A method for preparing a crop nutrient using a by-product of macrobrachium rosenbergii and applications thereof

Abstract

The present application belongs to the technical field of agricultural waste recycling, and particularly relates to a method for preparing crop nutrient agent by using by-product of Macrobrachium Nipponense, wherein the by-product of Macrobrachium Nipponense is dried, ground into shrimp shell powder, mixed with water, and treated by electron beam irradiation; the shrimp shell powder is put into a fermentation tank, water is added to obtain shrimp shell powder treatment liquid, Bacillus subtilis YS-45 is added for stirring fermentation, and Clostridium butyricum CICC 10390 is added for static fermentation; the fermentation liquid is filtered and added into the fermentation tank, and brown sugar, K2HPO4 and MgSO4 are added for fermentation, so that the crop nutrient agent is obtained. The method effectively recycles and utilizes the nutritional value of the by-product of Macrobrachium Nipponense, and is used for preparing the crop nutrient agent for the first time, greatly degrades the organic macromolecules in the by-product of Macrobrachium Nipponense, improves the utilization value, increases the added value, and has low cost and good effect, and can be further applied to rice and other crop foliar fertilizers to promote crop yield growth.

Description

Technical Field

[0001] This invention belongs to the field of agricultural waste recycling technology, and in particular relates to a method and application for preparing crop nutrients using by-products of Procambarus clarkii. Background Technology

[0002] The red swamp crayfish (Procambarus clarkii), commonly known as the crayfish, belongs to the class Crustacea of ​​the phylum Arthropoda. Native to North America, my country has become a major producer and consumer of red swamp crayfish by-products after many years of development. By-products such as shells and heads generated during the consumption or processing of red swamp crayfish account for 70-85% of the raw materials. These by-products are rich in proteins, lipids, carbohydrates, and other high-molecular-weight complex organic compounds. For a long time, these by-products have not been well utilized, resulting not only in resource waste but also serious environmental pollution. Fully exploring the potential value of red swamp crayfish by-products is of great significance for achieving their full utilization and mitigating environmental pollution problems.

[0003] Currently, in terms of utilizing the by-products of *Procambarus clarkii*, only a small portion of crayfish shells are recycled in China. Typically, the shells are washed, dried, crushed, and disinfected to produce shell powder, which is then used as a feed additive. Many researchers have also conducted studies on extracting chitin, astaxanthin, protein peptides, and chitosan from *Procambarus clarkii* by-products, but the technology is not yet mature and is still some distance from industrialization. How to efficiently utilize *Procambarus clarkii* by-products and increase their added value is an urgent problem to be solved.

[0004] In order to fully utilize the nutritional value of the by-products of the red prawn, it is essential to develop a nutrient-rich crop nutrient to expand its uses and increase its added value. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the background art above and to provide a method for preparing crop nutrients using the by-products of Procambarus clarkii.

[0006] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0007] A method for preparing crop nutrients using by-products of the red swamp crayfish includes the following steps:

[0008] (1) Dry the by-products of the red prawn and grind them into shrimp shell powder. Then add water and mix well. After standing, treat with electron beam irradiation.

[0009] (2) The shrimp shell powder obtained after electron beam irradiation in step (1) is placed in a fermentation tank, water is added to obtain shrimp shell powder treatment liquid, Bacillus subtilis is added and stirred for fermentation, and then Clostridium butyricum is added for static fermentation.

[0010] (3) Filter the fermentation liquid obtained in step (2), add the obtained fermentation filtrate to the fermentation tank, add brown sugar, K2HPO4 and MgSO4 and stir to ferment, then carry out static fermentation, and finally filter the fermentation liquid to obtain the crop nutrient.

[0011] The purpose of the secondary fermentation in this invention is twofold: firstly, to allow the added macronutrients required by the crop to undergo a polymerization reaction with the amino acids and peptides in the fermentation broth, forming a crop nutrient rich in amino acids and oligopeptides; and secondly, to make the fermentation more complete and the degradation of macromolecules more thorough.

[0012] In the above-mentioned method for preparing crop nutrients using by-products of *Procambarus clarkii*, preferably, the by-products of *Procambarus clarkii* include the shell and head of the crayfish, which contain proteins, lipids, carbohydrates, minerals, etc.; the protein content of the by-products of *Procambarus clarkii* is 35-45%, the lipid content is 7-12%, the carbohydrate content is 8-12%, and the mineral content is 0.5-2.5%.

