Waste frozen product harmless resource regeneration method based on microalgae synergistic fermentation

Abstract

The invention provides a waste frozen product harmless resource regeneration method based on microalgae synergistic fermentation, and belongs to the technical field of waste frozen product harmless treatment. The preparation process comprises the following steps: pretreatment of waste frozen products; carrying out synergistic fermentation on the pretreated frozen microalgae; and directionally preparing the product. According to the method, in the pretreatment stage, ozone water is adopted for sterilization, citric acid is used for adjusting the pH value to be acidic, synergistic fermentation of bacillus and lactic acid bacteria is combined, harmless treatment is achieved, multi-stage resource utilization is achieved based on microalgae synergistic fermentation, and the additional value is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of harmless treatment of discarded frozen products, and in particular to a harmless resource regeneration method for discarded frozen products based on microalgae collaborative fermentation. Background Art

[0002] Currently, the main treatment technologies for discarded frozen products include physical, chemical, and biological treatment. Physical treatment, such as crushing and screening, provides only preliminary treatment for discarded frozen products and cannot achieve harmlessness or resource recovery. Chemical treatment may introduce harmful substances, causing secondary pollution. Traditional microbial fermentation technology in biological treatment, while capable of degrading organic matter to a certain extent, suffers from low treatment efficiency and low added value.

[0003] In the field of bioprocessing, microalgae, as microorganisms with efficient photosynthesis and robust metabolic capacity, have recently demonstrated tremendous potential in waste treatment and resource recovery. Microalgae can utilize organic matter in frozen waste as a carbon and nitrogen source for growth and reproduction, while also accumulating useful substances such as oils, proteins, and polysaccharides. However, single-use microalgae treatments often face challenges such as limited ability to degrade complex components and long fermentation cycles.

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

[0005] Therefore, we proposed a harmless resource regeneration method for discarded frozen products based on microalgae collaborative fermentation that is efficient, environmentally friendly, and can achieve high-value resource utilization. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a harmless resource regeneration method for discarded frozen products based on microalgae collaborative fermentation.

[0007] A harmless resource regeneration method for discarded frozen products based on microalgae collaborative fermentation comprises the following steps: S1: pretreatment of discarded frozen products, comprising thawing and crushing the discarded frozen products, sterilizing them with ozone water, and then adjusting the pH for acidification to obtain pretreated frozen products; S2: microalgae collaborative fermentation of the pretreated frozen products, comprising first fermenting the pretreated frozen products with Bacillus subtilis, Bacillus licheniformis, and lactic acid bacteria, followed by filtration to obtain fermentation liquid and fermentation solids, then enzymatically hydrolyzing the fermentation liquid, inoculating the enzymatic hydrolysate with Chlorella for microalgae collaborative fermentation, and obtaining a microalgae collaborative fermentation mixture; S3: directed preparation of products, comprising filtering the microalgae collaborative fermentation mixture to obtain microalgae biomass and microalgae metabolic liquid, mixing the fermentation solids and microalgae biomass to prepare protein feed, and mixing the microalgae metabolic liquid with humic acid to prepare biofertilizer.

[0008] Furthermore, step S1 is a pretreatment of the discarded frozen products, specifically comprising the following steps: S1.1: placing the discarded frozen products in a 4-5°C refrigerated environment for thawing, crushing them with an ultra-high-speed shear crusher after thawing, passing them through a 2-3 cm sieve after crushing, and crushing the substandard materials for a second time to ensure that the particle size is ≤3 cm to obtain crushed materials; S1.2: placing the crushed materials in a closed space, with a built-in ozone generator with an ozone concentration of 8-10 mg / L, sterilizing them for 30-40 minutes, and then purging with nitrogen for 10-12 minutes to obtain sterilized crushed materials; S1.3: adding 15-18wt% citric acid solution to the sterilized crushed materials, stirring to adjust the pH to 3.5-4.5, and then reacting at 40-45°C for 2-3 hours, and then adding baking soda to adjust the pH to 5.0-6.0 to obtain pretreated frozen products.

