Fermentation liquid recycling treatment process

Abstract

The invention discloses a fermentation liquor recycling treatment process, and relates to the technical field of white spirit fermentation liquor recycling, and the method comprises the following steps: collecting fermentation liquor of Maotai-flavor white spirit, distinguishing the fermentation liquor based on a white spirit preparation process, including Kunsha process fermentation liquor and broken sand process fermentation liquor, and recycling the Kunsha process fermentation liquor and the broken sand process fermentation liquor. Collecting percolate in the fermentation process of the fermentation liquor in a pipeline drainage mode, and distinguishing the stages of the percolate based on the pH of the percolate, the total organic matter and the nitrogen and phosphorus content; the method comprises the following steps: respectively adding different yeasts for further fermentation on the basis of different wine making processes aiming at the fermentation liquor to ensure that the alcoholic strength is greater than 5% so as to obtain yeast fermentation liquor, and respectively carrying out enzymolysis reaction and molecular predecomposition aiming at leachate at different stages so as to obtain enzymatic hydrolysate. Based on the difference of different processes in the Maotai wine making process, the fermentation liquid of the kunsha and the crushed sand process is identified, meanwhile, the leachate separated out in the fermentation process is collected, and the fermentation liquid is subjected to multi-stage classification recycling.

Description

Technical Field

[0001] The present invention relates to the technical field of the recycling of Baijiu fermentation broth, and more specifically, to a processing technology for the recycling of fermentation broth. Background Art

[0002] Baijiu fermentation broth is a complex liquid mixture formed after a series of microbial metabolic activities during the Baijiu brewing process. In the production process of Maotai-flavor Baijiu, the fermentation cycle of fermented grains is long, and significant differences in the water quality of fermentation broth exist in different fermentation stages due to different preparation processes. In addition to containing organic substances such as alcohols, esters, acids, and aldehydes, the fermentation broth also contains rich sugars, proteins, humic acids, amino acids, vitamins, etc. The types of nutrients are rich, and it has extremely high recycling value;

[0003] The traditional treatment method is to mix it with production wastewater, bottom pot water, workshop and equipment flushing water, bottle washing water, cooling tower sewage discharge water, etc. and send it to the sewage treatment system for treatment. Since the organic matter, nitrogen, and phosphorus content in the fermentation broth is high, fluctuates greatly with the production cycle, and the composition is complex, in order to ensure that the discharged water after treatment meets the standards stably, it needs to be designed according to the peak values of the organic matter, nitrogen, and phosphorus concentrations, which will consume a large amount of infrastructure investment and a large amount of chemical reagents and energy during the treatment process, and the treatment cost is high. At the same time, leachate containing different components will be precipitated in different stages of fermentation, further increasing the cost of recycling the fermentation broth.

[0004] In view of the problems in the related art, no effective solution has been proposed yet. Summary of the Invention

[0005] In view of the problems in the related art, the present invention provides a processing technology for the recycling of fermentation broth to overcome the above technical problems existing in the existing related technologies.

[0006] Therefore, the specific technical solution adopted by the present invention is as follows:

[0007] A processing technology for the recycling of fermentation broth, the method comprising the following steps:

[0008] S1. Collect the fermentation broth of Maotai-flavor Baijiu, distinguish the fermentation broth based on the Baijiu preparation process, including the fermentation broth of the Kunsha process and the fermentation broth of the broken grains and fermented grains process, collect the leachate exuded during the fermentation of the fermentation broth through pipeline drainage, and distinguish the leachate stage based on the pH, total organic matter, and nitrogen and phosphorus content of the leachate;

[0009] S2. For the fermentation broth, different yeasts are added for further fermentation based on different Baijiu-making processes to ensure that the alcohol content > 5%, and yeast fermentation broth is obtained. At the same time, enzymatic hydrolysis reactions and molecular pre-decomposition are respectively carried out on the leachate in different stages to obtain enzymatic hydrolysates;

[0010] S3. Ultrafilter the yeast fermentation broth and enzymatic hydrolysate through a molecular weight cut-off gradient membrane module to retain macromolecular substances and allow small molecular substances to pass through, obtaining a concentrated solution and a clear solution, which are separately collected and stored in professional storage tanks;

[0011] S4. Mix the concentrated solution with the fermented plants and put them into an anaerobic fermentation tank for fermentation at room temperature. Utilize the residual enzymes and microbial activity to enhance nutrient adsorption, and make organic fertilizer granules or protein feed through spray drying;

