A harmless resource recycling method of waste frozen products based on microalgae synergistic fermentation

Abstract

The application provides a harmless resource recycling method of waste frozen products based on microalgae synergistic fermentation, and belongs to the technical field of harmless treatment of waste frozen products; a preparation process thereof comprises the following steps: pretreatment of waste frozen products; microalgae synergistic fermentation of pretreated frozen products; and directional preparation of products. In the pretreatment stage, ozone water sterilization is adopted, citric acid is used to adjust the pH to be acidic, and the synergistic fermentation of bacillus and lactic acid bacteria is combined, so that harmless treatment is achieved, and multi-stage resource utilization is realized based on the microalgae synergistic fermentation, and the added value is improved.

Description

Technical Field

[0001] This invention relates to the field of harmless treatment technology for waste frozen products, specifically to a method for harmless resource regeneration of waste frozen products based on microalgae co-fermentation. Background Technology

[0002] Currently, the main technologies for treating waste frozen products include physical treatment, chemical treatment, and biological treatment. Physical treatment, such as crushing and screening, can only perform preliminary treatment of waste frozen products and cannot achieve harmlessness and resource recycling; chemical treatment may introduce harmful substances and cause secondary pollution; traditional microbial fermentation technology in biological treatment can degrade organic matter to a certain extent, but it suffers from low treatment efficiency and low added value of products.

[0003] In the field of biological treatment, microalgae, as microorganisms with highly efficient photosynthesis and strong metabolic capabilities, have shown great potential in waste treatment and resource recycling in recent years. Microalgae can utilize organic matter in frozen waste as carbon and nitrogen sources for growth and reproduction, while accumulating useful substances such as lipids, proteins, and polysaccharides. However, single-method microalgae treatment often faces challenges such as limited degradation capacity for complex components and long fermentation cycles.

[0004] Waste frozen food contains harmful microorganisms such as pathogens and putrefactive bacteria. If not handled properly, it can easily lead to the spread of these microorganisms, posing a threat to the environment and human health. Furthermore, the nutrients in waste frozen food are not fully utilized, resulting in resource waste.

[0005] Therefore, we propose a highly efficient, environmentally friendly, and resource-high-value utilization method for the harmless recycling of waste frozen products based on microalgae co-fermentation. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a method for the harmless resource regeneration of waste frozen products based on microalgae co-fermentation.

[0007] A method for the harmless resource recycling of waste frozen products based on microalgae co-fermentation includes the following steps:

[0008] S1: Pre-treatment of waste frozen products

[0009] After the waste frozen products are thawed and crushed, they are sterilized with ozone, and then acidified by adjusting the pH to obtain pretreated frozen products.

[0010] S2: Microalgae co-fermentation of pretreated frozen products

[0011] First, Bacillus subtilis, Bacillus licheniformis, and lactic acid bacteria were used to ferment the pretreated frozen products. After filtration, fermentation broth and fermentation solids were obtained. Then, the fermentation broth was enzymatically hydrolyzed, and the hydrolysate was inoculated with Chlorella for microalgae co-fermentation to obtain a microalgae co-fermentation mixture.

[0012] S3: Directional preparation of the product

[0013] The microalgae co-fermentation mixture is filtered to obtain microalgae biomass and microalgae metabolite. The fermentation solids and microalgae biomass are mixed to prepare protein feed, and the microalgae metabolite and humic acid are mixed to prepare bio-fertilizer.

[0014] Furthermore, the pretreatment of waste frozen products in step S1 specifically includes the following steps:

[0015] S1.1: Place the waste frozen products in a refrigerated environment at 4-5℃ to thaw. After thawing, crush them using an ultra-high-speed shear crusher. After crushing, pass them through a 2-3cm sieve. Crush the substandard materials a second time to ensure that the particle size is ≤3cm to obtain crushed materials.

[0016] S1.2: Place the crushed material in a closed space, with an ozone generator installed. The ozone concentration is 8-10 mg / L. Sterilize for 30-40 minutes, then purge with nitrogen for 10-12 minutes to obtain sterilized crushed material.

[0017] S1.3: Add 15-18wt% citric acid solution to the sterilized and crushed material, stir to adjust the pH to 3.5-4.5, then react at 40-45℃ for 2-3 hours, and then add baking soda to adjust the pH to 5.0-6.0 to obtain the pretreated frozen product.

