A method for recovering nutrients for animal feed from corn steep liquor

Abstract

The application discloses a method for recycling nutrients in corn syrup for animal feed. The method mainly comprises the following steps: first, adjusting the oxidation-reduction potential of the corn syrup with hydrogen peroxide to eliminate sulfite ions therein; then, adjusting the pH value of the corn syrup to 12.0-12.5 with quicklime to degrade mycotoxins therein, and then readjusting the pH value to about 7.0 with phosphoric acid; then, uniformly mixing the detoxified neutral corn syrup with corn skin and corn cob powder at a set ratio, inoculating bacillus subtilis, and carrying out solid-state tumbling fermentation; and finally, obtaining a fermentation finished product through airflow drying. Almost all nutrients in the corn syrup that can be used for producing animal feed are recycled in the dry finished product.

Description

Technical Field

[0001] This invention belongs to the field of feed processing and animal breeding, and specifically relates to a method for producing animal feed ingredients using corn steep liquor as the main protein raw material. Background Technology

[0002] Corn steep liquor is a byproduct of corn starch processing plants. In the past six years (2020-2025), my country's annual production of corn steep liquor has exceeded 3 million tons. With a protein content of around 20%, corn steep liquor is a good source of feed protein. However, its extremely complex composition, containing various substances toxic to animals, particularly high concentrations of mycotoxins (mainly aflatoxin, zearalenone, vomitoxin, fumonisin, and ochratoxin), severely limits its application in animal feed.

[0003] For a long time, researchers both at home and abroad have conducted extensive research and exploration on this issue, developing a variety of enzyme preparations that can degrade these toxins. However, the application results have not been ideal. There are two main reasons: first, the production cost of these enzyme preparations is relatively high; second, these enzyme preparations have strong specificity, with each enzyme preparation basically only able to degrade one type of mycotoxin, thus greatly increasing production costs.

[0004] Currently, there are two main uses for corn steep liquor: one is as a raw material for liquid fermentation enzymes, amino acids, and antibiotics (as a source of biotin), with an addition ratio in liquid culture media not exceeding 2.0%. Its consumption is limited, and corn starch factories typically sell it at extremely low prices (less than 120 yuan per ton), or even give it away for free. The other use is to produce spray-dried corn husks using corn husks as a carrier. However, the toxins in corn steep liquor are largely not degraded, so the application rate of spray-dried corn husks in feed is extremely low, resulting in very poor economic benefits.

[0005] In conclusion, how to efficiently utilize corn steep liquor is a key technical problem that urgently needs to be solved by those skilled in the art.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the technical problems to be solved by the present invention are mainly in the following three aspects: 1) 1) Recover effective nutrients, especially protein, from corn steep liquor; 2) Degrade mycotoxins in corn steep liquor, with a degradation rate of over 90% for the five major mycotoxins; 3) The designed production process is economical, reasonable, and has great practical value.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: The method for recovering animal feed nutrients from corn steep liquor provided by the present invention includes the following steps: 1) Detoxification treatment of corn steep liquor ① Adjusting the redox potential Add hydrogen peroxide to corn steep liquor to oxidize the sulfites, reducing the sulfite content to below 0.5 mmol / L or the sulfur dioxide concentration to below 30.0 ppm; ② Detoxification treatment of corn steep liquor by alkalization Then, quicklime is used to adjust the pH of the corn steep liquor to 12.0 or higher (usually controlled between 12.0 and 12.5) to fully degrade the mycotoxins in it; ③ Corn steep liquor after alkalization Then, use phosphoric acid to adjust the pH of the alkalized corn steep liquor back to between 6.8 and 7.2; ④ Add fermentable sugar Add fermentable sugars (such as glucose, sucrose, etc.) to the detoxified neutral corn steep liquor and stir well to obtain detoxified corn steep liquor; ⑤ Adjust the temperature of the detoxified corn steep liquor In order to quickly start fermentation, the temperature of the virus-free corn steep liquor needs to be adjusted to between 34-40℃; 2) Solid-state fermentation of virus-free corn steep liquor ① Mixed inoculation Pour corn husks, corn cob powder, cellulase, xylanase, and fermentation bacteria into the fermentation tank, and finally add detoxified corn syrup. Mix evenly by turning and tossing, and then distribute evenly in the fermentation tank. ② Turning and fermentation Fermentation is carried out in a fermentation tank to obtain fermented material; During the fermentation process, if the material temperature does not exceed 40℃, static fermentation is used; if it exceeds 40℃, turning and stirring fermentation is started. When the moisture content of the material is below 36% during the fermentation process, add detoxified corn syrup and restart the turning and fermentation process. Control the thickness of the material to not exceed 45cm. If it is close to 45cm (or exceeds 40cm), stop adding material. 3) Airflow drying The fermented material is dried by airflow to obtain the fermented product, with the moisture content controlled below 12% (generally around 10%).

