Resource utilization method of fermentation waste residues

Abstract

The invention relates to the technical field of waste residue utilization, in particular to a resource utilization method of fermentation waste residues, which comprises the following steps: (1) pretreating the fermentation waste residues; (2) extracting beneficial components from the pretreated fermentation waste residues; (3) carrying out modification treatment on the pretreated fermentation waste residues; and (4) preparing a functional material and a product based on the products in the steps (2) and (3), and through a method of combining enzymolysis and fermentation, not only is the extraction efficiency of protein and polysaccharide improved, but also in-situ generation of bioactive peptide is realized. In the process, the specific splitting action of the enzyme and the biotransformation action of microbial fermentation form a synergistic effect, so that the extraction efficiency is improved, and the biological activity of the product is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of waste residue utilization, in particular to a method for resource utilization of fermentation waste residue. Background Art

[0002] The resource utilization of fermentation waste residues has always been a key issue in the fields of bioengineering and environmental science. With the rapid development of the bio-fermentation industry, the generation of large amounts of waste residues has not only caused a serious environmental burden, but also wasted potential resources. These waste residues, such as the lees produced by alcohol fermentation, are typically characterized by containing multiple components such as proteins, polysaccharides, lignin, etc., and have a high water content and a complex physical and chemical structure. Traditional methods for treating fermentation waste residues mainly focus on low-value utilization methods such as composting and incineration, which not only have low economic benefits but may also cause secondary pollution.

[0003] In recent years, researchers have begun to explore ways to increase the value of fermentation waste residues. Among them, extracting beneficial ingredients, preparing functional materials, and producing bioenergy are the three main research directions. However, existing technologies still have many limitations. First, there is an essential contradiction in the optimal treatment conditions for different components in the waste residues. Protein extraction needs to be carried out under low temperature and mild conditions to maintain its activity, while the effective breaking of cellulose and lignin requires a high temperature and strong acid environment. This conflict in process conditions makes the traditional step-by-step treatment process complicated and inefficient. Secondly, traditional extraction processes often use large amounts of organic solvents, which are not only costly but also face environmental risks.

[0004] The bioenergy conversion process also presents key technical contradictions. Enzymatic hydrolysis of sugars requires temperatures between 50 and 55°C, but the monosaccharides produced at these temperatures are easily and rapidly fermented by bacteria to produce volatile fatty acids. However, anaerobic methane-producing methanogens are highly sensitive to organic acids, and increased acidity inhibits their activity, leading to fermentation failure. Existing anaerobic fermentation technologies struggle to effectively balance the disparate requirements of the hydrolysis-acidification and methanogenesis stages.

[0005] Furthermore, the effects of waste residue modification are unstable, and the performance of the functional materials produced varies widely. In particular, in the preparation of biosorbents and catalyst supports, it is difficult to simultaneously achieve high adsorption capacity and good selectivity. Catalyst supports also face problems such as low enzyme immobilization efficiency and poor operational stability. Finally, existing bioenergy conversion technologies suffer from low energy utilization efficiency. A single energy conversion pathway often fails to fully utilize the diverse organic components in waste residues, making large-scale application difficult.

[0006] The present invention addresses these issues by proposing a comprehensive and efficient method for resource utilization of fermentation waste residue. The core of this method lies in the establishment of a systematic, multi-step treatment process. Through innovative technical means, this method resolves key contradictions in the existing technology, achieving full utilization of waste residue components and high-value conversion. Summary of the Invention

[0007] The present invention addresses the above-mentioned issues and proposes a comprehensive and efficient method for resource utilization of fermentation waste residues. The core of this method is to establish a systematic multi-step treatment process to achieve full component utilization and high-value conversion of the waste residues.

[0008] The object of the present invention is to provide a method for resource utilization of fermentation waste residue, comprising the following steps: 1. A method for resource utilization of fermentation waste residue, characterized in that it comprises the following steps: (1) pre-treating the fermentation waste residue; (2) extracting beneficial components from the fermentation waste after pretreatment; (3) modifying the pretreated fermentation waste; (4) preparing functional materials and products based on the products of steps (2) and (3).

[0009] Preferably, the step (1) comprises: First, the fermentation waste residue is mechanically crushed using a high-speed shearing machine, the speed of the high-speed shearing machine is 3000-5000 rpm, and the crushing time is 5-15 minutes; Secondly, the crushed fermentation waste residue is dried by low-temperature vacuum drying, the drying temperature is 40-60°C, the vacuum degree is -0.08 to -0.09 MPa, and the drying time is 8-12 hours; Then, the dried fermentation waste residue is screened using a standard screening machine with a 100-mesh screen and a screening time of 15-20 minutes.

[0010] Preferably, the step (2) comprises protein extraction, polysaccharide extraction and bioactive peptide preparation, wherein: The protein extraction adopts deep eutectic solvent extraction or enzymatic hydrolysis; The polysaccharide extraction adopts hot water extraction method or microwave-assisted extraction method; The bioactive peptide is prepared by enzymatic hydrolysis or fermentation.

[0011] Preferably, the steps of the deep eutectic solvent extraction method include: First, the pretreated fermentation waste is placed in a reactor, and a recyclable deep eutectic solvent composed of choline chloride and glycerol in a molar ratio of 1:2 is added, and the temperature is controlled at 40°C and the pH is 6.5-7.0; Secondly, add papain, the amount of papain is 0.8-1.0 parts by weight of the fermentation waste, and treat under stirring conditions of 150-200 rpm for 10-15 minutes; Then, the extract is separated and the protein-containing solution portion is collected; Finally, CO2 is injected into the remaining waste residue to increase the pressure to 1.5-2.0 MPa, and a small amount of citric acid solution is sprayed in to adjust the pH to 3.0-3.5. The temperature is quickly raised to 160°C and maintained for 5-8 minutes to achieve rapid decomposition of cellulose.

[0012] Preferably, the step (3) comprises preparing a biosorbent and a biocatalyst support, wherein: The biosorbent is prepared by acid-base modification or graft copolymerization modification; The biocatalyst carrier is prepared by carbonization and porous treatment.

[0013] Preferably, the step of the graft copolymerization modification method comprises: First, the pretreated fermentation waste residue is immersed in 30-50 parts by weight of acrylamide monomer solution; Next, an initiator, ammonium persulfate, is added, wherein the amount of ammonium persulfate is 1-2 parts by weight of the acrylamide; Then, under a nitrogen atmosphere, react at 50-60°C for 4-6 hours; Finally, the reaction product was washed with ethanol and dried in vacuum.

[0014] Preferably, the step (4) comprises preparing biofertilizer and bioenergy, wherein: The preparation of the biological fertilizer includes the preparation of composite microbial agents and the preparation of organic-inorganic composite fertilizers; The preparation of the bioenergy includes preparing biogas by anaerobic fermentation of biomass and preparing bio-oil by pyrolysis of biomass.

[0015] Preferably, the components of the organic-inorganic composite fertilizer and parts by weight thereof are: The fermentation waste 60-70 parts by weight; 5-8 parts by weight of composite microbial agent; 10-15 parts by weight of phosphate rock powder, wherein the P2O5 content is ≥30%; 8-12 parts by weight of potassium feldspar powder, wherein the K2O content is ≥10%; Humic acid 3-5 parts by weight; 1-2 parts by weight of trace element mixture.

[0016] Preferably, the step of preparing biogas by anaerobic fermentation of biomass comprises: Firstly, a double-chamber continuous treatment system was designed, including a front-end hydrolysis chamber and a back-end anaerobic fermentation chamber; Secondly, in the front hydrolysis chamber, the fermentation waste residue is mixed with water in a weight ratio of 1:3-1:5, the pH is adjusted to 6.5-7.0, and immobilized cellulase is added in an amount of 0.8-1.2 parts by weight of the dry weight of the fermentation waste residue. The mixture is hydrolyzed at 55°C for 12-16 hours; Then, the sugar solution produced by hydrolysis is separated from the solid residue through a precision filtration system, and the sugar solution is immediately cooled to 38°C and the pH is adjusted to 7.0-7.2; Finally, the cooled sugar solution is slowly dripped into the rear UASB reactor at a rate of 0.5-1.0 L / h. The temperature of the UASB reactor is maintained at 35-38°C, the pH is controlled at 7.0-7.5, and the hydraulic retention time is 15-20 days.

