EM bacteria stock solution, EM bacteria fermentation liquor as leather auxiliaries, and preparation method and application thereof

Abstract

The application provides an EM bacteria stock solution, an EM bacteria fermentation liquor, a preparation method and application thereof as a leather aid, and belongs to the technical field of probiotic fermentation. The application provides application of the EM bacteria liquor in preparation of leather. The application of the EM bacteria liquor in the tanning process can improve the effect of hide soaking, shorten the time required in the tanning process, increase the water content of the pelt, and make the dry and hard salted hide better recover to the fresh hide state, which is beneficial to subsequent processing. The EM bacteria liquor can also be applied in the blue wet hide rewetting in the tanning process, improves the rewetting effect of the blue wet hide, and reduces the oil content of the blue wet hide. Further, the EM bacteria liquor can effectively reduce the concentration of important pollutants such as COD, ammonia nitrogen and solid content in the wastewater generated in each step of the tanning process, and is environment-friendly.

Description

Technical Field

[0001] This invention belongs to the field of probiotic fermentation technology, specifically relating to an EM bacteria stock solution, EM bacteria fermentation broth, and their preparation method and application as a leather auxiliaries. Background Technology

[0002] EM (Effective Microorganisms) is a live microbial preparation composed of over 80 species of microorganisms from more than 10 genera, including photosynthetic bacteria, actinomycetes, yeasts, lactic acid bacteria, and Bacillus. It was first invented in 1982 by Professor Teruo Higa, an applied microbiologist at the University of the Ryukyus in Japan. The various microorganisms in EM products coexist and interact, developing together and performing multiple functions. They can rapidly promote the decomposition of organic matter such as animal and plant residues and inhibit the growth of putrefactive bacteria and other pathogens. It has been widely used in organic fertilizer fermentation, aquaculture, agricultural fruit and vegetable cultivation, and environmental protection for wastewater and sludge treatment, but its effective utilization in the leather industry has not yet been fully realized.

[0003] As more and more industries advocate the use of more biodegradable bio-based materials to replace petrochemical materials in order to meet carbon emission reduction policies, reduce COD concentration in wastewater, and alleviate the difficulty and cost of wastewater treatment, the leather industry, as a traditional industry, uses a large number of chemical materials and generates a large amount of wastewater. Therefore, the use of more bio-based materials to replace petrochemical materials is imperative. Currently, the most commonly used bio-based materials in the leather industry are enzyme preparations such as proteases, trypsin, and lipases, as well as lignin derivatives and polysaccharide derivatives, but their usage is relatively small and has not yet played a key role. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the purpose of this invention is to provide the application of EM bacterial solution in the leather making process. Applying the EM bacterial solution to fur leather making can effectively reduce the COD concentration and other pollutant content in the wastewater during leather making, while also improving the quality of the leather.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] This invention provides the application of EM bacterial solution in the preparation of leather, wherein the application includes any one or more of the following (1) to (4):

[0007] (1) Application in soaking fur in water;

[0008] (2) Application in liming fur;

[0009] (3) Application in deliming and softening of fur;

[0010] (4) Application in fur rewetting.

[0011] This invention provides a method for preparing leather using EM bacterial solution as a leather auxiliary agent, comprising the following steps:

[0012] After mixing fur, water, and EM bacterial solution, the mixture is soaked in water to obtain soaked fur.

[0013] The water-soaked fur is then subjected to an ash-soaking treatment to obtain ash-soaked fur;

[0014] The ash-soaked fur is layered to obtain the top layer fur;

[0015] The top-grain fur is subjected to a de-ashing and softening treatment to obtain de-ashed and softened fur.

[0016] The deashed and softened fur is then pickled and tanned to obtain leather.

[0017] Preferably, the liming process includes: mixing soaked fur, water, lime, sodium hydrosulfide, sodium sulfide and EM bacterial solution for liming to obtain limed fur;

[0018] The deashing and softening treatment includes: mixing the top layer of fur, water, deashing agent and EM bacterial solution for deashing and then softening to obtain deashed and softened fur.

[0019] This invention provides a method for rehydrating leather, comprising the following steps:

[0020] The fur is acidified to obtain acidified fur.

