Method for producing biological bacterial fertilizer from tylosin residues

Abstract

The invention discloses a method for producing a biological bacterial fertilizer from tylosin residues, and relates to the technical field of organic fertilizers. When the biological bacterial fertilizer is prepared, cotton straw powder is depolymerized with sulfuric acid to prepare cotton straw polyol; the preparation method comprises the following steps: sequentially reacting chitosan with methyl acrylate and triethylene tetramine to prepare modified chitosan; pig manure, wood chips, a complex microbial inoculant and tylosin mushroom dregs are uniformly mixed for aerobic composting, and a cured mushroom dreg mixture is prepared; and uniformly mixing the cotton straw polyol, the modified chitosan, the dihydroxyl-terminated polydimethylsiloxane, the polymethylene polyphenyl polyisocyanate and the cured mushroom dreg mixture, and carrying out extrusion molding to obtain the biological bacterial fertilizer. The biological bacterial fertilizer prepared by the invention has the advantages of low tylosin residue and slow release.

Description

Technical Field

[0001] The invention relates to the technical field of organic fertilizers, in particular to a method for producing biological fertilizer from tylosin bacterial residue. Background Art

[0002] One of the major challenges facing my country's antibiotic pharmaceutical companies today is the proper and harmless disposal and resource utilization of microbial pharmaceutical residues. Failure to properly handle these residues can lead to antibiotic resistance, potentially posing environmental and human health risks. This can severely hinder the healthy development of my country's antibiotic pharmaceutical industry.

[0003] Aerobic composting is an environmentally friendly technology that not only effectively reduces the harmful effects of antibiotic bacterial residues but also allows them to be converted into organic fertilizer for resource recovery. This study selected tylosin bacterial residues as the research subject. Based on their rich organic matter content and the readily biodegradable nature of tylosin, the aerobic composting process was used to render them harmless. Summary of the Invention

[0004] The object of the present invention is to provide a method for producing biological fertilizer from tylosin bacterial residue to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: A method for producing biological fertilizer from tylosin bacterial residue comprises the following steps: uniformly mixing pig manure, sawdust, a composite bacterial agent, and tylosin bacterial residue, and performing aerobic composting to obtain a mature bacterial residue mixture; uniformly mixing cotton straw polyol, modified chitosan, a mixture of dihydroxy-terminated polydimethylsiloxane, polymethylene polyphenyl polyisocyanate, and the mature bacterial residue mixture, and extruding and molding the mixture to obtain the biological fertilizer; The cotton straw polyol is prepared by depolymerizing cotton straw powder with sulfuric acid; The modified chitosan is prepared by reacting chitosan with methyl acrylate and triethylenetetramine in sequence; The composite bacterial agent is prepared by uniformly mixing Aspergillus oryzae, Enterococcus faecalis and lactic acid bacteria.

[0006] As an optimization, the method for producing biological fertilizer from tylosin bacterial residue includes the following preparation steps: (1) Weigh 90-100 parts of polyethylene glycol, 10-12 parts of glycerol, 3-4 parts of concentrated sulfuric acid, and 20-24 parts of cotton straw powder by mass; place the polyethylene glycol, glycerol, and concentrated sulfuric acid in a reaction kettle and mix them evenly; stir them at 55-65°C and 100-200 r / min for 18-22 minutes; heat them to 158-160°C; add the cotton straw powder; continue stirring for 80-90 minutes; and cool them to room temperature to obtain cotton straw polyol; (2) Pre-modified chitosan, triethylenetetramine, and methanol were mixed uniformly in a mass ratio of 1:(2-3):(12-14), stirred at 60-62°C and 100-200 r / min for 1-2 h, filtered under reduced pressure, washed with methanol 4-6 times, and dried at 75-85°C under vacuum conditions for 8-10 h to obtain modified chitosan; (3) Weigh 10-12 parts of pig manure, 8-10 parts of sawdust, 1-1.2 parts of compound microbial agent, and 46-50 parts of tylosin residue by mass; mix the pig manure, sawdust, compound microbial agent, and tylosin residue evenly and perform aerobic composting. Adjust the initial moisture content to 63%-65%. Manually turn the compost every 5 days. The aerobic composting time is 24-26 days to obtain a matured residue mixture. (4) Weigh 10-12 parts of cotton straw polyol, 12-14 parts of modified chitosan, 14-16 parts of dihydroxy-terminated polydimethylsiloxane, 20-22 parts of matured fungus residue mixture, and 8-10 parts of polymethylene polyphenyl polyisocyanate by mass; mix the cotton straw polyol, modified chitosan, and dihydroxy-terminated polydimethylsiloxane evenly, stir at 10-30°C and 80-100 r / min for 8-10 minutes, add the matured fungus residue mixture, and continue stirring for 20-30 minutes, add polymethylene polyphenyl polyisocyanate, and continue stirring for 5-7 minutes, extrude and shape the material, and dry it at 70-80°C for 8-10 hours to obtain a biofertilizer.