[0017] Preferably, the step of preparing bio-oil by pyrolysis of biomass comprises: First, the pretreated fermentation waste residue is dried to a moisture content of <10 parts by weight, and then ground to a particle size of <2 mm; Secondly, in a fluidized bed reactor, the fermentation waste residue is heated to 450-550°C at a heating rate of 100-150°C / min under a nitrogen atmosphere for rapid pyrolysis, and the pyrolysis steam residence time is controlled to be 1-2 seconds; Then, the pyrolysis products were rapidly condensed to collect the bio-oil; Again, the aqueous phase and the oil phase were separated by centrifugation; Finally, the oil phase is subjected to vacuum distillation, and the 200-350°C fraction is collected. 5-10 parts by weight of activated carbon is used for adsorption at 60-70°C for 2-3 hours under stirring, and the refined bio-oil is obtained by filtration.

[0018] The innovations and technical effects of the present invention are mainly reflected in the following aspects: First, the present invention utilizes an innovative multi-step pretreatment process. Through a combination of mechanical crushing, low-temperature vacuum drying, and precise screening, the specific surface area of the waste residue is significantly increased, laying the foundation for subsequent processing. During this process, mechanical forces break down the cell wall structure within the waste residue, while low-temperature vacuum drying maximizes the retention of active ingredients. The synergistic effect of these two processes significantly increases the release rate of the active ingredients.

[0019] Secondly, for the extraction of beneficial components, the present invention has developed a green and efficient extraction system. By combining enzymatic hydrolysis with fermentation, this method not only improves the extraction efficiency of proteins and polysaccharides, but also enables the in situ generation of bioactive peptides. In this process, the specific cleavage action of the enzyme and the biotransformation action of microbial fermentation create a synergistic effect, improving extraction efficiency and enhancing the bioactivity of the product.

[0020] Furthermore, this invention has achieved a breakthrough in waste residue modification. Through a carefully designed acid-base modification and heat treatment process, a high-performance biosorbent and catalyst support were successfully prepared. During this process, the acid-base treatment introduced a large number of functional groups, enhancing the material's adsorption capacity, while the heat treatment optimized the pore structure, increasing the specific surface area and catalytic activity. The combination of these two treatment methods results in a material with both versatility and high stability.

[0021] Finally, this invention innovatively proposes a combined process for biofertilizer preparation and bioenergy production. The addition of a composite microbial inoculant not only enhances fertilizer effectiveness but also improves the soil microecological environment. In bioenergy production, the combination of anaerobic fermentation and pyrolysis technologies achieves diversified and high-quality energy products. This combined process fully utilizes both the organic and inorganic components in waste residue, maximizing resource utilization efficiency.

[0022] The innovation of this invention lies not only in the technological improvements of each unit, but more importantly, in the construction of a complete, recyclable technology system. Each link in this system has been carefully designed, forming organic connections and synergistic effects with each other. For example, the increased specific surface area during pretreatment not only facilitates the subsequent extraction process but also creates favorable conditions for material modification. Furthermore, the byproducts of the extraction process can be used as raw materials for bioenergy production, achieving a cascaded waste utilization.

[0023] At the molecular level, each processing step in the present invention fully considers the structural characteristics and reaction mechanisms of the substance. For example, during protein extraction, the selected enzymes are able to precisely recognize and cleave specific peptide bonds, ensuring extraction efficiency while avoiding excessive protein hydrolysis. In the preparation of the biosorbent, functional groups such as carboxyl and hydroxyl groups introduced by acid and base treatment enhance the adsorption capacity for heavy metal ions through coordination, while the graphitized structure formed by heat treatment improves the adsorption performance for organic pollutants.

[0024] The beneficial effects of the present invention are manifold. First, it significantly improves the resource utilization efficiency of fermentation waste residue, converting the original waste into a variety of high-value-added products. Second, the method is environmentally friendly, minimizing the use of chemical reagents and reducing environmental risks. Furthermore, the products prepared by the present invention are multifunctional and high-performance, greatly expanding their scope of application. Finally, this comprehensive resource utilization method provides new ideas and technical support for the sustainable development of the fermentation industry.

[0025] In summary, the present invention not only solves the technical difficulties in fermentation waste treatment, but also creates considerable economic and environmental benefits. It represents a major breakthrough in the field of waste resource utilization and contributes an innovative solution to the circular economy and sustainable development. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] Example 1

[0029] This embodiment provides a method for resource utilization of fermentation waste residue, which fully utilizes the organic matter and nutrients in the fermentation waste residue and achieves high-value utilization of the waste. The specific steps are as follows: (1) Pretreatment of fermentation waste residue First, the fermentation waste residue was mechanically crushed using a high-speed shear (model: HSS-100) at a speed of 3000 rpm for 5 minutes. This step significantly increases the specific surface area of the waste residue, facilitating subsequent processing and component extraction. Secondly, the crushed waste residue was dried using a low-temperature vacuum drying method using a vacuum drying oven (model: VOS-301) at a temperature of 40°C, a vacuum degree of -0.08 MPa, and a drying time of 8 hours. This process effectively reduces the moisture content of the waste residue while maximizing the retention of active ingredients. The dried waste residue was then sieved using a standard sieving machine (model: SY-200) using a 100-mesh screen for 15 minutes to ensure uniform particle size.

[0030] (2) Extraction of beneficial ingredients This step includes protein extraction, polysaccharide extraction and bioactive peptide preparation.

[0031] a) Protein extraction utilizes a deep eutectic solvent extraction method: The pretreated waste residue is placed in a dedicated reactor and a pre-prepared, recyclable deep eutectic solvent (composed of choline chloride and glycerol in a 1:2 molar ratio) is added. The reaction temperature is controlled at 40°C and the pH is 6.5. Papain is added at a rate of 0.8 parts by weight relative to the weight of the waste residue, and the reaction is stirred at 150 rpm for 12 minutes. The extract is then separated, and the protein-containing fraction is collected. CO2 is injected into the remaining waste residue to increase the pressure to 1.5 MPa. A small amount of citric acid solution is simultaneously sprayed in to adjust the pH to 3.2. The temperature is then rapidly raised to 160°C and maintained for 6 minutes to achieve rapid decomposition of cellulose. The extract is concentrated by ultrafiltration and spray-dried to obtain a protein powder. This method not only effectively extracts protein from the waste residue but also allows for continuous processing of the cellulose component in the same reactor, significantly simplifying the process.

[0032] b) Polysaccharide extraction is performed using hot water extraction: pretreatment waste residue is mixed with deionized water in a weight ratio of 1:15 and refluxed at 90°C for 2 hours. Filter, collect the filtrate, and concentrate it by rotary evaporation to 1 / 3 of its original volume. Add three volumes of 95% ethanol and incubate at 4°C overnight to precipitate polysaccharides. The precipitate is collected by centrifugation, washed with ethanol, and vacuum-dried to obtain crude polysaccharides. Polysaccharide extraction can increase the utilization value of waste residue, providing raw materials for functional foods and pharmaceuticals.

[0033] c) Bioactive peptides are prepared by enzymatic hydrolysis: a composite protease (consisting of trypsin EC 3.4.21.4 and papain EC 3.4.22.2) is used, with the total enzyme dosage being 2 parts by weight relative to the weight of the protein. Enzymatic hydrolysis is carried out at pH 7.5 and 45°C for 6 hours. The supernatant is then centrifuged and collected. The supernatant is concentrated using a nanofiltration membrane (molecular weight cut-off 1000 Da) and spray-dried to obtain a bioactive peptide powder. Bioactive peptides possess multiple physiological functions and can be used in the development of functional foods and health supplements.

[0034] (3) Waste residue modification treatment This step includes preparing the biosorbent and biocatalyst carrier.

[0035] a) The biosorbent is prepared using an acid-base modification method: pretreated waste residue is mixed with a 1M H2SO4 solution at a weight ratio of 1:8 and stirred at 60°C for 4 hours. The mixture is then filtered and washed with deionized water until neutral. The mixture is then treated with a 1M NaOH solution for 2 hours. The mixture is then washed, dried at 105°C for 12 hours, and ground and sieved to obtain the modified adsorbent. This modification method increases the specific surface area and adsorption capacity of the waste residue, making it a highly effective adsorbent for environmental pollutants.

[0036] b) The biocatalyst support was prepared using carbonization and porous treatment: First, the pretreatment waste residue was placed in a tube furnace (Model: OTF-1200X) and heated to 500°C at a heating rate of 5°C / min under a nitrogen atmosphere for 2 hours. The mixture was then naturally cooled to room temperature, ground, and sieved to obtain a carbonized support. The carbonized support was then mixed with potassium hydroxide in a weight ratio of 1:3 and thoroughly ground. Under a nitrogen atmosphere, the mixture was heated to 700°C at a heating rate of 5°C / min for 1 hour. After cooling, the support was washed with dilute hydrochloric acid and deionized water, and dried at 80°C to obtain a porous carbon support. This treatment significantly increases the support's specific surface area and porosity, improving its catalyst-carrying capacity.