[0021] The acidified fur was mixed with EM bacterial solution and degreased and rehydrated to obtain rehydrated fur.

[0022] Preferably, the EM bacterial solution includes EM stock solution and / or EM fermentation broth; the amount of EM bacterial solution added is 0.1% to 1.1% of the fur weight.

[0023] This invention provides an EM (Effective Microorganisms) stock solution as a leather auxiliary agent, comprising: photosynthetic bacteria, actinomycetes, yeast, compound lactic acid bacteria, and Bacillus; the compound lactic acid bacteria include Lactobacillus brevis, Bifidobacterium bifidum, Lactobacillus plantarum, Bifidobacterium lactis, and Lactobacillus acidophilus; the Bacillus includes any one or more of Bacillus subtilis, Bacillus licheniformis, Bacillus cereus, Bacillus megaterium, Bacillus mucilaginosus, Bacillus azotocinus, Bacillus spheroides, and Bacillus brevis; the yeast includes any one or more of Saccharomyces cerevisiae, Saccharomyces cerevisiae, Candida albicans, Pasteurella multocida, Rhus chinensis, Hansenula polymorpha, and Schizosoma fissicola.

[0024] Preferably, the photosynthetic bacteria have a bacterial activity of 1×10⁻⁶. 8 ~2×109 CFU / mL; the bacterial activity of the actinomycetes was 1×10⁻⁶. 8 ~1.8×10 9 CFU / mL; the activity of the yeast was 3 × 10⁻⁶. 8 ~1.2×10 9 CFU / mL; the bacterial activity of the compound lactic acid bacteria is 5×10⁻⁶. 8 ~1.7×10 9 CFU / mL; the bacterial activity of the Bacillus was 1×10⁻⁶. 8 ~7×10 8 CFU / mL; the live bacteria ratio of Lactobacillus brevis, Lactobacillus bifidum, Lactobacillus plantarum, Bifidobacterium lactis and Lactobacillus acidophilus in the compound lactic acid bacteria is 0.5-1.5:0.5-1:0.5-2:1-4:1-3.

[0025] This invention provides an EM (Effective Microorganisms) fermentation broth, comprising the following components by mass percentage: 1%–10% EM stock solution, 10%–70% fermentation broth, and the remainder being water;

[0026] The fermentation broth comprises the following components by mass percentage:

[0027] It contains 3%–15% collagen hydrolysate or leather waste, 5%–15% sugar, 0.5%–1% inorganic salts, 0%–1% organic acids, and 68%–89.5% water.

[0028] Preferably, the method for preparing the collagen hydrolysate includes the following steps:

[0029] Tanning waste, decomposing enzyme preparation and water are mixed and then enzymatically hydrolyzed to obtain collagen hydrolysate.

[0030] The mass ratio of the tanning waste to water is (1-2):(2-10); the amount of the decomposing enzyme preparation added is 1%-5% of the mass of the tanning waste.

[0031] The decomposing enzyme preparation includes alkaline protease and lipase; the mass ratio of alkaline protease to lipase is (2-8):(1-2); the enzyme activity of alkaline protease is 50,000-200,000 U / g; the enzyme activity of lipase is 50,000-100,000 U / g.

[0032] This invention provides a method for preparing the EM bacteria fermentation broth described in the above technical solution, comprising the following steps:

[0033] The EM stock solution, fermentation broth, and water are mixed and fermented to obtain the EM fermentation broth.

[0034] Beneficial effects:

[0035] This invention provides the application of EM bacterial solution in the preparation of leather, wherein the application includes any one or more of the following (1) to (4):

[0036] (1) Application in soaking fur in water;

[0037] (2) Application in liming fur;

[0038] (3) Application in deliming and softening of fur;

[0039] (4) Application in fur rewetting.