[0013] Preferably, in step (1), the shrimp shell powder is ground and then passed through a 20-mesh sieve; the moisture content of the shrimp shell powder after adding water is 15-30%, and the standing time is more than 24 hours.

[0014] Preferably, in step (1), the dose of the electron beam irradiation treatment is 10-20 kGy.

[0015] Preferably, in step (2), the shrimp shell powder obtained after electron beam irradiation treatment has a water content of 80-90% after being added to water, and the pH value of the shrimp shell powder treatment solution is 7-8.

[0016] Preferably, in step (2), the mass ratio of Bacillus subtilis and Clostridium butyricum is 1:1-1.5.

[0017] Preferably, in step (2), the temperature for stirring fermentation is 30-45℃, the rotation speed is 220-260rpm, and the fermentation time is 24-72h; the temperature for static fermentation is 25-40℃, and the fermentation time is 24-48h.

[0018] Preferably, in step (3), the mixture is filtered through a 50-mesh sieve; the mass ratio of the fermentation filtrate, brown sugar, K2HPO4, and MgSO4 is 10:1-2:0.1-0.5:0.1-0.3.

[0019] Preferably, in step (3), the temperature of stirring fermentation is 30-45℃, the rotation speed is 140-170rpm, and the fermentation time is 24-48h; the temperature of static fermentation is 25-40℃, and the fermentation time is 24-48h; the final fermentation liquid is filtered through an 80-mesh sieve, and the crop nutrient is diluted with water 20-30 times when used.

[0020] Without irradiation and microbial fermentation treatment, the by-products of *Procambarus clarkii* have few soluble components when added to water, with most being insoluble and having low nutritional value. However, this invention, through a combined irradiation and microbial fermentation treatment, significantly increases the content of water-soluble components in the *Procambarus clarkii* by-products, especially amino acids, oligopeptides, and total nutrients, resulting in higher nutritional value and wider applications. It can be used as a crop nutrient, significantly increasing its added value. The pretreatment methods of grinding, sieving, and adding water in this invention primarily aim to improve the electron beam irradiation effect, reduce the irradiation dose, and save costs. The use of an electron accelerator for irradiation provides a favorable environment for microbial fermentation, resulting in a fermentation broth with a richer nutrient content.

[0021] Based on a general inventive concept, the present invention also provides the application of Procambarus clarkii by-products in the preparation of crop nutrients.

[0022] Based on a general inventive concept, the present invention also provides an application of the crop nutrient prepared by the above method. The application method of the crop nutrient is as follows: after fertilizing rice according to conventional methods during the rice growth cycle, the crop nutrient is sprayed onto the rice leaves at the tillering stage, heading and flowering stage, and grain filling and ripening stage.

[0023] Tillering stage: The crop nutrient solution is prepared with water to a concentration of 0.2%-0.4%, and the application rate is 70-80 kg / mu;

[0024] During the heading and flowering stage: the crop nutrient solution is prepared with water to a concentration of 0.3%-0.5%, and the application rate is 50-60 kg / mu;

[0025] Grain filling and ripening stage: Prepare a 0.4%-0.6% mass concentration solution of the crop nutrient agent with water, and spray at a rate of 40-50 kg / mu.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. The method of the present invention effectively recovers and utilizes the nutritional value of the by-products of the red swamp crayfish and is used for the first time in the preparation of crop nutrients. On the one hand, it greatly degrades the organic macromolecules in the by-products of the red swamp crayfish, improves its utilization value, increases its added value, and has good economic and ecological benefits. On the other hand, the method is low in cost, effective, green and environmentally friendly, reduces pollution to the environment, and can promote the development of the red swamp crayfish industry.