[0037] (4) Preparation of functional materials and products This step includes the preparation of biofertilizer and bioenergy.

[0038] a) Biofertilizer preparation: First, a composite microbial inoculant was prepared. Azotobacter chroococcum ATCC9043, phosphate-solubilizing bacteria (Bacillus megaterium ATCC 14581), and potassium-solubilizing bacteria (Bacillus mucilaginosus CGMCC 1.1741) were cultured in their respective liquid cultures at 28°C with shaking at 150 rpm for 24 hours. The three bacterial cultures were mixed in a 1:1:1 volume ratio, and 5 parts by weight of sodium alginate was added as a protective agent. The resulting composite microbial inoculant powder was spray-dried.

[0039] Next, an organic-inorganic composite fertilizer was prepared. The formula (parts by weight) was as follows: 60 parts fermentation waste residue, 5 parts composite microbial agent, 10 parts phosphate rock powder (30% P₂O₅ content), 8 parts potassium feldspar powder (10% K₂O content), 3 parts humic acid, and 1 part trace element mixture. The components were mixed in appropriate proportions and granulated using a twin-screw extruder (model: SHJ-36). The extrusion temperature was controlled at 60°C and the screw speed was 200 rpm. After granulation, the product was dried at 60°C for 4 hours, cooled, and packaged to obtain the final product. This composite fertilizer not only provides a comprehensive range of nutrients but also improves fertilizer effectiveness and soil health through the action of microorganisms.

[0040] b) Bioenergy production: Biogas was produced by anaerobic fermentation of biomass. First, a two-chamber continuous treatment system was designed, consisting of a front-end hydrolysis chamber and a back-end anaerobic fermentation chamber. In the front-end hydrolysis chamber, fermentation waste was mixed with water at a weight ratio of 1:3, and the pH was adjusted to 6.5. Immobilized cellulase (immobilized on the porous carbon support prepared in Step 3) was added at a dosage of 0.8 parts by weight relative to the dry weight of the waste, and the mixture was hydrolyzed at 55°C for 12 hours. The resulting sugar solution was separated from the solid residue using a precision filtration system (0.45 μm pore size). The sugar solution was immediately cooled to 38°C using a plate heat exchanger, and the pH was monitored and adjusted online to 7.0. Using a programmable control system, the cooled sugar solution was slowly dripped into the back-end UASB reactor at a rate of 0.5 L / h. The reactor temperature was maintained at 35°C, the pH was controlled at 7.0, and the hydraulic retention time was 15 days. Finally, the generated biogas was desulfurized and dehydrated. This staged treatment process effectively separates the hydrolysis-acidification and methanogenesis stages, increasing biogas production and methane content.

[0041] Example 2

[0042] This embodiment provides a method for resource utilization of fermentation waste residue, which uses medium-intensity treatment parameters to balance treatment effect and energy consumption. The specific steps are as follows: (1) Pretreatment of fermentation waste residue First, the fermentation waste was mechanically crushed using a high-speed shearing machine at a speed of 4000 rpm for 10 minutes. Next, the crushed waste was dried using a low-temperature vacuum drying method at a temperature of 50°C and a vacuum of -0.085 MPa for 10 hours. The dried waste was then sieved using a standard sieving machine for 17 minutes.

[0043] (2) Extraction of beneficial ingredients a) Protein extraction was performed using a deep eutectic solvent extraction method: the pretreated waste residue was placed in a reactor and a recyclable deep eutectic solvent consisting of choline chloride and glycerol in a 1:2 molar ratio was added. The temperature was maintained at 40°C and the pH at 6.8. Papain was added at a concentration of 0.9 parts by weight based on the weight of the waste residue, and the mixture was stirred at 180 rpm for 14 minutes. The extract was separated, and the protein-containing fraction was collected. CO2 was injected into the remaining waste residue to increase the pressure to 1.8 MPa. Simultaneously, citric acid solution was sprayed in to adjust the pH to 3.0. The temperature was then rapidly raised to 160°C and maintained for 7 minutes to achieve rapid decomposition of cellulose. The extract was concentrated by ultrafiltration and freeze-dried to obtain a protein powder.

[0044] b) Polysaccharide extraction was performed using microwave-assisted extraction (MAS-II). The pretreatment waste residue was mixed with deionized water in a weight ratio of 1:12. The microwave power was set to 700 W and the extraction time was 17 minutes. Subsequent steps were the same as for the hot water extraction method.

[0045] c) Bioactive peptides were prepared by fermentation using lactic acid bacteria (Lactobacillus plantarum ATCC14917). Pretreatment waste residue was mixed with sterile water at a weight ratio of 1:5, and the pH was adjusted to 6.7. An inoculum of 6 parts by weight was used, and anaerobically fermented at 37°C for 60 hours. The fermentation broth was centrifuged, and the supernatant was concentrated by ultrafiltration and reverse osmosis, followed by spray drying to produce the fermented peptide powder.

[0046] (3) Waste residue modification treatment a) The biosorbent was prepared using a graft copolymerization modification method: pre-treated waste residue was immersed in 40 parts by weight of acrylamide (AM) monomer solution. Ammonium persulfate (APS) was added as an initiator at a ratio of 1.5 parts by weight to AM. The reaction was carried out at 55°C under a nitrogen atmosphere for 5 hours. The product was washed with ethanol and vacuum dried to obtain the grafted modified adsorbent.

[0047] b) Biocatalyst Support Preparation: Carbonization and porous treatment were used. First, the pretreated waste residue was heated to 600°C under an N2 atmosphere at a heating rate of 7.5°C / min and held for 3 hours. The carbonized support was then mixed with KOH at a weight ratio of 1:4 and heated to 800°C under an N2 atmosphere at a heating rate of 5°C / min and held for 1.5 hours.

[0048] (4) Preparation of functional materials and products a) Biofertilizer preparation: The composite microbial inoculant was prepared as in Example 1. The organic-inorganic composite fertilizer formula (parts by weight) was: 65 parts fermentation waste, 6.5 parts composite microbial inoculant, 12.5 parts phosphate rock powder, 10 parts potassium feldspar powder, 4 parts humic acid, and 1.5 parts trace element mixture. The extrusion temperature was controlled at 70°C and the screw speed at 250 rpm. After granulation, the pellets were dried at 60°C for 5 hours.

[0049] b) Bioenergy production: Biogas is produced using a dual-chamber continuous treatment system. In the front hydrolysis chamber, the fermentation waste residue is mixed with water in a weight ratio of 1:4, and the pH is adjusted to 6.8. Immobilized cellulase is added in an amount of 1.0 parts by weight of the dry weight of the waste residue, and the hydrolysis treatment is carried out at 55°C for 14 hours. The sugar solution is separated from the solid residue by a precision filtration system, the sugar solution is cooled to 38°C, and the pH is adjusted to 7.2. The sugar solution is dripped into the rear UASB reactor at a rate of 0.8L / h, the temperature is maintained at 36°C, the pH is controlled at 7.2, and the hydraulic retention time is 18 days. The biogas is stored after desulfurization and dehydration.

[0050] At the same time, biomass pyrolysis is used to prepare bio-oil. First, the pretreated fermentation waste residue is dried to a moisture content of <8 parts by weight and ground to a particle size of <1.5 mm. Secondly, in a fluidized bed reactor, the waste residue is heated to 500°C at a heating rate of 125°C / min under a nitrogen atmosphere for rapid pyrolysis, and the residence time of the pyrolysis steam is controlled to be 1.5 seconds. Then, the pyrolysis product is rapidly condensed to collect the bio-oil. Again, the aqueous phase and the oil phase are separated by centrifugation. Finally, the oil phase is subjected to reduced pressure distillation, and the 200-350°C fraction is collected. It is then adsorbed with 7.5 parts by weight of activated carbon at 65°C for 2.5 hours under stirring, and filtered to obtain refined bio-oil.

[0051] Example 3

[0052] This embodiment provides a method for resource utilization of fermentation waste residue, which uses high-intensity treatment parameters to achieve the best treatment effect. The specific steps are as follows: (1) Pretreatment of fermentation waste residue First, the fermentation waste was mechanically crushed using a high-speed shearing machine at a speed of 5000 rpm for 15 minutes. Next, the crushed waste was dried using a low-temperature vacuum drying method at a temperature of 60°C and a vacuum of -0.09 MPa for 12 hours. The dried waste was then sieved using a standard sieving machine for 20 minutes.

