Method for degrading resistant genes in penicillin fermentation residue

Abstract

This application provides a method for degrading antibiotic resistance genes in penicillin fermentation residue, comprising: Step S1, providing penicillin fermentation residue to be treated. The penicillin fermentation residue contains at least one target antibiotic resistance gene. Step S2, subjecting the penicillin fermentation residue to gamma ray irradiation treatment. This application addresses the problems of low removal rate of antibiotic resistance genes (ARGs), easy rebound, high treatment cost, and high risk of secondary pollution in existing penicillin fermentation residue treatment technologies by subjecting the penicillin fermentation residue to gamma ray irradiation treatment.

Description

Technical Field

[0001] This application belongs to the field of hazardous waste treatment technology, specifically relating to a method for degrading resistance genes in penicillin fermentation residue. Background Technology

[0002] The industrial production of penicillin antibiotics mainly relies on microbial fermentation. In large-scale bioreactors, strains such as Penicillium chrysogenum grow, multiply, and synthesize the target product. After fermentation, in addition to containing a large amount of penicillin, culture medium residues, mycelia, and metabolic byproducts also accumulate. The solid formed after filtration and separation—that is, antibiotic fermentation residue—generally has a moisture content of 70%–95%.

[0003] The high production volume has also brought severe environmental challenges. Statistics show that producing one ton of antibiotic raw material generates approximately 8–10 tons of wet fermentation residue. This residue not only contains hundreds of mg / kg of active antibiotics, exerting strong selective pressure on sensitive microbial communities in the environment, but also contains abundant and stable antibiotic resistance genes (ARGs). These ARGs can persist in the natural environment for a long time, accumulating diversity through gene mutation and natural selection; they can also achieve horizontal transfer via mobile genetic elements such as plasmids, transposons, integrons, or bacteriophages, spreading drug resistance to environmental pathogens, thus threatening human gut microbiota and public health. Furthermore, the sensitizing properties of penicillin mean that its residues may trigger eco-allergic reactions. Since 2002, my country's Ministry of Agriculture and Rural Affairs and other relevant departments have prohibited the use of this type of fermentation residue in animal feed. In 2008, antibiotic fermentation residue was included in the "National Hazardous Waste List" and is subject to strict management and disposal as pharmaceutical waste.

[0004] Currently, common disposal methods for antibiotic fermentation residue include adsorption, incineration, landfill, composting, anaerobic / aerobic digestion, and advanced chemical or thermophysical treatment technologies. However, these methods still have certain limitations in practical applications. High-temperature treatment, while effectively destroying antibiotic resistance genes (ARGs), may damage the nutrients in the residue. For example, patent CN117680476A (a method for removing antibiotics, resistance genes, and solvents from antibiotic fermentation residue) uses pyrolysis technology at 350℃~750℃ to completely degrade antibiotics, ARGs, and solvents in the residue. However, the high-temperature process easily mineralizes nutrients such as nitrogen and phosphorus, weakening its resource potential. Incineration can achieve volume reduction, but due to the high moisture content of the residue, a large amount of auxiliary fuel is required to maintain the combustion temperature, increasing energy consumption and potentially generating highly toxic dioxins during combustion. Even after treatment, the ARG fragments contained in the fly ash still have the potential for horizontal transfer. Landfill technologies, such as patent CN114195564A (a method for efficiently removing antibiotic resistance gene contamination from button mushroom cultivation waste) which utilizes button mushroom waste for landfilling, and patent CN119977719A (a method for reducing the bioavailability of heavy metals and the abundance of tetracycline resistance genes in organic fertilizer) which adds humic acid to reduce the bioavailability of tetracycline ARGs, are simple to operate, but they pose a risk of leachate pollution and only achieve the transfer of pollutant media, failing to prevent the long-term survival of ARGs in anaerobic environments. Aerobic composting and anaerobic digestion, among other biological treatment technologies, can effectively degrade small-molecule antibiotics, balancing resource utilization and pollution control. Patent CN119977639A (A method for enhancing the removal of antibiotic resistance genes during composting) optimizes the microbial community structure by inoculating Bacillus preparations during the composting cooling period, increasing the ARGs removal rate to 97.07%. Patent CN114195564A (A method for efficiently removing antibiotic resistance gene contamination from button mushroom cultivation waste) achieves a 70-80% ARGs removal rate while retaining organic matter through co-culturing with scarab beetle larvae or nano-biochar. Patent CN109879561A utilizes Aspergillus niger organic acid to rapidly complex ARGs and heavy metals within 20 hours. However, the above-mentioned biological methods generally suffer from long treatment cycles (50-60 days) or ARGs rebound during the maturation period. This is closely related to microbial community succession and the proliferation of mobile genetic elements (MGEs), indicating that traditional biological methods cannot effectively block the spread of antibiotic resistance.