[0040] This invention applies EM (Effective Microorganisms) solution to the leather manufacturing process. As a leather auxiliary, the EM solution exhibits excellent wetting, penetrating, and moisturizing properties, and can be used as a soaking agent. Compared to traditional soaking agents, the EM solution significantly increases the water content of the fur, facilitating subsequent processes when used for soaking. In this invention, the EM solution, as a leather auxiliary, demonstrates excellent degreasing effects and can be used as a degreasing agent. When applied to fur degreasing, the degreasing effect is better than that achieved with traditional degreasing agents. In this invention, the EM solution, as a leather auxiliary, can also act as a rehumidifying agent to rehydrate the fur. Compared to rehumidifying agents used in traditional leather processing, the rehumidifying effect of the EM solution in this invention is better, resulting in softer rehydrated fur. Furthermore, the EM solution used in this invention provides better protection for the collagen in the fur, effectively reducing collagen loss in various processing steps, especially during the liming process. Furthermore, the use of EM (Effective Microorganisms) liquid as a leather auxiliary agent in this invention also promotes the tanning effect of chromium powder on leather, improving leather quality while reducing the chromium trioxide content in wastewater. Moreover, the use of EM liquid as a leather auxiliary agent in this invention can effectively reduce the solids, COD, and ammonia nitrogen content in wastewater generated during various processes in leather production.

[0041] This invention applies EM (Effective Microorganisms) solution to the leather tanning process, which can improve the soaking effect of raw hides, shorten the time required for tanning, increase the water content of fur, and allow dry, hardened salted raw hides to better recover to a fresh hide state, which is beneficial for subsequent processing. The EM solution described in this invention can also be applied to the rewetting of wet blue hides in the leather tanning process, improving the rewetting effect and reducing the oil content of wet blue hides.

[0042] In summary, the EM bacterial solution provided by this invention, when used as a leather auxiliary agent, can produce higher quality leather compared to using traditional chemical raw materials as leather auxiliaries, while also reducing the content of pollutants in the waste liquid. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0044] Figure 1 Image of fur obtained after pre-soaking in water and removing the flesh, as shown in Comparative Example 1;

[0045] Figure 2 Image of the fur obtained after pre-soaking in water and removing the flesh in Example 8;

[0046] Figure 3 This is a picture of the fur obtained after soaking in water in Comparative Example 1.

[0047] Figure 4 Image of the fur obtained after soaking in water in Example 8;

[0048] Figure 5 The image shows the fur obtained after immersion in ash, as shown in Comparative Example 1.

[0049] Figure 6 Image of the fur obtained after ash impregnation in Example 8;

[0050] Figure 7 The image shows the wet blue skin prepared by the method in Comparative Example 1.

[0051] Figure 8 The image shows the wet blue skin prepared by the method in Example 8.

[0052] Figure 9 The diagram shows the waste liquid before pre-soaking in water during the preparation process of Example 8 and Comparative Example 1;

[0053] Figure 10 The diagram shows the waste liquid after pre-soaking in water during the preparation process of Example 8 and Comparative Example 1;

[0054] Figure 11 The diagram shows the waste liquid before the main immersion in water during the preparation process of Example 8 and Comparative Example 1;

[0055] Figure 12 The diagram shows the waste liquid after the main immersion in water during the preparation process of Example 8 and Comparative Example 1;

[0056] Figure 13 The diagram shows the waste liquid after liming in the preparation process of Example 8 and Comparative Example 1;

[0057] Figure 14 The diagram shows the waste liquid after tanning in the preparation process of Example 8 and Comparative Example 1. Detailed Implementation

[0058] This invention provides the application of EM bacterial solution in the preparation of leather, wherein the application includes any one or more of the following (1) to (4):

[0059] (1) Application in soaking fur in water;

[0060] (2) Application in liming fur;

[0061] (3) Application in deliming and softening of fur;

[0062] (4) Application in fur rewetting.

[0063] This invention provides the application of EM (Effective Microorganisms) bacterial solution in leather production. In this invention, the EM bacterial solution is preferably used in the leather production process as a leather auxiliary agent. In this invention, the application of the EM bacterial solution as a leather auxiliary agent can replace any one or more of the soaking agents, degreasing agents, liming agents, and rehydration agents in traditional leather tanning processes. Using the EM bacterial solution provided by this invention to replace any one or more of the soaking agents, degreasing agents, and liming agents in leather tanning processes can significantly reduce the content of solid waste, COD, and ammonia nitrogen in the wastewater generated by each production process. Using the EM bacterial solution provided by this invention to replace any one or more of the soaking agents, degreasing agents, liming agents, and rehydration agents in leather tanning processes, compared to traditional leather tanning processes, can improve leather quality and reduce the content of important pollutants in wastewater.

