Method for reducing content of zearalenone in fuel ethanol byproduct DDGS (distillers dried grains with soluble) by using nylon 66 and application of method

Abstract

The invention discloses a method for reducing the content of zearalenone in a fuel ethanol byproduct DDGS (distillers dried grains with soluble) by using nylon 66 and application of the method. The method comprises the following steps: adding 1.5-5% w / v of nylon 66 silk yarns with the fineness of 180-250 deniers into circulating reflux clear liquid in a fuel ethanol whole-grain method production process, and carrying out adsorption reaction at 60-80 DEG C for 2-4 hours, preferably 75 DEG C for 1.5 hours. The nylon 66 in the same batch can continuously treat three batches of clear liquid, and the adsorption efficiency of the first batch to the adsorption efficiency of the third batch are 57.3% + / -1.6%, 50.4% + / -2.8% and 33.5% + / -9.7% respectively. When the adsorption efficiency is lower than 35%, the nylon 66 can be subjected to regeneration treatment by standing for 4-5 days at room temperature through a 70% ethanol solution, and the regenerated nylon 66 can be repeatedly used. The method is simple and easy to implement, the content of zearalenone in DDGS can be effectively reduced, and the method has good industrial application value.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of fuel ethanol production, and specifically to a method for reducing the zearalenone content in DDGS, a byproduct of fuel ethanol, by utilizing nylon 66 and an application thereof. Background Art

[0002] Fuel ethanol, as an important renewable energy source, is widely used around the world. The whole corn grain method is currently the most commonly used fuel ethanol production process, and its basic process includes corn crushing, liquefaction, saccharification, fermentation, distillation and other steps. In this process, in addition to the main product ethanol, a large amount of by-products, namely dry distillers grains with solubles (DDGS) are also produced. DDGS is obtained by mixing and drying the concentrated clear liquid after fermentation with the wet grains. It is rich in protein and other nutrients, so it is widely used in the feed industry as a high-quality protein feed raw material.

[0003] In 2022, China's annual output of corn DDGS will reach about 5.7 million tons, which not only provides a large amount of high-quality raw materials for the feed industry, but also creates considerable added value for the fuel ethanol industry. Therefore, the production and utilization of DDGS are of great significance to promoting circular economy and sustainable development. However, the use of DDGS also faces severe challenges, among which the problem of excessive mycotoxin content has always been a major problem in the feed industry and the ethanol fermentation industry. The main reason for the excessive mycotoxin content in DDGS is that the corn raw materials may contain mycotoxins such as zearalenone (ZEN), which are not only difficult to degrade during the ethanol production process, but will be enriched in DDGS. In addition, in the whole-grain ethanol production process, the process of recycling the clear liquid containing incompletely utilized nutrients and fermentation products has reduced the discharge of waste liquid and improved resource utilization efficiency, but it has also aggravated the problem of increased mycotoxin contamination in DDGS.

[0004] ZEN has estrogen-like effects, which can cause harm to the reproductive system of animals, affect growth and development, and may pose a threat to human health through the food chain. Therefore, reducing the ZEN content in DDGS is of great significance to ensure feed safety and improve product value.

[0005] The existing technology mainly includes the following methods:

[0006] Application No. 201210335523.2 discloses a "biological degradation method for fungal toxins in grains and / or their by-products". This method uses engineered bacteria containing mycotoxin-degrading enzyme genes to ferment and produce ethanol, and converts the by-products into distiller's grain protein. Although this method can achieve ethanol production and toxin degradation at the same time, it has the following disadvantages: it may affect ethanol production and quality; engineered bacteria may remain in distiller's grain protein, causing multiple challenges such as safety, regulatory compliance and consumer acceptance.

[0007] Application No. 202211321123.6 discloses "a method for biodegrading mycotoxins in food or its by-products". This method simulates the internal environment of mammals and uses a variety of enzymes for oxidation, reduction and conjugation reactions to reduce the toxicity of mycotoxins and increase their water solubility. The disadvantages of this method include: it requires a variety of enzymes and is costly; the process is complex and difficult to operate; and there are challenges in the stability and reusability of the enzymes.

[0008] Application No. 201210376057.2 discloses "a material for adsorbing zearalenone and a preparation method thereof". The method has a high and stable adsorption rate for zearalenone in a neutral liquid environment. However, the clear liquid in the production of fuel ethanol is usually an acidic environment with a low pH value, which may affect the adsorption effect of the material on ZEN under low pH conditions, and there is uncertainty.