[0028] 2. This invention incorporates Bacillus subtilis YS-45 and Clostridium butyricum CICC 10390 for co-fermentation. The dry powder of Crayfish Clearwater Crayfish by-products contains 35-45% protein, 7-12% lipids, 8-12% carbohydrates, and 0.5-2.5% minerals. Bacillus subtilis YS-45 has excellent degradation effects on proteins and polysaccharides, and also has a certain degradation effect on lipids. The addition of Clostridium butyricum CICC 10390 further degrades the organic matter in Crayfish Clearwater Crayfish by-products, especially carbohydrates, which are significantly degraded into small molecules that can be directly absorbed by crops. It can also inhibit the growth of other harmful microorganisms. These bacteria are not simply added together; their fermentation (growth) conditions need to be optimized to obtain the best production process.

[0029] 3. The crop nutrient prepared by this invention can be used as a foliar fertilizer for rice, wheat, corn, soybeans, vegetables, flowers, melons and fruits, as well as various grains, oils and cash crops. It can significantly increase the yield of various rice varieties, and the effect is better than that of traditional plant nutrients. Detailed Implementation

[0030] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below in conjunction with the specification and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0031] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0032] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0033] Example 1:

[0034] A method for preparing crop nutrients using by-products of the red swamp crayfish includes the following steps:

[0035] (1) After drying the by-products of the red crayfish, crush them with a pulverizer, grind them, pass them through a 20-mesh sieve to make shrimp shell powder, add water to make shrimp shell powder (moisture content is shown in Table 3), let it stand for 24 hours, and then treat it with electron beam irradiation (irradiation dose is shown in Table 3).

[0036] (2) The shrimp shell powder obtained after electron beam irradiation treatment in step (1) is put into a fermentation tank. The shrimp shell powder is 10%, water is 89%, and Bacillus subtilis YS-45 is 0.5% by mass. The mixture is stirred and fermented for 48 hours. Then, 0.5% Clostridium butyricum CICC 10390 is added and the mixture is allowed to stand for 36 hours. The water-soluble component content in the fermentation liquid is 30-55% higher than that in the untreated liquid.

[0037] (3) Filter the fermentation liquid obtained in step (2) through a 50-mesh sieve, and add the fermentation filtrate to the fermentation tank. The raw material ratio is 1:10:0.3:0.1 for brown sugar, fermentation filtrate, K2HPO4 and MgSO4. After stirring and fermenting at 150 rpm and 35°C for 36 hours, let it stand for 36 hours at 30°C. Filter the solution after the second fermentation through an 80-mesh sieve. The filtrate is the finished crop nutrient product.

[0038] The present invention also provides the following comparative experiments:

[0039] 1. Effects of irradiation treatment on the main components and physicochemical properties of nutrients

[0040] The by-products of *Procambarus clarkii* with a water content of 25% were irradiated at a dose of 15 kGy, while the control group was not irradiated. Then, a mixed fermentation of *Bacillus subtilis* and *Clostridium butyricum* was carried out. The results are shown in Table 1.

[0041] Table 1. Effects of irradiation treatment on the main components and physicochemical properties of the nutrient solution.

[0042] project Untreated (control) Irradiation treatment pH value 6.5±0.6 5.5±0.5 Water-insoluble matter (g / L) 25.2±1.4 18.1±1.2 Amino acid content (mg / 100mL) 90.6±7.5 120.6±10.3 Total nutrients (g / L) 175.4±13.4 230.5±20.1 Oligopeptide content (mg / 100mL) 624.2±34.4 765.6±24.7

[0043] As shown in Table 1, the treated sample outperformed the control in all indicators. The amino acid, total nutrient, and oligopeptide contents were significantly higher than the control, with amino acid content increasing by 33.1%, total nutrient content by 31.4%, and oligopeptide content by 22.7%. Therefore, irradiation treatment can improve the nutritional value of the nutrient solution. This may be because irradiation acts on certain chemical bonds in the organic macromolecules of the Crayfish by-products, destroying the structure of the macromolecules, reducing their molecular weight, and providing a favorable environment for subsequent microbial fermentation.

[0044] 2. The effects of single-cell and mixed-cell fermentation on nutrients

[0045] The experiment was divided into two groups. The samples were by-products of Procambarus clarkii with a water content of 25%. One group of samples was irradiated with a dose of 20 kGy, while the other group of samples was not irradiated. Then, the two groups of samples were fermented with single cells and mixed cells, respectively. The results are shown in Table 2.

[0046] Table 2. Effects of single-cell and mixed-cell fermentation on nutrients.