[0064] In this invention, the EM bacterial solution preferably includes EM stock solution and / or EM fermentation broth.

[0065] In this invention, the EM stock solution preferably includes: photosynthetic bacteria, actinomycetes, yeast, compound lactic acid bacteria, and Bacillus; the compound lactic acid bacteria preferably include Lactobacillus brevis, Lactobacillus bifidum, Lactobacillus plantarum, Bifidobacterium lactis, and Lactobacillus acidophilus; the Bacillus preferably includes any one or more of Bacillus subtilis, Bacillus licheniformis, Bacillus cereus, Bacillus megaterium, Bacillus mucilaginosus, Bacillus azotocinus, Bacillus spheroidosa, and Bacillus brevis; the yeast preferably includes any one or more of Saccharomyces cerevisiae, Saccharomyces cerevisiae, Candida albicans, Pasteurella multocida, Saccharomyces rouxii, Hansenula polymorpha, and Schizosoma fissicola.

[0066] In this invention, the photosynthetic bacteria activity in the EM stock solution is preferably 1×10⁻⁶. 8 ~2×10 9 CFU / mL, more preferably 6×10⁻⁶ 8 ~1×10 9 CFU / mL; the activity level of the actinomycetes is preferably 1×10⁻⁶. 8 ~1.8×10 9 CFU / mL, more preferably 4×10⁻⁶ 8 ~8×10 8 CFU / mL; the preferred activity level of the yeast is 3 × 10⁻⁶. 8 ~1.2×109 CFU / mL, more preferably 7×10⁻⁶ 8 ~1×10 9 CFU / mL; the preferred bacterial count of the compound lactic acid bacteria is 5 × 10⁻⁶. 8 ~1.7×10 9 CFU / mL, more preferably 1×10⁻⁶ 9 ~1.3×10 9 CFU / mL; the preferred bacterial activity of the Bacillus is 1×10⁻⁶. 8 ~7×10 8 CFU / mL, more preferably 4×10⁻⁶ 8 ~6×10 8 CFU / mL; the liveness ratio of the compound lactic acid bacteria, including *Lactobacillus brevis*, *Lactobacillus bifidum*, *Lactobacillus plantarum*, *Bifidobacterium lactis*, and *Lactobacillus acidophilus*, is 0.5–1.5:0.5–1:0.5–2:1–4:1–3, more preferably 0.5:0.5:1:2:1.5. In this invention, the yeast preferably includes any one or more of *Saccharomyces cerevisiae*, *Saccharomyces grapeis*, *Candida albicans*, *Pasteurella multocida*, *Saccharomyces rouxifolia*, *Hansenula polymorpha*, and *Schizosaccharomyces cerevisiae*, more preferably *Saccharomyces grapeis*. In this invention, the Bacillus preferably includes any one or more of *Bacillus subtilis*, *Bacillus licheniformis*, *Bacillus cereus*, *Bacillus megaterium*, *Bacillus mucilaginosus*, *Bacillus azotocinus*, *Bacillus spheroides*, and *Bacillus brevis*, more preferably *Bacillus subtilis* and *Bacillus licheniformis*. In this invention, if the Bacillus is Bacillus subtilis and Bacillus licheniformis, the live cell ratio of Bacillus subtilis and Bacillus licheniformis is preferably 1-3:1-4; more preferably 1:1.

[0067] This invention does not specifically limit the source of the various microbial agents described in the above technical solutions; any conventional microbial agents in the art can be used. In this invention, the photosynthetic bacteria are preferably from Qingdao Genyuan Biotechnology Group Co., Ltd.; the actinomycetes are preferably from Qingdao Genyuan Biotechnology Group Co., Ltd.; the yeast is preferably from Angel Yeast Co., Ltd. or Jining Jinyijun Biotechnology Co., Ltd.; the compound lactic acid bacteria are preferably from Jining Jinyijun Biotechnology Co., Ltd.; and the Bacillus is preferably from Jining Jinyijun Biotechnology Co., Ltd.

