chromatography (HPLC) were as follows: column: Proshell 120-C18 column (150 × 4.6 mm, 4 μm); fluorescence detector: excitation wavelength 235 nm, emission wavelength 470 nm; flow rate: 1 mL / min; injection volume: 10 µL; acquisition time: 5 min; column temperature: 35℃; mobile phase: methanol:water = 4:1 (v / v).

[0077] The pH of the reaction system was adjusted to 7.0, the temperature was controlled at 40℃, and 0.5 mM Zn was added. 2+ , Mn 2+ Mg 2+ Co 2+ Cu 2+ ,Depend on Figure 4 B indicates that in Cu 2+ In the presence of these enzymes, dipeptidyl peptidase (DPP) III exhibits the best degradation effect on ZEN.

[0078] Adjust the pH of the reaction system to 5.0-10.0 and control the temperature at 40℃. Figure 5 As shown in B, the degradation rate of ZEN is highest at pH 8.0, with a degradation rate of 75% after 24 hours.

[0079] The reaction temperature was adjusted to 20-80℃ at pH=8.0. Figure 6 As shown in B, the degradation rate of ZEN reaches its highest at 60℃, and maintains a degradation rate of over 80% within the range of 50-80℃.

[0080] The pH of the reaction system was adjusted to 8.0, and the temperature was controlled at 60℃. The amounts of dipeptidyl peptidase (DPPⅢ) added were 10, 20, 30, 40, 50, and 60 µg, respectively. The results are as follows: Figure 7 As shown in B, the degradation rate of ZEN by dipeptidyl peptidase DPP III increases with the increase of the amount of dipeptidyl peptidase DPP III, but the increasing trend gradually slows down. From an economic point of view, the optimal enzyme amount is 20 µg.

[0081] The degradation rate of ZEN at different reaction times was investigated under the conditions of pH 8.0, temperature 60℃, and enzyme addition of 20 µg. The results are as follows: Figure 8 As shown in B, the degradation rate of AFB1 increases with time, reaching 98.80% at 24 h.

[0082] Application example: Degradation of AFB1 in peanut meal and corn flour contaminated with Aspergillus flavus by dipeptidyl peptidase III.

[0083] Grind the peanut meal and corn flour and pass them through an 80-mesh sieve. First, weigh 10 grams of peanut meal or corn flour into a 100 mL Erlenmeyer flask, add 5 mL of distilled water and mix thoroughly with the peanut meal and corn flour, then sterilize at 121°C for 20 minutes.

[0084] Add 500 μL of Aspergillus flavus spore suspension (5 × 10⁻⁶) to each conical flask. 5 spores·mL -1 The enzyme solution was thoroughly mixed with the sample and incubated for 7 days. After 7 days, dipeptidyl peptidase DPP III was dissolved in buffer (50 mM Tris-HCl, 0.5 mM CuSO4, pH 7.0) to final concentrations of 200 and 400 µg / mL, respectively. 50 mL of enzyme solutions of different concentrations were added to peanut meal and corn flour samples, respectively. The control group consisted of 50 mL of buffer solution without dipeptidyl peptidase DPP III. After reacting at 40℃ and 150 rpm for 24 hours, the supernatant was obtained from the reaction system by sonication and centrifugation. AFB1 was extracted by adding 20 mL of dichloromethane.

[0085] After drying under a nitrogen stream, the solution was redissolved in 1 mL of mobile phase, and then AFB1 was detected by high-performance liquid chromatography. Figure 9 It was found that dipeptidyl peptidase III (DPP) achieved degradation rates of 73.7% and 88.2% for AFB1 in peanut meal contaminated with Aspergillus flavus, respectively. Figure 10 It can be seen that dipeptidyl peptidase DPP Ⅲ has a degradation rate of 77.2% and 89.9% for AFB1 in corn flour contaminated with Aspergillus flavus, respectively.

[0086] Example 3: Analysis of AFB1 degradation products by purified dipeptidyl peptidase DPPⅢ prepared in Example 2

[0087] The reaction system for preparing the degradation products was as follows: 2.5 μg / mL AFB1, 50 mM Tris-HCl, 0.5 mM CuSO4, and 20 μg protein, reacted in the dark for 24 h. The composition and structure of the degradation products were analyzed and identified using ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS). The chromatographic column was a CORTECS™ UPLC C18 column (100 × 2.1 mm, 1.6 μm), and the mobile phase was methanol and 0.1% (v / v) formic acid in water. Mass spectrometry was performed in electrospray ionization (ESI) mode, with a scan range of 100–800 nm. m / z .Depend on Figure 11 It can be seen that the retention time of the degradation products is 0.84 min, combined with secondary mass spectrometry. Figure 12 The molecular formula of the degradation products is C 16 H 14 Based on the structure of AFB1, it is inferred that the degradation product is AFD1. This degradation product is generated by the action of dipeptidyl peptidase DPP III on the lactone ring of AFB1, leading to ring-opening decarboxylation of AFB1 to form AFD1.

[0088] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dipeptidyl peptidase DPP Ⅲ, the amino acid sequence of which is shown in SEQ ID No.

1.

2. The gene encoding the dipeptidyl peptidase DPP Ⅲ as described in claim 1.

3. The gene encoding dipeptidyl peptidase DPP III according to claim 2, characterized in that: The nucleotide sequence of the gene is shown in SEQ ID No. 2 or SEQ ID No.

3.

4. A recombinant plasmid containing the gene as described in claim 2 or 3.

5. Engineered bacteria containing the recombinant plasmid as described in claim 4.

6. An enzyme preparation containing the dipeptidyl peptidase DPP Ⅲ as described in claim 1.

7. The application of a biomaterial in the degradation of aflatoxin B1 and zearalenone, characterized in that, The biomaterial is selected from any one or more combinations of the following: (1) The dipeptidyl peptidase DPP III as described in claim 1; (2) The gene encoding dipeptidyl peptidase DPP Ⅲ as described in claim 2 or 3; (3) The recombinant plasmid according to claim 4; (4) The engineered bacteria as described in claim 5; (5) The enzyme preparation according to claim 6.

8. The application of the biomaterial according to claim 7 in the degradation of aflatoxin B1 and zearalenone, characterized in that: The degradation temperatures for aflatoxin B1 and zearalenone are 20-80℃, and the pH ranges from 6.0 to 10.0.

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