[0009] Application No. 202210471928.2 discloses "adsorption membrane, adsorption method and application thereof for adsorbing and removing fungal toxins from liquid". This method is aimed at liquid food and discloses the preparation and application of polydopamine and ionic liquid dual-modified nanofiber membranes with multiple fungal toxin adsorption effects, but the adsorption material production process is complicated, and its preparation process uses a variety of sodium dodecylbenzene sulfonate and N,N-dimethylformamide that are corrosive to the eyes, skin and respiratory tract. In addition, the document explicitly mentions that the amino and hydroxyl groups on the polydopamine structure of the adsorption material component, as well as the anions and cations, long carbon chains and p-π conjugation on the ionic liquid structure are the main functional groups for toxin adsorption, and nylon 6 is only one of the optional materials for making the fiber membrane base support. Furthermore, due to the small pore size of the nanomembrane, it can be foreseen that such nanocellulose membranes are easily blocked or even covered by particles in the clear liquid, resulting in the clear liquid being unable to pass through the nanomembrane and failing to adsorb toxins. Finally, there are important differences in structure between nylon 6 and nylon 66. Nylon 6 is made by the polymerization of caprolactam, and its monomer contains 6 carbon atoms. Nylon 66 is made by the alternating polymerization of adipic acid and hexamethylenediamine, and each monomer contains 6 carbon atoms. The two are different chemical substances.

[0010] Application No. 202011557650.8 discloses a "method for removing mycotoxins from grains". This method uses a nylon bag loaded with a variety of adsorbents mixed in a certain proportion, such as modified montmorillonite, yeast cell wall, activated carbon, and medical stone, to adsorb and detoxify grain mycotoxins. The nylon bag in this patent only serves as a carrier for loading the mixed adsorbent, making it easy and convenient to separate the adsorbent from the grain. There is no result showing the toxin adsorption effect of the nylon bag. Summary of the invention

[0011] To this end, the embodiment of the present invention provides a method and application thereof for reducing the zearalenone content in the fuel ethanol byproduct DDGS by using nylon 66. Specifically, it relates to the application of nylon 66 (PA66), a simple, economical, environmentally friendly and recyclable zearalenone (Zearalenone, ZEN) adsorption material and its regeneration process. The purpose of the present invention is to solve the problem of increased ZEN contamination content in DDGS (dried grains and solubles) caused by the reflux recycling of the clear liquid during the whole grain ethanol production process, while maintaining the advantages of the reflux recycling of the clear liquid, such as reducing waste liquid discharge and improving resource utilization efficiency.

[0012] In order to achieve the above purpose, the embodiment of the present invention provides the following technical solutions:

[0013] According to a first aspect of an embodiment of the present invention, the present invention provides a method for reducing the zearalenone content in the fuel ethanol byproduct DDGS by using nylon 66, wherein the nylon 66 thread is put into the circulating reflux clear liquid in the fuel ethanol whole grain production process for adsorption.

[0014] Nylon 66 is a polyamide (Polyhexamethylene adipamide) produced by the polymerization of hexamethylenediamine and adipic acid. It is a semi-crystalline polymer with good mechanical properties, wear resistance, chemical resistance and thermal stability. The repeating unit of nylon 66 is [NH-CO-(CH 2 ) 6 -CO-NH-(CH 2 ) 4 -CO] n Nylon 66 is a relatively economical material with high cost-effectiveness, suitable for large-scale production and application, and resistant to weak acids, weak bases and some organic solvents, which also enables it to maintain its performance in a changing chemical environment. There are no reports on the development or application of nylon 66 specifically for the adsorption and removal of zearalenone.

[0015] In the production of fuel ethanol and DDGS, existing zearalenone (ZEN) adsorbents have their own limitations. Activated carbon has strong adsorption capacity but is expensive and difficult to regenerate, and may reduce the nutritional value of DDGS; clay minerals and aluminosilicates have low costs but insufficient adsorption capacity and selectivity, and aluminosilicates may also affect the physical properties of DDGS; yeast cell walls have good biocompatibility but limited adsorption capacity and high cost; polymer adsorbents have high selectivity and capacity, but face high costs and potential food safety risks. Therefore, existing adsorbents may face challenges in terms of cost, adsorption performance, selectivity, regeneration and safety in the production and application of fuel ethanol and DDGS.