[0009] Furthermore, step S2 pre-treats the frozen product for microalgae collaborative fermentation, specifically comprising the following steps: S2.1: activating Bacillus subtilis, Bacillus licheniformis, and lactic acid bacteria respectively, mixing the activated Bacillus subtilis and Bacillus licheniformis to obtain a mixed fermentation strain; S2.2: placing the pre-treated frozen product into an aerated fermentation tank, then inoculating 8-10 wt% of the mixed fermentation strain of the pre-treated frozen product, aerobic fermentation at 37°C for 24-36 h, then inoculating 8-10 wt% of the lactic acid bacteria of the pre-treated frozen product, cooling to 32°C for anaerobic fermentation for 12-14 h, and fermenting. After completion, the fermentation liquid and fermentation solids are filtered; S2.3: 500-800U / g neutral protease and 200-300U / g lipase are added to the fermentation liquid, and then the pH is adjusted to 6.5-7, and then the fermentation liquid is stirred at 37°C and 100-120r / min for 2-3h. After the enzymatic hydrolysis is completed, the enzyme is inactivated at 80-90°C for 10-12min to obtain an enzymatic hydrolyzate; S2.4: The enzymatic hydrolyzate is filtered through a 0.22μm membrane, and after filtration, the chlorella is inoculated with chlorella, and the initial density of chlorella is 0.5-0.8g / L, and then a 3% The mixture was cultured in an atmosphere of 150-200 μmol / m² / s, a light intensity of 150-200 μmol / m² / s, a light-dark cycle of 12 h:12 h, and 25-27°C for 5-7 days to obtain a microalgae synergistic fermentation mixture.

[0010] Furthermore, the directional preparation of the product of step S3 specifically includes the following steps: S3.1: filtering the microalgae co-fermentation mixture to obtain microalgae biomass and microalgae metabolic liquid; S3.2: after mixing the fermentation solids and microalgae biomass, adding maltodextrin, the maltodextrin addition amount is 10-12wt%, and then spray drying to prepare protein feed; S3.3: vacuum concentrating the microalgae metabolic liquid to 20-30% of the original volume, mixing it with humic acid in a 1:1 ratio, and then adding bentonite binder, the bentonite binder addition amount is 5-8wt%, and granulating to obtain biofertilizer.

[0011] Furthermore, the concentration of ozone water in step S1.2 is 5-8 mg / L.

[0012] Furthermore, in step S2.1, Bacillus subtilis and Bacillus licheniformis are mixed in a mass ratio of 2-3:1.

[0013] Furthermore, the amount of maltodextrin added in step S3.2 is 10-12 wt%.

[0014] Furthermore, in step S3.3, the amount of bentonite binder added is 5-8 wt%.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: 1. The present invention adopts ozone sterilization in the pretreatment stage. Ozone, as a strong oxidant, can effectively kill pathogens and viruses in discarded frozen products, and decomposes into oxygen after the reaction, without chemical residual pollution. Nitrogen purge further removes residual ozone, ensuring the safety of the subsequent fermentation environment and avoiding secondary pollution that may be caused by traditional chemical disinfectants. The use of ozone sterilization instead of traditional high-temperature sterilization can retain nutrients such as protein and fat in frozen products to the greatest extent, improve the utilization rate of discarded frozen products, use citric acid to adjust the pH to acidic, combine with the synergistic fermentation of Bacillus and lactic acid bacteria, and inhibit the growth of putrefactive bacteria and pathogens through mechanisms such as acid production and competition for nutrients, forming a biosafety barrier, eliminating the spread of harmful microorganisms from the source, and achieving harmless treatment.

[0016] 2. The present invention first decomposes macromolecular organic matter through aerobic fermentation to produce small molecular carbon sources and amino acids; then anaerobic fermentation produces lactic acid to reduce the pH of the system, creating a suitable environment for the growth of microalgae, while inhibiting miscellaneous bacteria and reducing the energy consumption of the fermentation process; then enzymatic hydrolysis provides a carbon source for the microalgae, and the chlorella absorbs nitrogen and phosphorus pollutants in the fermentation liquid through photosynthesis, replacing the traditional sewage treatment process and reducing the cost of wastewater treatment. At the same time, the pollutants are converted into biomass, realizing "using waste to grow algae", and the photosynthesis of the chlorella is used to convert the organic matter and nitrogen and phosphorus pollutants in the fermentation liquid into microalgae biomass, while fixing , realize carbon recycling, realize multi-level resource utilization, and increase added value.