[0068] In this invention, the total bacterial activity of the EM stock solution is preferably 2.0 × 10⁻⁶. 9 ~1.5×10 10 CFU / mL, more preferably 4.5 × 10⁻⁶. 9 CFU / mL.

[0069] In this invention, the method for preparing the EM stock solution preferably includes the following steps:

[0070] Photosynthetic bacteria, actinomycetes, yeast, compound lactic acid bacteria and Bacillus were inoculated into a culture medium and fermented together to obtain EM stock solution.

[0071] In this invention, the co-fermentation culture medium preferably comprises molasses water culture medium. In this invention, the molasses water culture medium preferably comprises molasses and water; the mass ratio of molasses to water is preferably (1.5–2):100, more preferably 2:100. This invention does not have a particular limitation on the source of water, but purified water is preferred. In this invention, the mass ratio of the mixed photosynthetic bacteria, actinomycetes, yeast, compound lactic acid bacteria, and Bacillus is preferably (5–7):(2–4):(10–12):(12–15):(1–3). This invention further preferably involves adding 0.05–0.07 kg of photosynthetic bacteria, 0.02–0.04 kg of actinomycetes, 0.1–0.12 kg of yeast, 0.12–0.15 kg of compound lactic acid bacteria, and 0.01–0.03 kg of Bacillus to the molasses water culture medium for co-fermentation; the molasses water culture medium comprises 100 kg of purified water and 1.5–2 kg of molasses. More preferably, this invention involves adding 0.06 kg of photosynthetic bacteria, 0.02 kg of actinomycetes, 0.12 kg of yeast, 0.13 kg of compound lactic acid bacteria, and 0.022 kg of Bacillus to a molasses water culture medium for co-fermentation; the molasses water culture medium comprises 100 kg of purified water and 2 kg of molasses. In this invention, the co-fermentation temperature is preferably 30℃~50℃, more preferably 35℃~40℃, and more preferably 36℃. In this invention, the co-fermentation is preferably accompanied by rotation; the rotation speed is preferably 3000~5000 rpm, more preferably 3500~4500 rpm; the rotation is preferably carried out by a circulating pump; the co-fermentation time is preferably 7~30 days, more preferably 8~20 days, and more preferably 10 days. In this invention, the co-fermentation is preferably carried out in a fermenter. After the co-fermentation culture is completed, this invention preferably obtains the EM stock solution described in the above technical solution. In this invention, the bacterial count per unit volume of the EM stock solution is 2.0 × 10⁻⁶. 9 ~1.5×10 10 CFU / mL.

[0072] In this invention, the EM fermentation broth preferably comprises the following components by mass percentage: 1% to 10% of the EM stock solution described in the above technical solution, 10% to 70% of the fermentation culture broth, and the balance being water;

[0073] The fermentation broth preferably comprises the following components by mass percentage:

[0074] It contains 3%–15% collagen hydrolysate or leather waste, 5%–15% sugar, 0.5%–1% inorganic salts, 0%–1% organic acids, and 68%–89.5% water.

[0075] The EM fermentation broth of the present invention preferably comprises 1% to 10% EM stock solution, more preferably 1.5% to 5%, and more preferably 2% by mass percentage. In the present invention, the EM stock solution preferably comprises the EM stock solution described in the above technical solution or the EM stock solution prepared by the preparation method described in the above technical solution.

[0076] The EM fermentation broth of the present invention preferably comprises 10% to 70% fermentation culture medium by weight percentage, more preferably 20% to 50%, and more preferably 30%.

[0077] In this invention, the fermentation broth preferably comprises the following components by mass percentage:

[0078] It contains 3%–15% collagen hydrolysate or leather waste, 5%–15% sugar, 0.5%–1% inorganic salts, 0%–1% organic acids, and 68%–89.5% water.

[0079] In this invention, the fermentation broth preferably comprises 3% to 15% collagen hydrolysate or tanning waste by weight percentage. In this invention, the tanning waste preferably comprises any one or more of the following: fleshed leather residue after soaking raw hides, acid-treated leather scraps, limed leather scraps, delimed leather scraps, and wet blue leather shavings. When collagen hydrolysate is used as a component of the fermentation broth, the amount of collagen hydrolysate added is 3% to 15%, more preferably 5% to 15%, and more preferably 10%. When tanning waste is used as a component of the fermentation broth, the amount of tanning waste added is 3% to 15%, more preferably 3.3% to 5%, and more preferably 3.3%.