[0005] Advanced oxidation technologies such as ozone oxidation, Fenton's reagent, and UV / TiO2 have shown potential in deep treatment by attacking the molecular structure of antibiotics with hydroxyl radicals (·OH). Patent CN119874423A (A method for removing antibiotics and resistance genes in aerobic composting of chicken manure) adds potassium persulfate / zero-valent iron to the compost to drive free radical reactions and reduce the abundance of high-risk ARGs; patent CN115073230A (A method for enhanced removal of antibiotic resistance genes in aerobic composting) uses a zero-valent iron / hydrogen peroxide-based Fenton system to achieve a 98% ARG removal rate; and patent CN114315441A (A method for enhanced removal of antibiotic resistance genes in aerobic composting) introduces ozone during the compost cooling period to reduce intracellular ARGs by 2.02 log. Despite these technologies achieving high removal rates, their practical application remains somewhat limited. For example, the need for continuous addition of chemical oxidants increases costs; reaction efficiency is limited by environmental parameters such as temperature and pH; and mass transfer limitations in the solid matrix lead to low oxidant utilization (e.g., in the UV / TiO2 system, insufficient solid penetration depth makes it difficult to ensure uniform treatment within the bacterial residue). The challenge is that even if the original carrier bacteria die, ARGs can exist in the environment as free DNA for a long time, and can still be taken up and expressed by other microorganisms, continuously spreading drug resistance through horizontal transfer. Existing technologies are therefore caught in a dilemma: drastic methods such as high-temperature incineration, aimed at completely removing ARGs, often damage the bacterial residue structure, resulting in the loss of resource value; while biological methods, which retain nutrients, are not stable enough and cannot prevent the risk of transmission. Summary of the Invention

[0006] In view of this, this application provides a method for degrading antibiotic resistance genes in penicillin fermentation residue. By treating the penicillin fermentation residue with gamma rays, this method solves the problems of low removal rate of antibiotic resistance genes (ARGs), easy rebound, high treatment cost, and high risk of secondary pollution in existing penicillin fermentation residue treatment technologies.

[0007] This application provides a method for degrading resistance genes in penicillin fermentation residue, which includes the following steps.

[0008] Step S1: Provide the penicillin fermentation residue to be treated. The penicillin fermentation residue contains at least one resistance gene for the target antibiotic.

[0009] Step S2: Treat the penicillin fermentation residue with gamma rays.

[0010] In one specific embodiment of this application, gamma rays are employed. 60 Co or 137 Cs.

[0011] In one specific embodiment of this application, the absorbed dose of gamma ray irradiation treatment ranges from 10 kGy to 50 kGy.

[0012] In one specific embodiment of this application, when the penicillin fermentation residue is subjected to gamma irradiation treatment, the penicillin fermentation residue is in the form of a solid-liquid mixture.

[0013] In one specific embodiment of this application, the moisture content of the penicillin fermentation residue is between 70% and 95%.

[0014] In one specific embodiment of this application, at least one target antibiotic resistance gene includes one or more of tetA(58), msbA, bcrA, and TaeA.