[0018] Furthermore, the microalgae co-fermentation of the pretreated frozen product in step S2 specifically includes the following steps:

[0019] S2.1: Bacillus subtilis, Bacillus licheniformis, and lactic acid bacteria are activated separately, and the activated Bacillus subtilis and Bacillus licheniformis are mixed to obtain a mixed fermentation strain;

[0020] S2.2: The pretreated frozen product is loaded into an aerated fermentation tank, and then 8-10 wt% of mixed fermentation bacteria are inoculated into the pretreated frozen product. The product is then aerobically fermented at 37℃ for 24-36 hours. After that, 8-10 wt% of lactic acid bacteria are inoculated into the pretreated frozen product, and the temperature is lowered to 32℃ for anaerobic fermentation for 12-14 hours. After the fermentation is completed, the product is filtered to obtain the fermentation broth and fermentation solids.

[0021] S2.3: Add 500-800 U / g neutral protease and 200-300 U / g lipase to the fermentation broth, then adjust the pH to 6.5-7, and then stir and hydrolyze at 37℃ and 100-120 r / min for 2-3 hours. After the hydrolysis is completed, inactivate the enzyme at 80-90℃ for 10-12 minutes to obtain the hydrolysate.

[0022] S2.4: Filter the enzymatic hydrolysate through a 0.22 μm membrane, then inoculate with Chlorella at an initial density of 0.5-0.8 g / L. Afterward, purge with air containing 3% CO2 and maintain an irradiance of 150-200 μmol / m². 2 / s, light-dark cycle 12h:12h, cultured at 25-27℃ for 5-7d to obtain microalgae co-fermentation mixture.

[0023] Furthermore, the directional preparation of the product in step S3 specifically includes the following steps:

[0024] S3.1: Filter the microalgae co-fermentation mixture to obtain microalgae biomass and microalgae metabolite;

[0025] S3.2: After mixing fermented solids and microalgae biomass, maltodextrin is added at a concentration of 10-12 wt%, followed by spray drying to prepare protein feed.

[0026] S3.3: Vacuum concentrate the microalgae metabolite to 20-30% of its original volume, mix it with humic acid in a 1:1 ratio, then add bentonite binder at a rate of 5-8 wt%, and granulate to obtain bio-fertilizer.

[0027] Further, in step S2.1, Bacillus subtilis and Bacillus licheniformis are mixed in a mass ratio of 2-3:1.

[0028] Compared with the prior art, the present invention has at least the following beneficial effects:

[0029] 1. This invention employs ozone sterilization in the pretreatment stage. Ozone, as a strong oxidant, can effectively kill pathogens and viruses in waste frozen products. After the reaction, it decomposes into oxygen, leaving no chemical residue pollution. Nitrogen purging further removes residual ozone, ensuring a safe fermentation environment and avoiding secondary pollution that may be caused by traditional chemical disinfectants. Using ozone sterilization instead of traditional high-temperature sterilization can maximize the retention of nutrients such as proteins and fats in frozen products, improving the utilization rate of waste frozen products. Citric acid is used to adjust the pH to acidic, combined with the synergistic fermentation of Bacillus and lactic acid bacteria. Through mechanisms such as acid production and nutrient competition, the growth of putrefactive bacteria and pathogens is inhibited, forming a biosafety barrier and preventing the spread of harmful microorganisms from the source, achieving harmless treatment.

[0030] 2. This invention first decomposes macromolecular organic matter through aerobic fermentation to produce small-molecule carbon sources and amino acids; then, it produces lactic acid through anaerobic fermentation to lower the pH of the system, creating a suitable environment for microalgae growth, while inhibiting other bacteria and reducing energy consumption during the fermentation process. Subsequently, enzymatic hydrolysis provides carbon sources for microalgae. Chlorella absorbs nitrogen and phosphorus pollutants in the fermentation broth through photosynthesis, replacing traditional wastewater treatment processes, reducing wastewater treatment costs, and converting pollutants into biomass, achieving "algae cultivation from waste." Furthermore, by utilizing the photosynthesis of Chlorella, organic matter and nitrogen and phosphorus pollutants in the fermentation broth are converted into microalgal biomass, while CO2 is fixed, achieving carbon recycling and multi-level resource utilization, thereby increasing added value.

