A method for degrading residual antibiotics in fermentation waste of macrolide antibiotics

Abstract

This invention discloses a method for degrading residual antibiotics in fermentation waste containing macrolide antibiotics. The method includes using antibiotic fermentation residue as the degradation raw material, stainless steel beads as the grinding medium, and oxidants and co-oxidants as ball milling aids. The mixture is ground and reacted in a ball mill jar to complete the treatment of the fermentation residue. The antibiotic content in the ball-milled residue is reduced to below 99%, with the antibiotics losing their anti-viability, and the residue can be further used for the re-fermentation of erythromycin. This invention features a short process route, low reagent consumption and cost, simple operation, and the entire process is carried out under solid-phase conditions without solvents, resulting in high degradation efficiency. It is a method for treating macrolide antibiotic fermentation residue with good prospects for widespread application.

Description

Technical Field

[0001] This invention belongs to the field of organic solid waste treatment and comprehensive utilization technology, specifically relating to a method for degrading residual antibiotics in fermentation waste of macrolide antibiotics. Background Technology

[0002] Macrolide antibiotics are a class of broad-spectrum antibacterial drugs that exert their effects by inhibiting bacterial protein synthesis. They typically contain a macrolide ring of 12 to 16 carbon atoms, linked to a sugar group via a glycosidic bond. These drugs primarily target Gram-positive bacteria and some Gram-negative bacteria, such as Streptococcus pneumoniae and Staphylococcus aureus. Representative macrolide antibiotics include erythromycin, clarithromycin, and azithromycin. These drugs are widely used clinically to treat respiratory tract infections, skin and soft tissue infections, and Helicobacter pylori infections. However, bacterial resistance to macrolide antibiotics is becoming increasingly serious, mainly manifested as decreased affinity, which can be achieved through mechanisms such as bacterial ribosome modification or increased drug efflux. The main causes of resistance are antibiotic overuse and the discharge of antibiotic manufacturing waste.

[0003] Industrially, the production of macrolide antibiotics involves inoculating antibiotic-producing bacteria such as Streptomyces and Actinomycetes onto a culture medium and cultivating them. The fermentation process is controlled to induce antibiotic production through microbial fermentation. After fermentation, the fermentation broth is separated into solid and liquid components. The target antibiotic is found in the filtrate, while the remaining filter cake is called antibiotic fermentation residue. Statistics show that antibiotic fermentation residue mainly consists of mycelia of antibiotic-producing bacteria, metabolites produced during fermentation, a large amount of organic culture medium and its degradation products, as well as small amounts of residual antibiotics. If antibiotic fermentation residue is not properly disposed of, the residual antibiotics and their metabolites in the environment can cause chronic toxicity and endocrine disruption to aquatic organisms and humans, and increase bacterial resistance.