[0015] Compared with the prior art, the beneficial effects of the technical solution of this application are as follows: 1. Advantages of the mechanism of action: Unlike the physical destruction of pyrolysis (CN117680476A) or the chemical attack of oxidants (CN119874423A / CN115073230A), gamma rays break DNA chains directly or indirectly through water radiolysis via high-energy photons, which can inactivate ARGs and MGEs at the source.

[0016] 2. Process advantages: Gamma irradiation reaction conditions are mild and do not require high temperature, high pressure or chemical agents (compared to Fenton / persulfate system). High-penetrating rays can uniformly treat the inside of the bacterial residue (overcoming the limitation of ultraviolet penetration).

[0017] 3. Performance Objectives: To achieve the dual objectives of safe resource utilization by irradiating and partially degrading cellulose while retaining nitrogen, phosphorus, and organic matter to the maximum extent possible, and by irradiating and partially degrading cellulose to promote resource utilization.

[0018] In summary, this method provides a new approach to resolving the contradiction between "removal efficiency" and "resource retention" in antibiotic bacterial residue treatment, and offers a technically feasible and environmentally friendly solution for the safe disposal and recycling of antibiotic bacterial residue containing resistance genes. Attached Figure Description

[0019] Figure 1 The diagram shown is a flowchart illustrating a method for degrading resistance genes in penicillin fermentation residue according to an embodiment of this application.

[0020] Figure 2 The figure shown is a graph illustrating the relationship between the irradiation dose and the PG removal rate during the irradiation degradation of PG in bacterial residue according to an embodiment of this application.

[0021] Figure 3 The diagram shown is a schematic diagram of the degradation kinetics of PG in bacterial residue during irradiation degradation according to an embodiment of this application. Detailed Implementation

[0022] In the context of balancing removal efficiency and resource recovery value, ionizing irradiation technology has attracted much attention due to its unique mechanism and advantages. This technology utilizes high-energy rays to excite and ionize molecules, destroying the structure of pollutants through both direct and indirect pathways. A commonly used irradiation source is cobalt-60 (… 60 Cobalt-60 (Co) can release gamma rays of 1.17 MeV and 1.33 MeV, possessing extremely strong penetrating power. It can penetrate deep into bacterial substrates with high solid content, achieving uniform irradiation and efficient destruction of microorganisms and their genetic material. As a commonly used irradiation source, Cobalt-60... 60 The gamma rays emitted by Co have dual characteristic peaks of 1.17 MeV and 1.33 MeV, exhibiting extremely strong penetrating power. They can penetrate deep into high-solid-content matrices, uniformly irradiating and efficiently destroying microorganisms and genetic material. Their mechanism of action mainly includes the following three aspects: First, when gamma rays penetrate water-containing or solid bacterial residue, the secondary electrons generated through the Compton effect can directly ionize or excite DNA, generating base free radicals (DNA·). + First, gamma irradiation rapidly induces single- or double-strand breaks in DNA, causing resistance genes to lose their biological function. Second, reactive free radicals such as hydroxyl (·OH) generated during the radiolysis of water molecules during gamma irradiation react with DNA bases and deoxyribose, inducing base oxidation, sugar ring breakage, and strand breakage, forming multiple oxidative damage sites and further destroying the structure of ARGs. Third, gamma irradiation can effectively intervene in the horizontal transfer of ARGs by inhibiting the expression of key enzymes. When the cumulative dose reaches 30 kGy or more, the expression of integrase (intI1) and transposase (tnpA) is significantly downregulated; at a dose of 50 kGy, the degradation rate of different mobile genetic elements (MGEs) reaches 17.8%–74.5%, and irradiation can also increase MCFA yield by 132%, enhancing the resource value of bacterial residue.

[0023] Table 1. Comparison of key parameters between gamma irradiation and other ARGs removal technologies The above research revealed that gamma irradiation demonstrates efficient, safe, and environmentally friendly treatment potential for addressing the difficulty in completely removing resistance genes from penicillin fermentation residue. Based on this, at least one embodiment of this application proposes a method for degrading resistance genes in penicillin fermentation residue. This method for degrading resistance genes in penicillin fermentation residue is applicable to the harmless treatment of fermentation residue in the pharmaceutical industry, and is particularly suitable for removing residual penicillin resistance genes from penicillin fermentation residue.

