A kind of processing method of erythromycin thiocyanate bacterial residue

Abstract

The present invention provides a method for treating erythromycin thiocyanate residue, which comprises: A) subjecting erythromycin thiocyanate residue to electron beam irradiation treatment; B) inoculating anaerobic sludge with erythromycin thiocyanate residue obtained in step A) for anaerobic fermentation; C) subjecting the fermentation liquid obtained in step C) to electron beam irradiation deep treatment, enriching and concentrating the obtained fermentation liquid, and obtaining a biomass carbon source. The method for treating erythromycin thiocyanate residue provided by the present application combines electron beam pretreatment with anaerobic fermentation, and further subjecting the obtained fermentation liquid to electron beam deep treatment, thereby solving the problems of antibiotic residues and resistance genes in fermentation-type erythromycin thiocyanate residue; solving the problem that the amount of acid, alkali and oxidant added in the erythromycin thiocyanate residue treatment process is large, resulting in excessively high inorganic salt content in the subsequent residue; solving the problem that a large amount of clean water needs to be added for dilution, and the problem that macromolecular organic matter such as protein and lipid in mycelium is difficult to be utilized by microorganisms.

Description

Technical Field

[0001] The invention relates to the technical field of biological hazardous waste treatment, and in particular to a method for treating erythromycin thiocyanate bacterial residue. Background Art

[0002] Erythromycin thiocyanate is the thiocyanate salt of erythromycin and belongs to the macrolide antibiotics. Erythromycin thiocyanate is a key intermediate raw material for the synthesis of macrolide antibiotics such as erythromycin, roxithromycin, azithromycin and clarithromycin, and has a very high market value. However, erythromycin thiocyanate can only be obtained through microbial fermentation at present, and cannot be synthesized in large quantities artificially in the industry. Erythromycin thiocyanate residue is the remaining culture medium produced in the process of microbial fermentation to produce antibiotics. Generally, 8-10 tons of wet residue can be produced for every ton of antibiotics produced. If fresh erythromycin thiocyanate residue is not treated, it is easy to produce a foul odor if it is randomly piled up. At the same time, the residual antibiotics and resistance genes in the residue are easy to pollute the soil and water sources, produce super-resistant bacteria, and endanger human health.

[0003] The erythromycin thiocyanate residue contains mycelium, microbial metabolites, culture medium degradation products and residual antibiotics. It contains a large amount of crude protein, crude fiber, amino acids and trace elements, and has a high potential utilization value.

[0004] At present, the treatment processes of erythromycin thiocyanate residue include: mechanical stirring + ultrasonic pretreatment followed by drying; acidic activator, oxidant and catalyst treatment; high temperature and high pressure pretreatment followed by drying and composting; anaerobic digestion followed by dilution with clean water. CN101380509 B discloses a method for harmless treatment of macrolide antibiotic residue, which firstly adopts three-stage multi-loop countercurrent mechanical stirring + three-stage multi-loop drying + microbial inoculum fermentation. In this method, the countercurrent mechanical stirring needs to be assisted by ultrasonic waves, the drying process consumes a lot of energy and is prone to produce odor, and after drying, water needs to be added for adjustment and then fermented, resulting in a high cost and cumbersome process flow. CN 112408685 A discloses a method for adding an acidic activator, an oxidant and a catalyst to degrade erythromycin, and then adding an alkaline agent for neutralization after high temperature and high pressure sterilization. The large amount of inorganic salt used in this method will limit the use and dosage of the residue, and may induce environmental pollution such as soil salinization. The sterilization stage requires high temperature and high pressure conditions, and the acidic environment has higher requirements for equipment and has a high operating cost. Application No.: 201310162405.0 discloses a method for preparing organic fertilizer by degrading erythromycin at a temperature above 160°C and then drying it. This method requires a high temperature and high pressure environment, has extremely high requirements for energy and equipment, and has great safety hazards. The subsequent drying process will also produce odor and bad smell; CN104593433B discloses a method and equipment for treating antibiotic bacterial residues. This method first dilutes the bacterial residues with clean water and then performs anaerobic digestion. The dilution with clean water causes a large increase in the hazardous waste content.

[0005] Based on the problems existing in the above-mentioned erythromycin thiocyanate residue treatment process, the present invention proposes a technical process route of electron beam irradiation pretreatment + anaerobic hydrolysis acidification + electron beam deep treatment. Summary of the invention

[0006] The technical problem solved by the present invention is to provide a method for treating erythromycin thiocyanate bacterial residue, which can effectively remove the residual antibiotics and resistance genes in the erythromycin thiocyanate bacterial residue.