[0004] Traditionally, methods for treating bacterial residue include incineration, landfilling, and conversion into animal feed or fertilizer. In recent years, the harmless treatment of antibiotic bacterial residue has attracted increasing attention, with hydrothermal treatment, electron beam irradiation, anaerobic fermentation, and oxidative degradation technologies being increasingly used. Mechanochemistry, as an emerging and efficient technology, has many applications in metallurgy, materials synthesis, natural product extraction, drug synthesis and formulation, and has also shown great potential in the field of organic pollutant degradation in recent years. Patent CN110951637A discloses a new method for treating erythromycin bacterial residue. First, the erythromycin bacterial residue is acidified with a strong acid, then the pH is adjusted to 6.5–7.5, followed by concentration using a reverse osmosis device. The concentrate is then pre-frozen, vacuum freeze-dried, and pulverized to obtain erythromycin bacterial residue powder. The resulting bacterial residue powder can be used as a nutrient for erythromycin fermentation, replacing part of the soybean meal powder added to the erythromycin fermentation medium. Although this invention solves the problem of erythromycin pollution and realizes the resource utilization of bacterial residue, the operation process is cumbersome, and the invention uses a large amount of phosphoric acid, posing certain safety hazards. Patent CN219792952U discloses a treatment device for antibiotic fermentation bacterial residue. This device includes a pre-conditioning tank, a fully mixed anaerobic fermenter, and a sedimentation tank connected in sequence. In this device, the fully mixed anaerobic fermenter has an optimized water inlet form, allowing the bacterial residue to be directly fed into the fully mixed anaerobic fermenter without the need for other wastewater dilution and mixing, gas-liquid mixing, or nozzles. The structure is simpler, avoiding clogging problems after long-term operation, and allowing the bacterial residue to circulate and mix internally without mechanical stirring, saving the original bacterial residue heating cost. Although anaerobic fermentation utilizes the bacterial residue as a resource, it generates a large amount of wastewater and harmful gases during the process, and cannot completely degrade residual antibiotics in the antibiotic bacterial residue, posing certain environmental hazards in the future. Patent CN105624074A discloses a method for the harmless treatment of antibiotic fermentation residue. This invention involves adding glucose, a microbial complex inoculum, and grass powder to the antibiotic fermentation residue, mixing them thoroughly, and cultivating them into a solid fermentation inoculum. Then, this inoculum, grass powder, and fresh antibiotic fermentation residue are mixed in a specific weight ratio and fermented for 72-96 hours to obtain a high-protein, harmless antibiotic fermentation residue. The fermentation product is dried, ground, and sieved through a 60-mesh sieve to obtain a high-protein fermented microbial powder. While this invention achieves antibiotic degradation and resource utilization of the residue, the method is time-consuming, and the selection of the microbial complex inoculum is specific. Patent CN201611114029.8 discloses a method for the harmless treatment of fermented antibiotic fermentation residue. This invention uses hydrophilic acid-producing bacteria to perform high-temperature anaerobic acid-producing fermentation treatment on the fermented antibiotic fermentation residue. The residue is hydrolyzed and acidified, the antibiotic-producing bacteria in the residue are inactivated, and the residual antibiotics are degraded. Further biochemical treatment is then performed to render the antibiotic fermentation residue harmless and resource-efficient.Although this method can completely kill antibiotic-producing bacteria in the bacterial residue, leaving no antibiotic residue and eliminating the danger of drug-resistant bacteria and genes after biochemical treatment, the treatment time is long and it generates a large amount of toxic and harmful gases and wastewater, increasing the cost of secondary treatment.

[0005] Given the increasingly serious problem of antibiotic pollution and the lack of effective technologies and methods for treating macrolide antibiotics in solid materials, developing new technologies that eliminate macrolide antibiotic pollution in solids at low cost and high efficiency is of great significance for environmental protection and waste management. Summary of the Invention

[0006] The purpose of this invention is to completely degrade residual macrolide antibiotics in fermentation residues, while allowing the degraded antibiotic residues to be reused in fermentation, thus achieving comprehensive resource utilization. To overcome the problems of large amounts of chemical reagents, cumbersome processes, high costs, incomplete degradation, and lack of reuse of antibiotic residues in existing antibiotic fermentation residue degradation processes, a method for degrading residual antibiotics in macrolide antibiotic fermentation waste is proposed.

[0007] Based on previous fundamental research, this invention utilizes variable-valence transition metals and their salts as oxidants, and inexpensive non-oxidizing metal oxides with water absorption and solid-state electron transfer capabilities as auxiliaries in the reaction system; both together constitute a ball milling aid. Using a planetary ball mill, a certain proportion of the ball milling aid is added to the bacterial residue, and the mixture is ball-milled at a specific frequency for a period of time to directly degrade antibiotics. During the mechanochemical treatment, mechanical force activates the transition metal salts in the ball milling aid, transforming them into strong oxidants. Through complexation with the co-oxidant and the bacterial residue biomass, the lifetime of free radicals is extended, promoting the oxidative degradation of macrolide antibiotics. Since this invention is entirely carried out in the solid phase, it avoids precipitation and interference from thiol and hydroxyl complexes on the Fenton process. Furthermore, the reagents used are inexpensive, and the method is simple and easy to implement. No external washing solution is required after treatment, making it more environmentally friendly and economical.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A method for degrading residual antibiotics in fermentation waste of macrolide antibiotics includes the following steps: weighing antibiotic residue, adding ball milling aid and ball milling media, adjusting the ball mill speed, setting the ball milling time, and analyzing the residual antibiotic content in the ball-milled antibiotic residue by extraction and HPLC.