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] refer to Figure 1 A method for degrading resistance genes in penicillin fermentation residue includes the following steps.

[0026] Step S1: Provide the penicillin fermentation residue to be treated. The penicillin fermentation residue contains at least one resistance gene for the target antibiotic.

[0027] It should be noted that penicillin fermentation residue (which can be simply referred to as residue) is mainly a solid-liquid mixture produced during the penicillin fermentation process. It is a solid or semi-solid waste rich in antibiotic residues, microbial cells, and antibiotic resistance genes formed therefrom. The resistance genes in penicillin fermentation residue specifically refer to gene fragments that confer penicillin resistance to microorganisms, such as tetA(58), msbA, bcrA, TaeA, etc.

[0028] Step S2: Treat the penicillin fermentation residue with gamma rays.

[0029] In the above embodiments, by treating the penicillin fermentation residue with gamma rays, it is possible to efficiently and stably remove ARGs and their carrier MGEs from the antibiotic fermentation residue, significantly reduce the toxicity of the penicillin fermentation residue, significantly reduce the abundance of the target antibiotic resistance genes after irradiation, and maximize the retention of the residue's nutrients to achieve safe resource utilization.

[0030] Furthermore, this method is carried out at room temperature and pressure, requires no chemical reagents, is simple to operate, does not produce secondary pollution, and effectively retains the nutrients (nitrogen, phosphorus, potassium, organic matter, etc.) in the bacterial residue, ensuring its resource value. The irradiated bacterial residue exhibits significantly reduced biotoxicity and can be safely used in feed or fertilizer production. Gamma ray irradiation provides an efficient and environmentally friendly approach to the harmless and resource-based treatment of bacterial residue. Simultaneously, irradiation treatment can alter the microbial community structure, inhibit mobile genetic elements (MGEs), and block the horizontal transfer pathway of ARGs.

[0031] In at least one embodiment of this application, gamma rays are employed 60 Co or 137 Cs.

[0032] For example, cobalt-60 gamma ray irradiation technology has high energy and strong penetrating power, enabling it to uniformly penetrate bacterial residue with high solids content. During irradiation, the secondary electrons generated by the Compton effect of gamma rays can induce single-strand or double-strand breaks in DNA, while the reactive free radicals such as hydroxyl groups released by the irradiation of water molecules oxidize and attack the bases and backbone of ARGs, further damaging resistance genes and degrading residual penicillin. When the cumulative dose is ≥30 kGy, the expression of intI1 integrase and tnpA transposase can be significantly downregulated, effectively blocking the horizontal transfer of drug resistance genes.

[0033] Using cobalt-60 gamma ionization irradiation technology, antibiotic residues, ARGs, and their key carrier MGEs can be synergistically and efficiently degraded in penicillin fermentation residue at ambient temperature. This method not only significantly disrupts DNA structure and greatly reduces the biotoxicity of the residue through direct chain breaks and free radical attacks, but also, due to its non-thermal treatment characteristics, maximizes the retention of nutrients such as nitrogen, phosphorus, and potassium, as well as organic matter, ensuring the agricultural value of the treated residue. Furthermore, this method requires no chemical reagents, does not generate secondary pollution, and is simple and clean to operate, effectively overcoming the drawbacks of high energy consumption, secondary pollution, and incomplete treatment in incineration, landfill, or biological treatment processes. More importantly, the residue treated by this method has a significantly reduced content of harmful substances while retaining its nutritional components, making it suitable for direct use in feed or organic fertilizer production, achieving harmless treatment and high-value resource utilization of waste.

[0034] In at least one embodiment of this application, the absorbed dose of gamma irradiation during treatment ranges from 10 kGy to 50 kGy. Thus, by optimizing the irradiation dose, the synergistic degradation and inactivation of residual penicillin, ARGs, and their key mobile genetic elements (MGEs) in the fungal residue are achieved, while maximizing the retention of agricultural nutrients in the fungal residue.