[0007] As an optimization, the preparation method of the cotton straw powder in step (1) is as follows: grinding the cotton straw and passing it through a 60-mesh sieve, and drying it at 90-100° C. under vacuum conditions for 6-8 hours to obtain the cotton straw powder.

[0008] As an optimization, the mass fraction of the concentrated sulfuric acid in step (1) is 98%.

[0009] As an optimization, the model of the polyethylene glycol in step (1) is preferably PEG400.

[0010] As an optimization, the preparation method of the pre-modified chitosan in step (2) is as follows: chitosan, methyl acrylate and methanol are uniformly mixed in a mass ratio of 1:(2~3):(14~16), stirred at 60~62°C and 100~200r / min for 3~4h, filtered under reduced pressure, washed with methanol 3~5 times, and dried at 75~85°C under vacuum conditions for 6~8h to obtain pre-modified chitosan.

[0011] As an optimization, the chitosan has a deacetylation degree of 95% and a weight average molecular weight of 85 kDa.

[0012] As an optimization, the preparation method of the composite bacterial agent in step (3) is: Aspergillus oryzae, Enterococcus faecalis, and lactic acid bacteria are uniformly mixed in a mass ratio of 1:1.2:1.1 to prepare the composite bacterial agent.

[0013] As an optimization, the molecular weight of the dihydroxy-terminated polydimethylsiloxane in step (4) is 2000, and the manufacturer is Hubei Yamade Biopharmaceutical Co., Ltd.

[0014] As an optimization, the polymethylene polyphenyl polyisocyanate in step (4) is PM200, and the manufacturer is Guangzhou Xuxiang Chemical Co., Ltd.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are: When preparing the biological bacterial fertilizer, the present invention comprises the following steps: depolymerizing cotton straw powder with sulfuric acid to obtain cotton straw polyol; reacting chitosan with methyl acrylate and triethylenetetramine in sequence to obtain modified chitosan; uniformly mixing pig manure, wood chips, a composite bacterial agent and tylosin bacterial residue and performing aerobic composting to obtain a mature bacterial residue mixture; and uniformly mixing the cotton straw polyol, modified chitosan, a mixture of dihydroxy-terminated polydimethylsiloxane, polymethylene polyphenyl polyisocyanate and a mature bacterial residue mixture, and extruding and molding the mixture to obtain the biological bacterial fertilizer.

[0016] First, cotton straw powder is depolymerized with sulfuric acid to obtain cotton straw polyol, and the cotton straw powder is depolymerized into oligomers to form a large number of hydroxyl groups on the oligomers; the amino groups on chitosan are reacted with the carbon-carbon double bonds on methyl acrylate to obtain pre-modified chitosan; the acid methyl ester bond on the pre-modified chitosan is reacted with the amino groups on triethylenetetramine to obtain modified chitosan, and a large number of amino groups are introduced into the modified chitosan to increase the nitrogen content in the chitosan. The amino groups on the modified chitosan can react with the isocyanate groups on polymethylene polyphenyl polyisocyanate. The large number of amino groups on chitosan can also complex the metal ions in the mature fungus residue mixture to form a cross-linked network structure coated on the surface of the mature fungus residue mixture, thereby achieving the purpose of slow-release biological fertilizer and increasing the nitrogen content of biological fertilizer; the hydroxyl groups on cotton straw polyol and dihydroxy-terminated polydimethylsiloxane react with the isocyanate groups on polymethylene polyphenyl polyisocyanate to form a polyurethane film on the surface of biological fertilizer, and the siloxane on the dihydroxy-terminated polydimethylsiloxane can improve the hydrophobicity of the biological fertilizer surface and slow down the release rate of the biological fertilizer.

[0017] Secondly, the pig manure, sawdust, composite microbial agent and tylosin residue are evenly mixed and aerobic composted to obtain a matured residue mixture; adding the composite microbial agent during the aerobic fermentation process can improve the degree of aerobic fermentation, remove as much tylosin from the tylosin residue as possible, and reduce tylosin residue. DETAILED DESCRIPTION

[0018] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the 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.