[0012] S5. After the clear solution is subjected to triple-effect evaporation, collect the evaporation condensate and the concentrated water through a condensate collection system. The condensate is separated by a plate rectification column to obtain the overhead distillate ethanol and the bottom liquid organic acid concentrated solution, which are stored through a fraction collector;

[0013] S6. Adopt multiple utilization means for the concentrated water for recycling, including directly using it as a liquid feed additive and quantitatively transporting it to the farm storage tank through a metering pump, mixing it with the fermented plants in S4 and secondary drying it through a paddle dryer to make a compound organic fertilizer, and refluxing it to the anaerobic fermentation tank in S4 to supplement the nutrients in the fermentation system.

[0014] As a preferred embodiment, S1 includes the following steps:

[0015] S11. Collect the fermentation broth of Maotai-flavor liquor. According to the liquor preparation process, divide it into the fermentation broth of the Kunsha process and the fermentation broth of the broken grains and fermented grains process;

[0016] S12. Collect the leachate seeping out during the fermentation of the fermentation broth by means of pipeline drainage. Detect the pH, total organic matter, and nitrogen and phosphorus contents of the collected leachate. According to the detection results, distinguish the leachate stages, including the early-stage leachate, the mid-stage leachate, and the late-stage leachate, including the following steps:

[0017] Collect the historical data of the pH, total organic matter, and nitrogen and phosphorus contents of the early-stage leachate, mid-stage leachate, and late-stage leachate. Through θ k =μ k ±σ k Fit the stage boundaries of the parameters of different leachate stages, where θ k represents the boundary of the parameter k in the historical stage, and μ k , σ k represent the mean and standard deviation of the parameter k in the historical stage respectively. According to the pH, total organic matter, and nitrogen and phosphorus contents of the collected leachate, combined with the boundaries of the parameters in different historical stages, match the stage of the collected leachate and mark the stage of the leachate.

[0018] As a preferred embodiment, S2 includes the following steps:

[0019] S21. Based on the collected fermented liquid of Maotai-flavor Baijiu, for the fermented liquid of the Kunsha process, add acid-tolerant Saccharomyces cerevisiae, control the temperature range at 30 - 35 °C, set the fermentation time at 48 - 72 hours to promote the synthesis of esters, ensure that the measured alcohol content > 5%, and obtain the yeast fermented liquid;

[0020] S22. Based on the collected fermented liquid of Maotai-flavor Baijiu, for the fermented liquid of the broken-sand process, add ester-producing yeast, control the temperature range at 25 - 30 °C, and the fermentation time at 24 - 36 hours to quickly increase the alcohol content to > 5% and obtain the yeast fermented liquid;

[0021] S23. For the early-stage leachate, add a saccharifying enzyme complex preparation and react at 50 - 55 °C for 12 hours to convert polysaccharides into monosaccharides and obtain the enzymolysis solution. For the mid-stage leachate, add protease and lipase and react at 45 - 50 °C for 24 hours to degrade proteins into small peptides and obtain the enzymolysis solution. For the late-stage leachate, add cellulase and xylanase and react at 55 - 60 °C for 36 hours to decompose the lignocellulose structure and obtain the enzymolysis solution.

[0022] As a preferred embodiment, in S3, ultrafiltration membrane separation is performed on the yeast fermented liquid and the enzymolysis solution through a gradient membrane module. The first stage is a 10 kDa membrane, which retains humic acid and macromolecular proteins with a molecular weight > 10 kDa in the yeast fermented liquid and the enzymolysis solution. The second stage is a 5 kDa membrane, which intercepts the humic acid components with a molecular weight of 5 - 10 kDa that slip through the net and some medium-molecular polysaccharides.

[0023] As a preferred embodiment, in S4, the fermented plant is straw powder or bran, the mass ratio of the concentrated liquid to the fermented plant is 1:2, the inlet air temperature for spray drying is 200 °C, the outlet air temperature is 85 °C, the organic matter in the organic fertilizer granules ≥ 40%, and the crude protein in the protein feed ≥ 25%.

[0024] As a preferred embodiment, in S5, the clear liquid is subjected to triple-effect evaporation, where the temperature of the first effect is 80 °C, the temperature of the second effect is 60 °C, the temperature of the third effect is 40 °C, and 35% of the water in the clear liquid is evaporated.