[0007] In view of this, the present application provides a method for treating erythromycin thiocyanate residue, comprising the following steps:

[0008] A) treating erythromycin thiocyanate bacterial residue with electron beam irradiation;

[0009] B) inoculating anaerobic sludge with the erythromycin thiocyanate residue obtained in step A) for anaerobic fermentation;

[0010] C) subjecting the fermentation liquid obtained in step B) to electron beam irradiation deep treatment;

[0011] D) The fermentation liquid obtained in step C) is enriched and concentrated by centrifugal separation and membrane filtration to obtain a biomass carbon source.

[0012] Preferably, in step A), the electron beam accelerator energy of the electron beam irradiation treatment is 1-2 MeV, and the beam current is 30-80 mA.

[0013] Preferably, in step A), the absorbed dose of the erythromycin thiocyanate residue is 50-500 kGy.

[0014] Preferably, the anaerobic sludge is pre-treated with electron beam irradiation, and the absorbed dose of the electron beam irradiation deep treatment is 3-10 kGy.

[0015] Preferably, the initial pH of the anaerobic fermentation is 5-7, the temperature is 25-35°C, the inoculation amount of the anaerobic sludge is 2-5%VS (w / v) of the entire fermentation volume, the solid content of the anaerobic fermentation system is 3-6%; the anaerobic fermentation time is 5-10 days.

[0016] Preferably, in step C), the electron beam accelerator energy of the electron beam irradiation deep treatment is 1-2 MeV, the beam current is 30-80 mA, and the absorbed dose of the electron beam irradiation deep treatment is 30-100 kGy.

[0017] Preferably, the TS of the erythromycin thiocyanate residue is 7.21-9.32%, the VS is 5.67-7.30%, the moisture content is 90.68-92.79%, the pH is 4.98-5.84, the residual erythromycin in the residue mixed liquid is 108.34-434.79 ppm, the residue supernatant is 175.69-263.00 ppm, and the residue precipitate is 249.20-400.00 ppm.

[0018] The present application provides a method for treating erythromycin thiocyanate residue, which includes a sequentially performed electron beam pretreatment-anaerobic fermentation acid production-electron beam deep treatment-centrifugation-membrane filtration-biomass carbon source harmless technical route. The method for treating erythromycin thiocyanate residue provided by the present application combines electron beam pretreatment with anaerobic fermentation, and performs electron beam deep treatment again, which solves the problems of antibiotic residues and resistance genes in fermentation erythromycin thiocyanate residue; solves the problem of large dosage of acid, alkali and oxidant in the erythromycin thiocyanate residue treatment process, resulting in excessively high inorganic salt content in the subsequent residue; solves the problem of the need to add a large amount of clean water for dilution and the problem that macromolecular organic matter such as protein and lipid in the mycelium is difficult to be utilized by microorganisms.

[0019] Furthermore, the processing method provided in the present application solves the problem that the use of high-temperature and high-pressure heating equipment leads to high requirements for equipment maintenance and operation, and poses certain safety hazards; and solves the problem of generating a large amount of odor and high energy consumption during high-temperature drying. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A flow chart of a method for treating erythromycin thiocyanate residue provided by the present invention;

[0021] Figure 2 A curve diagram showing changes in dissolved organic matter during anaerobic processes in different fermentation bottles provided in Example 2 of the present invention;

[0022] Figure 3 This is a curve chart showing the change of erythromycin residues in the anaerobic process of different fermentation bottles provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0023] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0024] In view of the necessity and existing problems of treating erythromycin thiocyanate residue in the prior art, the present application provides a method for treating erythromycin thiocyanate residue, which solves the problem of antibiotic residues in fermentation-type erythromycin thiocyanate residue, especially erythromycin thiocyanate residue, by sequentially performing electron beam pretreatment-anaerobic fermentation acid production-electron beam deep treatment-centrifugal separation-membrane filtration; solves the problem that the amount of acid, alkali and oxidant and other agents added in the existing erythromycin thiocyanate residue treatment process is large, resulting in excessively high inorganic salt content in the subsequent residue; solves the problem that macromolecular organic matter such as protein and lipid in the mycelium is difficult to be utilized by microorganisms in the existing erythromycin thiocyanate residue treatment process. Specifically, an embodiment of the present invention discloses a method for treating erythromycin thiocyanate residue, comprising the following steps:

[0025] A) treating erythromycin thiocyanate residue with electron beam irradiation;

[0026] B) inoculating anaerobic sludge with the erythromycin thiocyanate residue obtained in step A) for anaerobic fermentation;

[0027] C) subjecting the fermentation liquid obtained in step B) to electron beam irradiation deep treatment;

[0028] D) The fermentation liquid obtained in step C) is enriched and concentrated by centrifugal separation and membrane filtration to obtain a biomass carbon source.

[0029] The technical process adopted by the present invention is: erythromycin thiocyanate residue - electron beam pretreatment - anaerobic fermentation acid production - electron beam deep treatment - biomass carbon source harmless technical route, such as Figure 1 shown.