[0016] The present invention innovatively proposes nylon 66 as a highly efficient adsorption material for the removal of zearalenone (ZEN) in the production of fuel ethanol and DDGS, and its application method. Compared with existing ZEN adsorbents, the present invention fully utilizes the advantages of nylon 66: as a cheap and easily available engineering plastic, nylon 66 not only has a mature industrial production base and significant cost advantages, but also has excellent chemical and physical stability, which is sufficient to cope with the harsh environment of fuel ethanol and DDGS production. In addition, the easy processing and molding characteristics of nylon 66 provide convenience for the design of the adsorption system, and its potential regeneration capacity also meets the dual needs of cost reduction and environmental protection. More importantly, nylon 66 is expected to efficiently adsorb ZEN while minimizing the impact on the nutritional value of DDGS, making it show a highly competitive application prospect in this field, and providing a potential new solution for solving the ZEN pollution problem in the production of fuel ethanol and DDGS.

[0017] Furthermore, the fineness of the nylon 66 yarn is 180-250 denier.

[0018] Furthermore, the nylon 66 thread is immersed in the acidic clear liquid circulated and refluxed in the fuel ethanol production process, and the adsorption reaction is carried out for 2-4 hours at 60-80°C, which is consistent with the temperature of the clear liquid in the fuel ethanol production process, to reduce the zearalenone content in the clear liquid, thereby reducing the accumulation of zearalenone in DDGS.

[0019] Furthermore, the amount of the nylon 66 thread is 1.5-5% w / v.

[0020] Furthermore, the adsorption reaction is carried out in the clear liquid treatment stage of the fuel ethanol production process, the temperature is 75° C., and the adsorption reaction lasts for 1.5 hours.

[0021] Furthermore, the same batch of nylon 66 filaments can continuously process three batches of clear liquid, among which the adsorption efficiencies of batches 1 to 3 are 57.3%±1.6%, 50.4%±2.8%, and 33.5%±9.7%, respectively, realizing the efficient utilization of the adsorption material and the continuous operation of the process.

[0022] Furthermore, when the adsorption efficiency is lower than 35%, the nylon 66 is regenerated, specifically comprising: removing the nylon 66 after the adsorption reaction from the adsorption system and draining the residual clear liquid, then immersing it in a 70% ethanol solution produced by a fuel ethanol factory, and leaving it at room temperature for 4-5 days to restore its adsorption capacity before reuse.

[0023] According to a second aspect of an embodiment of the present invention, the present invention provides application of any of the above methods in a whole-grain production process of corn fuel ethanol.

[0024] The embodiments of the present invention have the following advantages:

[0025] ① The present invention uses nylon 66 adsorption material to remove zearalenone (ZEN) in DDGS production, which has the following significant advantages:

[0026] Wide range of applications: Nylon 66 can maintain good adsorption even under high temperature, high ZEN pollution concentration and low pH conditions. Multiple adsorption can significantly reduce the ZEN content in the clear liquid (waste liquid), ensure that DDGS products meet the national ZEN limit standards in feed, and improve product quality and safety.

[0027] Simple operation: No pretreatment of the adsorption material is required before adding it to the feed liquid for ZEN adsorption.

[0028] Economic feasibility: Nylon 66 material is moderately priced and can be recycled many times, reducing processing costs. Its excellent mechanical and chemical stability further extends its service life, and it is not easily degraded in ethanol and aqueous solutions, avoiding secondary pollution.

[0029] Safe operation: Compared with dust-type adsorbent materials such as montmorillonite and activated carbon, the thread-like nylon 66 adsorbent material has the advantage of a dust-free operating environment, reduces the risk of occupational hazards, and protects the health of workers.

[0030] Environmentally friendly: 70% ethanol is used for desorption, avoiding the use of toxic and harmful solvents, and ethanol can be recycled and reused.

[0031] Process integration: This method is simple to operate and does not require any pretreatment of the adsorption material. It can be easily integrated into the existing DDGS production line. It optimizes resource allocation through cross-process resource utilization, maintains the advantages of clear liquid reflux recycling, and reduces waste liquid discharge.

[0032] No biosafety risk: Compared with methods using engineered bacteria, this method does not introduce exogenous biological factors, avoiding potential biosafety issues and regulatory barriers.