[0009] In step 1) of the above method, hydrogen peroxide is used to oxidize sulfite and adjust the redox potential of corn steep liquor. This not only eliminates the toxicity of sulfite, but also provides a good foundation for subsequent aerobic fermentation.

[0010] In some embodiments of the present invention, the mass ratio of corn steep liquor to hydrogen peroxide can be 100:(7-8) (wherein, the H2O2 content in the hydrogen peroxide is ≥ 27.5%), specifically 100:0.75; In some embodiments of the present invention, the process of adding hydrogen peroxide requires stirring (stirring speed such as 12 rpm). After the feeding is completed, stirring is stopped and the mixture is left to stand for 1-3 hours (specifically 2 hours).

[0011] In some embodiments of the present invention, the mass ratio of corn syrup to quicklime can be 100:(4-4.5) (wherein, the CaO content in the quicklime is ≥92.0%), specifically 100:4.25.

[0012] In some embodiments of the present invention, the process of adding quicklime requires stirring (stirring speed such as 12 rpm). After the feeding is completed, stirring is stopped and the mixture is left to stand for a period of time (usually controlled between 2 and 4 hours).

[0013] In some embodiments of the present invention, the mycotoxins mainly include aflatoxin B1, zearalenone, vomitoxin, fumonisin and ochratoxin, and the degradation rates of the above five main mycotoxins are all above 90% (among which the degradation rates of aflatoxin B1 and zearalenone reach above 98%).

[0014] In some embodiments of the present invention, the process of adding phosphoric acid requires stirring (stirring speed such as 12 rpm), and after the feeding is completed, stirring is continued for 5-15 minutes (specifically 10 minutes).

[0015] In some embodiments of the present invention, the fermentable sugar includes, but is not limited to, glucose, sucrose, maltose, fructooligosaccharides, etc. The purpose of adding fermentable sugars here is to rapidly initiate the growth and metabolism of Bacillus subtilis during the subsequent turning and turning process in the fermentation tank.

[0016] In one specific embodiment of the present invention, the fermentable sugar is glucose, and the amount of glucose added is 2.0%-4.0% of the initial mass of the corn steep liquor. After the glucose is added, stirring continues (e.g., stirring for 30 minutes) to ensure that the glucose is completely dissolved.

[0017] In some embodiments of the present invention, in order to quickly initiate fermentation, the temperature of the detoxified corn steep liquor (the mixed corn steep liquor obtained after adding glucose) needs to be adjusted to between 34-40°C. If the temperature of the mixed corn steep liquor obtained after adding glucose is already higher than 40°C, it should be allowed to cool naturally to the above-mentioned temperature range for a period of time. If the temperature of the mixed corn steep liquor obtained after adding glucose is lower than 34°C, it can be heated by passing steam.

[0018] In some embodiments of the present invention, in the mixed inoculation step 2), the mass ratio of corn husk, corn cob powder, and partially detoxified corn steep liquor (containing hydrogen peroxide, quicklime, phosphoric acid, etc.) is 3:2:15.

[0019] In some embodiments of the present invention, in the mixed inoculation step 2), the mass ratio of corn husk, corn cob powder, cellulase, and xylanase is 3:2:0.002:0.002.