[0053] (2) Extraction of beneficial ingredients a) Protein extraction using a deep eutectic solvent extraction method: The pretreated waste residue is placed in a high-pressure reactor and a recyclable deep eutectic solvent consisting of choline chloride and glycerol in a 1:2 molar ratio is added. The temperature is maintained at 40°C and the pH is maintained at 7.0. Papain is added at a rate of 1.0 part by weight relative to the weight of the waste residue, and the mixture is stirred at 200 rpm for 15 minutes. The extract is separated, and the protein-containing fraction is collected. CO2 is injected into the remaining waste residue to increase the pressure to 2.0 MPa. Simultaneously, citric acid solution is sprayed in to adjust the pH to 3.0. The temperature is then rapidly raised to 160°C and maintained for 8 minutes to achieve rapid decomposition of cellulose. The extract is concentrated by ultrafiltration and freeze-dried to obtain a protein powder.

[0054] b) Polysaccharide extraction was performed using hot water extraction: pretreatment waste residue was mixed with deionized water in a weight ratio of 1:15 and refluxed at 95°C for 3 hours. Filter the mixture, and the filtrate was concentrated to 1 / 3 of its original volume by rotary evaporation. Four volumes of 95% ethanol were added, and the mixture was allowed to stand at 4°C overnight to precipitate the polysaccharides. The precipitate was collected by centrifugation, washed with ethanol, and vacuum dried to obtain crude polysaccharides.

[0055] c) Bioactive peptides were prepared by enzymatic hydrolysis: a composite protease (consisting of trypsin EC 3.4.21.4 and papain EC 3.4.22.2) was used at a total enzyme dosage of 3 parts by weight relative to the protein weight. Enzymatic hydrolysis was performed at pH 8.0 and 50°C for 8 hours. The supernatant was then centrifuged and concentrated using a nanofiltration membrane (molecular weight cut-off 1000 Da) and spray-dried to obtain a bioactive peptide powder.

[0056] (3) Waste residue modification treatment a) The biosorbent was prepared using an acid-base modification method: pretreatment waste residue was mixed with a 2M H2SO4 solution at a weight ratio of 1:8 and stirred at 70°C for 6 hours. The mixture was filtered and washed with deionized water until neutral. The mixture was then treated with a 2M NaOH solution for 3 hours. The mixture was washed, dried at 105°C for 12 hours, and ground and sieved to obtain the modified adsorbent.

[0057] b) Biocatalyst Support Preparation: Carbonization and porous treatment were used. First, the pretreated waste residue was heated to 700°C under an N2 atmosphere at a heating rate of 10°C / min and held for 4 hours. The carbonized support was then mixed with KOH at a weight ratio of 1:5 and heated to 900°C under an N2 atmosphere at a heating rate of 5°C / min and held for 2 hours.

[0058] (4) Preparation of functional materials and products a) Biofertilizer preparation: Preparation of the composite microbial inoculant: Nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and potassium-solubilizing bacteria were cultured in their respective liquid cultures at 30°C, with shaking at 180 rpm for 48 hours. The three bacterial cultures were mixed in a 1:1:1 volume ratio, and 10 parts by weight of sodium alginate was added as a protective agent. The mixture was spray-dried to obtain a composite microbial inoculant powder.

[0059] Organic-inorganic compound fertilizer formula (parts by weight): fermentation waste residue 70 parts, composite microbial agent 8 parts, phosphate rock powder (P2O5 content 35%) 15 parts, potassium feldspar powder (K2O content 12%) 12 parts, humic acid 5 parts, trace element mixture 2 parts. Mix all components in appropriate proportions and granulate using a twin-screw extruder at 80°C and a screw speed of 300 rpm. After granulation, dry at 60°C for 6 hours, cool, and package to obtain the final product.

[0060] b) Bioenergy production: Biogas production was achieved using a two-chamber continuous treatment system. A highly efficient two-chamber continuous treatment system was designed, consisting of a front-end hydrolysis chamber and a back-end anaerobic fermentation chamber. In the front-end hydrolysis chamber, fermentation waste was mixed with water at a weight ratio of 1:5, and the pH was adjusted to 7.0. Immobilized cellulase was added at a dosage of 1.2 parts by weight of the waste dry weight, and the process was hydrolyzed at 55°C for 16 hours. The sugar solution was separated from the solid residue using a precision filtration system (0.22 μm pore size). The sugar solution was rapidly cooled to 38°C using a high-efficiency plate heat exchanger, and the pH was monitored and adjusted online to 7.2. Using an intelligent control system, the sugar solution was precisely dripped into the back-end UASB reactor at a rate of 1.0 L / h. The reactor temperature was maintained at 38°C, the pH was controlled at 7.5, and the hydraulic retention time was 20 days. Finally, the generated biogas was efficiently desulfurized and dehydrated, achieving stable production of biogas with a high methane content.

[0061] Example 4

[0062] This embodiment provides a method for resource utilization of fermentation waste residue, which comprehensively considers treatment effect, energy consumption and economic benefits and adopts optimized treatment parameters. The specific steps are as follows: (1) Pretreatment of fermentation waste residue First, the fermentation waste was mechanically crushed using a high-speed shearing machine at a speed of 4500 rpm for 12 minutes. Next, the crushed waste was dried using a low-temperature vacuum drying method at a temperature of 55°C and a vacuum of -0.085 MPa for 11 hours. The dried waste was then sieved using a standard sieving machine for 18 minutes.

[0063] (2) Extraction of beneficial ingredients a) Protein extraction was performed using a deep eutectic solvent extraction method: the pretreated waste residue was placed in a reactor and a recyclable deep eutectic solvent consisting of choline chloride and glycerol in a 1:2 molar ratio was added. The temperature was maintained at 40°C and the pH at 6.8. Papain was added at a concentration of 0.95 parts by weight relative to the weight of the waste residue, and the mixture was stirred at 180 rpm for 13 minutes. The extract was separated, and the protein-containing fraction was collected. CO2 was injected into the remaining waste residue to increase the pressure to 1.8 MPa. Simultaneously, citric acid solution was sprayed in to adjust the pH to 3.2. The temperature was then rapidly raised to 160°C and maintained for 7 minutes to achieve rapid decomposition of cellulose. The extract was concentrated by ultrafiltration and freeze-dried to obtain a protein powder.

[0064] b) Polysaccharide extraction was performed using microwave-assisted extraction (MAS-II). The pretreatment waste residue was mixed with deionized water in a weight ratio of 1:13. The microwave power was set to 750W and the extraction time was 18 minutes. Subsequent steps were the same as for the hot water extraction method.

[0065] c) Bioactive peptides were prepared by fermentation using lactic acid bacteria (Lactobacillus plantarum ATCC14917). Pretreatment waste residue was mixed with sterile water in a weight ratio of 1:4, and the pH was adjusted to 6.8. An inoculum of 6.5 parts by weight was used, and anaerobically fermented at 37°C for 66 hours. The fermentation broth was centrifuged, and the supernatant was concentrated by ultrafiltration and reverse osmosis, followed by spray drying to produce the fermented peptide powder.

[0066] (3) Waste residue modification treatment a) The biosorbent was prepared using a graft copolymerization method: pretreated waste residue was immersed in 45 parts by weight of acrylamide (AM) monomer solution. Ammonium persulfate (APS) was added as an initiator at a concentration of 1.8 parts by weight of AM. The reaction was carried out at 58°C under a nitrogen atmosphere for 5.5 hours. The product was washed with ethanol and dried under vacuum to obtain the grafted modified adsorbent.

[0067] b) Biocatalyst Support Preparation: Carbonization and porous treatment were used. First, the pretreated waste residue was heated to 650°C under an N2 atmosphere at a heating rate of 8°C / min and held for 3.5 hours. The carbonized support was then mixed with KOH at a weight ratio of 1:4.5 and heated to 850°C under an N2 atmosphere at a heating rate of 5°C / min and held for 1.8 hours.

[0068] (4) Preparation of functional materials and products a) Biofertilizer preparation: Preparation of the composite microbial inoculant: Nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and potassium-solubilizing bacteria were cultured in their respective liquid cultures at 29°C, with shaking at 165 rpm for 36 hours. The three bacterial cultures were mixed in a 1:1:1 volume ratio, and 7.5 parts by weight of sodium alginate was added as a protective agent. The mixture was spray-dried to obtain a composite microbial inoculant powder.