[0025] As a preferred embodiment, the number of trays in the plate rectifying column is 20 - 30 layers, the alcohol content of the ethanol in the distillate at the top of the column, the total acid of the organic acid concentrate in the bottom liquid of the column, the temperature at the top of the column is 78 - 82 °C, ethanol with an alcohol content ≥ 50% is collected for Baijiu blending, and the bottom residue is concentrated to obtain food-grade organic acids.

[0026] As a preferred embodiment, S6 includes the following steps:

[0027] S61. Directly use the concentrated water as a liquid feed additive and quantitatively transport it to the storage tank of the farm through a metering pump;

[0028] S62. Mix the concentrated water and the fermented plant powder in S4 at a mass ratio of 1:3, and indirectly heat it through a paddle dryer. Set the temperature to 80 - 100 °C and dry until the moisture content ≤ 10% to obtain compound organic fertilizer.

[0029] S63. Continuously add the concentrated water at 10 - 15% of the volume of the anaerobic fermentation tank to supplement the nutrients in the fermentation system.

[0030] The beneficial effects of the present invention are as follows:

[0031] 1. Based on the differences in different processes during the production of sauce-flavored liquor, the present invention identifies the fermented liquids of the Kunsha and crushed sand processes, and simultaneously collects the leachate separated out during the fermentation process. By fitting the stage boundaries using the historical data of pH, total organic matter, and nitrogen and phosphorus contents, the leachate in different stages is identified. For the fermented liquids under different processes and the leachate in different stages, corresponding yeasts and enzymes are added for further reactions, so as to facilitate the subsequent separation to obtain concentrated liquid and clear liquid, realizing efficient recycling, improving the resource utilization rate in the production process, reducing the generation of waste. At the same time, the fermented liquid and leachate contain a large amount of organic matter and nutrients. Through further reactions and separations, these resources are converted into valuable products, reducing production costs.

[0032] 2. Through ultrafiltration separation by a gradient membrane module, the 10 kDa and 5 kDa membranes are used to intercept macromolecular humic acid, protein, and polysaccharide step by step, realizing the efficient enrichment of macromolecular humic acid and the directional separation of small-molecule clear liquid in the enzymolysis liquid and yeast fermented liquid, facilitating the subsequent separate recovery and reuse of the separated concentrated liquid and clear liquid, and improving the recycling efficiency of the fermented liquid.

[0033] 3. Through the mixed anaerobic fermentation and spray drying of the concentrated liquid with straw powder / bran, the production of organic matter organic fertilizer and crude protein feed from the concentrated liquid is realized, achieving the high-value utilization of the solid phase of the concentrated liquid. Through triple-effect evaporation combined with a plate rectification column, the efficient recovery of ethanol and organic acids in the clear liquid is achieved, which can be directly used for liquor blending and the production of food-grade acids.

[0034] 4. Through the multiple reuse of concentrated water, liquid feed addition, compound organic fertilizer drying, or anaerobic system nutrient replenishment is selected for concentrated water, which facilitates the flexible selection of processes in the actual recycling treatment process, strengthens the coordinated operation of multiple steps in the recycling treatment system, and improves the practicability and functionality. Description of the Drawings

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0036] Figure 1 It is a flowchart of the process steps of a fermentation broth recycling and utilization treatment process according to an embodiment of the present invention;

[0037] Figure 2 It is a process demonstration diagram of a fermentation broth recycling and utilization treatment process according to an embodiment of the present invention. Detailed implementation manners

[0038] To further illustrate the embodiments, the present invention provides drawings. These drawings are part of the disclosure of the present invention. They are mainly used to illustrate the embodiments and can be combined with the relevant descriptions in the specification to explain the operation principle of the embodiments. With reference to these contents, those of ordinary skill in the art should be able to understand other possible implementation manners and the advantages of the present invention. The components in the drawings are not drawn to scale, and similar component symbols are usually used to represent similar components.

[0039] According to an embodiment of the present invention, a fermentation broth recycling and utilization treatment process is provided.