[0031] 3. This invention produces protein feed by mixing fermented solids with microalgae biomass and then spray-drying it. The protein content can reach more than 45%, and it is rich in probiotics and β-carotene. It can be directly used for livestock and poultry breeding, replacing some traditional protein sources such as soybean meal and reducing feed costs. After the microalgae metabolite is concentrated, it is compounded with humic acid and bentonite to form an organic-inorganic compound bio-fertilizer rich in amino acids, trace elements and humus. It can improve soil structure and enhance water and fertilizer retention capacity. It is suitable for economic crops such as fruits, vegetables and flowers, realizing the recycling of nutrients in waste for farmland. It can also be directly used for saline-alkali land remediation. Attached Figure Description

[0032] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate embodiments of the invention and, together with the specification, further serve to explain the principles of the invention and enable those skilled in the art to practice and use the invention.

[0033] Figure 1 This is a flowchart of a method for harmless resource regeneration of waste frozen products based on microalgae co-fermentation, as used in an embodiment of the present invention. Detailed Implementation

[0034] The following describes in detail a method for the harmless resource regeneration of frozen waste products based on microalgae co-fermentation, provided by the present invention, with reference to the accompanying drawings and specific embodiments. It should be noted that, to make the embodiments more detailed, the following embodiments are the best and preferred embodiments; those skilled in the art can also use other alternative methods to implement some known technologies; and the accompanying drawings are only for more specific description of the embodiments and are not intended to specifically limit the present invention.

[0035] Example 1

[0036] A method for the harmless resource recycling of waste frozen products based on microalgae co-fermentation, such as... Figure 1 As shown, it includes the following steps:

[0037] S1: Pre-treatment of waste frozen products

[0038] S1.1: The waste frozen products are thawed in a 4℃ cold storage environment. After thawing, they are crushed using an ultra-high speed shear crusher. After crushing, they are passed through a 2cm sieve. The substandard materials are crushed a second time to ensure that the particle size is ≤3cm, and the crushed materials are obtained.

[0039] S1.2: Place the crushed material in a closed space, with an ozone generator installed. The ozone concentration is 8 mg / L. Sterilize for 30 minutes, then purge with nitrogen for 10 minutes to obtain sterilized crushed material.

[0040] S1.3: Add 15wt% citric acid solution to the sterilized and crushed material, stir to adjust the pH to 3.5, then react at 40℃ for 2 hours, and then add baking soda to adjust the pH to 5.0 to obtain the pretreated frozen product.

[0041] S2: Microalgae co-fermentation of pretreated frozen products

[0042] S2.1: Bacillus subtilis, Bacillus licheniformis, and lactic acid bacteria were activated separately, and the activated Bacillus subtilis and Bacillus licheniformis were mixed in a mass ratio of 2:1 to obtain a mixed fermentation strain;

[0043] S2.2: The pretreated frozen product is loaded into an aerated fermentation tank, then inoculated with 8 wt% of mixed fermentation bacteria from the pretreated frozen product, and aerobic fermentation is carried out at 37℃ for 24 hours. Then, 8 wt% of lactic acid bacteria from the pretreated frozen product is inoculated, and the temperature is lowered to 32℃ for anaerobic fermentation for 12 hours. After fermentation, the product is filtered to obtain fermentation broth and fermentation solids.

[0044] S2.3: Add 500 U / g neutral protease and 200 U / g lipase to the fermentation broth, then adjust the pH to 6.5, and then stir at 37℃ and 100 r / min for 2 h for enzymatic hydrolysis. After the enzymatic hydrolysis is completed, inactivate the enzyme at 80℃ for 10 min to obtain the enzymatic hydrolysate.

[0045] S2.4: Filter the enzymatic hydrolysate through a 0.22 μm membrane, then inoculate with Chlorella vulgaris at an initial density of 0.5 g / L. Afterward, purge with air containing 3% CO2 and maintain an irradiance of 150 μmol / m². 2 / s, light-dark cycle 12h:12h, cultured at 25℃ for 5d, to obtain microalgae co-fermentation mixture;

[0046] S3: Directional preparation of the product

[0047] S3.1: Filter the microalgae co-fermentation mixture to obtain microalgae biomass and microalgae metabolite;

[0048] S3.2: After mixing fermented solids and microalgae biomass, maltodextrin is added at a concentration of 10 wt%, followed by spray drying to prepare protein feed;

[0049] S3.3: Vacuum concentrate the microalgae metabolite to 20% of its original volume, mix it with humic acid in a 1:1 ratio, then add bentonite binder at a rate of 5 wt%, and granulate to obtain bio-fertilizer.