[0019] Example 1: A method for producing biological fertilizer from tylosin bacterial residue, comprising the following preparation steps: (1) Grind the cotton straw and pass it through a 60-mesh sieve. Dry it at 90°C under vacuum for 8 h to obtain cotton straw powder. Weigh 90 parts by mass of polyethylene glycol, 10 parts by mass of glycerol, 3 parts by mass of 98% concentrated sulfuric acid, and 20 parts by mass of cotton straw powder. Place the polyethylene glycol, glycerol, and concentrated sulfuric acid in a reactor and mix them evenly. Stir them at 55°C and 100 rpm for 22 min, heat them to 158°C, add the cotton straw powder, continue stirring for 90 min, and cool them to room temperature to obtain cotton straw polyol. (2) Chitosan, methyl acrylate and methanol were mixed in a mass ratio of 1:2:14, stirred at 60°C and 100 r / min for 4 h, filtered under reduced pressure, washed with methanol 3 times, and dried at 75°C under vacuum for 8 h to obtain pre-modified chitosan; pre-modified chitosan, triethylenetetramine and methanol were mixed in a mass ratio of 1:2:12, stirred at 60°C and 100 r / min for 2 h, filtered under reduced pressure, washed with methanol 4 times, and dried at 75°C under vacuum for 10 h to obtain modified chitosan; (3) Weigh 10 parts of pig manure, 8 parts of sawdust, 1 part of composite microbial agent, and 46 parts of tylosin residue by mass; mix the pig manure, sawdust, composite microbial agent, and tylosin residue evenly and perform aerobic composting. Adjust the initial moisture content to 63%. Manual composting is performed every 5 days. The aerobic composting time is 24 days to obtain a matured residue mixture. (4) Weigh 10 parts of cotton straw polyol, 12 parts of modified chitosan, 14 parts of dihydroxy-terminated polydimethylsiloxane, 20 parts of mature mushroom residue mixture, and 8 parts of polymethylene polyphenyl polyisocyanate by mass; mix the cotton straw polyol, modified chitosan, and dihydroxy-terminated polydimethylsiloxane evenly, stir at 10°C, 80 r / min for 10 min, add the mature mushroom residue mixture and continue stirring for 30 min, add polymethylene polyphenyl polyisocyanate and continue stirring for 7 min, extrude and shape the material, and dry it at 70°C for 10 h to obtain a biofertilizer.

[0020] Example 2: A method for producing biological fertilizer from tylosin bacterial residue, comprising the following preparation steps: (1) Grind the cotton straw and pass it through a 60-mesh sieve. Dry it at 95°C under vacuum for 7 h to obtain cotton straw powder. Weigh 95 parts of polyethylene glycol, 11 parts of glycerol, 3.5 parts of 98% concentrated sulfuric acid, and 22 parts of cotton straw powder by mass. Place the polyethylene glycol, glycerol, and concentrated sulfuric acid in a reactor and mix them evenly. Stir at 60°C and 150 rpm for 20 min, heat to 159°C, add the cotton straw powder, continue stirring for 85 min, and cool to room temperature to obtain cotton straw polyol. (2) Chitosan, methyl acrylate and methanol were mixed in a mass ratio of 1:2.5:15, stirred at 61 °C and 150 r / min for 3.5 h, filtered under reduced pressure, washed with methanol 4 times, and dried at 80 °C under vacuum for 7 h to obtain pre-modified chitosan; pre-modified chitosan, triethylenetetramine and methanol were mixed in a mass ratio of 1:2.5:13, stirred at 61 °C and 150 r / min for 1.5 h, filtered under reduced pressure, washed with methanol 5 times, and dried at 80 °C under vacuum for 9 h to obtain modified chitosan; (3) Weigh 11 parts of pig manure, 9 parts of sawdust, 1.1 parts of composite microbial agent, and 48 parts of tylosin residue by mass; mix the pig manure, sawdust, composite microbial agent, and tylosin residue evenly and perform aerobic composting. Adjust the initial moisture content to 64%. Manual composting is performed every 5 days. The aerobic composting time is 25 days to obtain a matured residue mixture. (4) Weigh 11 parts of cotton straw polyol, 13 parts of modified chitosan, 15 parts of dihydroxy-terminated polydimethylsiloxane, 21 parts of matured fungus residue mixture, and 9 parts of polymethylene polyphenyl polyisocyanate by mass; mix the cotton straw polyol, modified chitosan, and dihydroxy-terminated polydimethylsiloxane evenly, stir at 20°C, 90 r / min for 9 minutes, add the matured fungus residue mixture and continue stirring for 25 minutes, add polymethylene polyphenyl polyisocyanate and continue stirring for 6 minutes, extrude and shape the material, and dry it at 75°C for 9 hours to obtain a biofertilizer.