[0047]

[0048]

[0049] Table 2 shows that irradiation treatment can promote the fermentation of by-products of *Procambarus clarkii* by the strains, and increase the content of amino acids, oligopeptides, and total nutrients in the fermentation broth. The fermentation effect of mixed bacteria is significantly better than that of single bacteria. Among single bacteria, *Bacillus subtilis* YS-45 has the best fermentation effect. The combination of *Bacillus subtilis* YS-45 and *Clostridium butyricum* CICC10390 has the best fermentation effect. This is because *Bacillus subtilis* YS-45 and *Clostridium butyricum* CICC10390 have a mutually beneficial and promoting effect during the fermentation process. *Bacillus subtilis* YS-45 has a good degradation effect on macromolecules such as proteins and polysaccharides, providing oligosaccharides and other raw materials for the fermentation of *Clostridium butyricum* CICC10390. *Clostridium butyricum* CICC10390 has a good degradation effect on oligosaccharides and can inhibit the growth of other harmful microorganisms, providing energy and a good growth environment for *Bacillus subtilis* YS-45.

[0050] 3. Effect of irradiation on the solubility of by-products from Procambarus clarkii

[0051] Table 3. Effects of irradiation treatment on the solubility of by-products from Procambarus clarkii under different water contents.

[0052]

[0053] The by-products of *Procambarus clarkii* contain various organic macromolecules that are not easily soluble in water. After irradiation treatment of *Procambarus clarkii* by-products with different water contents, they were dried, ground, and then distilled water was added. The solubility (wt.%) was measured, and the results are shown in Table 3. Table 3 shows that for *Procambarus clarkii* by-products with different water contents treated with the same irradiation dose, the solubility increased with increasing water content. When the water content reached 30%, further increases in water content had no significant effect on the solubility. For *Procambarus clarkii* by-products with the same water content treated with different irradiation doses, the solubility increased with increasing dose. The rate of increase in solubility was faster when the irradiation dose was between 3-20 kGy, and slower when the irradiation dose was greater than 20 kGy.

[0054] Example 2:

[0055] The crop nutrient of this invention is mainly used for rice, but can also be used for rice, wheat, corn, soybeans, vegetables, flowers, melons and other fruit trees, as well as various grains, oils and cash crops, primarily through foliar spraying. The following example uses rice spraying, with different rice varieties as experimental materials (rice varieties include Nongxiang 42, Xiangzaoxian 45, Xiangfu 994, and C Liangyou 608), and water as a control. Foliar fertilizers (including the crop nutrient of this invention, traditional plant nutrients, and urea) were sprayed during the tillering, heading and flowering, and grain-filling and ripening stages. Other conditions remained consistent across treatments to verify the application effect of the crop nutrient prepared in Example 1.

[0056] The crop nutrient of the present invention was prepared in Example 1. The water content of the by-product of the red swamp crayfish before irradiation was 25%, and the irradiation dose was 20 kGy.

[0057] The preparation method of the above-mentioned traditional plant nutrient solution includes the following steps: pulverize soybean meal and pass it through a 60-mesh sieve for later use. Prepare a fermentation culture base in a fermenter by adding 60g of soybean meal, 10g of white sugar, 3g of KH2PO3 and 1000mL of water. Sterilize the mixture with high-pressure steam at 121℃ for 30min. After cooling, inoculate the fermentation inoculum at a rate of 5% and ferment at 250r / min and 37℃ for 3 days. Filter the solution through double-layer gauze. The filtrate is the plant nutrient solution.

[0058] The spraying method is as follows: After applying fertilizer according to conventional methods during the rice growth cycle, spray the rice leaves with various foliar fertilizers at the tillering stage, heading and flowering stage, and grain filling and ripening stage.

[0059] Tillering stage: Prepare a 0.3% mass concentration solution of each foliar fertilizer with water. The solution should be prepared evenly, at a rate of 780 kg / mu.

[0060] During the heading and flowering stage: each foliar fertilizer should be mixed with water to prepare a 0.4% mass concentration solution. The solution should be prepared evenly, at a rate of 60 kg / mu.

[0061] Grain filling and ripening stage: Prepare a 0.5% mass concentration solution of each foliar fertilizer with water. The solution should be prepared evenly, at a rate of 50 kg / mu.