[0050] Example 2

[0051] A method for the harmless resource recycling of waste frozen products based on microalgae co-fermentation, such as... Figure 1 As shown, it includes the following steps:

[0052] S1: Pre-treatment of waste frozen products

[0053] S1.1: Place the waste frozen products in a 5℃ cold storage environment to thaw. After thawing, crush them using an ultra-high speed shear crusher. After crushing, pass them through a 3cm sieve. Crush the substandard materials a second time to ensure that the particle size is ≤3cm to obtain crushed materials.

[0054] S1.2: Place the crushed material in a closed space, with an ozone generator installed. The ozone concentration is 8 mg / L. Sterilize for 40 minutes, then purge with nitrogen for 12 minutes to obtain sterilized crushed material.

[0055] S1.3: Add 15wt% citric acid solution to the sterilized and crushed material, stir to adjust the pH to 4.5, then react at 40℃ for 2 hours, and then add baking soda to adjust the pH to 6.0 to obtain the pretreated frozen product.

[0056] S2: Microalgae co-fermentation of pretreated frozen products

[0057] S2.1: Bacillus subtilis, Bacillus licheniformis, and lactic acid bacteria are activated separately, and the activated Bacillus subtilis and Bacillus licheniformis are mixed in a mass ratio of 3:1 to obtain a mixed fermentation strain;

[0058] S2.2: The pretreated frozen product is loaded into an aerated fermentation tank, then inoculated with 10 wt% of mixed fermentation bacteria from the pretreated frozen product, and aerobic fermentation is carried out at 37℃ for 24 hours. Then, 8 wt% of lactic acid bacteria from the pretreated frozen product is inoculated, and the temperature is lowered to 32℃ for anaerobic fermentation for 12 hours. After fermentation, the product is filtered to obtain fermentation broth and fermentation solids.

[0059] S2.3: Add 800 U / g neutral protease and 300 U / g lipase to the fermentation broth, then adjust the pH to 6.5, and then stir at 37℃ and 120 r / min for 3 h for enzymatic hydrolysis. After the enzymatic hydrolysis is completed, inactivate the enzyme at 90℃ for 12 min to obtain the enzymatic hydrolysate.

[0060] S2.4: Filter the enzymatic hydrolysate through a 0.22 μm membrane, then inoculate with Chlorella vulgaris at an initial density of 0.5 g / L. Afterward, purge with air containing 3% CO2 and maintain an irradiance of 200 μmol / m². 2 / s, light-dark cycle 12h:12h, cultured at 27℃ for 7d, to obtain microalgae co-fermentation mixture;

[0061] S3: Directional preparation of the product

[0062] S3.1: Filter the microalgae co-fermentation mixture to obtain microalgae biomass and microalgae metabolite;

[0063] S3.2: After mixing fermented solids and microalgae biomass, maltodextrin is added at a concentration of 10 wt%, followed by spray drying to prepare protein feed;

[0064] S3.3: Vacuum concentrate the microalgae metabolite to 20% of its original volume, mix it with humic acid in a 1:1 ratio, then add bentonite binder at a rate of 5 wt%, and granulate to obtain bio-fertilizer.

[0065] Example 3

[0066] A method for the harmless resource recycling of waste frozen products based on microalgae co-fermentation, such as... Figure 1 As shown, it includes the following steps:

[0067] S1: Pre-treatment of waste frozen products

[0068] S1.1: The waste frozen products are thawed in a 4℃ cold storage environment. After thawing, they are crushed using an ultra-high speed shear crusher. After crushing, they are passed through a 2cm sieve. The substandard materials are crushed a second time to ensure that the particle size is ≤3cm, and the crushed materials are obtained.

[0069] S1.2: Place the crushed material in a closed space, with an ozone generator installed. The ozone concentration is 10 mg / L. Sterilize for 30 minutes, then purge with nitrogen for 10 minutes to obtain sterilized crushed material.

[0070] S1.3: Add 18wt% citric acid solution to the sterilized and crushed material, stir to adjust the pH to 4.5, then react at 40℃ for 2 hours, and then add baking soda to adjust the pH to 6.0 to obtain the pretreated frozen product.