[0017] 3. The present invention mixes fermented solids with microalgae biomass and spray-dries them to produce protein feed with a protein content of more than 45%. The feed is rich in probiotics and β-carotene and can be directly used in livestock and poultry breeding, replacing some traditional protein sources such as soybean meal and reducing feed costs. The microalgae metabolic fluid is concentrated and compounded with humic acid and bentonite to form an organic-inorganic composite biofertilizer rich in amino acids, trace elements, and humus. The biofertilizer can improve soil structure and enhance water and fertilizer retention capacity. It is suitable for cash crops such as fruits, vegetables, and flowers, realizes the agricultural recycling of nutrients in waste, and can also be directly used for saline-alkali land remediation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, further serve to explain the principles of the invention and to enable one skilled in the art to make and use the invention.

[0019] Figure 1 This is a flow chart of a method for harmless resource regeneration of discarded frozen products based on microalgae collaborative fermentation adopted in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] The following, combined with the accompanying drawings and specific examples, describes in detail a method for harmless resource recycling of frozen waste products based on microalgae-based co-fermentation. It is also noted that, for the sake of completeness, the following examples are best and preferred embodiments, and those skilled in the art may employ alternative methods for implementing known techniques. Furthermore, the accompanying drawings are intended only to provide a more detailed description of the embodiments and are not intended to limit the present invention.

[0021] Example 1: A method for harmless resource regeneration of discarded frozen products based on microalgae cooperative fermentation, such as Figure 1As shown, it includes the following steps: S1: pretreatment of waste frozen products, S1.1: placing the waste frozen products in a 4°C cold storage environment for thawing, and crushing them with an ultra-high-speed shear crusher after thawing. After crushing, the materials that do not meet the standards are sieved with a 2 cm sieve, and the substandard materials are crushed for the second time to ensure that the particle size is ≤3 cm to obtain crushed materials; S1.2: placing the crushed materials in a closed space, with a built-in ozone generator, the ozone concentration is 8 mg / L, sterilizing for 30 minutes, and then nitrogen purging for 10 minutes to obtain sterilized crushed materials; S1.3: adding 15wt% citric acid solution to the sterilized crushed materials, stirring to adjust the pH to 3.5, and then reacting at 40°C for 2 hours, and then adding baking soda to adjust the pH to 5.0 to obtain pretreated frozen products; S2: microalgae synergistic fermentation of pretreated frozen products, S2.1: activating Bacillus subtilis, Bacillus licheniformis, and lactic acid bacteria respectively, The activated Bacillus subtilis and Bacillus licheniformis were mixed in a mass ratio of 2:1 to obtain a mixed fermentation strain; S2.2: the pretreated frozen product was placed in an aerated fermentation tank, and then 8wt% of the mixed fermentation strain of the pretreated frozen product was inoculated, and aerobic fermentation was carried out at 37°C for 24h, and then 8wt% of the lactic acid bacteria of the pretreated frozen product was inoculated, and the temperature was lowered to 32°C for anaerobically fermented for 12h. After the fermentation was completed, the fermentation liquid and fermentation solids were obtained by filtration; S2.3: 500U / g neutral protease and 200U / g lipase were added to the fermentation liquid, and then the pH was adjusted to 6.5, and then the liquid was stirred for enzymolysis at 37°C and 100r / min for 2h. After the enzymolysis was completed, the enzyme was inactivated at 80°C for 10min to obtain an enzymolysis solution; S2.4: the enzymolysis solution was filtered through a 0.22μm membrane, and after filtration, chlorella was inoculated, and the initial density of chlorella was 0.5g / L, and then a 3% air, under a light intensity of 150 μmol / m² / s, a light-dark cycle of 12h:12h, and 25°C, and cultured for 5 days to obtain a microalgae synergistic fermentation mixture; S3: directional preparation of products, S3.1: filtering the microalgae synergistic fermentation mixture to obtain microalgae biomass and microalgae metabolic liquid; S3.2: after mixing the fermentation solids and microalgae biomass, adding maltodextrin in an amount of 10wt%, and then spray drying to prepare a protein feed; S3.3: vacuum concentrating the microalgae metabolic liquid to 20% of the original volume, mixing it with humic acid in a ratio of 1:1, and then adding bentonite binder in an amount of 5wt%, granulating to obtain a biofertilizer.