[0033] ②Application prospects

[0034] The present invention provides an innovative solution for the production process of corn fuel ethanol, which can effectively control the accumulation of mycotoxins in DDGS, improve product quality and safety, meet environmental protection requirements, reduce production costs, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0036] Figure 1 The application process of the nylon 66 thread adsorption-regeneration process provided by the present invention in ZEN control of DDGS production;

[0037] Figure 2 The HPLC spectrum of residual ZEN in the control clear solution and the clear solution after adsorption by nylon 66 (PA66) thread provided by the present invention;

[0038] Figure 3 The adsorption and desorption curves of ZEN in a clear liquid by the original PA66 thread provided by the present invention, wherein A: multiple continuous adsorption kinetic curves of ZEN in a clear liquid by the original PA66 thread, B: desorption kinetic curves of ZEN in 70% ethanol by the original PA66 thread after continuous adsorption;

[0039] Figure 4 The adsorption and desorption curves of ZEN in the clear liquid by the regenerated PA66 yarn provided by the present invention, wherein A: multiple continuous adsorption kinetic curves of ZEN in the clear liquid by the regenerated PA66 yarn, B: desorption kinetic curves of ZEN in 70% ethanol by the regenerated PA66 yarn after multiple continuous adsorptions;

[0040] Figure 5 The present invention provides an analysis of the changes in nylon 66 before and after adsorption of ZEN based on ATR-FTIR spectroscopy, wherein the black curve is the spectrum of the nylon 66 thread before adsorption of ZEN, and the red curve is the spectrum of the nylon 66 thread after adsorption of ZEN. DETAILED DESCRIPTION

[0041] The following is a description of the implementation of the present invention by specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] See also Figure 1 The present invention provides an application process of nylon 66 thread adsorption-regeneration process in ZEN control of DDGS production. The specific contents are as follows:

[0043] (1) Production of fuel ethanol: The common whole-grain production process of fuel ethanol in this field is that the corn kernels are crushed into fine powder of about 20 mesh after impurities are removed, water is added to make a slurry, and the mixture is stirred at 60°C and pH 5.0 for 0.5-1h. Then, amylase is added, liquefied at 90°C for 2-3h, cooled to 32°C, and the pH value is adjusted to 3.5. Then, saccharifying enzyme is added, yeast is added and fermented for about 60h, and distilled to obtain ethanol of different concentrations and residual mash.

[0044] (2) Treatment of the remaining mash: The remaining mash is subjected to solid-liquid separation, and the lower precipitate is dried to obtain DDGS. The upper clear liquid is an acid solution with a pH of 3.5-3.8 and a temperature of 70-75°C. Nylon 66 is added to the acid solution for ZEN adsorption treatment.

[0045] Example 1

[0046] 1 Materials

[0047] Polyamide 66 (nylon 66) yarn with 210 denier (D, Denier) was purchased from Shenzhen Teli Chemical Fiber Co., Ltd., and 210D means that the weight of each 9000-meter-long yarn is 210 grams. Zearalenone (ZEN) standard was purchased from ROMER International Trade (Beijing) Co., Ltd., and methanol (chromatographic grade), acetonitrile (chromatographic grade) and ethanol (analytical grade) were purchased from Fisher Company, USA and Sinopharm Chemical Reagent Co., Ltd. AcquityUPLC BEH C18 liquid chromatography column was purchased from Waters Company, USA.

[0048] 2 Instruments

[0049] High performance liquid chromatography system UltiMate 3000, Thermo Fisher Scientific; constant temperature water bath HH.S11-Ni3K, Beijing Changan Yongchuang Scientific Instrument Co., Ltd.

[0050] 3. Treatment methods

[0051] 3.1 Pretreatment of the clear liquid

[0052] Since the ZEN concentration in the original clear solution is low, in order to ensure the sensitivity and accuracy of ZEN detection, the concentration of ZEN in the clear solution is increased to above 1ppm by adding a higher concentration of ZEN standard solution. Specific method: Accurately weigh 5.0mg of ZEN standard, dissolve it in 1mL of chromatographic grade acetonitrile, and prepare a standard stock solution with a concentration of 5μg / μL. Take 200μL of the standard stock solution and add it to 1L of acidic clear solution (the original clear solution provided by the fuel ethanol company, pH = 3.5), shake at 220rpm for 1 hour, and obtain a clear solution with pH = 3.5 and a final concentration of 1μg / mL for subsequent adsorption experiments.