[0020] In a specific embodiment of the present invention, the cellulase activity is ≥1000 U / g; the xylanase activity is ≥50,000 U / g.

[0021] In some embodiments of the present invention, in the mixing and inoculation step 2), the fermentation bacteria are Bacillus subtilis, and the initial viable bacteria content (inoculation concentration) in the mixture is preferably controlled between 200 million CFU / g and 500 million CFU / g.

[0022] In some embodiments of the present invention, the corn cob powder mentioned in step 2) can be corn cob powder crushed to a mesh size of 60 or higher, which can absorb about 2.5 times its own weight in water.

[0023] In some embodiments of the present invention, for ease of operation, in step 2), the replenishment of detoxified corn syrup is carried out in a one-time replenishment manner, that is, all the remaining detoxified corn syrup prepared according to the plan is added to the fermentation tank at one time, and no further replenishment is made even if the moisture content of the material drops below 36% again in the subsequent process.

[0024] In some embodiments of the present invention, in the turning and fermentation step of step 2), if the moisture content of the material is less than 33% and the material temperature no longer rises, it indicates that the fermentation is basically over, the turning and fermentation is stopped, and then the material is left to stand for 4-8 hours before proceeding to the next step (airflow drying).

[0025] In some embodiments of the present invention, the dried product obtained in step 3) contains corn husks, corn cob powder, protein from corn steep liquor (including a small amount of protein converted from non-protein nitrogen), Bacillus subtilis cells, calcium lactate, and calcium hydrogen phosphate. These substances can be used in animal feed (especially for laying hens and growing-finishing pigs).

[0026] The above method also includes the steps of material preparation and design before implementation: designing solid-state turning fermentation in the fermentation tank, and calculating the required raw materials, corresponding auxiliary materials, and raw materials required for detoxification treatment of corn liquor based on production equipment, site and environmental conditions.

[0027] During fermentation, the maximum thickness of the material pile should be controlled to not exceed 45cm.

[0028] The main ingredient is corn steep liquor, and the main auxiliary ingredients are corn husks and corn cob powder.

[0029] The main raw materials required for detoxification of corn steep liquor are hydrogen peroxide, quicklime, and phosphoric acid.

[0030] In addition, glucose, cellulase, and xylanase need to be added during the fermentation process.

[0031] Fermentation bacteria need to be inoculated when starting fermentation.

[0032] In the above method, the mass ratio of corn steep liquor, corn husks and corn cob powder is controlled between 20:3:2 and 25:3:2.

[0033] Compared with the prior art, the present invention has the following beneficial effects: ① Using the method of this invention, the degradation rate of five major mycotoxins can reach more than 90% (among which the degradation rate of aflatoxin B1 and zearalenone reaches more than 98%). After actual production verification, this fermented product can be used in animal feed in a large proportion (the maximum usage rate in compound feed reaches 12%).

[0034] ② It has obvious advantages in economic benefits, with each ton of corn syrup adding more than 200 yuan in value. Attached Figure Description

[0035] Figure 1 This is a process flow diagram of the method for recovering animal feed nutrients from corn steep liquor according to the present invention. Detailed Implementation

[0036] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0037] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0038] The following examples use iodometric titration to determine sulfite levels. The specific method is as follows: 1. Method Principles Iodometric determination of sulfite is a classic and widely used chemical analysis method. Its core is to utilize the reducing property of sulfite ions. The core principle is based on redox reactions: under acidic or neutral conditions, sulfite reacts quantitatively with iodine, and the endpoint is determined by the color change of starch indicator.

[0039] An excess of iodine standard solution is added to the sample, where the iodine oxidizes the sulfite to sulfate. After the reaction is complete, the remaining iodine is back-titrated with sodium thiosulfate standard solution. The sulfite content can be calculated based on the amount of sodium thiosulfate consumed.