[0069] Organic-inorganic compound fertilizer formula (parts by weight): 68 parts fermentation waste residue, 7 parts composite microbial agent, 13 parts phosphate rock powder (P₂O₅ content 33%), 11 parts potassium feldspar powder (K₂O content 11%), 4.5 parts humic acid, and 1.8 parts trace element mixture. The components were mixed in appropriate proportions and granulated using a twin-screw extruder at a temperature of 75°C and a screw speed of 275 rpm. After granulation, the product was dried at 60°C for 5.5 hours, cooled, and packaged to obtain the final product.

[0070] b) Bioenergy production: Biogas is produced using a dual-chamber continuous treatment system. In the front hydrolysis chamber, the fermentation waste residue is mixed with water in a weight ratio of 1:4, and the pH is adjusted to 6.8. Immobilized cellulase is added in an amount of 1.0 weight part of the dry weight of the waste residue, and the hydrolysis treatment is carried out at 55°C for 15 hours. The sugar solution is separated from the solid residue by a precision filtration system, the sugar solution is cooled to 38°C, and the pH is adjusted to 7.1. The sugar solution is dripped into the back-end UASB reactor at a rate of 0.8L / h, the temperature is maintained at 37°C, the pH is controlled at 7.3, and the hydraulic retention time is 18 days.

[0071] At the same time, biomass pyrolysis is used to prepare bio-oil. First, the pretreated fermentation waste residue is dried to a moisture content of <7 parts by weight and ground to a particle size of <1.8 mm. Secondly, in a fluidized bed reactor, the waste residue is heated to 525°C at a heating rate of 135°C / min under a nitrogen atmosphere for rapid pyrolysis, and the pyrolysis steam residence time is controlled to be 1.7 seconds. Then, the pyrolysis product is rapidly condensed to collect the bio-oil. Again, the aqueous phase and the oil phase are separated by centrifugation. Finally, the oil phase is subjected to reduced pressure distillation, and the 200-350°C fraction is collected. It is then adsorbed with 8 parts by weight of activated carbon at 68°C for 2.8 hours under stirring, and filtered to obtain refined bio-oil.

[0072] Through the above four embodiments, the present invention provides a comprehensive and efficient method for resource utilization of fermentation waste residue. This method successfully solves key technical problems existing in the prior art, such as the contradiction between protein extraction and cellulose treatment, and the contradiction between enzymatic hydrolysis of sugars and methanogen fermentation, through multi-step pretreatment, deep eutectic solvent extraction, waste residue modification treatment and functional material preparation. It realizes the high-value utilization of all components of the waste residue and provides innovative technical support for the sustainable development of the fermentation industry.

[0073] Comparative Example 1: Resource Utilization of Fermentation Waste Residue Using a Single Pretreatment Method This comparative example is intended to verify the necessity of multi-step pretreatment and is compared with Example 1. The specific steps are as follows: (1) Pretreatment of fermentation waste residue Only mechanical crushing method was adopted to process the fermentation waste residue using a high-speed shearing machine with the rotation speed set at 3000 rpm and the processing time being 5 minutes.

[0074] (2) Extraction of beneficial ingredients The same methods as in Example 1 were used for protein extraction, polysaccharide extraction and bioactive peptide preparation.

[0075] (3) Waste residue modification treatment The biosorbent and biocatalyst carrier were prepared in the same manner as in Example 1.

[0076] (4) Preparation of functional materials and products The biofertilizer and bioenergy were prepared using the same method as in Example 1.

[0077] Results: Compared with Example 1, the product yields in this comparative example were significantly reduced. Protein extraction decreased by approximately 25%, polysaccharide extraction decreased by approximately 30%, and bioactive peptide production decreased by approximately 20%. This indicates that mechanical disruption alone fails to adequately disrupt the structure of the fermentation waste residue, resulting in reduced extraction efficiency of beneficial components. Furthermore, the adsorption capacity of the biosorbent decreased by approximately 35%, and the specific surface area of the biocatalyst support decreased by approximately 40%, further demonstrating the importance of multi-step pretreatment for improving waste residue utilization efficiency.

[0078] Comparative Example 2: Protein Extraction by Traditional Solvent Extraction This comparative example aims to verify the superiority of the deep eutectic solvent extraction method and is compared with Example 2. The specific steps are as follows: (1) Pretreatment of fermentation waste residue The same method as in Example 2 was used for pretreatment.

[0079] (2) Extraction of beneficial ingredients a) Protein extraction was performed using the alkaline extraction and acid precipitation method: pretreated waste residue was mixed with 0.2 M NaOH solution at a weight ratio of 1:10 and stirred at 55°C for 2.5 hours. Centrifuge at 5500 rpm for 20 minutes. The supernatant was collected, the pH adjusted to 4.8 with hydrochloric acid, and allowed to stand for 2 hours to allow protein precipitation. Centrifuge again, collect the precipitate, and freeze-dry to obtain protein powder.

[0080] b) The polysaccharide extraction and bioactive peptide preparation methods were the same as in Example 2.

[0081] (3) Waste residue modification treatment The same method as in Example 2 was used to prepare the biosorbent and biocatalyst carrier.

[0082] (4) Preparation of functional materials and products The biofertilizer and bioenergy were prepared using the same method as in Example 2.

[0083] Results Analysis: Compared with Example 2, the protein extraction process in this comparative example not only took longer (2.5 hours vs. 14 minutes) and consumed more energy, but also resulted in a significantly lower extraction yield (by approximately 18%). More importantly, the protein extracted using the alkaline extraction and acid precipitation method showed significantly reduced activity, with solubility decreasing by approximately 15% and emulsification properties by approximately 12%. Furthermore, the inability to continuously process the cellulose component in the same reactor increased overall process complexity and reduced equipment utilization. This fully demonstrates the significant advantages of deep eutectic solvent extraction in improving extraction efficiency, reducing energy consumption, and maintaining protein activity.

[0084] Comparative Example 3: Organic-inorganic compound fertilizer without microbial agents This comparative example is intended to verify the effect of the composite microbial agent in biofertilizer and is compared with Example 2. The specific steps are as follows: (1) Pretreatment of fermentation waste residue The same method as in Example 2 was used for pretreatment.

[0085] (2) Extraction of beneficial ingredients The same methods as in Example 2 were used for protein extraction, polysaccharide extraction and bioactive peptide preparation.

[0086] (3) Waste residue modification treatment The same method as in Example 2 was used to prepare the biosorbent and biocatalyst carrier.

[0087] (4) Preparation of functional materials and products a) Biofertilizer preparation: Formula of organic-inorganic compound fertilizer (parts by weight): fermentation waste residue 71.5, phosphate rock powder 12.5, potassium feldspar powder 10, humic acid 4, trace element mixture 1.5. The remaining preparation steps are the same as in Example 2.

[0088] b) Bioenergy production: Bio-oil was prepared using the same method as in Example 2.

[0089] Results: Compared to Example 2, the organic-inorganic composite fertilizer prepared in this comparative example exhibited lower fertilizer efficiency in field trials. Crop yield decreased by approximately 20%, and the soil microbial diversity index decreased by approximately 30%. This confirms the important role of composite microbial inoculants in enhancing fertilizer effectiveness and improving soil ecology. Furthermore, the fertilizer's slow-release properties were significantly reduced, and nutrient utilization efficiency decreased by approximately 25%, further demonstrating the key role of composite microbial inoculants in regulating nutrient release and improving utilization efficiency.

[0090] Comparative Example 4: Preparation of bioactive peptides by single enzymatic hydrolysis This comparative example aims to verify the superiority of the method for preparing bioactive peptides by combining compound enzymatic hydrolysis and fermentation, and is compared with Example 3. The specific steps are as follows: (1) Pretreatment of fermentation waste residue The same method as in Example 3 was used for pretreatment.

[0091] (2) Extraction of beneficial ingredients a) The protein extraction and polysaccharide extraction methods were the same as those in Example 3.

[0092] b) Preparation of bioactive peptides: A single enzymatic hydrolysis method was used, using papain (EC 3.4.22.2) at 3 parts by weight of the protein. Hydrolysis was performed at pH 7.0 and 50°C for 8 hours. Subsequent processing steps were the same as in Example 3.

[0093] (3) Waste residue modification treatment The biosorbent and biocatalyst support were prepared using the same method as in Example 3.

[0094] (4) Preparation of functional materials and products The biofertilizer and bioenergy were prepared using the same method as in Example 3.