[0010] Furthermore, the antibiotic fermentation residue is the fermentation waste of macrolide antibiotics, specifically one of the following: erythromycin fermentation residue or avermectin fermentation residue.

[0011] Furthermore, the ball milling aid includes an oxidant and a co-oxidant. The oxidant is one or a mixture of several of ferric chloride, ferrous chloride, ferric sulfate, ferrous sulfate, potassium ferrate, copper chloride, copper oxide, manganese dioxide, and iron powder, preferably ferric chloride. The co-oxidant is one of calcium oxide, magnesium oxide, zinc oxide, and silicon dioxide, preferably calcium oxide. The oxidant accounts for 10%-90% of the total mass of the ball milling aid, preferably 40%. Furthermore, the mass ratio of the ball milling aid to the antibiotic bacterial residue is 5%-90%, preferably 50%. The milling media are stainless steel grinding balls, and the ball-to-material ratio is 1:1-10:1, preferably 8:1.

[0012] Furthermore, the diameter of the stainless steel grinding balls is 10-25 mm, preferably 15 mm; the grinding frequency is 100-500 rpm, preferably 350 rpm; and the grinding time is 50-250 min, preferably 150 min.

[0013] Compared with the prior art, the beneficial effects of the present invention are mainly reflected in:

[0014] (1) Compared with traditional methods such as incineration, landfill, feed production and fertilizer production, this invention not only achieves cheap and efficient degradation of antibiotics, but also allows the treated bacterial residue to be directly reused and fermented to produce antibiotics.

[0015] (2) The oxidant and additives used in this invention are abundant in nature and will not cause secondary pollution to the environment.

[0016] (3) This invention is carried out under solid phase conditions, and will not generate waste gas or waste liquid. The solid powder is easy to store and the treated bacterial residue powder can be directly used as fermentation raw material.

[0017] (4) The degradation conditions described in this invention are simple to operate, have a short processing time, and have high degradation efficiency. Attached Figure Description

[0018] Figure 1 The diagram shows the effect of selecting oxidants and co-oxidants on the degradation of erythromycin.

[0019] Figure 2 The ratio of oxidant to co-oxidant and the ratio of ball milling aid to bacterial residue affect the degradation effect of erythromycin;

[0020] Figure 3 The effects of ball-to-material ratio, ball milling speed, ball milling time, and ball milling bead diameter on erythromycin degradation;

[0021] Figure 4 Evaluation of the antibacterial effect of the samples (calculated based on the impact on the growth of Staphylococcus aureus). Detailed Implementation

[0022] The present invention will be further described below with reference to the embodiments and the accompanying drawings, but the scope of protection of the present invention is not limited thereto.

[0023] Example 1

[0024] The degradation rate of erythromycin was determined using the following method: The sample was extracted with extraction buffer (5 mL 0.01 M / L Tris-0.02 M / L CaCl2, pH = 6) by vortexing at 2500 rpm for 2 min. Then, 15 mL of extraction solvent was added to the above 50 mL centrifuge tube, and vortexing was continued for 3 min to ensure complete dispersion. Finally, the sample was centrifuged at 10000 rpm for 5 min. The lower layer of the centrifuged liquid was evaporated to dryness, reconstituted with 10 mL of methanol solution, filtered through a 0.45 μm organic membrane, and transferred to a 2 mL amber glass vial for liquid chromatography analysis. The erythromycin content was determined by high performance liquid chromatography (HPLC) using an Agilent C10 ... 18 A 250 mm × 4.6 mm, 1.7 μm column was used, maintained at 25 °C, with isocratic elution. Mobile phase A (0.01 M, KH₂PO₄) / B (acetonitrile) = 60%:40% was employed. The injection volume was 10 μL, the flow rate was 0.68 mL / min, and the run time was 45 min. The erythromycin content was obtained using the external standard method based on the standard curve, and the residual erythromycin content (g / kg) in the sample was then calculated.