[0040] 2. The key reaction formula is as follows: 2.1 Reaction of sulfites with iodine SO3² - + I2 + H2O → SO4² - + 2I - + 2H + 2.2 The reaction for titrating the remaining iodine I2+ 2Na2S2O3→ 2NaI + Na2S4O6 3. Measurement Procedures and Calculations 3.1 Reagent Preparation Iodine standard solution: The concentration is generally c(I2) = 0.05 mol / L.

[0041] Sodium thiosulfate standard solution: The concentration is generally c(Na2S2O3) = 0.05 mol / L.

[0042] Hydrochloric acid solution: For example, a diluted solution of (1+1).

[0043] Starch indicator solution: 10 g / L, i.e., 1% soluble starch solution (must be prepared fresh before use).

[0044] 3.2 Operating Procedures 3.2.1 Sampling: Accurately transfer an appropriate amount of sample (e.g., 50-100 mL of water sample) into a 250 mL iodine flask.

[0045] 3.2.2 Adding acid and iodine: Add 5 mL of hydrochloric acid solution (1+1), then accurately add 20.00 mL of iodine standard solution using a pipette, immediately tighten the stopper, and shake well.

[0046] 3.2.3 Dark reaction: Place the iodine flask in the dark for 5 minutes to ensure the reaction is complete.

[0047] 3.2.4 Titration: Titrate with sodium thiosulfate standard solution until the solution turns light yellow, add 1 mL of starch indicator solution, and continue titrating until the blue color just disappears. Record the amount of sodium thiosulfate used, V1 (mL).

[0048] 3.2.5 Blank test: Take an equal volume of pure water to replace the sample, follow the same steps, and record the amount of sodium thiosulfate used, V0 (mL).

[0049] 3.3 Calculation Formula Sulfite content (as SO3²) - (mg / L) can be calculated using the following formula:

[0050] V0: Volume of sodium thiosulfate consumed in the blank test (mL) V1: Volume of sodium thiosulfate consumed by the sample (mL) c: Concentration of sodium thiosulfate standard solution (mol / L) 32.03: Sulfite (SO3²) - The molar mass (g / mol) of . V: Sample volume (mL) 3.4 Interference and Precautions 3.4.1 Interfering substances: Sulfides, nitrites, organic matter, and copper ions can interfere with the determination, potentially leading to results that are too high or too low. When determining complex samples, it is important to eliminate interference.

[0051] 3.4.2 Sample stability: Sulfites are easily oxidized by oxygen in the air. They should be measured as soon as possible after sampling to avoid loss.

[0052] The methods for determining mycotoxins in feed involved in the following examples are as follows: People's Republic of China Agricultural Industry Standard NY / T2071-2011, Determination of aflatoxin, zearalenone and T-2 toxin in feed, liquid chromatography-tandem mass spectrometry.

[0053] People's Republic of China Entry-Exit Inspection and Quarantine Industry Standard SN / T3136-2012, Determination of aflatoxin, ochratoxin, fumonisin B1, deoxynivalenol, T-2 toxin and HT-2 toxin in exported peanuts, cereals and their products.

[0054] People's Republic of China Agricultural Industry Standard NY / T1970-2010, Determination of Fumonisin in Feed.

[0055] People's Republic of China National Standard GB / T30956-2014, Determination of Deoxynivalenol in Feed, Immunoaffinity Column Purification—High Performance Liquid Chromatography. Note: Deoxynivalenol is vomitoxin.

[0056] Example 1 1. Implementation Location A fermented feed production workshop of a large feed group in Shaanxi Province.

[0057] 2 Related Equipment ① Fermentation tank It is 50 meters long and 8 meters wide. It is equipped with two turning machines, each with a 75kW motor. The turning discs can move forward, backward, left, and right, turning all the materials in the fermentation tank. Twelve sensors for measuring material temperature and twelve sensors for measuring material moisture content are evenly installed at the bottom of the fermentation tank.

[0058] ② Corn syrup processing tank The cylindrical tank, with an internal diameter of 4.8 meters and a height of 6.6 meters, is constructed of reinforced concrete. A 35kW mixing motor is installed on top. Four layers of mixing blades are installed, spaced 1.5 meters apart, with the lowest blade 0.4 meters from the bottom of the tank. The diameter of each blade is 3.6 meters.