[0030] The present invention firstly treats the erythromycin thiocyanate residue with electron beam irradiation. The electron beam irradiation is a unique advanced oxidation-reduction technology, which is a direct irradiation of high-energy electron beams and the excitation of water molecules by electron beams to produce •OH, O2• - ,HO2•,e aq − , •H and other active particles' oxidation-reduction effect (as shown in the following formula); when irradiated, the system will produce chemical and biological effects, achieving the effect of removing organic matter and killing microorganisms at the same time.

[0031] H2O •OH(2.7)+e aq - (2.6)+H•(0.55)+H2(0.45)+H2O2(0.71)+H + (2.6).

[0032] Compared with traditional advanced oxidation technology, electron beam irradiation can treat fermentation erythromycin thiocyanate residue more efficiently and at a lower cost because the electron beam pollution control system has more active particles, more complex oxidation-reduction processes, richer reaction effects and more diverse process combinations.

[0033] In the present application, the electron beam irradiation treatment is specifically as follows: the evenly mixed erythromycin thiocyanate residue is pumped into the electron beam irradiation pretreatment unit through a screw pump, and the energy of the electron beam accelerator is adjusted to 1~2MeV, and the beam current is 30~80mA, so that the absorbed dose of the residue reaches 50~500kGy; more specifically, the energy of the electron beam accelerator of the electron beam irradiation treatment is 1.2~1.8MeV, the beam current is 40~50mA, and the absorbed dose is 100~200kGy.

[0034] The irradiated bacterial residue is put into the anaerobic fermentation unit and inoculated with anaerobic sludge for anaerobic fermentation; the anaerobic sludge is irradiated in advance, the absorption dose is 3-10 kGy, and the treatment is 30-60 minutes to inhibit the methanogens therein. The inoculation ratio of the anaerobic sludge is 2-5% VS (w / v), the initial pH of the anaerobic fermentation is adjusted to 5-7 with dilute hydrochloric acid or dilute sodium hydroxide, the reaction temperature of the anaerobic fermentation is controlled to 25-35°C, the solid content is 3%-6%, and the anaerobic fermentation acid production is started, and the anaerobic fermentation reaction time is controlled to be 5-10 days; more specifically, the absorption dose is 5-8 kGy, the treatment time is 40-60 minutes, the temperature of the anaerobic fermentation is 30-35°C, and the time is 5-7 days.

[0035] The present application then injects the fermentation liquid after the anaerobic fermentation reaction into an electron beam irradiation reactor for deep treatment, and adjusts the electron beam accelerator energy to 1~2Mev, the beam current to 30~80mA, and the absorbed dose to 30~100kGy. More specifically, the electron beam accelerator energy is 1.5~2MeV, the beam current is 40~80mA, and the absorbed dose is 50~100kGy. In this process, the degradation of antibiotic residues and resistance genes in the anaerobic fermentation liquid after deep electron beam treatment can be detected by liquid chromatography-mass spectrometry and fluorescence quantitative PCR technology.

[0036] In the present application, the anaerobic fermentation liquid after electron beam deep treatment is finally enriched and concentrated by centrifugal separation and membrane filtration to prepare a biomass carbon source for supplementing the carbon source of the denitrification reaction in the biochemical system of sewage treatment.

[0037] In order to further understand the present invention, the method for treating erythromycin thiocyanate residue provided by the present invention is described in detail below in conjunction with the embodiments, and the protection scope of the present invention is not limited by the following embodiments.

[0038] The erythromycin thiocyanate residue used in the following examples of the present invention was taken from an erythromycin thiocyanate fermentation workshop in Xinjiang, and the various indicators are shown in Table 1; Table 1 Basic properties of erythromycin thiocyanate residue used in the present invention

[0039] Example 1

[0040] Electron beam pretreatment of erythromycin thiocyanate residue: The uniformly mixed erythromycin thiocyanate residue is pumped into the electron beam irradiation pretreatment unit through a screw pump, and the electron accelerator energy is adjusted to 2MeV and the beam current is 50mA, so that the absorbed dose of the residue reaches 200kGy;

[0041] Pretreatment of anaerobic inoculum sludge: The anaerobic inoculum sludge is pumped into the electron beam irradiation treatment unit, and the electron accelerator energy is adjusted to 2Mev and the beam current is 2mA, so that the absorbed dose of the anaerobic inoculum sludge reaches 5kGy;

[0042] Anaerobic fermentation acid production: the anaerobic inoculated sludge was mixed with the erythromycin thiocyanate residue after electron beam pretreatment. The inoculation ratio of the anaerobic sludge was 3% VS (w / v). The solid content of the anaerobic fermentation acid production system was controlled at 5%. Then, the pH was adjusted to 7.0 with dilute hydrochloric acid. After sealing, anaerobic fermentation acid production was carried out. The temperature of anaerobic fermentation acid production was 35°C, and the reaction time was controlled to 7 days.