[0025] Degradation rate (erythromycin) % = (Antibiotic content in the bacterial residue after degradation / Antibiotic content in the bacterial residue before degradation) * 100%

[0026] Example 2

[0027] Using erythromycin bacterial residue as the research object, 5g of antibiotic bacterial residue was weighed, and 1.5g of ferric chloride (FeCl3), 1.5g of calcium oxide (CaO), and 63g of 15mm stainless steel balls were added. The ball mill speed was adjusted to 350rpm, and the ball milling time was 150min. The content of the antibiotic bacterial residue after ball milling was analyzed by HPLC after extraction, and the degradation rate of erythromycin in the bacterial residue was calculated according to the method described in Example 1.

[0028] Example 3

[0029] Using erythromycin bacterial residue as the research object, 5g of antibiotic bacterial residue was weighed, and 1.5g of ferrous chloride (FeCl2), 1.5g of CaO, and 63g of 15mm stainless steel balls were added. The ball mill speed was adjusted to 350rpm, and the ball milling time was 150min. The content of the antibiotic bacterial residue after ball milling was analyzed by HPLC after extraction, and the degradation rate of erythromycin in the bacterial residue was calculated according to the method described in Example 1.

[0030] Example 4

[0031] Using erythromycin bacterial residue as the research object, 5g of antibiotic bacterial residue was weighed, and 1.5g of ferric sulfate (Fe2(SO4)3), 1.5g of CaO, and 63g of 15mm stainless steel balls were added. The ball mill speed was adjusted to 350rpm, and the ball milling time was 150min. The content of the antibiotic bacterial residue after ball milling was analyzed by HPLC after extraction, and the degradation rate of erythromycin in the bacterial residue was calculated according to the method described in Example 1.

[0032] Example 5

[0033] Using erythromycin bacterial residue as the research object, 5g of antibiotic bacterial residue was weighed, and 1.4g of ferrous sulfate (FeSO4), 1.5g of CaO, and 63g of 15mm stainless steel balls were added. The ball mill speed was adjusted to 350rpm, and the ball milling time was 150min. The content of the antibiotic bacterial residue after ball milling was analyzed by HPLC after extraction, and the degradation rate of erythromycin in the bacterial residue was calculated according to the method described in Example 1.

[0034] Example 6

[0035] Using erythromycin bacterial residue as the research object, 5g of antibiotic bacterial residue was weighed, and 1.5g of copper chloride (CuCl2), 1.5g of CaO, and 63g of 15mm stainless steel balls were added. The ball mill speed was adjusted to 350rpm, and the ball milling time was 150min. The content of the antibiotic bacterial residue after ball milling was analyzed by HPLC after extraction, and the degradation rate of erythromycin in the bacterial residue was calculated according to the method described in Example 1.

[0036] Example 7

[0037] Using erythromycin bacterial residue as the research object, 5g of antibiotic bacterial residue was weighed, and 1.5g of potassium ferrate (K2FeO4), 1.5g of CaO, and 63g of 15mm stainless steel balls were added. The ball mill speed was adjusted to 350rpm, and the ball milling time was 150min. The content of the antibiotic bacterial residue after ball milling was analyzed by HPLC after extraction, and the degradation rate of erythromycin in the bacterial residue was calculated according to the method described in Example 1.