[0059] 3 raw materials See Table 1 for the sources.

[0060] See Table 2 for quantities and prices.

[0061] Table 1: Sources of raw materials (Example 1)

[0062] Table 2: Quality requirements, quantity, and price of raw materials (Example 1)

[0063] Total cost of raw materials: 48,222 yuan.

[0064] 4. Operation process ① Pretreatment of corn steep liquor Start the mixer, set the speed to 12 rpm, and gradually add 80 tons of corn slurry at a feed rate of about 200 kg / min.

[0065] After feeding is complete, gradually add 600 kg of hydrogen peroxide at a feeding rate of approximately 200 kg / min. After feeding is finished, stop stirring, let stand for 2 hours, and take samples to analyze the sulfurous acid content. Confirm that the sulfite content is below 0.5 mmol / L (or the sulfur dioxide concentration is below 30.0 ppm).

[0066] Restart the mixer, setting the speed to 12 rpm, and gradually add 3400 kg of quicklime at a rate of approximately 100 kg / min. This stage will release a significant amount of heat, causing the overall temperature of the corn syrup to rise by about 12°C. After adding the materials, let the mixture stand for 4 hours and then take samples to analyze the degradation rate of mycotoxins. It was confirmed that the degradation rates of the five major mycotoxins were all above 90% (with aflatoxin B1 and zearalenone reaching degradation rates above 98%).

[0067] Restart the stirring, set the speed to 12 rpm, and gradually add 650 kg of phosphoric acid, controlling the flow rate at approximately 50 kg / min. After the addition is complete, continue stirring for 10 minutes, and take a sample for analysis; the pH value is 6.85.

[0068] Continue adding 2400 kg of glucose, maintaining a flow rate of 200 kg / min. After adding the glucose, continue stirring for 30 minutes to ensure complete dissolution.

[0069] The temperature of the corn steep liquor was measured at 32℃ (at which time the ambient air temperature was 18℃).

[0070] High-temperature steam (steam pressure 0.08 to 0.12 MPa) is introduced into the processing tank while stirring continuously (12 rpm) until the corn syrup temperature rises to 40°C. Then heating is stopped and the mixture is ready for use.

[0071] ② Mixed inoculation In the fermentation tank, add 12 tons of corn husks, 8 tons of corn cob powder, 8 kg of cellulase, 8 kg of xylanase, and 100 kg of Bacillus subtilis powder in sequence. Finally, add 60 tons of corn steep liquor (containing hydrogen peroxide, quicklime, phosphoric acid, etc.) that has undergone detoxification treatment in step ① above. Mix the liquor evenly using a turning machine. Then distribute it evenly in the fermentation tank.

[0072] ③ Turning and fermenting Based on data transmitted from the probe sensors, the temperature of the material is controlled to not exceed 40℃. Once the temperature of the material exceeds 40℃, the turning and tumbling process is initiated.

[0073] When the moisture content of the fermentation material is below 36%, add all the remaining detoxified corn syrup (control the material thickness to not exceed 45cm) and restart the turning and fermentation process.

[0074] Stop turning and turning when the moisture content of the material drops below 33%, and let it stand for 4 hours before proceeding to the next stage of drying.

[0075] The entire operation takes about 30 hours, and the fermentation process takes about 26 hours.

[0076] ④ Airflow drying The fermented product was air-dried in a drum dryer to obtain 62.2 tons of dried product with a moisture content of 10.2%, a protein content of 27.4%, a calcium lactate content of 12.6%, and a dicalcium phosphate content of 1.24%.

[0077] Protein, calcium lactate, and dicalcium phosphate are all excellent raw materials for animal feed and can be used in the production of animal feed (especially for laying hens and growing-finishing pigs).

[0078] The price of this dried product can reach at least 2,400 yuan per ton, and this batch can generate a profit of more than 40,000 yuan, making the economic benefits extremely significant.