[0080] In this invention, the method for preparing the collagen hydrolysate preferably includes the following steps:

[0081] Tanning waste, decomposing enzyme preparation and water are mixed and then enzymatically hydrolyzed to obtain collagen hydrolysate.

[0082] The mass ratio of the tanning waste to water is (1-2):(2-10); the amount of the decomposing enzyme preparation added is 1%-5% of the mass of the tanning waste.

[0083] The decomposing enzyme preparation includes alkaline protease and lipase; the mass ratio of alkaline protease to lipase is (2-8):(1-2); the enzyme activity of alkaline protease is 50,000-200,000 U / g; the enzyme activity of lipase is 50,000-100,000 U / g.

[0084] In this invention, tanning waste, a decomposing enzyme preparation, and water are mixed and then enzymatically hydrolyzed to obtain collagen hydrolysate. In this invention, the mass ratio of tanning waste to water is preferably (1-2):(2-10), more preferably 1:(2-4), and even more preferably 1:2. In this invention, the amount of the decomposing enzyme preparation added is preferably 1%-5% of the mass of the tanning waste, more preferably 1%-2%, and even more preferably 1%. In this invention, the decomposing enzyme preparation preferably includes alkaline protease and lipase. In this invention, the mass ratio of the alkaline protease to lipase is (2-8):(1-2), and even more preferably 2.5:1. In this invention, the enzyme activity of the alkaline protease is preferably 50,000-200,000 U / g, more preferably 150,000-200,000 U / g; the enzyme activity of the lipase is preferably 50,000-100,000 U / g, and even more preferably 80,000-100,000 U / g. In this invention, the decomposing enzyme preparation can be prepared in-house or can utilize conventional commercially available products. In this invention, the decomposing enzyme preparation is preferably KORUTAGF-2, sourced from Qihe Lihou Chemical Co., Ltd.; KORUTAGF-2 comprises alkaline protease, lipase, and alkaline filler. In this invention, the enzymatic hydrolysis temperature is preferably 55℃~80℃, more preferably 55℃; the enzymatic hydrolysis time is preferably 3~48h, further preferably 4~12h, more preferably 5h. In this invention, the enzymatic hydrolysis is preferably accompanied by rotation, the rotation speed is preferably 20~60rpm, more preferably 60rpm. The enzymatic hydrolysis in this invention preferably continues until no solid residue remains in the enzymatic hydrolysis system. In this invention, when the tanning waste is wet blue leather dander, it is preferable to extend the enzymatic hydrolysis time or increase the amount of decomposing enzyme preparation added; the extended treatment time is preferably extended to 24~48h; the increased amount of decomposing enzyme preparation added is preferably 2%~5% of the tanning waste material. In this invention, when the tanning waste is the residue of fleshed leather after soaking raw hides, limed leather scraps, or delimed leather scraps, the preferred amount of the decomposing enzyme preparation is 1%–2%, the preferred enzymatic hydrolysis temperature is 55°C, and the preferred enzymatic hydrolysis time is 3–5 hours. In this invention, the decomposing enzyme preparation can decompose the tanning waste into collagen hydrolysates such as polypeptides, amino acids, and water-soluble protein solutions. Preferably, this invention obtains completely decomposed collagen hydrolysates without solid residue through enzymatic hydrolysis. In this invention, the enzymatic hydrolysis is preferably carried out in a rotary drum. This invention prepares collagen hydrolysates from tanning waste, and further utilizes these hydrolysates or directly applies tanning waste to prepare EM (Effective Microorganisms) fermentation broth. This fully utilizes waste from the tanning industry, turning waste into treasure by transforming it into collagen hydrolysates. The decomposed small molecules effectively improve penetration and dispersion, assisting other materials to better penetrate the leather. In the leather, it also plays a role in moisturizing and filling, improving adhesion to the leather, which helps reduce material usage and optimize the operation of each process.