[0038] Example 8

[0039] Using erythromycin bacterial residue as the research object, 5g of antibiotic bacterial residue was weighed, and 1.5g of iron powder, 1.5g of CaO, and 63g of 15mm stainless steel balls were added. The ball mill speed was adjusted to 350rpm, and the ball milling time was 150min. The content of the antibiotic bacterial residue after ball milling was analyzed by HPLC after extraction, and the degradation rate of erythromycin in the bacterial residue was calculated according to the method described in Example 1.

[0040] Example 9

[0041] Using erythromycin bacterial residue as the research object, 5g of antibiotic bacterial residue was weighed, and 1.5g of manganese dioxide, 1.5g of CaO, and 63g of 15mm stainless steel balls were added. The ball mill speed was adjusted to 350rpm, and the ball milling time was 150min. The content of the antibiotic bacterial residue after ball milling was analyzed by HPLC after extraction, and the degradation rate of erythromycin in the bacterial residue was calculated according to the method described in Example 1.

[0042] Example 10

[0043] Using erythromycin bacterial residue as the research object, 5g of antibiotic bacterial residue was weighed, and 1.5g of copper oxide, 1.5g of CaO, and 63g of 15mm stainless steel balls were added. The ball mill speed was adjusted to 350rpm, and the ball milling time was 150min. The content of the antibiotic bacterial residue after ball milling was analyzed by HPLC after extraction, and the degradation rate of erythromycin in the bacterial residue was calculated according to the method described in Example 1.

[0044] like Figure 1 As shown in A, it can be seen that the degradation effect of antibiotics in bacterial residue varies greatly depending on the oxidant used. Among them, divalent and trivalent iron salts have the best degradation effect, and ferric chloride is significantly better than other iron salts, which is consistent with the Fenton oxidation principle.

[0045] Example 11

[0046] Using erythromycin bacterial residue as the research object, 5g of antibiotic bacterial residue was weighed, and 1.5g of FeCl3, 1.5g of zinc oxide (ZnO), and 63g of 15mm stainless steel balls were added. The ball mill speed was adjusted to 350rpm, and the ball milling time was 150min. The content of the antibiotic bacterial residue after ball milling was analyzed by HPLC after extraction, and the degradation rate of erythromycin in the bacterial residue was calculated according to the method described in Example 1.

[0047] Example 12

[0048] Using erythromycin bacterial residue as the research object, 5g of antibiotic bacterial residue was weighed, and 1.5g of FeCl3, 1.5g of magnesium oxide (MgO), and 63g of 15mm stainless steel balls were added. The ball mill speed was adjusted to 350rpm, and the ball milling time was 150min. The content of the antibiotic bacterial residue after ball milling was analyzed by HPLC after extraction, and the degradation rate of erythromycin in the bacterial residue was calculated according to the method described in Example 1.

[0049] Example 13

[0050] Using erythromycin bacterial residue as the research object, 5g of antibiotic bacterial residue was weighed, and 1.5g of FeCl3, 1.5g of silicon dioxide (SiO2), and 63g of 15mm stainless steel balls were added. The ball mill speed was adjusted to 350rpm, and the ball milling time was 150min. The content of the antibiotic bacterial residue after ball milling was analyzed by HPLC after extraction, and the degradation rate of erythromycin in the bacterial residue was calculated according to the method described in Example 1.

[0051] like Figure 1 As shown in B, it can be seen that the use of different co-oxidants also affects the degradation effect. The role of co-oxidants is to absorb water and assist in the transfer of electrons in the solid phase. Therefore, calcium oxide, which has the functions of absorbing water and transferring electrons, has the best effect.

[0052] Example 14

[0053] Using erythromycin bacterial residue as the research object, 5g of antibiotic bacterial residue was weighed, and different proportions of FeCl3 and CaO were added to maintain a total mass of 3g. 63g of 15mm stainless steel balls were added, and the ball mill speed was adjusted to 350rpm for 150min. The content of the ball-milled antibiotic bacterial residue was analyzed by HPLC after extraction. The ratio of oxidant and adjuvant was optimized based on the erythromycin degradation rate. Figure 2 As shown in A, the results indicate that the degradation efficiency changes with the increase of CaO amount. The degradation rate is the highest when FeCl3 accounts for 40% of the total reagent amount, indicating that the oxidant can be activated best under this condition, and there are sufficient auxiliaries to mediate the electron transfer of the solid-phase system during the reaction.