[0043] Anaerobic fermentation liquid deep treatment: The fermentation liquid after anaerobic fermentation was put into the electron beam irradiation reactor for deep treatment to remove residual antibiotics and resistance genes. The electron accelerator energy was adjusted to 2Mev and the beam current was 50mA, so that the absorbed dose of the fermentation liquid was 100kGy. The degradation of antibiotic residues and resistance genes in the anaerobic fermentation liquid before and after electron beam deep treatment was detected by liquid chromatography-mass spectrometry and fluorescence quantitative PCR technology. The results are shown in Table 2.

[0044] Preparation of biomass carbon source from anaerobic fermentation liquid: Anaerobic fermentation liquid is deeply treated by electron beam, and then enriched and concentrated to produce biomass carbon source, which is used to supplement the carbon source of denitrification reaction in sewage treatment biochemical system.

[0045] Example 2

[0046] Pretreatment of erythromycin thiocyanate residue: The uniformly mixed erythromycin thiocyanate residue was pumped into the electron beam irradiation pretreatment unit through a screw pump, and the electron accelerator energy was adjusted to 2MeV and the beam current was 50mA, so that the absorbed dose of the residue reached 150kGy; untreated erythromycin thiocyanate residue was used as a control;

[0047] Pretreatment of anaerobic inoculum sludge: The anaerobic inoculum sludge was put into the electron beam irradiation treatment unit, and the electron accelerator energy was adjusted to 2Mev and the beam current was 2mA, so that the absorbed dose of the anaerobic inoculum sludge reached 5kGy; the anaerobic inoculum sludge not treated with electron beam irradiation was used as the control;

[0048] Anaerobic fermentation acid production: the anaerobic inoculum sludge after electron beam irradiation was mixed with the erythromycin thiocyanate residue after electron beam pretreatment, the erythromycin thiocyanate residue without electron beam irradiation pretreatment was mixed with the anaerobic inoculum sludge after electron beam irradiation as a control, and the erythromycin thiocyanate residue without electron beam irradiation pretreatment was mixed with the anaerobic inoculum sludge without electron beam irradiation treatment as a control. The inoculation ratio of the anaerobic inoculum sludge was 3% VS (w / v), and the solid content of the anaerobic fermentation acid production system was controlled at 3%. Then, the pH was adjusted to 7.0 with dilute hydrochloric acid, and the anaerobic fermentation acid production was carried out after sealing. The temperature of anaerobic fermentation acid production was 35°C, and the reaction time was controlled to 8 days. The changes of dissolved organic matter and erythromycin residue during the anaerobic fermentation process are as follows: Figure 2 , Figure 3 shown.

[0049] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0050] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for treating erythromycin thiocyanate residues, comprising the following steps: A) subjecting erythromycin thiocyanate bacteria residue to electron beam irradiation treatment; B) inoculating anaerobic sludge with the erythromycin thiocyanate residue obtained in step A) to perform anaerobic fermentation; the anaerobic sludge is pre-treated with electron beam irradiation, and the absorbed dose of the electron beam irradiation deep treatment is 3 to 10 kGy; C) subjecting the fermentation liquid obtained in step B) to electron beam irradiation deep treatment; the initial pH of the anaerobic fermentation is 5-7, the temperature is 25-35° C., the inoculation amount of the anaerobic sludge is 2-5% VS (w / v) of the entire fermentation volume, the solid content of the anaerobic fermentation system is 3-6%; the time of the anaerobic fermentation is 5-10 days; D) The fermentation liquid obtained in step C) is enriched and concentrated by centrifugal separation and membrane filtration to obtain a biomass carbon source.

2. The processing method according to claim 1, characterized in that: In step A), the electron beam accelerator energy of the electron beam irradiation treatment is 1-2 MeV, and the beam current is 30-80 mA.

3. The processing method according to claim 1, characterized in that: In step A), the absorbed dose of the erythromycin thiocyanate residue is 50 to 500 kGy.

4. The processing method according to claim 1, characterized in that: In step C), the electron beam accelerator energy of the electron beam irradiation deep treatment is 1-2 MeV, the beam current is 30-80 mA, and the absorbed dose of the electron beam irradiation deep treatment is 30-100 kGy.

5. The processing method according to claim 1, characterized in that: The TS of the erythromycin thiocyanate residue is 7.21-9.32%, the VS is 5.67-7.30%, the moisture content is 90.68-92.79%, the pH is 4.98-5.84, the residual erythromycin in the residue mixed liquid is 108.34-434.79 ppm, the residue supernatant is 175.69-263.00 ppm, and the residue precipitate is 249.20-400.00 ppm.

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