[0062] Table 4: Effects of different foliar fertilizers on the yield of various rice varieties

[0063]

[0064] As shown in Table 4, the crop nutrient solution used in this invention can significantly increase the yield of various types of rice, and the effect is better than that of traditional plant nutrients. This indicates that this invention effectively recovers and utilizes the nutritional value of the by-products of the red swamp crayfish and is used for the first time in the preparation of crop nutrients. It greatly degrades the organic macromolecules in the by-products of the red swamp crayfish, improves its utilization value, increases its added value, and is low in cost and effective.

Claims

1. A method for preparing crop nutrients using by-products of *Procambarus clarkii*, characterized in that, Includes the following steps: (1) The by-products of the red prawn are dried and ground into shrimp shell powder, then water is added and mixed evenly. After standing, the shrimp shell powder is treated with electron beam irradiation. The shrimp shell powder is ground and passed through a 20-mesh sieve. The water content of the shrimp shell powder after adding water is 15-30%, the standing time is more than 24 hours, and the dose of electron beam irradiation treatment is 10-20 kGy. (2) Place the shrimp shell powder obtained after electron beam irradiation treatment in step (1) into a fermentation tank, add water to obtain shrimp shell powder treatment solution, and add Bacillus subtilis ( Bacillus subtilis After stirring and fermentation, then add Clostridium butyricum (Clostridium butyricum). Clostridium butyricum The shrimp shell powder obtained after electron beam irradiation treatment is added to water, with the water content being 80-90% by mass, and the pH value of the shrimp shell powder treatment solution being 7-8; the mass ratio of Bacillus subtilis and Clostridium butyricum is 1:1-1.5; the temperature for stirring fermentation is 30-45℃, the rotation speed is 220-260 rpm, and the fermentation time is 24-72 h; the temperature for static fermentation is 25-40℃, and the fermentation time is 24-48 h. (3) Filter the fermentation liquid obtained in step (2), and add the obtained fermentation filtrate to the fermentation tank. Add brown sugar, K2HPO4 and MgSO4 in the mass ratio of fermentation filtrate, brown sugar, K2HPO4 and MgSO4 of 10:1-2:0.1-0.5:0.1-0.3 and stir for fermentation. Then carry out static fermentation. Finally, filter the fermentation liquid to obtain the crop nutrient.

2. The method for preparing crop nutrients using by-products of *Procambarus clarkii* according to claim 1, characterized in that, The by-products of the red swamp crayfish include the crayfish shell and head; the protein content of the by-products is 35-45%, the lipid content is 7-12%, the carbohydrate content is 8-12%, and the mineral content is 0.5-2.5%.

3. The method for preparing crop nutrients using by-products of *Procambarus clarkii* according to claim 1, characterized in that, In step (3), the filter is made using a 50-mesh sieve.

4. The method for preparing crop nutrients using by-products of *Procambarus clarkii* according to any one of claims 1-3, characterized in that, In step (3), the temperature for stirring fermentation is 30-45℃, the rotation speed is 140-170rpm, and the fermentation time is 24-48h; the temperature for static fermentation is 25-40℃, and the fermentation time is 24-48h; the final fermentation liquid is filtered through an 80-mesh sieve, and the crop nutrient is diluted with water 20-30 times before use.

5. The application of a by-product of *Procambarus clarkii* in the preparation of crop nutrients, characterized in that... The method for preparing the crop nutrient is as described in any one of claims 1-4.

6. The application of a crop nutrient prepared by the method according to any one of claims 1-4, characterized in that, The application method of the crop nutrient is as follows: After fertilizing the rice using conventional methods during the rice growth cycle, spray the crop nutrient onto the rice leaves at the tillering stage, heading and flowering stage, and grain filling and ripening stage. Tillering stage: The crop nutrient solution is prepared with water to a concentration of 0.2%-0.4%, and the spraying rate is 70-80 kg / mu; During the heading and flowering stage: the crop nutrient solution is prepared with water to a concentration of 0.3%-0.5%, and the application rate is 50-60 kg / mu; Grain filling and ripening stage: Prepare a 0.4%-0.6% mass concentration solution of the crop nutrient agent with water, and spray at a rate of 40-50 kg / mu.

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