[0022] Example 2: A method for harmless resource regeneration of discarded frozen products based on microalgae cooperative fermentation, such as Figure 1As shown, it includes the following steps: S1: pretreatment of waste frozen products, S1.1: placing the waste frozen products in a 5°C cold storage environment for thawing, and crushing them with an ultra-high-speed shear crusher after thawing. After crushing, pass them through a 3cm sieve, and crush the substandard materials for the second time to ensure that the particle size is ≤3cm to obtain crushed materials; S1.2: placing the crushed materials in a closed space, with a built-in ozone generator, the ozone concentration is 8mg / L, sterilizing for 40min, and then purging with nitrogen for 12min to obtain sterilized crushed materials; S1.3: adding 15wt% citric acid solution to the sterilized crushed materials, stirring to adjust the pH to 4.5, and then reacting at 40°C for 2h, and then adding baking soda to adjust the pH to 6.0 to obtain pretreated frozen products; S2: microalgae synergistic fermentation of pretreated frozen products, S2.1: activating Bacillus subtilis, Bacillus licheniformis, and lactic acid bacteria respectively, The activated Bacillus subtilis and Bacillus licheniformis were mixed in a mass ratio of 3:1 to obtain a mixed fermentation strain; S2.2: the pretreated frozen product was placed in an aerated fermentation tank, and then 10 wt% of the mixed fermentation strain of the pretreated frozen product was inoculated, and aerobic fermentation was carried out at 37°C for 24 hours, and then 8 wt% of the lactic acid bacteria of the pretreated frozen product was inoculated, and the temperature was lowered to 32°C for anaerobically fermented for 12 hours. After the fermentation was completed, the fermentation liquid and fermentation solids were obtained by filtration; S2.3: 800 U / g neutral protease and 300 U / g lipase were added to the fermentation liquid, and then the pH was adjusted to 6.5, and then the liquid was stirred for enzymolysis at 37°C and 120 r / min for 3 hours. After the enzymolysis was completed, the enzyme was inactivated at 90°C for 12 minutes to obtain an enzymolysis solution; S2.4: the enzymolysis solution was filtered through a 0.22 μm membrane, and after filtration, chlorella was inoculated, and the initial density of chlorella was 0.5 g / L, and then a solution containing 3% air, under a light intensity of 200 μmol / m² / s, a light-dark cycle of 12h:12h, and 27°C, and cultured for 7 days to obtain a microalgae synergistic fermentation mixture; S3: directional preparation of products, S3.1: filtering the microalgae synergistic fermentation mixture to obtain microalgae biomass and microalgae metabolic liquid; S3.2: after mixing the fermentation solids and microalgae biomass, adding maltodextrin in an amount of 10wt%, and then spray drying to prepare a protein feed; S3.3: vacuum concentrating the microalgae metabolic liquid to 20% of the original volume, mixing it with humic acid in a ratio of 1:1, and then adding bentonite binder in an amount of 5wt%, granulating to obtain a biofertilizer.