[0021] Example 3: A method for producing biological fertilizer from tylosin bacterial residue, comprising the following preparation steps: (1) Grind cotton straw and pass it through a 60-mesh sieve. Dry it at 100°C for 6 h under vacuum conditions to obtain cotton straw powder. Weigh 100 parts by mass of polyethylene glycol, 12 parts by mass of glycerol, 4 parts by mass of 98% concentrated sulfuric acid, and 24 parts by mass of cotton straw powder. Place polyethylene glycol, glycerol, and concentrated sulfuric acid in a reactor and mix them evenly. Stir at 65°C and 200 r / min for 18 min, heat to 160°C, add cotton straw powder, continue stirring for 90 min, and cool to room temperature to obtain cotton straw polyol. (2) Chitosan, methyl acrylate and methanol were mixed in a mass ratio of 1:3:16, stirred at 62°C and 200 r / min for 3 h, filtered under reduced pressure, washed with methanol 5 times, and dried at 85°C under vacuum for 6 h to obtain pre-modified chitosan; pre-modified chitosan, triethylenetetramine and methanol were mixed in a mass ratio of 1:3:14, stirred at 62°C and 200 r / min for 1 h, filtered under reduced pressure, washed with methanol 6 times, and dried at 85°C under vacuum for 8 h to obtain modified chitosan; (3) Weigh 12 parts of pig manure, 10 parts of sawdust, 1.2 parts of composite microbial agent, and 50 parts of tylosin residue by mass; mix the pig manure, sawdust, composite microbial agent, and tylosin residue evenly and perform aerobic composting. Adjust the initial moisture content to 65%. Manual composting is performed every 5 days. The aerobic composting time is 26 days to obtain a matured residue mixture. (4) Weigh 12 parts of cotton straw polyol, 14 parts of modified chitosan, 16 parts of dihydroxy-terminated polydimethylsiloxane, 22 parts of matured fungus residue mixture, and 10 parts of polymethylene polyphenyl polyisocyanate by mass; mix the cotton straw polyol, modified chitosan, and dihydroxy-terminated polydimethylsiloxane evenly, stir at 30°C and 100 r / min for 8 minutes, add the matured fungus residue mixture and continue stirring for 20 minutes, add polymethylene polyphenyl polyisocyanate and continue stirring for 7 minutes, extrude and shape the material, and dry it at 80°C for 8 hours to obtain a biofertilizer.

[0022] Comparative Example 1: A method for producing biological fertilizer from tylosin bacterial residue, comprising the following preparation steps: (1) Chitosan, methyl acrylate, and methanol were mixed evenly in a mass ratio of 1:2.5:15, stirred at 61°C and 150 r / min for 3.5 h, filtered under reduced pressure, washed with methanol 4 times, and dried at 80°C under vacuum for 7 h to obtain pre-modified chitosan; pre-modified chitosan, triethylenetetramine, and methanol were mixed evenly in a mass ratio of 1:2.5:13, stirred at 61°C and 150 r / min for 1.5 h, filtered under reduced pressure, washed with methanol 5 times, and dried at 80°C under vacuum for 9 h to obtain modified chitosan; (2) Weigh 11 parts of pig manure, 9 parts of sawdust, 1.1 parts of composite microbial agent, and 48 parts of tylosin residue by mass; mix the pig manure, sawdust, composite microbial agent, and tylosin residue evenly and perform aerobic composting. Adjust the initial moisture content to 64%. Manual turning is performed every 5 days during the composting process. The aerobic composting time is 25 days to obtain a matured residue mixture. (3) Weigh 13 parts of modified chitosan, 15 parts of dihydroxy-terminated polydimethylsiloxane, 21 parts of matured fungus residue mixture, and 9 parts of polymethylene polyphenyl polyisocyanate by mass; mix the modified chitosan and dihydroxy-terminated polydimethylsiloxane evenly, stir at 20°C, 90 r / min for 9 minutes, add the matured fungus residue mixture and continue stirring for 25 minutes, add polymethylene polyphenyl polyisocyanate and continue stirring for 6 minutes, extrude and shape the material, and dry it at 75°C for 9 hours to obtain biological fertilizer.