[0095] Results: Compared with Example 3, the bioactive peptides prepared in this comparative example performed poorly in terms of diversity and functionality. The diversity of peptide distribution decreased by about 40%, the antioxidant activity decreased by about 35%, and the immunomodulatory ability decreased by about 30%. This confirms that the combined enzymatic hydrolysis and fermentation method can produce more diverse and more bioactive peptides. At the same time, due to the reduction in peptide diversity, the stability and tolerance of the product during application are also correspondingly reduced, which further illustrates the advantages of the method of the present invention in improving the quality and application value of bioactive peptides.

[0096] Comparative Example 5: Biocatalyst carrier without porous treatment This comparative example aims to verify the effect of porous treatment on the performance of biocatalyst carriers and compares it with Example 4. The specific steps are as follows: (1) Pretreatment of fermentation waste residue The same method as in Example 4 was used for pretreatment.

[0097] (2) Extraction of beneficial ingredients The same methods as in Example 4 were used for protein extraction, polysaccharide extraction and bioactive peptide preparation.

[0098] (3) Waste residue modification treatment a) The biosorbent was prepared in the same manner as in Example 4.

[0099] b) Biocatalyst Support Preparation: Carbonization alone was used without porous treatment. The pretreated waste residue was heated to 650°C at a heating rate of 8°C / min under a nitrogen atmosphere and held for 3.5 hours. After cooling, the carbonized support was ground.

[0100] (4) Preparation of functional materials and products The biofertilizer and bioenergy were prepared using the same method as in Example 4.

[0101] Analysis of results: Compared with Example 4, the performance of the biocatalyst carrier prepared in this comparative example is significantly reduced. The specific surface area is reduced by about 70%, the porosity is reduced by about 65%, and the catalyst loading capacity is reduced by about 60%. This leads to a significant decrease in the efficiency of the catalytic reaction, a decrease in the conversion rate by about 55%, and a decrease in the selectivity by about 40%. In particular, in the process of applying immobilized cellulase to biogas production, the stability of the enzyme activity is significantly reduced, and the half-life of the enzyme activity is reduced from 120 hours to only 40 hours. This fully demonstrates the key role of porous treatment in improving the performance of biocatalyst carriers, and also verifies the innovation and effectiveness of the method of the present invention in improving the resource utilization value of waste residues.

[0102] Comparative Example 6: Conventional single-tank anaerobic fermentation to produce biogas This comparative example aims to verify the advantages of the dual-chamber continuous treatment system in biogas production and is compared with Example 3. The specific steps are as follows: (1) Pretreatment of fermentation waste residue The same method as in Example 3 was used for pretreatment.

[0103] (2) Extraction of beneficial ingredients The same methods as in Example 3 were used for protein extraction, polysaccharide extraction and bioactive peptide preparation.

[0104] (3) Waste residue modification treatment The biosorbent and biocatalyst support were prepared using the same method as in Example 3.

[0105] (4) Preparation of functional materials and products a) The method for preparing the biofertilizer was the same as that in Example 3.

[0106] b) Bioenergy production: Biogas was produced using conventional single-tank anaerobic fermentation. Fermentation waste was mixed with water at a weight ratio of 1:5, and the pH was adjusted to 7.0. Cellulase was added at a rate of 1.2 parts by weight based on the dry weight of the waste. Anaerobic fermentation was carried out in a single CSTR (continuously stirred reactor). The reactor temperature was maintained at 38°C, the pH was controlled at 7.2, and the hydraulic retention time was 20 days.

[0107] Analysis of results: Compared with Example 3, the biogas production in this comparative example was significantly reduced (by approximately 30%), the methane content decreased by approximately 15%, and the gas production stability was poor. Acidification often occurred during the fermentation process, leading to interruptions in gas production. This is primarily because, in a single reactor, the organic acids produced by hydrolysis and acidification inhibit the activity of methanogens, leading to fermentation failure. Furthermore, the gas production rate of single-tank fermentation fluctuated significantly, hindering a stable energy supply. This fully demonstrates the advantages of the dual-chamber continuous treatment system of the present invention in resolving the conflict between the hydrolysis and acidification stages and methanogenesis, providing an innovative technical solution for efficient and stable biogas production.

[0108] Through the six comparative examples above, we systematically verified the necessity and superiority of each key step and technique in the present invention. These comparative results fully demonstrate the innovative and practical value of the present method in improving the resource utilization efficiency of fermentation waste residue, product quality, and overall benefits. Furthermore, these comparative examples also demonstrate, from different perspectives, the synergistic effects between the various technical links in the present invention, further highlighting the overall innovativeness and systematic nature of the present invention.

[0109] Experimental design and evaluation methods: 1. Pretreatment effect evaluation Experimental purpose: To evaluate the effects of multi-step pretreatment on the structural breakdown and release of beneficial components of fermentation waste.

[0110] Experimental methods: (a) Scanning electron microscopy observation: The morphology of waste slag particles was observed using a JSM-7800F field emission scanning electron microscope.

[0111] (b) Specific surface area: The specific surface area was determined using the BET method using a Micromeritics ASAP 2460 surface area analyzer.

[0112] (c) Release rate of active ingredients: The protein release rate was determined by the Bradford method, and the polysaccharide release rate was determined by the phenol-sulfuric acid method.

[0113] 2. Protein Extraction Efficiency and Quality Evaluation Experimental purpose: To evaluate the effects of different extraction methods on protein yield and quality.

[0114] Experimental methods: (a) Protein yield: The total nitrogen content was determined by the Kjeldahl method and converted to protein content.

[0115] (b) Protein purity: Protein composition was analyzed by SDS-PAGE electrophoresis.

[0116] (c) Functional evaluation: determination of protein solubility, emulsification and foaming properties.

[0117] (d) Solvent recovery: The recovery of deep eutectic solvents was evaluated and determined by HPLC.

[0118] 3. Functional evaluation of bioactive peptides Experimental purpose: To evaluate the functional properties of bioactive peptides obtained by different preparation methods.

[0119] Experimental methods: (a) Antioxidant activity: DPPH free radical scavenging assay and ABTS assay were used to determine the antioxidant activity.

[0120] (b) ACE inhibitory activity: determined by the Cushman and Cheung method.

[0121] (c) Immunomodulatory capacity: assessed by in vitro lymphocyte proliferation assay.

[0122] 4. Biosorbent Performance Evaluation Experimental purpose: To evaluate the adsorption performance of the modified biosorbent.

[0123] Experimental methods: (a) Adsorption capacity: Using methylene blue as a model pollutant, the maximum adsorption capacity was determined.

[0124] (b) Adsorption kinetics: Determine the adsorption amount at different time points and fit the adsorption kinetic model.

[0125] (c) Regeneration performance: Five adsorption–desorption cycles were performed, and the changes in adsorption capacity were measured.

[0126] 5. Biocatalyst Support Performance Evaluation Experimental purpose: To evaluate the effect of the prepared carrier on enzyme immobilization.

[0127] Experimental methods: (a) Enzyme immobilization efficiency: Lipase was used as a model enzyme to determine the immobilization efficiency.

[0128] (b) Enzyme activity retention: The activity of the immobilized enzyme was measured and compared with that of the free enzyme.

[0129] (c) Operational stability: The immobilized enzyme was used 10 times continuously and the activity change was measured.

[0130] (d) pH adaptability: The activity retention of the immobilized enzyme was determined under different pH conditions (pH 3-10).

[0131] 6. Evaluation of compound fertilizer effects Experimental purpose: To evaluate the fertilizer efficiency of the prepared organic-inorganic compound fertilizer.

[0132] Experimental methods: (a) Pot experiment: A 60-day pot experiment was conducted using wheat as the test crop.

[0133] (b) Nutrient release characteristics: The release curves of nitrogen, phosphorus and potassium were determined using the soil column leaching method.

[0134] (c) Soil microbial activity: Soil urease and sucrase activities were measured.

[0135] (d) Long-term fertilizer effect: A 120-day field trial was conducted to evaluate the long-term effectiveness of the fertilizer.

[0136] 7. Bioenergy conversion efficiency evaluation Experimental purpose: To evaluate the energy conversion efficiency of the combined anaerobic fermentation and pyrolysis process.

[0137] Experimental methods: (a) Biogas production and composition: Biogas production was determined and biogas components were analyzed by gas chromatography.

[0138] (b) Bio-oil yield and calorific value: The bio-oil yield was determined and the calorific value was measured using a calorimeter.

[0139] (c) Energy conversion efficiency: Calculate the total energy input and output to obtain the energy conversion efficiency.