[0023] Example 3: A method for harmless resource regeneration of discarded frozen products based on microalgae cooperative fermentation, such as Figure 1As shown, the method comprises the following steps: S1: pretreatment of waste frozen products, S1.1: placing the waste frozen products in a 4°C cold storage environment for thawing, crushing them with an ultra-high-speed shear crusher after thawing, passing them through a 2 cm sieve after crushing, crushing the substandard materials for the second time to ensure that the particle size is ≤3 cm, and obtaining crushed materials; S1.2: placing the crushed materials in a closed space, using a built-in ozone generator with an ozone concentration of 10 mg / L, sterilizing them for 30 minutes, and then purging them with nitrogen for 10 minutes to obtain sterilized crushed materials; S1.3: adding 18 wt% citric acid solution to the sterilized crushed materials, stirring and adjusting the pH to 4.5, and then reacting them at 40°C for 2 hours, and then adding baking soda to adjust the pH to 6.0 to obtain pretreated frozen products; S2: microalgae co-fermentation of the pretreated frozen products, S2.1: activating Bacillus subtilis, Bacillus licheniformis, and lactic acid bacteria respectively, The activated Bacillus subtilis and Bacillus licheniformis were mixed in a mass ratio of 3:1 to obtain a mixed fermentation strain; S2.2: the pretreated frozen product was placed in an aerated fermentation tank, and then 10 wt% of the mixed fermentation strain of the pretreated frozen product was inoculated, and aerobic fermentation was carried out at 37 ° C for 24 hours, and then 10 wt% of the pretreated frozen product was inoculated with lactic acid bacteria, and the temperature was lowered to 32 ° C for anaerobically fermented for 12 hours. After the fermentation was completed, the fermentation liquid and fermentation solids were obtained by filtration; S2.3: 800 U / g neutral protease and 300 U / g lipase were added to the fermentation liquid, and then the pH was adjusted to 7, and then the liquid was stirred for enzymolysis at 37 ° C and 100 r / min for 2 hours. After the enzymolysis was completed, the enzyme was inactivated at 80 ° C for 10 minutes to obtain an enzymolysis solution; S2.4: the enzymolysis solution was filtered through a 0.22 μm membrane, and after filtration, chlorella was inoculated, and the initial density of chlorella was 0.8 g / L, and then a 3% air, under a light intensity of 150 μmol / m² / s, a light-dark cycle of 12h:12h, and 25°C, and cultured for 5 days to obtain a microalgae synergistic fermentation mixture; S3: directional preparation of products, S3.1: filtering the microalgae synergistic fermentation mixture to obtain microalgae biomass and microalgae metabolic liquid; S3.2: after mixing the fermentation solids and microalgae biomass, adding maltodextrin in an amount of 12wt%, and then spray drying to prepare a protein feed; S3.3: vacuum concentrating the microalgae metabolic liquid to 30% of the original volume, mixing it with humic acid in a ratio of 1:1, and then adding bentonite binder in an amount of 8wt%, granulating to obtain a biofertilizer.

[0024] Comparative Example 1: Compared with Example 1, the difference of Comparative Example 1 is that Comparative Example 1 removes step S1.2, and the crushed material in step S1.1 is sterilized by traditional high temperature to obtain sterilized crushed material. The remaining steps remain unchanged and the waste frozen product is treated harmlessly, which is recorded as Comparative Example 1.

[0025] The sterilized crushed materials prepared in Examples 1-3 and Comparative Example 1 were subjected to pathogen inactivation rate determination. The determination results are shown in Table 1.

[0026] Table 1. Inactivation rate determination results of Examples 1-3 and Comparative Example 1 From the data in Table 1, it can be seen that 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.

[0027] The β-carotene content of the microalgae biomass in Examples 1-3 was determined. The results are shown in Table 2.

[0028] Table 2. Results of β-carotene content determination in microalgae biomass from Examples 1-3 From the data in Table 2, it can be seen that the β-carotene content of the microalgae biomass in the present invention is 12.5-12.7 mg / g, which is rich in β-carotene and can be directly used in high-value-added feed.

[0029] The biofertilizer prepared in Examples 1-3 was used for conventional fertilization of saline-alkali land. After 90 days, the change rate of soil electrical conductivity was measured. The conductivity change rate = (soil electrical conductivity after 90 days - initial electrical conductivity) / initial electrical conductivity × 100%. The measurement results are shown in Table 3.

[0030] Table 3. Results of the change rate of soil electrical conductivity of biofertilizers in Examples 1-3 From the data in Table 3, it can be seen that biofertilizer can significantly reduce soil electrical conductivity and achieve the effect of repairing saline-alkali land.

[0031] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may 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 one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A method for harmless resource regeneration of discarded frozen products based on microalgae collaborative fermentation, characterized in that: The method comprises the following steps: S1: pre-treating the discarded frozen products, thawing and crushing the discarded frozen products, sterilizing them with ozone, and then adjusting the pH to perform acidification to obtain pre-treated frozen products; S2: Microalgae co-fermentation of pre-treated frozen products. The pre-treated frozen products are first fermented with Bacillus subtilis, Bacillus licheniformis, and lactic acid bacteria, and then filtered to obtain fermentation liquid and fermentation solids. The fermentation liquid is then enzymatically hydrolyzed, and the enzymatic hydrolyzate is inoculated with Chlorella for microalgae co-fermentation to obtain a microalgae co-fermentation mixture. S3: Directed preparation of products. The microalgae co-fermentation mixture is filtered to obtain microalgae biomass and microalgae metabolic liquid. The fermentation solids and microalgae biomass are mixed to prepare protein feed, and the microalgae metabolic liquid and humic acid are mixed to prepare biofertilizer.