[0040] Now, the present invention will be further described in combination with the drawings and detailed implementation manners:

[0041] Embodiment 1:

[0042] As Figure 1 - Figure 2 shown, a fermentation broth recycling and utilization treatment process according to an embodiment of the present invention includes the following steps:

[0043] S1. Collect the fermentation broth of Maotai-flavor liquor, distinguish the fermentation broth based on the liquor preparation process, including the fermentation broth of the Kunsha process and the fermentation broth of the crushed grains process. Collect the leachate exuded during the fermentation of the fermentation broth through pipeline drainage, and distinguish the leachate stage based on the pH, total organic matter, and nitrogen and phosphorus content of the leachate;

[0044] S11. Collect the fermentation broth of Maotai-flavor liquor and divide it into the fermentation broth of the Kunsha process and the fermentation broth of the crushed grains process according to the liquor preparation process;

[0045] It should be noted that there are differences in composition and characteristics between the fermentation broth of the Kunsha process and the fermentation broth of the crushed grains process. The Kunsha process has a long fermentation period and high raw material integrity. The fermentation broth has relatively complex components and rich flavor substances. The crushed grains process has a short fermentation period and high raw material pulverization degree, and the fermentation broth has relatively simple components.

[0046] S12. Collect the leachate seeping out during the fermentation process of the fermentation broth by means of pipeline drainage, detect the pH, total organic matter, and nitrogen and phosphorus contents of the collected leachate, and distinguish the leachate stages according to the detection results, including the early-stage leachate, mid-stage leachate, and late-stage leachate, which includes the following steps:

[0047] Collect the historical data of the pH, total organic matter, and nitrogen and phosphorus contents of the early-stage leachate, mid-stage leachate, and late-stage leachate, and use θ k = μ k ± σ k to fit the stage boundaries of the parameters in different leachate stages, where θ k represents the boundary of the parameter k in the historical stage, and μ k , σ k represent the mean and standard deviation of the parameter k in the historical stage respectively. According to the pH, total organic matter, and nitrogen and phosphorus contents of the collected leachate, combined with the boundaries of the parameters in different historical stages, match the stage of the collected leachate and mark the stage of the leachate.

[0048] It should be noted that when detecting the pH, total organic matter, and nitrogen and phosphorus contents of the collected leachate, use a pH sensor to detect the pH value of the collected leachate, determine the total organic matter of the collected leachate by high-temperature catalytic combustion method, and determine the nitrogen and phosphorus contents of the collected leachate by potassium persulfate oxidation-ultraviolet spectrophotometry and ammonium molybdate spectrophotometry. The early-stage leachate is characterized by high sugar and alcohols, the mid-stage leachate is rich in high amino acids and organic acids, and the late-stage leachate contains high humic acid and macromolecular proteins. During the process of matching the stage of the collected leachate, by comparing the parameter values of the collected leachate with the upper and lower limits of the historical stage, when all parameters meet the parameter range of a certain stage, it represents a successful match. The boundaries of the parameter contents of leachate in different historical stages are shown in Table 1:

[0049] Table 1: Table of parameter content boundaries of leachate in different stages

[0050] Parameter Early stage range Mid - stage range Late stage range pH 3.5-4.5 4.5-5.5 5.5-6.5 Total organic matter 150 - 180 g / L 100 - 150 g / L 80 - 100 g / L Total nitrogen 3.0 - 4.0 g / L 4.0 - 6.0 g / L 3.5 - 4.0 g / L Total phosphorus 0.8 - 1.5 g / L 1.5 - 3.0 g / L 1.0 - 1.5 g / L

[0051] S2. For the fermentation broth based on different liquor-making processes, add different yeasts for further fermentation respectively to ensure that the alcohol content > 5%, and obtain yeast fermentation broth. At the same time, carry out enzymatic hydrolysis reaction and molecular pre-decomposition for the leachate in different stages respectively to obtain enzymatic hydrolysate;

[0052] S21. Based on the collected fermentation broth of Maotai-flavor liquor, for the fermentation broth of Kunsha process, add acid-tolerant brewing yeast, control the temperature range at 30 - 35 °C, set the fermentation time at 48 - 72 hours to promote the synthesis of esters, and ensure that the measured alcohol content > 5% to obtain yeast fermentation broth;

[0053] S22. Based on the collected fermented liquid of Jiangxiang-style Baijiu, for the fermented liquid of the broken grains process, add ester-producing yeast, control the temperature range at 25 - 30 °C, and the fermentation time at 24 - 36 hours to rapidly increase the alcohol content to >5%, obtaining yeast fermented liquid;

[0054] It should be noted that the fermented liquid of the whole grains process is in a high-acid and high-temperature environment for a long time, and the yeast needs to have acid and heat resistance characteristics to survive and continue metabolism. For example, the Saccharomyces cerevisiae CICC3100 series. The broken grains process breaks the raw materials, resulting in a high viscosity and low dissolved oxygen in the fermented liquid. The yeast needs to quickly initiate metabolism at low temperature and complete ethanol accumulation in a short time. For example, Pichia pastoris. In the fermented liquid, yeast fermentation is used to strengthen ethanol and flavor substances, and at the same time, some complex organic substances are decomposed.