[0140] (d) Biogas production stability: The biogas production was continuously monitored for 30 days to evaluate the stability of gas production.

[0141] Experimental results Table 1. Pretreatment effect evaluation results sample Specific surface area (m² / g) Protein release rate (%) Polysaccharide release rate (%) Example 1 45.8 72.3 74.6 Example 2 53.2 78.5 80.3 Example 3 59.4 84.2 86.5 Example 4 56.7 81.6 83.8 Comparative Example 1 32.5 54.2 56.5 Comparative Example 2 54.3 79.4 81.2 Comparative Example 3 55.1 80.2 82.1 Comparative Example 4 55.8 80.9 82.8 Comparative Example 5 55.3 80.5 82.4 Comparative Example 6 56.8 81.8 83.9 Table 2. Protein extraction efficiency and quality evaluation results sample Protein yield (%) Protein purity (%) Solubility (%) Emulsification index (m² / g) Foaming properties (%) Solvent recovery rate (%) Example 1 82.5 88.3 92.1 158.4 175.6 97.2 Example 2 85.7 90.6 94.5 164.2 182.3 96.8 Example 3 89.8 93.4 96.8 172.5 189.6 98.1 Example 4 87.9 92.1 95.6 168.9 186.2 97.5 Comparative Example 1 61.8 85.2 88.9 143.2 165.3 - Comparative Example 2 70.2 86.5 80.3 144.5 163.8 - Comparative Example 3 86.4 91.2 95.2 165.1 183.4 97.1 Comparative Example 4 70.6 82.5 86.3 134.2 158.6 - Comparative Example 5 87.2 91.8 95.4 167.2 184.7 97.3 Comparative Example 6 87.5 92 95.5 168.1 185.3 97.4 Table 3. Functional evaluation results of bioactive peptides sample DPPH clearance rate (%) ABTS clearance rate (%) ACE inhibition rate (%) Lymphocyte proliferation rate (%) Example 1 72.3 75.8 68.5 162.4 Example 2 78.6 81.4 73.9 172.8 Example 3 84.3 87.2 79.5 183.6 Example 4 81.7 84.5 76.8 178.2 Comparative Example 1 54.2 56.7 51.3 125.7 Comparative Example 2 77.9 80.7 73.1 171.5 Comparative Example 3 78.2 81 73.5 172.3 Comparative Example 4 54.8 57.2 52.6 128.5 Comparative Example 5 78.7 81.6 74 173.1 Comparative Example 6 79.8 82.5 75.2 174.9 Table 4. Biosorbent performance evaluation results sample Maximum adsorption capacity (mg / g) Adsorption equilibrium time (min) Capacity retention after 5 cycles (%) Example 1 192.3 42 93.5 Example 2 221.5 35 95.8 Example 3 248.7 30 97.2 Example 4 235.2 33 96.4 Comparative Example 1 125 65 82.6 Comparative Example 2 220.8 36 95.6 Comparative Example 3 214.6 38 94.9 Comparative Example 4 207.3 40 94.2 Comparative Example 5 141.3 58 84.7 Comparative Example 6 228.5 34 96.1 Table 5. Biocatalyst support performance evaluation results sample Enzyme immobilization efficiency (%) Enzyme activity retention rate (%) Activity retention rate after 10 uses (%) Activity retention rate in the pH range of 4-9 (%) Example 1 82.6 87.3 84.2 78.5 Example 2 87.8 91.5 88.3 84.2 Example 3 93.5 95.7 92.4 90.3 Example 4 90.7 93.8 90.5 87.6 Comparative Example 1 53.4 58.2 51.7 45.3 Comparative Example 2 86.9 90.7 87.4 83.5 Comparative Example 3 85.3 89.1 85.8 81.9 Comparative Example 4 83.7 87.6 84.5 80.2 Comparative Example 5 56.2 61.5 54.8 48.6 Comparative Example 6 89.2 92.4 89.1 85.8 Table 6. Results of compound fertilizer effect evaluation sample Wheat yield increase rate (%) Nitrogen utilization rate (%) <![CDATA[Soil urease activity (μg NH4⁺ / g·h)]]> Soil sucrase activity (mg glucose / g·h) Nutrient release rate after 120 days (%) Example 1 25.3 64.8 47.5 2.95 22.3 Example 2 30.6 70.3 53.6 3.32 26.8 Example 3 36.2 75.7 60.2 3.74 31.5 Example 4 33.5 73.1 57.1 3.55 29.2 Comparative Example 1 18.9 53.2 37.8 2.25 15.6 Comparative Example 2 29.8 69.5 52.9 3.28 26.2 Comparative Example 3 15.2 49.3 33.5 1.96 13.1 Comparative Example 4 27.5 67.2 50.3 3.15 24.6 Comparative Example 5 30.1 69.8 53.2 3.3 26.5 Comparative Example 6 31.2 70.9 54.3 3.36 27.3 Table 7. Bioenergy conversion efficiency evaluation results sample Biogas production (m³ / kg VS) Methane content (%) Bio-oil yield (wt%) Bio-oil calorific value (MJ / kg) Total energy conversion efficiency (%) Biogas production stability (coefficient of variation %) Example 1 0.48 62.5 18.6 28.3 65.2 15.3 Example 2 0.54 66.7 21.4 30.1 69.8 12.1 Example 3 0.62 72.3 24.7 32.5 75.6 8.4 Example 4 0.58 69.5 23.2 31.4 72.9 10.2 Comparative Example 1 0.36 54.3 15.2 25.6 57.1 23.6 Comparative Example 2 0.53 65.9 21.1 29.8 69.2 12.5 Comparative Example 3 0.52 65.1 20.8 29.5 68.4 12.8 Comparative Example 4 0.51 64.2 20.3 29.1 67.5 13.2 Comparative Example 5 0.5 63.4 19.6 28.7 66.3 13.9 Comparative Example 6 0.43 57.8 22.9 31.2 62.4 24.5 Based on the above experimental results, we can draw the following conclusions: Example 3 showed the best overall performance, reaching the highest level in all indicators, which shows that the high-intensity treatment parameters adopted in this solution can maximize the resource utilization potential of fermentation waste residue.

[0142] Multi-step pretreatment significantly increases the specific surface area of the waste residue and the release rate of active ingredients. The specific surface area of Example 3 reached 59.4 m² / g, 82.8% higher than that of Comparative Example 1, significantly improving the efficiency of subsequent processing. During pretreatment, mechanical forces disrupted the cell wall structure of the waste residue, while low-temperature vacuum drying maximized the retention of active ingredients. The synergistic effect of these two methods significantly increased the release rate of active ingredients.

[0143] The deep eutectic solvent extraction method exhibits significant advantages. The protein yield in Example 3 reached 89.8%, 27.9% higher than the traditional alkaline extraction and acid precipitation method (Comparative Example 2, 70.2%). More importantly, deep eutectic solvent extraction maintains the integrity and functionality of the protein, with solubility, emulsification, and foaming properties significantly superior to those of traditional methods. Furthermore, the high recovery rate of the deep eutectic solvent (98.1%) demonstrates the cost-effectiveness and environmental friendliness of this method. The application of a "pressure + pH" switching strategy enables continuous protein extraction and cellulose decomposition in the same reactor, greatly simplifying the process flow and improving equipment utilization.

[0144] The bioactive peptide prepared in Example 3 exhibited excellent multifunctionality. Its DPPH clearance rate reached 84.3%, its ACE inhibition rate reached 79.5%, and its lymphocyte proliferation rate reached 183.6%, significantly exceeding that achieved by a single enzymatic hydrolysis method (Comparative Example 4). This multifunctional synergy, derived from the combined effects of complex enzymatic hydrolysis and fermentation, not only increased the diversity of peptide segments but also enhanced their bioactivity, providing high-quality raw materials for the development of functional foods and health supplements.

[0145] The biosorbent prepared in Example 3 exhibited excellent performance. Its maximum adsorption capacity reached 248.7 mg / g, its adsorption equilibrium time was only 30 minutes, and it exhibited excellent regeneration performance (capacity retention of 97.2% after five cycles). This was attributed to the numerous functional groups introduced through graft copolymerization, which enhanced its adsorption capacity for pollutants and formed a stable chemical structure, improving the material's recyclability.

[0146] Porosification is crucial for improving support performance. The support in Example 3 demonstrated an enzyme immobilization efficiency of 93.5% and an enzyme activity retention rate of 95.7%. It also maintained excellent activity (90.3%) across the pH range of 4-9, significantly exceeding that of Comparative Example 5, which lacked porosification. This broad pH adaptability stems from the microenvironmental protection provided by the porous structure and is of great value for the industrial application of immobilized enzymes.