[0035] Specifically, the bacterial residue to be treated is loaded into an irradiation container; it is then placed into a cobalt-60 gamma ray irradiation device, and the irradiation time is precisely controlled to allow the bacterial residue to absorb an irradiation dose of 10 kGy to 50 kGy; after irradiation, the treated samples are collected for subsequent testing and utilization. For example, experimental verification showed that after 50 kGy irradiation treatment, the penicillin residue in the penicillin fermentation bacterial residue was less than 50 mg / kg, and the average abundance of the target resistance gene decreased by approximately 42%.

[0036] In at least one embodiment of this application, when penicillin fermentation residue is subjected to gamma irradiation treatment, the penicillin fermentation residue is in the form of a solid-liquid mixture.

[0037] In at least one embodiment of this application, the moisture content of the penicillin fermentation residue is between 70% and 95%.

[0038] For example, by controlling the gamma ray irradiation dose (10 kGy~50 kGy), penicillin fermentation residue (moisture content 70%-95%) was irradiated. This irradiation treatment can effectively destroy the DNA structure of target resistance genes (such as tetA(58), msbA, bcrA, TaeA), significantly reduce their abundance (about 42% reduction when the absorbed dose is 50 kGy), and synergistically degrade residual penicillin (penicillin degradation rate greater than 90% when the absorbed dose is 30 kGy).

[0039] In at least one embodiment of this application, at least one target antibiotic resistance gene includes one or more of tetA(58), msbA, bcrA and TaeA.

[0040] Example 1: Basic properties and irradiation treatment conditions of penicillin fermentation residue This embodiment aims to introduce the basic properties of penicillin fermentation residue used in the research and the basic conditions for gamma ray irradiation treatment.

[0041] The penicillin fermentation residue sample was taken from a penicillin manufacturer in China, and its basic properties were determined as shown in Table 2 below.

[0042] Table 2 Physicochemical properties of penicillin fermentation residue samples The bacterial residue was irradiated using a cobalt-60 gamma ray source. The dose rate was generally set at 164 Gy / min, and the treatment temperature was controlled at 25±2℃. The original pH of the bacterial residue was approximately 5.1. The absorbed dose was controlled by adjusting the irradiation time, ranging from 10 kGy to 50 kGy, with a control group (0 kGy) included.

[0043] Antibiotic bacterial residue samples before and after irradiation were centrifuged at 6000-8000 rpm for 8-10 minutes. The residue precipitate was collected and frozen for preservation. Miseq high-throughput sequencing was used to analyze the microbial community structure in the residue.

[0044] The basic experimental procedure is roughly as follows: (1) DNA extraction from bacterial residue samples; (2) DNA fragmentation to approximately 400 bp using Covaris M220; (3) PCR amplification using the NEXTFLEX™ Rapid DNA-Seq Kit to construct a PE library; (4) Bridge PCR and sequencing. The obtained raw sequences were then optimized, assembled, and predicted. ARG information annotation and analysis were performed on the CARD database of the Meiji Bioinformatics Cloud online analysis platform. For MGEs, Diamond Blastp was used to align the ORFs in the metagenomics with sequences in the mobileOG database. If a sequence met the requirements of ≥90% sequence identity and an alignment length ≥50 bp, it was annotated as an MGE fragment. Both ARGs and MGEs are presented as relative abundance, with RPKM as the normalized value.

[0045] Example 2: Effect of irradiation on the degradation of penicillin in penicillin fermentation residue This embodiment focuses on the effect of irradiation on the removal of residual antibiotics (PG) and antibiotic resistance genes (ARGs) in penicillin bacterial residue.