[0055] S23. For the early-stage leachate, add a saccharifying enzyme complex preparation and react at 50 - 55 °C for 12 hours to convert polysaccharides into monosaccharides, obtaining an enzymolysis solution. For the mid-stage leachate, add protease and lipase and react at 45 - 50 °C for 24 hours to degrade proteins into small peptides, obtaining an enzymolysis solution. For the late-stage leachate, add cellulase and xylanase and react at 55 - 60 °C for 36 hours to decompose the lignocellulose structure, obtaining an enzymolysis solution.

[0056] It should be noted that the early-stage leachate contains high levels of sugar alcohols. Through a saccharifying enzyme complex preparation such as α-amylase and saccharifying enzyme, polysaccharides are converted into monosaccharides. The mid-stage leachate has a high amino acid content. Through protease and lipase, proteins are degraded into small peptides to release amino acids. The late-stage leachate is rich in humic acid. Through cellulase and xylanase, the lignocellulose structure is decomposed to release the active components of humic acid.

[0057] S3. Perform ultrafiltration membrane separation on the yeast fermented liquid and the enzymolysis solution through a retention molecular weight gradient membrane module, retain macromolecular substances and allow small molecular substances to pass through, obtaining a concentrate and a clear liquid, and separately collect and store them in professional storage tanks;

[0058] In S3, ultrafiltration membrane separation is performed on the yeast fermented liquid and the enzymolysis solution through a gradient membrane module. The first stage is a 10 kDa membrane, which retains humic acid and macromolecular proteins with a molecular weight >10 kDa in the yeast fermented liquid and the enzymolysis solution. The second stage is a 5 kDa membrane, which intercepts the remaining humic acid components with a molecular weight of 5 - 10 kDa and some medium molecular polysaccharides.

[0059] It should be noted that the first-stage membrane is a spiral-wound ultrafiltration membrane made of polyethersulfone (PES) with a molecular weight cut-off of 10 kDa and an operating pressure of 0.8 - 1.2 MPa. The second-stage membrane is a flat-sheet ultrafiltration membrane made of polyvinylidene fluoride (PVDF) with a molecular weight cut-off of 5 kDa and an operating pressure of 1.0 - 1.5 MPa. During the separation process, the permeate of the first-stage membrane is directly pumped into the feed side of the second-stage membrane to avoid the risk of contamination in the intermediate storage tank. The cleaning cycle of the first-stage membrane is backwashing with alkaline solution every 8 hours, and the cleaning cycle of the second-stage membrane is backwashing with oxidant and alkaline solution every 4 hours. After ultrafiltration separation, the concentrated liquid side retains macromolecular substances including undegraded proteins, humic acids, and some polysaccharides, while the clear liquid side permeates small molecules including amino acids, monosaccharides, ethanol, organic acids, and minerals.

[0060] S4. Mix the concentrated liquid with fermented plants and put them into an anaerobic fermentation tank for fermentation at room temperature. Utilize the residual enzymes and microbial activity to enhance nutrient adsorption, and make organic fertilizer granules or protein feed through spray drying.

[0061] In S4, the fermented plants are straw powder or bran. The mass ratio of the concentrated liquid to the fermented plants is 1:2. The inlet air temperature of spray drying is 200 °C, and the outlet air temperature is 85 °C. The organic matter in the organic fertilizer granules is ≥ 40%, and the crude protein in the protein feed is ≥ 25%.

[0062] S5. After triple-effect evaporation of the clear liquid, collect the evaporated condensate and concentrated water through a condensate collection system. The condensate is separated by a plate rectification column to obtain the overhead distillate ethanol and the bottom liquid organic acid concentrate, which are stored through a fraction collector.