[0053] 3.2 Preliminary evaluation of the adsorption capacity of PA66 yarn for ZEN in high-temperature acidic liquid

[0054] Accurately weigh 0.125g of PA66 thread, add it to 5mL of clear liquid (2.5% w / v adsorbent dosage) without any treatment, mix thoroughly and ensure that the adsorbent material is completely immersed in the clear liquid. According to the conditions of the clear liquid in the production section of the fuel ethanol enterprise, place it in a 75℃ water bath for adsorption reaction for 1.5h. Set up 3 parallel experiments for each treatment, and use the clear liquid without adsorbent material as a control. After the adsorption is completed, 200μL of clear liquid (turbid liquid with tiny particles) is aspirated by oscillation and mixing, add an equal volume of anhydrous ethanol, mix thoroughly, and centrifuge at 11000rpm for 10min at 4℃. Carefully aspirate part of the supernatant and load it on an ultra-high performance liquid chromatograph to determine the residual ZEN in the clear liquid after adsorption. According to the formula: adsorption rate (%) = 1-residual ZEN peak area after adsorption treatment / control ZEN peak area, calculate the ZEN adsorption rate, and evaluate the ZEN adsorption effect of PA66 thread in acidic clear liquid at 75℃. Results are shown in Figure 2 and Table 1.

[0055] Table 1 Adsorption rate of ZEN in clear liquid by PAA thread

[0056]

[0057] Results: Under the above experimental conditions, PA66 yarns showed excellent ZEN adsorption performance. Compared with the control group, the ZEN adsorption rate of the PA66 yarn-treated group was as high as 59.2%. It is worth noting that this significant adsorption effect was achieved without any pretreatment of the PA66 yarns. This result highlights the potential of PA66 yarns as ZEN adsorption materials, especially in high-temperature acidic (pH = 3.5, 75 ° C) environments such as fuel ethanol production. Considering the relatively low adsorbent dosage (2.5% w / v) used in the experiment, the high-efficiency adsorption capacity of PA66 yarns is even more valuable.

[0058] 3.3 Evaluation of multiple continuous ZEN adsorption capacity of virgin PA66 filaments

[0059] The clear solution without adding PA66 silk thread was set as the control group, and the clear solution with 2.5% (w / v) adsorption material was set as the adsorption treatment group. The control and adsorption treatment were set up 3 times each; adsorption was carried out at a temperature of 75℃ for 1.5h; 200μl of the control and adsorption treatment samples were respectively taken and added with an equal volume of anhydrous ethanol, oscillated and mixed evenly, centrifuged at 11000rpm, 4℃, for 10 minutes, and part of the supernatant was carefully taken for high-performance liquid chromatography analysis to detect the residual ZEN in the clear solution after adsorption, and the adsorption rate was calculated according to the above formula. The clear solution after adsorption treatment was discarded as much as possible, the adsorption material was retained, and new clear solution was added again. ZEN adsorption treatment and residual ZEN analysis were carried out under the same conditions, and the experiment was repeated 8 times. With the number of continuous adsorption as the horizontal axis and the adsorption rate as the vertical axis, the adsorption kinetic curve was drawn to comprehensively evaluate the adsorption performance and durability of PA66 silk thread.

[0060] See also Figure 3

A

[0061] 3.4 Regeneration (desorption) of adsorption material PA66 thread

[0062] After completing 8 consecutive adsorptions, the PA66 thread was removed from the adsorption system and the residual clear liquid was drained. Then, it was completely immersed in 5 mL of 70% ethanol solution. 400 μL of samples were taken on the 1st, 2nd, 3rd, 4th and 5th days of immersion, and the content of desorbed ZEN in the ethanol solution was analyzed by HPLC. The desorption kinetic curve of ZEN was plotted with the desorption time as the horizontal axis and the fluorescence response value of the desorbed ZEN (reflecting the ZEN content) as the vertical axis.

[0063] See also Figure 3

B

[0064] 3.5 Evaluation of multiple continuous ZEN adsorption capacity of recycled PA66 yarn

[0065] The regenerated adsorbent material was soaked in 70% ethanol and rinsed with deionized water for 3 times to drain the residual water. The regenerated adsorbent material was re-tested according to the above multiple continuous adsorption tests and desorption tests to draw the ZEN adsorption curve and ZEN desorption kinetic curve respectively.

[0066] See also Figure 4

A

B

[0067] 3.6 High-performance liquid chromatography detection method for ZEN

[0068] Acquity UPLC BEH C18 column (1.7 μm, 2.1×100 mm) was used as the chromatographic column; the mobile phase consisted of 0.02% formic acid water (A), methanol (B) and acetonitrile (C) in a ratio of 46:8:46; the flow rate was set at 0.15 mL / min, and the injection volume was 2 μL. The excitation wavelength of fluorescence detection was 274 nm, and the emission wavelength was 440 nm. The column temperature was maintained at 40°C. The elution was performed using a gradient program: 15% C was maintained from 0 to 7.5 min, 100% C was increased from 7 to 10.5 min, and 15% C was returned from 10.5 to 18.00 min.