[0023] Comparative Example 2: A method for producing biological fertilizer from tylosin bacterial residue, comprising the following preparation steps: (1) Grind the cotton straw and pass it through a 60-mesh sieve. Dry it at 95°C under vacuum for 7 h to obtain cotton straw powder. Weigh 95 parts of polyethylene glycol, 11 parts of glycerol, 3.5 parts of 98% concentrated sulfuric acid, and 22 parts of cotton straw powder by mass. Place the polyethylene glycol, glycerol, and concentrated sulfuric acid in a reactor and mix them evenly. Stir at 60°C and 150 rpm for 20 min, heat to 159°C, add the cotton straw powder, continue stirring for 85 min, and cool to room temperature to obtain cotton straw polyol. (2) Weigh 11 parts of pig manure, 9 parts of sawdust, 1.1 parts of composite microbial agent, and 48 parts of tylosin residue by mass; mix the pig manure, sawdust, composite microbial agent, and tylosin residue evenly and perform aerobic composting. Adjust the initial moisture content to 64%. Manual turning is performed every 5 days during the composting process. The aerobic composting time is 25 days to obtain a matured residue mixture. (3) Weigh 11 parts of cotton straw polyol, 13 parts of modified chitosan, 15 parts of dihydroxy-terminated polydimethylsiloxane, 21 parts of matured fungus residue mixture, and 9 parts of polymethylene polyphenyl polyisocyanate by mass; mix the cotton straw polyol, chitosan, and dihydroxy-terminated polydimethylsiloxane evenly, stir at 20°C, 90 r / min for 9 minutes, add the matured fungus residue mixture and continue stirring for 25 minutes, add polymethylene polyphenyl polyisocyanate and continue stirring for 6 minutes, extrude and shape the material, and dry it at 75°C for 9 hours to obtain a biofertilizer.

[0024] Comparative Example 3: A method for producing biological fertilizer from tylosin bacterial residue, comprising the following preparation steps: (1) Grind the cotton straw and pass it through a 60-mesh sieve. Dry it at 95°C under vacuum for 7 h to obtain cotton straw powder. Weigh 95 parts of polyethylene glycol, 11 parts of glycerol, 3.5 parts of 98% concentrated sulfuric acid, and 22 parts of cotton straw powder by mass. Place the polyethylene glycol, glycerol, and concentrated sulfuric acid in a reactor and mix them evenly. Stir at 60°C and 150 rpm for 20 min, heat to 159°C, add the cotton straw powder, continue stirring for 85 min, and cool to room temperature to obtain cotton straw polyol. (2) Chitosan, methyl acrylate and methanol were mixed in a mass ratio of 1:2.5:15, stirred at 61 °C and 150 r / min for 3.5 h, filtered under reduced pressure, washed with methanol 4 times, and dried at 80 °C under vacuum for 7 h to obtain pre-modified chitosan; pre-modified chitosan, triethylenetetramine and methanol were mixed in a mass ratio of 1:2.5:13, stirred at 61 °C and 150 r / min for 1.5 h, filtered under reduced pressure, washed with methanol 5 times, and dried at 80 °C under vacuum for 9 h to obtain modified chitosan; (3) Weigh 11 parts of pig manure, 9 parts of sawdust, and 48 parts of tylosin residue by mass; mix the pig manure, sawdust, and tylosin residue evenly and perform aerobic composting. Adjust the initial moisture content to 64%. Manual turning is performed every 5 days during the composting process. The aerobic composting time is 25 days to obtain a matured residue mixture. (4) Weigh 11 parts of cotton straw polyol, 13 parts of modified chitosan, 15 parts of dihydroxy-terminated polydimethylsiloxane, 21 parts of matured fungus residue mixture, and 9 parts of polymethylene polyphenyl polyisocyanate by mass; mix the cotton straw polyol, modified chitosan, and dihydroxy-terminated polydimethylsiloxane evenly, stir at 20°C, 90 r / min for 9 minutes, add the matured fungus residue mixture and continue stirring for 25 minutes, add polymethylene polyphenyl polyisocyanate and continue stirring for 6 minutes, extrude and shape the material, and dry it at 75°C for 9 hours to obtain a biofertilizer.