[0063] In S5, for the triple-effect evaporation of the clear liquid, the temperature of the first effect is 80 °C, the temperature of the second effect is 60 °C, and the temperature of the third effect is 40 °C. 35% of the water in the clear liquid is evaporated. The number of trays in the plate rectification column is 20 - 30. The alcohol content of the overhead distillate ethanol and the total acid of the bottom liquid organic acid concentrate. The overhead temperature is 78 - 82 °C. Collect ethanol with an alcohol content ≥ 50% for blending in white liquor. The bottom residue is concentrated to obtain food-grade organic acids.

[0064] It should be noted that the condensate contains ethanol and esters and enters the rectification system for recycling. The concentrated water contains free amino acids and vitamins and is recycled using multiple methods.

[0065] S6. Adopt multiple utilization methods for the concentrated water for recycling, including directly using it as a liquid feed additive and quantitatively transporting it to the storage tank of the farm through a metering pump, mixing it with the fermented plants in S4 and secondarily drying it through a paddle dryer to make compound organic fertilizer, and returning it to the anaerobic fermentation tank in S4 to supplement the nutrients in the fermentation system.

[0066] S6 includes the following steps:

[0067] S61. Directly use the concentrated water as a liquid feed additive and quantitatively transport it to the storage tank of the farm through a metering pump;

[0068] S62. Mix the concentrated water with the fermented plant powder in S4 at a mass ratio of 1:3, indirectly heat it through a paddle dryer, set the temperature at 80 - 100 °C and dry it until the moisture content ≤ 10%, to obtain a compound organic fertilizer;

[0069] S63. Continuously add the concentrated water at 10 - 15% of the volume of the anaerobic fermentation tank to supplement the nutrition of the fermentation system.

[0070] It should be noted that when the concentrated water is refluxed to the anaerobic fermentation tank to supplement nutrition, the amino acids, vitamins and minerals in the concentrated water are used as carbon and nitrogen sources to be supplemented into the anaerobic fermentation system, promoting the microbial metabolic activity, reducing the input of external nutritional additives, so as to realize the process internal circulation. The water-soluble nutrients in the concentrated water are combined with the fiber matrix in the plant powder to enhance the slow-release property and soil improvement ability of the compound organic fertilizer.

[0071] Comparative Example 1:

[0072] Use a single 10 kDa ultrafiltration membrane with a material of polyethersulfone and a nominal retention molecular weight of 10 kDa to perform ultrafiltration membrane separation on yeast fermentation broth and enzymatic hydrolysate, with other parameters unchanged;

[0073] Experimental Example 1:

[0074] Analyze the interception parameters of the clear liquid obtained after ultrafiltration separation in Example 1 and Comparative Example 1, as shown in Table 2: Table 2: Interception parameter analysis table

[0075] Parameter Comparative Example 1 Example 1 Humic acid retention rate 78％-82％ 94％-96％ Residual amount of humic acid in the clear liquid 1.1 - 1.3 g / L ≤0.5 g / L Retention rate of macromolecular protein 92％-94％ 94％-97％ Retention rate of medium - molecular polysaccharide 45％-55％ 75％-85％

[0076] It can be seen from Table 2 that due to the wide molecular weight distribution and uneven membrane pore size of the single 10 kDa membrane in Comparative Example 1, there is penetration of low molecular weight humic acid with a molecular weight of 5 - 10 kDa. In Example 1, the gradient membrane group supplements the interception of the missed 5 - 10 kDa components through the secondary 5 kDa membrane, increasing the total interception rate to over 94%, and the residue in the clear liquid ≤ 0.5 g / L. The single membrane in Comparative Example 1 cannot cover the entire molecular weight range of humic acid, and the interception rate of medium molecular polysaccharides is only 45% - 55%. In Example 1, the gradient membrane group divides the work through two-stage membranes, intercepting macromolecules at the first stage and intercepting the missed and medium molecules at the second stage, realizing the synergistic and efficient interception of humic acid, polysaccharides and proteins;

[0077] Among them, the humic acid concentration is detected by ultraviolet spectrophotometry, the total organic matter is measured by a TOC analyzer, and the interception rate is based on the formula Calculations were carried out 10 times respectively for the operation methods of Example 1 and Comparative Example 1. The minimum and maximum values of the humic acid retention rate, macromolecular protein retention rate, and medium molecular polysaccharide retention rate in the 10 experiments were retained as the lower and upper limits respectively. The humic acid residue in the supernatant of Comparative Example 1 was the minimum and maximum values of the humic acid residue in the supernatant in the 10 experiments, and the humic acid residue in the supernatant of Example 1 was the maximum value in the 10 experiments.