2. The method for harmless resource regeneration of discarded frozen products based on microalgae cooperative fermentation according to claim 1, characterized in that: Step S1 is the pretreatment of the discarded frozen products, which specifically includes the following steps: S1.1: placing the discarded frozen products in a 4-5°C refrigerated environment for thawing, and crushing them with an ultra-high-speed shear crusher after thawing. After crushing, the materials that do not meet the standards are sieved with a 2-3 cm sieve, and the materials that do not meet the standards are crushed for the second time to ensure that the particle size is ≤3 cm to obtain crushed materials; S1.2: placing the crushed materials in a closed space, with a built-in ozone generator, the ozone concentration is 8-10 mg / L, sterilizing for 30-40 minutes, and then nitrogen purging for 10-12 minutes to obtain sterilized crushed materials; S1.3: adding 15-18wt% citric acid solution to the sterilized crushed materials, stirring to adjust the pH to 3.5-4.5, and then reacting at 40-45°C for 2-3 hours, and then adding baking soda to adjust the pH to 5.0-6.0 to obtain pretreated frozen products.

3. The method for harmless resource regeneration of discarded frozen products based on microalgae cooperative fermentation according to claim 2, characterized in that: Step S2 is to pre-treat the frozen product for microalgae cooperative fermentation, specifically comprising the following steps: S2.1: activating Bacillus subtilis, Bacillus licheniformis, and lactic acid bacteria respectively, mixing the activated Bacillus subtilis and Bacillus licheniformis to obtain a mixed fermentation strain; S2.2: placing the pre-treated frozen product into an aerated fermentation tank, then inoculating 8-10wt% of the mixed fermentation strain of the pre-treated frozen product, aerobic fermentation at 37°C for 24-36h, then inoculating 8-10wt% of the pre-treated frozen product for anaerobic fermentation at 32°C for 12-14h, and fermentation is completed. Then filter to obtain fermentation liquid and fermentation solids; S2.3: add 500-800U / g neutral protease and 200-300U / g lipase to the fermentation liquid, then adjust the pH to 6.5-7, and then stir and hydrolyze at 37℃, 100-120r / min for 2-3h. After the enzymatic hydrolysis is completed, inactivate the enzyme at 80-90℃ for 10-12min to obtain enzymatic solution; S2.4: filter the enzymatic solution through a 0.22μm membrane, inoculate Chlorella after filtration, the initial density of Chlorella is 0.5-0.8g / L, and then pass 3% The mixture was cultured in an atmosphere of 150-200 μmol / m² / s, a light intensity of 150-200 μmol / m² / s, a light-dark cycle of 12 h:12 h, and 25-27°C for 5-7 days to obtain a microalgae synergistic fermentation mixture.

4. The method for harmless resource regeneration of discarded frozen products based on microalgae cooperative fermentation according to claim 3, characterized in that: The directional preparation of the product of step S3 specifically includes the following steps: S3.1: filtering the microalgae co-fermentation mixture to obtain microalgae biomass and microalgae metabolic liquid; S3.2: after mixing the fermentation solids and microalgae biomass, adding maltodextrin, the maltodextrin addition amount is 10-12wt%, and then spray drying to prepare protein feed; S3.3: vacuum concentrating the microalgae metabolic liquid to 20-30% of the original volume, mixing it with humic acid in a 1:1 ratio, and then adding bentonite binder, the bentonite binder addition amount is 5-8wt%, and granulating to obtain biofertilizer.

5. The method for harmless resource regeneration of discarded frozen products based on microalgae cooperative fermentation according to claim 2, characterized in that: The concentration of ozone water in step S1.2 is 5-8 mg / L.

6. The method for harmless resource regeneration of discarded frozen products based on microalgae cooperative 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.

7. The method for harmless resource regeneration of discarded frozen products based on microalgae cooperative fermentation according to claim 4, characterized in that: The amount of maltodextrin added in step S3.2 is 10-12 wt%.

8. The method for harmless resource regeneration of discarded frozen products based on microalgae cooperative fermentation according to claim 4, characterized in that: In step S3.3, the amount of bentonite binder added is 5-8wt%.

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