[0046] The concentration of residual penicillin G (PG) in the supernatant of bacterial residue before and after irradiation was determined by high-performance liquid chromatography (HPLC). The antibiotic removal rate was calculated using the following formula: In the formula, C0 represents the initial concentration, and C represents the concentration after irradiation. The sample pretreatment procedure is as follows: The bacterial residue and extract (acetonitrile:formic acid = 3:1) are mixed and shaken for 10 min, then centrifuged at 8000 rpm for 8-10 min. The supernatant is collected, and this process is repeated once and the supernatants are combined. The combined supernatant is then passed sequentially through an EMRLipid column to remove organic impurities, followed by purification through a C18 solid-phase extraction column. Afterward, the supernatant is purged with nitrogen until nearly dry, reconstituted with 1 mL of acetonitrile:water (1:1), and finally filtered through a 0.45 μm filter membrane before injection. The internal standard recovery rate is 80%–110%, and the limit of quantitation is 1.0 mg / kg. Chromatographic conditions are detailed in Table 3. Quantification is performed using a standard curve established by the external standard method.

[0047] Table 3 HPLC detection conditions for the target antibiotic like Figure 2 and Figure 3 As shown, ionizing irradiation can effectively degrade residual PG in penicillin bacterial residue, and the PG removal rate increases with increasing absorbed dose. At an absorbed dose of 30 kGy, ionizing irradiation can remove approximately 91% of the PG in the penicillin bacterial residue. However, as the absorbed dose increases to 50 kGy, the improvement in PG removal rate is limited.

[0048] Example 3: Effect of irradiation on the removal of resistance genes (ARGs) in penicillin fermentation residue This embodiment uses metagenomic high-throughput sequencing to assess the abundance changes of major ARGs in fungal residue samples.

[0049] The composition of ARGs in penicillin bacterial residue before and after irradiation treatment showed a high degree of similarity. Ionizing irradiation reduced the types of ARGs and the number of specific ARGs in the penicillin bacterial residue. Table 4 shows that after irradiation treatment with 25 kGy, the average relative abundance of common ARGs in the penicillin bacterial residue decreased by 37%; when the irradiation dose increased to 50 kGy, the average relative abundance of ARGs further decreased by 42%. This indicates that the removal rate of ARGs in penicillin bacterial residue increases with increasing absorbed dose.

[0050] Table 4. Number of common and unique ARGs in penicillin bacterial residue under different dosage treatments Sequencing results detected 14 ARGs types, of which multidrug resistance, macrolide lincomycin-streptomycin (MLS), and tetracycline genes accounted for 65%. After irradiation, the relative abundance of the MLS gene macB decreased to about 1 / 1.7 of the original level; genes such as tetA(58), msbA, bcrA, and TaeA also showed significant decreases; key resistance genes such as mecC and arlS were also significantly reduced (Table 5).

[0051] Table 5. Relative abundance changes of major resistance genes (ARGs) at different irradiation doses. Overall, the relative abundance of various ARGs continued to decrease with increasing irradiation dose, indicating that this method can not only efficiently destroy antibiotic molecules, but also significantly weaken the biological function of resistance genes in penicillin fermentation residue, thereby reducing the risk of drug resistance transmission.

[0052] Example 4: Effects of irradiation on mobile genetic elements (MGEs) in penicillin fermentation residue This embodiment investigates the inhibitory effect of irradiation on MGEs, a key carrier of ARGs, in penicillin fermentation residue. MGEs in the residue can directly affect the abundance of ARGs and participate in the horizontal transfer of ARGs.

[0053] The acquisition, basic property determination, and irradiation treatment conditions of the penicillin bacterial residue samples were the same as described in Example 1. Immediately after irradiation treatment, the bacterial residue samples were centrifuged, and the precipitate was collected for subsequent analysis.

[0054] The method for extracting total DNA from the bacterial residue precipitate was the same as described in Example 3. The extracted total DNA was then subjected to metagenomic high-throughput sequencing, and the sequencing data was compared with professional databases to identify, annotate, and quantify the types and relative abundance of mobile genetic elements (MGEs) in the sample.

[0055] Analysis of metagenomic high-throughput sequencing data showed that ionizing irradiation treatment effectively reduced the overall abundance of mesenchymal growth factors (MGEs) in penicillin bacterial residue. Compared with the untreated original residue (0 kGy), the average relative abundance of MGEs in the penicillin bacterial residue decreased by 26% after irradiation at 25 kGy; and after irradiation at 50 kGy, the average relative abundance of MGEs further decreased significantly by 33%. This indicates that the removal rate of MGEs increases with increasing irradiation dose (Table 6).