[0079] Example 2 1. Implementation Location Same as Example 1.

[0080] 2 Related Equipment Same as Example 1.

[0081] 3 raw materials The source is the same as in Example 1.

[0082] See Table 3 for quantities and prices.

[0083] Table 3: Quality requirements, quantity, and price of raw materials (Example 2)

[0084] Total cost of raw materials: 56,058 yuan.

[0085] 4. Operation process ① Pretreatment of corn steep liquor Start the mixer, set the speed to 12 rpm, and gradually add 100 tons of corn slurry at a feed rate of about 200 kg / min.

[0086] After feeding is complete, gradually add 750 kg of hydrogen peroxide at a feeding rate of approximately 200 kg / min. After feeding is finished, stop stirring, let stand for 2 hours, and take samples to analyze the sulfite content. Confirm that the sulfite content is below 0.5 mmol / L (or the sulfur dioxide concentration is below 30.0 ppm).

[0087] Restart the stirring, set the speed to 12 rpm, and gradually add 4250 kg of quicklime at a rate of approximately 100 kg / min. After adding the material, let it stand for 2 hours, and then take samples to analyze the degradation rate of mycotoxins. It was confirmed that the degradation rates of the five major mycotoxins were all above 90% (among which aflatoxin B1 and zearalenone reached degradation rates of over 98%).

[0088] Restart the stirring, set the speed to 12 rpm, and gradually add 800 kg of phosphoric acid, controlling the flow rate at approximately 50 kg / min. After the addition is complete, continue stirring for 10 minutes, and take a sample for analysis; the pH value is 6.95.

[0089] Continue adding 3000 kg of glucose, maintaining a flow rate of 200 kg / min. After adding the glucose, continue stirring for 30 minutes to ensure complete dissolution.

[0090] The temperature of the corn steep liquor was measured at 35℃ (at which time the ambient air temperature was 24℃).

[0091] stand-by.

[0092] ② Mixed inoculation In the fermentation tank, add 12 tons of corn husks, 8 tons of corn cob powder, 8 kg of cellulase, 8 kg of xylanase, and 200 kg of Bacillus subtilis powder in sequence. Finally, add 60 tons of corn steep liquor (containing hydrogen peroxide, quicklime, phosphoric acid, etc.) that has undergone detoxification treatment in step ① above. Mix the liquor evenly using a turning machine. Then distribute it evenly in the fermentation tank.

[0093] ③ Turning and fermenting Based on data transmitted from the probe sensors, the temperature of the material is controlled to not exceed 40℃. Once the temperature of the material exceeds 40℃, the turning and tumbling process is initiated.

[0094] When the moisture content of the fermentation material is below 36%, add all the remaining detoxified corn syrup (control the material thickness to not exceed 45cm) and restart the turning and fermentation process.

[0095] Stop turning and turning when the moisture content of the material drops below 33%, and let it stand for 8 hours before proceeding to the next stage of drying.

[0096] The entire operation takes about 34 hours, of which the fermentation process takes about 26 hours.

[0097] ④ Airflow drying The fermented product was air-dried in a drum dryer, and a total of 73.2 tons of dried product was obtained, with a moisture content of 10.2%, a protein content of 28.8%, a calcium lactate content of 13.4%, and a dicalcium phosphate content of 1.32%.

[0098] Protein, calcium lactate, and dicalcium phosphate are all excellent raw materials for animal feed and can be used in the production of animal feed (especially for laying hens and growing-finishing pigs).

[0099] The price of this dried product can reach at least 2,400 yuan per ton, and this batch can generate a profit of more than 50,000 yuan, making the economic benefits extremely significant.

[0100] The present invention has been described in detail above. For those skilled in the art, the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope, and without requiring unnecessary experiments. Although specific embodiments have been given, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including changes made using conventional techniques known in the art that depart from the scope disclosed herein. Some of the essential features can be applied within the scope of the following appended claims.