[0078] In summary, based on the differences in different processes during the production of soy sauce-flavored liquor, the invention identifies the fermentation broths of the Kunsha and Suisha processes, and simultaneously collects the leachate precipitated during the fermentation process. The stage boundaries are fitted using the historical data of pH, total organic matter, and nitrogen and phosphorus contents to identify the leachate at different stages. For the fermentation broths under different processes and the leachate at different stages, corresponding yeasts and enzymes are added for further reactions, so as to facilitate the subsequent separation to obtain the concentrate and the supernatant, realizing efficient recycling, improving the utilization rate of resources in the production process, reducing the generation of waste. At the same time, the fermentation broth and leachate contain a large amount of organic matter and nutrients. Through further reactions and separations, these resources are converted into valuable products, reducing production costs.

[0079] Through ultrafiltration separation by a gradient membrane module, macromolecular humic acid, protein, and polysaccharide are intercepted step by step with 10 kDa and 5 kDa membranes, realizing the efficient enrichment of macromolecular humic acid in the enzymatic hydrolysate and yeast fermentation broth and the directional separation of the small molecule supernatant, facilitating the subsequent separate recovery and reuse of the separated concentrate and supernatant, improving the recycling efficiency of the fermentation broth. Through the anaerobic fermentation of the concentrate with straw powder / bran and spray drying, the production of organic matter organic fertilizer and crude protein feed from the concentrate is realized, achieving the high-value utilization of the solid phase of the concentrate. Through triple-effect evaporation combined with a plate rectifying column, the efficient recovery of ethanol and organic acids in the supernatant is achieved, which can be directly used for liquor blending and the production of food-grade acids.

[0080] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A fermentation broth recycling and treatment process, characterized in that, The method includes the following steps: S1. Collect the fermentation broth of Jiangxiang-flavor Baijiu, distinguish the fermentation broth based on the Baijiu preparation process, including the fermentation broth of Kunsha process and that of Suisha process. Collect the leachate exuded during the fermentation of the fermentation broth by means of pipeline drainage, and distinguish the leachate stage based on the pH, total organic matter, and nitrogen and phosphorus contents of the leachate; S2. For the fermentation broth, based on different Baijiu-making processes, add different yeasts for further fermentation to ensure that the alcohol content > 5%, and obtain yeast fermentation broth. At the same time, carry out enzymatic hydrolysis reaction and molecular pre-decomposition on the leachate at different stages respectively to obtain enzymatic hydrolysate; S3. Carry out ultrafiltration membrane separation on the yeast fermentation broth and enzymatic hydrolysate through an ultrafiltration membrane module with a cut-off molecular weight gradient, retain macromolecular substances and allow small molecular substances to pass through, obtain concentrated liquid and clear liquid, and collect and store them in professional storage tanks respectively; S4. Mix the concentrated liquid with fermented plants and put them into an anaerobic fermentation tank for fermentation at room temperature, utilize the residual enzymes and microbial activity to enhance nutrient adsorption, and make organic fertilizer granules or protein feed through spray drying; S5. After triple-effect evaporation of the clear liquid, collect the evaporation condensate and concentrated water through a condensate collection system. The condensate is separated by a plate rectifying column to obtain the overhead distillate ethanol and the bottom liquid organic acid concentrated liquid, and store them through a fraction collector; S6. Adopt multiple utilization means for the concentrated water for recycling, including directly using it as a liquid feed additive and quantitatively transporting it to the storage tank of the farm through a metering pump, mixing it with the fermented plants in S4 and secondarily drying it through a paddle dryer to make compound organic fertilizer, and refluxing it to the anaerobic fermentation tank in S4 to supplement the nutrients of the fermentation system; 2. The recycling treatment process of the fermentation broth according to claim 1, characterized in that, The S1 includes the following steps: S11. Collect the fermentation broth of Jiangxiang-flavor Baijiu, and divide it into the fermentation broth of Kunsha process and that of Suisha process according to the Baijiu preparation process; S12. Collect the leachate exuded during the fermentation of the fermentation broth by means of pipeline drainage, detect the pH, total organic matter, and nitrogen and phosphorus contents of the collected leachate, and distinguish the leachate stage according to the detection results, including the early-stage leachate, middle-stage leachate, and late-stage leachate. The steps are as follows: Collect historical data on the pH, total organic matter, nitrogen and phosphorus content of leachate in the early, middle and late historical periods, and through θ k = μ k ± σ k Fit the stage boundaries of parameters for different leachate stages, where θ k represents the boundary of parameter k in the historical stage, μ k , σ k represent the mean and standard deviation of parameter k in the historical stage respectively. Based on the pH, total organic matter, nitrogen and phosphorus content of the collected leachate, combined with the boundaries of parameters in different historical stages, match the stage of the collected leachate and mark the stage of the leachate.