[0147] Composite microbial inoculants play a key role in improving fertilizer effectiveness. The composite fertilizer in Example 3 increased wheat yield by 36.2%, achieved a nitrogen utilization rate of 75.7%, and exhibited significant long-term effectiveness (nutrient release remained at 31.5% after 120 days), a 138.2% increase over Comparative Example 3, which lacked a microbial inoculant. The synergistic effect of microorganisms, organic matter, and minerals not only enhances nutrient utilization efficiency but also improves soil quality, providing strong support for sustainable agriculture.

[0148] The dual-chamber continuous processing system demonstrates significant advantages in biogas production. Example 3 achieved a biogas yield of 0.62 m³ / kg VS, with a methane content of 72.3%. This yield was highly stable (with a coefficient of variation of only 8.4%), far exceeding the conventional single-tank fermentation (Comparative Example 6). This is due to the effective separation of the hydrolysis-acidification and methanogenesis stages, which avoids the inhibition of methanogens by organic acids and achieves efficient and stable biogas production. Furthermore, the application of pyrolysis technology also achieves high bio-oil yield and calorific value. The combination of these two energy conversion pathways maximizes energy output, with a total energy conversion efficiency of 75.6%.

[0149] The present invention has achieved many unexpected technical effects: a) The combination of deep eutectic solvent extraction and a "pressure + pH" switching strategy not only resolves the process conflicts between protein extraction and cellulose processing, but also brings the additional benefits of reducing equipment investment by 20-25% and energy consumption by 30-35%.

[0150] b) The dual-chamber continuous treatment system not only increases biogas production, but also significantly improves gas production stability, reducing the coefficient of variation from 24.5% to 8.4%, ensuring a stable energy supply.

[0151] c) The biocatalyst support maintains high activity (>90%) over a wide pH range of 4-9, significantly expanding its application range and exceeding the performance of conventional immobilized enzyme supports.

[0152] d) The long-term effectiveness of the compound fertilizer (nutrient release rate of 31.5%) in a 120-day field trial far exceeded expectations, providing new ideas for reducing fertilization frequency and improving nutrient utilization efficiency.

[0153] e) Bioactive peptides simultaneously possess powerful antioxidant capacity, ACE inhibitory activity, and immunomodulatory ability. This multifunctional synergy is difficult to achieve with a single preparation method, opening up a new path for the development of high-value-added functional products.

[0154] In summary, the present invention successfully resolves the key technical contradictions in the resource utilization of fermentation waste residue through a systematic multi-step treatment process, achieving high-value utilization of all components of the waste residue. The various technical links form an organic synergistic effect, mutually promoting each other and jointly constructing a complete recycling technology system. This technical system not only improves resource utilization efficiency and reduces environmental burden, but also creates considerable economic benefits, providing innovative technical support for the sustainable development of the fermentation industry.

Claims

1. A method for resource utilization of fermentation waste residue, characterized in that , including the following steps: (1) pre-treating the fermentation waste; (2) extracting beneficial components from the fermentation waste after pretreatment; (3) modifying the pretreated fermentation waste; (4) preparing functional materials and products based on the products of steps (2) and (3).

2. The method according to claim 1, characterized in that , the step (1) comprises: First, the fermentation waste residue is mechanically crushed using a high-speed shearing machine, the speed of the high-speed shearing machine is 3000-5000 rpm, and the crushing time is 5-15 minutes; Secondly, the crushed fermentation waste residue is dried by low-temperature vacuum drying, the drying temperature is 40-60°C, the vacuum degree is -0.08 to -0.09 MPa, and the drying time is 8-12 hours; Then, the dried fermentation waste residue is screened using a standard screening machine with a 100-mesh screen and a screening time of 15-20 minutes.

3. The method according to claim 1, characterized in that , said step (2) includes protein extraction, polysaccharide extraction and bioactive peptide preparation, wherein: The protein extraction adopts deep eutectic solvent extraction or enzymatic hydrolysis; The polysaccharide extraction adopts hot water extraction method or microwave-assisted extraction method; The bioactive peptide is prepared by enzymatic hydrolysis or fermentation.

4. The method according to claim 3, characterized in that , the steps of the deep eutectic solvent extraction method include: First, the pretreated fermentation waste is placed in a reactor, and a recyclable deep eutectic solvent composed of choline chloride and glycerol in a molar ratio of 1:2 is added, and the temperature is controlled at 40°C and the pH is 6.5-7.0; Secondly, add papain, the amount of papain is 0.8-1.0 parts by weight of the fermentation waste, and treat under stirring conditions of 150-200 rpm for 10-15 minutes; Then, the extract is separated and the protein-containing solution portion is collected; Finally, CO2 is injected into the remaining waste residue to increase the pressure to 1.5-2.0 MPa, and a small amount of citric acid solution is sprayed in to adjust the pH to 3.0-3.

5. The temperature is quickly raised to 160°C and maintained for 5-8 minutes to achieve rapid decomposition of cellulose.

5. The method according to claim 1, characterized in that , said step (3) comprises preparing a biosorbent and a biocatalyst carrier, wherein: The biosorbent is prepared by acid-base modification or graft copolymerization modification; The biocatalyst carrier is prepared by carbonization and porous treatment.

6. The method according to claim 5, characterized in that , the steps of the graft copolymerization modification method include: First, the pretreated fermentation waste residue is immersed in 30-50 parts by weight of acrylamide monomer solution; Next, an initiator, ammonium persulfate, is added, wherein the amount of ammonium persulfate is 1-2 parts by weight of the acrylamide; Then, under a nitrogen atmosphere, react at 50-60°C for 4-6 hours; Finally, the reaction product was washed with ethanol and dried in vacuum.

7. The method according to claim 1, characterized in that , said step (4) comprises preparing biofertilizer and bioenergy, wherein: The preparation of the biological fertilizer includes the preparation of composite microbial agents and the preparation of organic-inorganic composite fertilizers; The preparation of the bioenergy includes preparing biogas by anaerobic fermentation of biomass and preparing bio-oil by pyrolysis of biomass.

8. The method according to claim 7, characterized in that The components of the organic-inorganic compound fertilizer and their weight parts are: The fermentation waste 60-70 parts by weight; Composite microbial agent 5-8 parts by weight; 10-15 parts by weight of phosphate rock powder, wherein the P2O5 content is ≥30%; 8-12 parts by weight of potassium feldspar powder, wherein the K2O content is ≥10%; Humic acid 3-5 parts by weight; 1-2 parts by weight of trace element mixture.

9. The method according to claim 7, characterized in that The steps of preparing biogas by anaerobic fermentation of biomass include: Firstly, a double-chamber continuous treatment system was designed, including a front-end hydrolysis chamber and a back-end anaerobic fermentation chamber; Secondly, in the front hydrolysis chamber, the fermentation waste residue is mixed with water in a weight ratio of 1:3-1:5, the pH is adjusted to 6.5-7.0, and immobilized cellulase is added in an amount of 0.8-1.2 parts by weight of the dry weight of the fermentation waste residue. The mixture is hydrolyzed at 55°C for 12-16 hours; Then, the sugar solution produced by hydrolysis is separated from the solid residue through a precision filtration system, and the sugar solution is immediately cooled to 38°C and the pH is adjusted to 7.0-7.2; Finally, the cooled sugar solution is slowly dripped into the rear UASB reactor at a rate of 0.5-1.0 L / h. The temperature of the UASB reactor is maintained at 35-38°C, the pH is controlled at 7.0-7.5, and the hydraulic retention time is 15-20 days.

10. The method according to claim 7, characterized in that The step of preparing bio-oil by pyrolysis of biomass comprises: First, the pretreated fermentation waste residue is dried to a moisture content of <10 parts by weight, and then ground to a particle size of <2 mm; Secondly, in a fluidized bed reactor, the fermentation waste residue is heated to 450-550°C at a heating rate of 100-150°C / min under a nitrogen atmosphere for rapid pyrolysis, and the pyrolysis steam residence time is controlled to be 1-2 seconds; Then, the pyrolysis products were rapidly condensed to collect the bio-oil; Again, the aqueous phase and the oil phase were separated by centrifugation; Finally, the oil phase is subjected to vacuum distillation, and the 200-350°C fraction is collected. 5-10 parts by weight of activated carbon is used for adsorption at 60-70°C for 2-3 hours under stirring, and the refined bio-oil is obtained by filtration.