[0054] Example 15

[0055] Using erythromycin bacterial residue as the research object, 5g of antibiotic bacterial residue was weighed and mixed with FeCl3 and CaO in a 2:3 ratio (FeCl3 accounting for 40% of the total mass). The total amount of ball milling aid was varied, and 63g of 15mm stainless steel balls were added. The ball mill speed was adjusted to 350rpm, and the ball milling time was 150min. The content of the antibiotic bacterial residue after ball milling was analyzed by HPLC after extraction. The ratio of ball milling aid to bacterial residue was optimized by measuring the erythromycin degradation rate. Figure 2 As shown in B, the results indicate that the degradation efficiency changes with the increase of the amount of ball milling aid. The degradation rate is the highest when the ball milling aid accounts for 50% of the total ground material, and it does not increase with the amount added. This indicates that under this condition, the oxidant is sufficient to catalyze the oxidation reaction and oxidize all antibiotics. In order to increase the throughput, 50% was selected as the amount of ball milling aid.

[0056] Example 16

[0057] Using erythromycin bacterial residue as the research object, different masses of antibiotic bacterial residue were weighed, and 40% of the residue's mass of FeCl3 and CaO were added. The ratio of oxidant to co-oxidant was 2:3, and 63g of 15mm stainless steel balls were added. The ball-to-material ratio was varied to 1:1, 2:2, 4:1, 8:1, 10:1, and 20:1, with the ball mill speed adjusted to 350 rpm and the milling time to 150 min. The content of the antibiotic bacterial residue after ball milling was analyzed by HPLC after extraction. The ball-to-material ratio was optimized by the erythromycin degradation rate. Figure 3As shown in A, the results indicate that the degradation efficiency first increases and then decreases with the increase of the ball-to-material ratio, reaching its maximum when the ball-to-material ratio is 8:1. This suggests that under these conditions, there is sufficient space for movement within the ball mill jar, and the ball mill can provide sufficient mechanical energy to catalyze the oxidation reaction.

[0058] Example 17

[0059] Using erythromycin bacterial residue as the research object, 5g of antibiotic bacterial residue was weighed, and 1.0g FeCl3, 1.5g CaO, and 63g of 15mm stainless steel balls were added. The ball mill speed was adjusted to 100rpm, 150rpm, 200rpm, 250rpm, 300rpm, 350rpm, 400rpm, 450rpm, and 500rpm, with a ball milling time of 150min. The content of the antibiotic bacterial residue after ball milling was analyzed by HPLC after extraction. The ball milling time was optimized based on the erythromycin degradation rate. Figure 3 As shown in B, the results indicate that the degradation efficiency increases with increasing ball milling frequency, reaching its maximum and equilibrium at a ball milling frequency of 350 rpm. This suggests that this condition provides sufficient reaction energy and avoids the energy being converted into heat, thus preventing energy waste.

[0060] Example 18

[0061] Using erythromycin bacterial residue as the research object, 5g of antibiotic bacterial residue was weighed, and 1.0g of FeCl3 and 1.5g of CaO were added. Then, 63g of stainless steel balls with diameters of 5mm, 10mm, 15mm, 20mm, and 25mm were added respectively. The ball mill speed was adjusted to 350rpm, and the ball milling time was 150min. The content of the antibiotic bacterial residue after ball milling was analyzed by HPLC after extraction. The diameter of the stainless steel balls was optimized based on the erythromycin degradation rate. Figure 3 As shown in D, the results indicate that as the diameter of the grinding ball increases, the mechanical force provided is significantly enhanced, and the degradation rate increases. However, when the diameter of the grinding ball is greater than 15 mm, the kinetic energy provided decreases significantly due to the reduced movement space, thus the degradation rate decreases. Therefore, the optimal diameter of the grinding ball is 15 mm.