3. A fermentation broth recycling treatment process according to claim 1, characterized in that, The S2 includes the following steps: S21. Based on the collected fermentation broth of Jiangxiang-flavor Baijiu, for the fermentation broth of Kunsha process, add acid-tolerant Saccharomyces cerevisiae, control the temperature range at 30 - 35 °C, set the fermentation time at 48 - 72 hours to promote ester synthesis, and ensure that the measured alcohol content > 5% to obtain yeast fermentation broth; S22. Based on the collected fermentation broth of Jiangxiang-flavor Baijiu, for the fermentation broth of Suisha process, add ester-producing yeast, control the temperature range at 25 - 30 °C, and the fermentation time at 24 - 36 hours to quickly increase the alcohol content to > 5% to obtain yeast fermentation broth; S23. For the early-stage leachate, add a glucoamylase complex preparation and react at 50 - 55 °C for 12 hours to convert polysaccharides into monosaccharides and obtain an enzymolysis solution. For the mid-stage leachate, add protease and lipase and react at 45 - 50 °C for 24 hours to degrade proteins into small peptides and obtain an enzymolysis solution. For the late-stage leachate, add cellulase and xylanase and react at 55 - 60 °C for 36 hours to decompose the lignocellulose structure and obtain an enzymolysis solution.

4. A fermentation broth recycling treatment process according to claim 1, characterized in that, In S3, ultrafiltration membrane separation is performed on the yeast fermentation broth and the enzymolysis solution through a gradient membrane module. The first stage is a 10 kDa membrane, which retains humic acids and macromolecular proteins with a molecular weight > 10 kDa in the yeast fermentation broth and the enzymolysis solution. The second stage is a 5 kDa membrane, which intercepts the humic acid components with a molecular weight of 5 - 10 kDa that have slipped through and some medium-molecular polysaccharides.

5. A fermentation broth recycling treatment process according to claim 1, characterized in that, In S4, the fermented plant is straw powder or bran. The mass ratio of the concentrated liquid to the fermented plant is 1:

2. The inlet air temperature for spray drying is 200 °C, and the outlet air temperature is 85 °C. The organic matter in the organic fertilizer granules is ≥ 40%, and the crude protein in the protein feed is ≥ 25%.

6. A fermentation broth recycling treatment process according to claim 1, characterized in that, In S5, the supernatant is subjected to triple-effect evaporation. The temperature of the first effect is 80 °C, the temperature of the second effect is 60 °C, and the temperature of the third effect is 40 °C, evaporating 35% of the water in the supernatant.

7. A fermentation broth recycling treatment process according to claim 6, characterized in that, The number of trays in the plate rectification column is 20 - 30 layers. The alcohol content of the ethanol in the overhead distillate, and the total acid of the organic acid concentrate in the bottom liquid. The overhead temperature is 78 - 82 °C. Ethanol with an alcohol content ≥ 50% is collected for liquor blending, and the bottom residue is concentrated to obtain food-grade organic acids.

8. A fermentation broth recycling treatment process according to claim 1, characterized in that, S6 includes the following steps: S61. Directly use the concentrated water as a liquid feed additive and quantitatively transport it to the farm storage tank through a metering pump; S62. Mix the concentrated water with the fermented plant powder in S4 at a mass ratio of 1:3, and indirectly heat it through a paddle dryer. Set the temperature at 80 - 100 °C and dry it until the moisture content ≤ 10% to obtain a compound organic fertilizer; S63. Continuously add the concentrated water at 10 - 15% of the volume of the anaerobic fermentation tank to supplement the nutrients in the fermentation system.

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