[0025] Comparative Example 4: A method for producing biological fertilizer from tylosin bacterial residue, comprising the following preparation steps: (1) Grind the cotton straw and pass it through a 60-mesh sieve. Dry it at 95°C under vacuum for 7 h to obtain cotton straw powder. Weigh 95 parts of polyethylene glycol, 11 parts of glycerol, 3.5 parts of 98% concentrated sulfuric acid, and 22 parts of cotton straw powder by mass. Place the polyethylene glycol, glycerol, and concentrated sulfuric acid in a reactor and mix them evenly. Stir at 60°C and 150 rpm for 20 min, heat to 159°C, add the cotton straw powder, continue stirring for 85 min, and cool to room temperature to obtain cotton straw polyol. (2) Chitosan, methyl acrylate and methanol were mixed in a mass ratio of 1:2.5:15, stirred at 61 °C and 150 r / min for 3.5 h, filtered under reduced pressure, washed with methanol 4 times, and dried at 80 °C under vacuum for 7 h to obtain pre-modified chitosan; pre-modified chitosan, triethylenetetramine and methanol were mixed in a mass ratio of 1:2.5:13, stirred at 61 °C and 150 r / min for 1.5 h, filtered under reduced pressure, washed with methanol 5 times, and dried at 80 °C under vacuum for 9 h to obtain modified chitosan; (3) Weigh 11 parts of pig manure, 9 parts of sawdust, 1.1 parts of composite microbial agent, and 48 parts of tylosin residue by mass; mix the pig manure, sawdust, composite microbial agent, and tylosin residue evenly and perform aerobic composting. Adjust the initial moisture content to 64%. Manual composting is performed every 5 days. The aerobic composting time is 25 days to obtain a matured residue mixture. (4) Weigh 11 parts of cotton straw polyol, 13 parts of modified chitosan, 21 parts of mature fungus residue mixture, and 9 parts of polymethylene polyphenyl polyisocyanate by mass; mix the cotton straw polyol and modified chitosan evenly, stir at 20°C, 90 r / min for 9 minutes, add the mature fungus residue mixture and continue stirring for 25 minutes, add polymethylene polyphenyl polyisocyanate and continue stirring for 6 minutes, extrude and shape the material, and dry it at 75°C for 9 hours to obtain a biofertilizer.

[0026] Comparative Example 5: A method for producing biological fertilizer from tylosin bacterial residue, comprising the following preparation steps: (1) Grind the cotton straw and pass it through a 60-mesh sieve. Dry it at 95°C under vacuum for 7 h to obtain cotton straw powder. Weigh 95 parts of polyethylene glycol, 11 parts of glycerol, 3.5 parts of 98% concentrated sulfuric acid, and 22 parts of cotton straw powder by mass. Place the polyethylene glycol, glycerol, and concentrated sulfuric acid in a reactor and mix them evenly. Stir at 60°C and 150 rpm for 20 min, heat to 159°C, add the cotton straw powder, continue stirring for 85 min, and cool to room temperature to obtain cotton straw polyol. (2) Chitosan, methyl acrylate and methanol were mixed in a mass ratio of 1:2.5:15, stirred at 61 °C and 150 r / min for 3.5 h, filtered under reduced pressure, washed with methanol 4 times, and dried at 80 °C under vacuum for 7 h to obtain pre-modified chitosan; pre-modified chitosan, triethylenetetramine and methanol were mixed in a mass ratio of 1:2.5:13, stirred at 61 °C and 150 r / min for 1.5 h, filtered under reduced pressure, washed with methanol 5 times, and dried at 80 °C under vacuum for 9 h to obtain modified chitosan; (3) Weigh 11 parts of pig manure, 9 parts of sawdust, 1.1 parts of composite microbial agent, and 48 parts of tylosin residue by mass; mix the pig manure, sawdust, composite microbial agent, and tylosin residue evenly and perform aerobic composting. Adjust the initial moisture content to 64%. Manual composting is performed every 5 days. The aerobic composting time is 25 days to obtain a matured residue mixture. (4) Weigh 11 parts of cotton straw polyol, 13 parts of modified chitosan, 15 parts of dihydroxy-terminated polydimethylsiloxane, and 21 parts of matured fungus residue mixture by mass. Mix the cotton straw polyol, modified chitosan, and dihydroxy-terminated polydimethylsiloxane evenly, stir at 20°C, 90 r / min for 9 minutes, add the matured fungus residue mixture, and continue stirring for 25 minutes. Extrude the material into a mold, and dry it at 75°C for 9 hours to obtain a biofertilizer.

[0027] Test Example 1 Tylosin residue test: The content of tylosin in the prepared organic fertilizer was determined by liquid chromatography with an ultraviolet detector.

[0028] Tylosin technical solution: Accurately weigh 0.100 g of tylosin technical, dissolve it in 10 ml of methanol, dilute to 100 ml with ultrapure water, and store in a refrigerator at 4°C.

[0029] Use pH=2.5 phosphate buffer as the mobile phase: accurately weigh 1.36 g of potassium dihydrogen phosphate and dissolve it in water. Adjust the pH to 2.5 with phosphoric acid and make up the volume in a 1000 mL volumetric flask.

[0030] A 100 ppm tylosin solution was used to perform a full-wavelength UV scan within the range of 200-600 nm.

[0031] Chromatographic conditions: The chromatographic column was an Agilent TC-C18 column (4.6 mm × 250 mm, 5 μm), and the mobile phase was an acetonitrile-0.01 mol / L potassium dihydrogen phosphate solution (pH = 2.5) gradient elution system. Elution conditions were as follows: acetonitrile: potassium dihydrogen phosphate solution (volume ratio: 25:75) for 0-9 min, 50:50 for 10-19 min, and 75:25 for 19-25 min. Flow rate: 1 mL / min, detection wavelength: 290 nm, injection volume: 20 μL, column temperature: 30°C. Results are shown in Table 1.