[0069] 3.7 Infrared spectroscopy analysis

[0070] The specific steps of using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) to analyze zearalenone (ZEN) adsorbed on nylon 66 are as follows: set the scanning range of the ATR-FTIR spectrometer to 4000cm-1 to 400cm-1, the number of scans to 45 times, and the resolution to 4cm-1; perform a background scan before the sample test to eliminate environmental and instrument background interference; spread the samples to be tested (including the control group nylon 66 without ZEN adsorption and the sample group nylon 66 adsorbed ZEN) evenly on the surface of the single reflection ATR crystal, ensure that the sample completely covers the crystal and maintains close contact, and apply appropriate pressure to obtain good optical contact; scan each sample for about 90 seconds and collect infrared spectra. The test results are as follows: Figure 5 As shown, the black curve and the red curve are the spectra of nylon 66 thread before and after adsorption of ZEN.

[0071] By comparing the ATR-FTIR spectra of nylon 66 before and after adsorption of zearalenone (ZEN), it was found that the NH stretching vibration peak (about 3299cm-1), CH stretching vibration peak (about 2929cm-1 and 2855cm-1) and fingerprint peak (1465cm-1 and 1419cm-1) of nylon 66 (red spectrum) after adsorption all changed slightly, indicating that these groups may be involved in the adsorption process. More importantly, the amide I band (C=O stretching vibration, about 1634cm-1) and amide II band (NH bending and CN stretching vibration, about 1533cm-1) belonging to the amide group of nylon 66 both shifted slightly to the low wavenumber direction after adsorption of ZEN, and the peak intensity and / or shape changed. These changes strongly prove that nylon 66 forms hydrogen bonds with ZEN molecules through its amide groups (-C=O and -NH), thereby achieving the adsorption of ZEN. In summary, the FTIR spectral analysis results strongly support the conclusion that nylon 66 effectively adsorbs zearalenone through a hydrogen bonding mechanism.

[0072] In summary: PA66 yarn can reduce the ZEN content in the clear liquid, and at the same time effectively control the ZEN contamination in DDGS generated by the subsequent production process; a batch of adsorbent materials can be repeatedly put into the liquid for continuous adsorption, which simplifies the process flow; ethanol in the fuel ethanol production process is innovatively used for the regeneration of nylon 66 adsorbent materials, realizing the cross-recycling of ethanol in ZEN desorption and fuel production processes, greatly improving resource efficiency and reducing overall operating costs.

[0073] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A method for reducing the zearalenone content in DDGS, a byproduct of fuel ethanol, by using nylon 66, characterized in that: The nylon 66 thread is put into the circulating reflux clear liquid in the whole-grain production process of fuel ethanol for adsorption.

2. The method according to claim 1, characterized in that The fineness of the nylon 66 yarn is 180-250 denier.

3. The method according to claim 1, characterized in that: The nylon 66 thread is immersed in the acidic clear liquid used for circulation and reflux in the fuel ethanol production process, and the adsorption reaction is carried out for 2-4 hours at 60-80°C, which is suitable for the temperature of the clear liquid in the fuel ethanol production process, so as to reduce the zearalenone content in the clear liquid, thereby reducing the accumulation of zearalenone in DDGS.

4. The method according to claim 3, characterized in that The amount of the nylon 66 thread is 1.5-5% w / v.

5. The method according to claim 3, characterized in that: The adsorption reaction is carried out in the clear liquid treatment stage of the fuel ethanol production process at a temperature of 75° C. for 1.5 hours.

6. The method according to claim 3, characterized in that The same batch of nylon 66 filaments can continuously process three batches of clear liquid, among which the adsorption efficiencies of batches 1 to 3 are 57.3%±1.6%, 50.4%±2.8%, and 33.5%±9.7%, respectively, realizing the efficient utilization of adsorption materials and the continuous operation of the process.

7. The method according to claim 3, characterized in that When the adsorption efficiency is lower than 35%, the nylon 66 thread is regenerated, specifically including: removing the nylon 66 thread after the adsorption reaction from the adsorption system and draining the residual clear liquid, then immersing it in a 70% ethanol solution produced by a fuel ethanol factory, and leaving it at room temperature for 4-5 days to restore its adsorption capacity before reuse.

8. Use of the method according to any one of claims 1 to 7 in the whole-grain production process of corn fuel ethanol.

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