[0056] Table 6. Effects of irradiation on the relative abundance of mobile genetic elements (MGEs) in penicillin bacterial residue. In particular, the relative abundance of key MGEs directly related to horizontal gene transfer, such as integrase genes (intI), transposase genes (tnpA), and conjugation transfer-related genes (traI), showed a significant decreasing trend after irradiation treatment. In summary, gamma irradiation treatment helps to block the horizontal diffusion pathway of ARGs in the environment.

[0057] Example 5: Effects of irradiation on the microbial community structure in penicillin fermentation residue This embodiment aims to elucidate the effects of ionizing radiation on the microbial community structure and diversity in penicillin fermentation residue, thereby studying the impact of irradiation on the spread of antibiotic resistance genes (ARGs) by altering the microbial host environment.

[0058] This embodiment uses the same sample preparation and irradiation conditions (0, 25 kGy, 50 kGy) as in Examples 1 and 3, and immediately after treatment, the penicillin fermentation residue precipitate is collected by centrifugation. The total DNA extraction and metagenomic sequencing procedures are the same as described above. Metagenomic sequencing analysis of the extracted total DNA is performed to analyze the microbial community structure.

[0059] The untreated (0 kGy) original bacterial residue samples exhibited the highest microbial richness (Chao1 and Ace indices) and diversity (Shannon and Simpson indices), with abundant and evenly distributed microbial species. With increasing irradiation dose, both the microbial richness and diversity indices in the penicillin fermentation bacterial residue samples showed a trend of first decreasing and then slightly increasing. When the irradiation dose reached 50 kGy, the microbial richness and diversity indices in the bacterial residue samples decreased. This indicates that high-dose irradiation can effectively reduce microbial abundance and diversity (Table 7).

[0060] Table 7. Effects of irradiation on the microbial community and key hosts of penicillin bacterial residue. Network co-occurrence analysis further revealed that *Enterococcus* is a highly associated host for both ARGs and MGEs, and its abundance significantly decreased after 50 kGy treatment, thereby indirectly reducing the risk of horizontal transfer. Therefore, ionizing irradiation remodeled the microbial community structure and diversity of penicillin bacterial residue, reducing overall microbial abundance and the number of key hosts (such as *Enterococcus*), thus inhibiting ARGs and their horizontal transfer potential in the residue.

[0061] It should be noted that the combination of the technical features in the embodiments of this application is not limited to the combination methods described in the embodiments of this application or the combination methods described in specific embodiments. All technical features described in this application can be freely combined or combined in any way, unless they contradict each other.

[0062] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the term "comprising" only indicates that it includes the explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0063] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications or equivalent substitutions made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for degrading resistance genes in penicillin fermentation residue, characterized in that, Step S1: Provide penicillin fermentation residue to be treated, wherein the penicillin fermentation residue contains at least one target antibiotic resistance gene; Step S2: Treat the penicillin fermentation residue with gamma rays.

2. The method for degrading resistance genes in penicillin fermentation residue according to claim 1, characterized in that, Gamma rays are used 60 Co or 137 Cs.

3. The method for degrading resistance genes in penicillin fermentation residue according to claim 1, characterized in that, The absorbed dose range of gamma ray irradiation treatment is 10 kGy to 50 kGy.

4. The method for degrading resistance genes in penicillin fermentation residue according to claim 1, characterized in that, When penicillin fermentation residue is treated with gamma rays, it is in the form of a solid-liquid mixture.

5. The method for degrading resistance genes in penicillin fermentation residue according to claim 4, characterized in that, The moisture content of penicillin fermentation residue is between 70% and 95%.

6. A method for degrading resistance genes in penicillin fermentation residue according to any one of claims 1 to 5, characterized in that, At least one of the target antibiotic resistance genes includes one or more of tetA(58), msbA, bcrA, and TaeA.

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