[0071] S2: Microalgae co-fermentation of pretreated frozen products

[0072] S2.1: Bacillus subtilis, Bacillus licheniformis, and lactic acid bacteria are activated separately, and the activated Bacillus subtilis and Bacillus licheniformis are mixed in a mass ratio of 3:1 to obtain a mixed fermentation strain;

[0073] S2.2: The pretreated frozen product is loaded into an aerated fermentation tank, then inoculated with 10 wt% of mixed fermentation bacteria from the pretreated frozen product, and aerobic fermentation is carried out at 37℃ for 24 hours. Then, 10 wt% of lactic acid bacteria from the pretreated frozen product is inoculated, and the temperature is lowered to 32℃ for anaerobic fermentation for 12 hours. After fermentation, the product is filtered to obtain fermentation broth and fermentation solids.

[0074] S2.3: Add 800 U / g neutral protease and 300 U / g lipase to the fermentation broth, then adjust the pH to 7, and then stir at 37℃ and 100 r / min for 2 h for enzymatic hydrolysis. After the enzymatic hydrolysis is completed, inactivate the enzyme at 80℃ for 10 min to obtain the enzymatic hydrolysate.

[0075] S2.4: Filter the enzymatic hydrolysate through a 0.22 μm membrane, then inoculate with Chlorella vulgaris at an initial density of 0.8 g / L. Afterward, purge with air containing 3% CO2 and maintain an irradiance of 150 μmol / m². 2 / s, light-dark cycle 12h:12h, cultured at 25℃ for 5d, to obtain microalgae co-fermentation mixture;

[0076] S3: Directional preparation of the product

[0077] S3.1: Filter the microalgae co-fermentation mixture to obtain microalgae biomass and microalgae metabolite;

[0078] S3.2: After mixing fermented solids and microalgae biomass, maltodextrin is added at a concentration of 12 wt%, and then spray-dried to prepare protein feed.

[0079] S3.3: Vacuum concentrate the microalgae metabolite to 30% of its original volume, mix it with humic acid in a 1:1 ratio, then add bentonite binder at a rate of 8 wt%, and granulate to obtain bio-fertilizer.

[0080] Comparative Example 1

[0081] Compared with Example 1, the difference of Comparative Example 1 is that step S1.2 is removed in Comparative Example 1, and the crushed material in step S1.1 is sterilized by traditional high temperature to obtain sterilized crushed material. The remaining steps are unchanged for the harmless treatment of waste frozen products, and it is referred to as Comparative Example 1.

[0082] The pathogen inactivation rate of the sterilized and crushed materials prepared in Examples 1-3 and Comparative Example 1 was determined, and the results are shown in Table 1.

[0083] Table 1. Inactivation rate determination results of Examples 1-3 and Comparative Example 1

[0084] Inactivation rate (%) Example 1 99.97 Example 2 99.98 Example 3 99.97 Comparative Example 1 99.96

[0085] As can be seen from the data in Table 1, ozone water sterilization can achieve the same sterilization effect as traditional high-temperature sterilization. Ozone water sterilization does not require high-temperature treatment, can retain the protein and fat nutrients in frozen products, can reduce energy consumption, and has no nutrient loss.

[0086] The β-carotene content of the microalgae biomass in Examples 1-3 was determined, and the results are shown in Table 2.

[0087] Table 2. Results of β-carotene content determination in microalgal biomass in Examples 1-3

[0088] β-carotene content (mg / g) Example 1 12.7 Example 2 12.5 Example 3 12.5

[0089] As can be seen from the data in Table 2, the β-carotene content of the microalgae biomass in this invention is 12.5-12.7 mg / g, which is rich in β-carotene and can be directly used as high-value-added feed.

[0090] The bio-fertilizers prepared in Examples 1-3 were used to apply conventional fertilization to saline-alkali land. After 90 days, the change rate of soil electrical conductivity was measured. The change rate of electrical conductivity = (soil electrical conductivity after 90 days - initial electrical conductivity) / initial electrical conductivity × 100%. The measurement results are shown in Table 3.

[0091] Table 3. Results of the rate of change of soil electrical conductivity in Examples 1-3

[0092] Rate of change of conductivity (%) Example 1 -32.3 Example 2 -32.4 Example 3 -32.6

[0093] As can be seen from the data in Table 3, bio-fertilizers can significantly reduce soil electrical conductivity, thus achieving the effect of restoring saline-alkali land.