[0032] Table 1

[0033] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 5 in Table 1, it can be found that the biological fertilizer prepared by the present invention has the advantage of low tylosin residue.

[0034] By comparison, the tylosin content of Examples 1 to 3 is less than that of Comparative Example 3, indicating that the pig manure, sawdust, composite bacterial agent, and tylosin residue are evenly mixed and aerobic composted to obtain a matured residue mixture; adding the composite bacterial agent during the aerobic fermentation process can improve the degree of aerobic fermentation, remove as much tylosin as possible from the tylosin residue, and reduce tylosin residue.

[0035] Test Example 2 Sustained release performance test Test Method: The slow-release effect was evaluated by measuring the average release rates of nitrogen, phosphorus, and potassium in the prepared organic fertilizers over a 10-day period, according to HG / T 4216-2011. Each group was tested five times, and the average values ​​were recorded. The results are shown in Table 2.

[0036] Table 2

[0037] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 5 in Table 2, it can be found that the biological fertilizer prepared by the present invention has good slow-release performance.

[0038] By comparison, the average nitrogen release rate, the average phosphorus release rate, and the average potassium release rate of Examples 1 to 3 are all lower than the average nitrogen release rate, the average phosphorus release rate, and the average potassium release rate of Comparative Example 1, indicating that cotton straw polyol is prepared by depolymerizing cotton straw powder with sulfuric acid, and the cotton straw powder is depolymerized into oligomers, forming a large number of hydroxyl groups on the oligomers; the hydroxyl groups on the cotton straw polyol react with the isocyanate groups on the polymethylene polyphenyl polyisocyanate to form a polyurethane film on the surface of the biological fertilizer, thereby slowing down the release rate of the biological fertilizer.

[0039] By comparison, the average nitrogen release rate, the average phosphorus release rate, and the average potassium release rate of Examples 1 to 3 are all lower than the average nitrogen release rate, the average phosphorus release rate, and the average potassium release rate of Comparative Example 2, indicating that the amino group on the chitosan reacts with the carbon-carbon double bond on methyl acrylate to prepare the pre-modified chitosan; the acid methyl ester bond on the pre-modified chitosan reacts with the amino group on triethylenetetramine to prepare the modified chitosan, and a large number of amino groups are introduced into the modified chitosan to increase the nitrogen content in the chitosan. The amino groups on the modified chitosan can react with the isocyanate groups on the polymethylene polyphenyl polyisocyanate, and the large number of amino groups on the chitosan can also complex the metal ions in the mature fungus residue mixture to form a cross-linked network structure coated on the surface of the mature fungus residue mixture, thereby achieving the purpose of slow-release biological fertilizer; By comparison, the average nitrogen release rate, the average phosphorus release rate, and the average potassium release rate of Examples 1 to 3 are all lower than the average nitrogen release rate, the average phosphorus release rate, and the average potassium release rate of Comparative Example 4, indicating that the hydroxyl group on the dihydroxy-terminated polydimethylsiloxane reacts with the isocyanate group on the polymethylene polyphenyl polyisocyanate to form a polyurethane film on the surface of the biological fertilizer, and the siloxane on the dihydroxy-terminated polydimethylsiloxane can improve the hydrophobicity of the biological fertilizer surface and slow down the release rate of the biological fertilizer.

[0040] By comparison, the average nitrogen release rate, the average phosphorus release rate, and the average potassium release rate of Examples 1 to 3 are all lower than the average nitrogen release rate, the average phosphorus release rate, and the average potassium release rate of Comparative Example 5, indicating that the isocyanate group on the polymethylene polyphenyl polyisocyanate reacts with the hydroxyl groups on the cotton straw polyol and the dihydroxy-terminated polydimethylsiloxane, and reacts with the amino group on the modified chitosan to form a polyurethane film on the surface of the biological fertilizer, thereby slowing down the release rate of the biological fertilizer.

[0041] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for producing biological fertilizer from tylosin bacteria residue, characterized in that: The method for producing biological fertilizer from tylosin bacterial residue comprises the following steps: uniformly mixing pig manure, sawdust, a composite bacterial agent, and tylosin bacterial residue, and performing aerobic composting to obtain a mature bacterial residue mixture; uniformly mixing cotton straw polyol, modified chitosan, a mixture of dihydroxy-terminated polydimethylsiloxane, polymethylene polyphenyl polyisocyanate, and the mature bacterial residue mixture, and extruding and molding the mixture to obtain the biological fertilizer; The cotton straw polyol is prepared by depolymerizing cotton straw powder with sulfuric acid; The modified chitosan is prepared by reacting chitosan with methyl acrylate and triethylenetetramine in sequence; The composite bacterial agent is prepared by uniformly mixing Aspergillus oryzae, Enterococcus faecalis and lactic acid bacteria.