Claims

1. A method for recovering animal feed nutrients from corn steep liquor, comprising the following steps: 1) Detoxification treatment of corn steep liquor Hydrogen peroxide is added to corn steep liquor to oxidize the sulfites, reducing the sulfite content to below 0.5 mmol / L or the sulfur dioxide concentration to below 30.0 ppm. Then, quicklime is used to adjust the pH of the corn steep liquor to 12.0 or higher to degrade the mycotoxins. Next, phosphoric acid is used to adjust the alkalized corn steep liquor, bringing its pH back to between 6.8 and 7.

2. Fermentable sugars are then added and stirred thoroughly to obtain detoxified corn steep liquor. The temperature of the detoxified corn steep liquor is then adjusted to between 34 and 40°C. 2) Solid-state fermentation of virus-free corn steep liquor Corn husks, corn cob powder, cellulase, xylanase, and fermentation bacteria are poured into a fermentation tank. Finally, some of the detoxified corn syrup is added, and the mixture is evenly mixed by turning and tossing. Then, it is evenly distributed in the fermentation tank for fermentation to obtain fermented product. During the fermentation process, if the material temperature does not exceed 40℃, static fermentation is used; if it exceeds 40℃, turning and stirring fermentation is started. When the moisture content of the material is below 36% during the fermentation process, add detoxified corn syrup and restart the turning and fermentation process. 3) The fermented material is dried by airflow to obtain the fermented product, which is a nutrient for animal feed.

2. The method according to claim 1, characterized in that: In step 1), the mass ratio of corn steep liquor to hydrogen peroxide is 100:(7-8), wherein the H2O2 content in the hydrogen peroxide is ≥ 27.5%. And / or, the process of adding hydrogen peroxide requires stirring. After the feeding is completed, stop stirring and let it stand for 1-3 hours.

3. The method according to claim 1 or 2, characterized in that: In step 1), the mass ratio of corn syrup to quicklime is 100:(4-4.5), wherein the CaO content in the quicklime is ≥92.0%; And / or, the process of adding quicklime requires stirring. After feeding is completed, stop stirring and let it stand for 2 to 4 hours.

4. The method according to any one of claims 1-3, characterized in that: In step 1), the amount of fermentable sugar added is 2%-4% of the mass of corn steep liquor; And / or, the fermentable sugars include, but are not limited to, glucose, sucrose, maltose, and fructooligosaccharides.

5. The method according to any one of claims 1-4, characterized in that: In step 2), the mass ratio of corn husk, corn cob powder, cellulase, and xylanase is 3:2:0.002:0.002; wherein the cellulase activity is ≥1000 U / g; and the xylanase activity is ≥50,000 U / g. And / or, the mass ratio of corn husk, corn cob powder, and part of the detoxified corn steep liquor is 3:2:15; And / or, the fermentation bacteria are Bacillus subtilis, and the initial viable bacteria content in the mixture is controlled between 200 million CFU / g and 500 million CFU / g.

6. The method according to any one of claims 1-5, characterized in that: The mass ratio of corn syrup, corn husk and corn cob powder in step 1) is controlled between 20:3:2 and 25:3:

2.

7. The method according to any one of claims 1-6, characterized in that: In step 2), the corn cob powder is corn cob powder that has been crushed to a mesh size of 60 or higher.

8. The method according to any one of claims 1-7, characterized in that: In step 2), the replenishment of detoxified corn syrup is done in a one-time replenishment manner, that is, all the remaining detoxified corn syrup prepared according to the plan is added to the fermentation tank at once, and no further replenishment is made even if the moisture content of the material drops below 36% again in the subsequent process.

9. The method according to any one of claims 1-8, characterized in that: In step 2), when the moisture content of the material is below 33% and the material temperature no longer rises during the fermentation process, stop turning and tossing, and then let it stand for 4-8 hours before proceeding to the next step. And / or, during fermentation, control the maximum stacking thickness of the material to not exceed 45cm.

10. The method according to any one of claims 1-9, characterized in that: In step 3), the moisture content of the fermented product is controlled below 12%; And / or, the fermented product is used in animal feed, particularly in laying hen and / or growing-finishing pig feed.

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