[0094] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for the harmless resource regeneration of waste frozen products based on microalgae co-fermentation, characterized in that, Includes the following steps: S1: Pre-treatment of waste frozen products After the waste frozen products are thawed and crushed, they are sterilized with ozone, and then acidified by adjusting the pH to obtain pretreated frozen products. S2: Microalgae co-fermentation of pretreated frozen products First, Bacillus subtilis, Bacillus licheniformis, and lactic acid bacteria were used to ferment the pretreated frozen products. After filtration, fermentation broth and fermentation solids were obtained. Then, the fermentation broth was enzymatically hydrolyzed, and the hydrolysate was inoculated with Chlorella for microalgae co-fermentation to obtain a microalgae co-fermentation mixture. S3: Directional preparation of the product The microalgae co-fermentation mixture is filtered to obtain microalgae biomass and microalgae metabolite. The fermentation solids and microalgae biomass are mixed to prepare protein feed, and the microalgae metabolite and humic acid are mixed to prepare bio-fertilizer.

2. The method for harmless resource regeneration of waste frozen products based on microalgae co-fermentation according to claim 1, characterized in that, Step S1, the pretreatment of waste frozen products, specifically includes the following steps: S1.1: Place the waste frozen products in a refrigerated environment at 4-5℃ to thaw. After thawing, crush them using an ultra-high-speed shear crusher. After crushing, pass them through a 2-3cm sieve. Crush the substandard materials a second time to ensure that the particle size is ≤3cm to obtain crushed materials. S1.2: Place the crushed material in a closed space, with an ozone generator installed. The ozone concentration is 8-10 mg / L. Sterilize for 30-40 minutes, then purge with nitrogen for 10-12 minutes to obtain sterilized crushed material. S1.3: Add 15-18wt% citric acid solution to the sterilized and crushed material, stir to adjust the pH to 3.5-4.5, then react at 40-45℃ for 2-3 hours, and then add baking soda to adjust the pH to 5.0-6.0 to obtain the pretreated frozen product.

3. The method for harmless resource regeneration of waste frozen products based on microalgae co-fermentation according to claim 2, characterized in that, Step S2, the co-fermentation of microalgae for pretreatment of frozen products, specifically includes the following steps: S2.1: Bacillus subtilis, Bacillus licheniformis, and lactic acid bacteria are activated separately, and the activated Bacillus subtilis and Bacillus licheniformis are mixed to obtain a mixed fermentation strain; S2.2: The pretreated frozen product is loaded into an aerated fermentation tank, and then 8-10 wt% of mixed fermentation bacteria are inoculated into the pretreated frozen product. The product is then aerobically fermented at 37℃ for 24-36 hours. After that, 8-10 wt% of lactic acid bacteria are inoculated into the pretreated frozen product, and the temperature is lowered to 32℃ for anaerobic fermentation for 12-14 hours. After the fermentation is completed, the product is filtered to obtain the fermentation broth and fermentation solids. S2.3: Add 500-800 U / g neutral protease and 200-300 U / g lipase to the fermentation broth, then adjust the pH to 6.5-7, and then stir and hydrolyze at 37℃ and 100-120 r / min for 2-3 hours. After the hydrolysis is completed, inactivate the enzyme at 80-90℃ for 10-12 minutes to obtain the hydrolysate. S2.4: Filter the enzymatic hydrolysate through a 0.22 μm membrane, then inoculate with Chlorella at an initial density of 0.5-0.8 g / L. Afterward, purge with air containing 3% CO2 and maintain an irradiance of 150-200 μmol / m². 2 / s, light-dark cycle 12h:12h, cultured at 25-27℃ for 5-7d to obtain microalgae co-fermentation mixture.

4. The method for harmless resource regeneration of waste frozen products based on microalgae co-fermentation according to claim 3, characterized in that, The directional preparation of the product in step S3 specifically includes the following steps: S3.1: Filter the microalgae co-fermentation mixture to obtain microalgae biomass and microalgae metabolite; S3.2: After mixing fermented solids and microalgae biomass, maltodextrin is added at a concentration of 10-12 wt%, followed by spray drying to prepare protein feed. S3.3: Vacuum concentrate the microalgae metabolite to 20-30% of its original volume, mix it with humic acid in a 1:1 ratio, then add bentonite binder at a rate of 5-8 wt%, and granulate to obtain bio-fertilizer.

5. A method for harmless resource regeneration of frozen waste products based on microalgae co-fermentation according to claim 3, characterized in that, In step S2.1, Bacillus subtilis and Bacillus licheniformis are mixed in a mass ratio of 2-3:1.

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