2. The method for producing biological fertilizer from tylosin bacteria residue according to claim 1, wherein The method for producing biological fertilizer from tylosin bacterial residue comprises the following preparation steps: (1) Weigh 90-100 parts of polyethylene glycol, 10-12 parts of glycerol, 3-4 parts of concentrated sulfuric acid, and 20-24 parts of cotton straw powder by mass; place the polyethylene glycol, glycerol, and concentrated sulfuric acid in a reaction kettle and mix them evenly; stir them at 55-65°C and 100-200 r / min for 18-22 minutes; heat them to 158-160°C; add the cotton straw powder; continue stirring for 80-90 minutes; and cool them to room temperature to obtain cotton straw polyol; (2) Pre-modified chitosan, triethylenetetramine, and methanol were mixed uniformly in a mass ratio of 1:(2-3):(12-14), stirred at 60-62°C and 100-200 r / min for 1-2 h, filtered under reduced pressure, washed with methanol 4-6 times, and dried at 75-85°C under vacuum conditions for 8-10 h to obtain modified chitosan; (3) Weigh 10-12 parts of pig manure, 8-10 parts of sawdust, 1-1.2 parts of compound microbial agent, and 46-50 parts of tylosin residue by mass; mix the pig manure, sawdust, compound microbial agent, and tylosin residue evenly and perform aerobic composting. Adjust the initial moisture content to 63%-65%. Manually turn the compost every 5 days. The aerobic composting time is 24-26 days to obtain a matured residue mixture. (4) Weigh 10-12 parts of cotton straw polyol, 12-14 parts of modified chitosan, 14-16 parts of dihydroxy-terminated polydimethylsiloxane, 20-22 parts of matured fungus residue mixture, and 8-10 parts of polymethylene polyphenyl polyisocyanate by mass; mix the cotton straw polyol, modified chitosan, and dihydroxy-terminated polydimethylsiloxane evenly, stir at 10-30°C and 80-100 r / min for 8-10 minutes, add the matured fungus residue mixture, and continue stirring for 20-30 minutes, add polymethylene polyphenyl polyisocyanate, and continue stirring for 5-7 minutes, extrude and shape the material, and dry it at 70-80°C for 8-10 hours to obtain a biofertilizer.

3. The method for producing biological fertilizer from tylosin bacteria residue according to claim 2, wherein The preparation method of the cotton straw powder in step (1) is as follows: grinding the cotton straw and passing it through a 60-mesh sieve, and drying it at 90-100° C. for 6-8 hours under vacuum conditions to obtain the cotton straw powder.

4. The method for producing biological fertilizer from tylosin bacteria residue according to claim 2, wherein The mass fraction of the concentrated sulfuric acid in step (1) is 98%.

5. The method for producing biological fertilizer from tylosin bacteria residue according to claim 2, wherein The model of the polyethylene glycol in step (1) is preferably PEG400.

6. The method for producing biological fertilizer from tylosin bacteria residue according to claim 2, wherein The preparation method of the pre-modified chitosan in step (2) is as follows: chitosan, methyl acrylate and methanol are uniformly mixed in a mass ratio of 1:(2~3):(14~16), stirred at 60~62°C and 100~200r / min for 3~4h, filtered under reduced pressure, washed with methanol 3~5 times, and dried at 75~85°C under vacuum conditions for 6~8h to obtain pre-modified chitosan.

7. The method for producing biological fertilizer from tylosin bacteria residue according to claim 6, wherein The chitosan has a deacetylation degree of 95% and a weight-average molecular weight of 85 kDa.

8. The method for producing biological fertilizer from tylosin bacteria residue according to claim 2, wherein The preparation method of the composite bacterial agent in step (3) is as follows: Aspergillus oryzae, Enterococcus faecalis, and lactic acid bacteria are uniformly mixed in a mass ratio of 1:1.2:1.1 to prepare the composite bacterial agent.

9. The method for producing biological fertilizer from tylosin bacteria residue according to claim 2, wherein The molecular weight of the dihydroxy-terminated polydimethylsiloxane in step (4) is 2000.

10. The method for producing biological fertilizer from tylosin bacteria residue according to claim 2, wherein: The polymethylene polyphenyl polyisocyanate described in step (4) is PM200.

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