[0062] Example 19

[0063] Using erythromycin bacterial residue as the research object, 5g of antibiotic bacterial residue was weighed, and 1.0g of FeCl3, 1.5g of CaO, and 63g of 15mm stainless steel balls were added. The ball mill speed was adjusted to 350rpm, and the ball milling times were set to 50min, 100min, 150min, 200min, and 250min. The content of the antibiotic bacterial residue after ball milling was analyzed by HPLC after extraction. The ball milling time was optimized by the erythromycin degradation rate. Figure 3As shown in C, the results indicate that the degradation efficiency increases with increasing ball milling time, reaching its maximum and equilibrium at 150 minutes. This suggests that sufficient reaction energy is provided under these conditions, and 150 minutes is the optimal time to further increase efficiency.

[0064] Example 20

[0065] The optimal degradation process was determined by weighing 5g of antibiotic bacterial residue, adding 1.0g FeCl3, 1.5g CaO, and 63g of 15mm stainless steel balls. The ball mill speed was adjusted to 350rpm, and the milling time was set to 150min. The content of the extracted antibiotic bacterial residue was analyzed by HPLC, and the degradation rate of erythromycin was obtained by comparing the concentration before milling. The experiment was repeated three times, and the erythromycin degradation rate was measured to be 99.53±0.12%. Further analysis by liquid chromatography-mass spectrometry (LC-MS) is shown in Table 1. The degradation products were mainly non-antibiotic-active ring-opening and oxidized erythromycin.

[0066] Table 1. Identification of Erythromycin Degradation Products

[0067]

[0068] Example 21

[0069] The degradation effect of avermectin was investigated by weighing 5g of antibiotic bacterial residue, adding 1.0g FeCl3, 1.5g CaO, and 63g of 15mm stainless steel balls. The ball mill speed was adjusted to 350rpm, and the milling time was set to 150min. The content of avermectin in the milled antibiotic bacterial residue was analyzed by HPLC after extraction, and the degradation rate of avermectin was obtained by comparing it with the concentration of avermectin before milling. The experiment was repeated three times, and the degradation rate of avermectin in the bacterial residue was 99.65±0.07%. Further analysis by liquid chromatography-mass spectrometry (LC-MS) showed, as shown in Table 2, that the degradation products were mainly non-antibiotic-active ring-opening and oxidized avermectin.

[0070] Table 2. Avermectin and its main degradation products

[0071]

[0072]

[0073] Example 22

[0074] To assess the antibacterial activity of the degraded erythromycin residue, the erythromycin residue degraded according to the method in Example 20 was used to evaluate the removal of the erythromycin from the residue using Staphylococcus aureus, a common antibiotic. First, a 100 mg / L erythromycin standard solution was prepared. Then, 5 g of the sample was weighed and dissolved in 30 mL of water. The solution was vortexed at 2500 rpm for 3 min, followed by centrifugation at 4000 rpm for 20 min. The supernatant was collected and filtered through a 0.45 μm filter membrane in a clean bench to remove the influence of microorganisms in the reaction solution. Then, different proportions of erythromycin residue supernatant were added and co-grown with Staphylococcus aureus. The OD of Staphylococcus aureus was then measured at intervals using a SHIMADZU UV-1800. 600 Value, such as Figure 4 As shown in the figure. Experimental results show that the untreated erythromycin residue almost completely inhibited the growth of Staphylococcus aureus, with the growth of Staphylococcus aureus less than 30% of that in the control group within 22 hours. In Example 20, the growth of Staphylococcus aureus was only slightly affected. Although it was slightly inhibited in the early stage, the growth of Staphylococcus aureus was basically the same as that in the control group after 24 hours. From the perspective of antibacterial performance, the treatment process described in Example 20 has a significantly better effect on removing antibiotics from erythromycin residue than the untreated residue. This indicates that the method can effectively remove antibiotics and prevent them from transforming into substances that still have antibiotic activity, completely eliminating their antibacterial activity and facilitating the reuse of the residue.

[0075] Example 23

[0076] Take 60g of peptone, the degraded bacterial residue and original bacterial residue described in Example 20, 20g / L peptone, 0.2g / L KH2PO4, and 0.25g / L magnesium sulfate to prepare erythromycin shake-flask fermentation medium. After sterilization, transfer 50mL of fermentation broth to a 250mL Erlenmeyer flask. The strain selected is BNCC Saccharopolyspora erythraea 153143, which is activated. A 1cm piece is cut from the already grown plate. 2 Spores were inoculated, and after inoculation, the culture was fermented at 34℃ and 220 rpm for 120 h. 1% n-propanol was added after 24 h of shake-flask fermentation. The erythromycin A content was measured by HPLC after fermentation. The experimental results are shown in Table 3 below. The results indicate that both the original bacterial residue and the antibiotic-free degraded bacterial residue described in Example 20 can be used as culture media for erythromycin fermentation. However, after inoculation with *B. redispersinium* (BNCC), the growth of the treated bacterial residue was not inhibited. Furthermore, the abundant protein from the degraded bacterial residue provided a high-quality nitrogen source for mycelial growth, and the erythromycin yield was significantly higher than that of fermentation using peptone and undegraded bacterial residue as nitrogen sources. This indicates that the above-mentioned fermented bacterial residue can be used as a nitrogen source for erythromycin culture, and its effect is superior to that of undegraded bacterial residue.

[0077] Table 3: Effect of bacterial residue on degradation and re-fermentation of erythromycin

[0078]

Claims

1. A method for degrading residual antibiotics in fermentation waste of macrolide antibiotics, characterized in that, The process includes the following steps: weighing antibiotic bacterial residue, adding ball milling aid and ball milling media, adjusting the ball mill speed, setting the ball milling time, and analyzing the residual amount of antibiotics in the ball-milled antibiotic bacterial residue by extraction and HPLC. The ball milling aid includes an oxidant and a co-oxidant. The oxidant is one or a mixture of several of the following: ferric chloride, ferrous chloride, ferric sulfate, ferrous sulfate, potassium ferrate, copper chloride, copper oxide, manganese dioxide, and iron powder. The co-oxidant is one of calcium oxide, magnesium oxide, zinc oxide, and silicon dioxide. The oxidant accounts for 10%-90% of the total mass of the ball milling aid. The mass ratio of the ball milling aid to the antibiotic residue is 5% to 90%, and the ball-to-material ratio is 1:1 to 10:

1.

2. The method for degrading residual antibiotics in macrolide antibiotic fermentation waste as described in claim 1, characterized in that, Antibiotic fermentation residue is the fermentation waste of macrolide antibiotics, and includes one of the following: erythromycin fermentation residue or avermectin fermentation residue.

3. The method for degrading residual antibiotics in macrolide antibiotic fermentation waste as described in claim 1, characterized in that, The oxidant is ferric chloride; the co-oxidant is calcium oxide; the oxidant accounts for 40% of the total mass of the ball milling aid.

4. The method for degrading residual antibiotics in macrolide antibiotic fermentation waste as described in claim 1, characterized in that, The mass ratio of the ball milling aid to the antibiotic bacterial residue is 50%; the ball milling media are stainless steel ball milling beads, and the ball-to-material ratio is 8:

1.

5. The method for degrading residual antibiotics in fermentation waste of macrolide antibiotics as described in claim 4, characterized in that, The diameter of the stainless steel grinding balls is 10~25 mm; the grinding frequency is 100~500 rpm; and the grinding time is 50~250 min.

6. The method for degrading residual antibiotics in fermentation waste of macrolide antibiotics as described in claim 5, characterized in that, The stainless steel grinding balls have a diameter of 15mm, a grinding frequency of 350 rpm, and a grinding time of 150 min.

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