[0085] In this invention, the fermentation broth preferably contains 5% to 15% sugar by mass percentage, more preferably 8% to 12%, and even more preferably 10%. In this invention, the sugar preferably includes any one or more of brown sugar, molasses, glucose, sucrose, and white sugar, and even more preferably molasses.

[0086] In this invention, the fermentation broth preferably comprises 0.5% to 1% inorganic salts by mass percentage, more preferably 0.5%. In this invention, the inorganic salts preferably comprise any one or more of sodium chloride, potassium chloride, and disodium hydrogen phosphate, more preferably sodium chloride.

[0087] In this invention, the fermentation broth preferably comprises 0-1% organic acid by mass percentage, more preferably 0.5-1%, and even more preferably 1%. In this invention, the organic acid preferably comprises one or more of lactic acid, formic acid, and acetic acid, more preferably lactic acid and / or formic acid, and even more preferably lactic acid.

[0088] In this invention, the fermentation broth preferably comprises 68% to 89.5% water by mass percentage, more preferably 70% to 80%, and even more preferably 78.5%. This invention does not have a particular limitation on the source of the water; conventional water in the art can be used. In this invention, the water is preferably purified water.

[0089] This invention does not impose any particular limitation on the preparation method of the fermentation culture medium; any conventional method in the art can be used. In this invention, the fermentation culture medium is preferably prepared by mixing collagen hydrolysate, molasses, sodium chloride, lactic acid, and purified water, and then stirring until homogeneous.

[0090] The EM fermentation broth of this invention preferably further comprises, by weight percentage, the balance of water, more preferably 68% water. This invention does not specifically limit the source of the water; any water conventional in the art can be used. In this invention, the water is preferably purified water.

[0091] In this invention, the method for preparing the EM bacteria fermentation broth preferably includes the following steps:

[0092] The EM stock solution, fermentation broth, and water are mixed and fermented to obtain the EM fermentation broth.

[0093] In this invention, the EM stock solution and fermentation broth are preferably mixed first, and then mixed with water. When mixing the EM stock solution and fermentation broth, the EM stock solution is preferably added to the fermentation broth first, and then water is added to the mixture. The fermentation temperature is preferably 30℃~50℃, more preferably 42℃~44℃; the fermentation time is preferably 1~30 days, more preferably 5~20 days, and more preferably 10~17 days; the pH of the fermentation broth is preferably controlled to be <4.0 during the fermentation process; and the fermentation is preferably carried out with the circulation pump running. After the fermentation is completed, the present invention preferably obtains an EM fermentation broth. In this invention, the fermentation is preferably carried out in a fermenter.

[0094] In this invention, when using EM (Effective Microorganisms) fermentation broth as a leather auxiliary agent, the EM fermentation broth is preferably added directly to the reaction system; when using EM stock solution as a leather auxiliary agent, the EM stock solution is preferably diluted before being added to the reaction system. The dilution factor described in this invention is preferably 5 to 30 times, more preferably 10 times.

[0095] This invention provides a method for preparing leather using EM bacterial solution as a leather auxiliary agent, comprising the following steps:

[0096] After mixing fur, water, and EM bacterial solution, the mixture is soaked in water to obtain soaked fur.

[0097] The water-soaked fur is then subjected to an ash-soaking treatment to obtain ash-soaked fur;

[0098] The ash-soaked fur is layered to obtain the top layer fur;

[0099] The top-grain fur is subjected to a de-ashing and softening treatment to obtain de-ashed and softened fur.

[0100] The deashed and softened fur is then pickled and tanned to obtain leather.

[0101] This invention does not impose any particular limitation on the equipment used for preparing leather; any conventional leather preparation equipment in the art can be used. In this invention, the preferred equipment for preparing leather is a rotary drum.

[0102] In this invention, the EM bacterial solution preferably includes the EM stock solution and / or EM fermentation broth described in the above technical solution.

[0103] This invention involves mixing fur, water, and EM (Effective Microorganisms) solution, followed by soaking to obtain soaked fur. In this invention, the fur is preferably salted fur. This invention does not have a specific limitation on the source of the salted fur; conventionally salted fur in the art can be used. In this invention, the soaking preferably includes a two-stage soaking. In this invention, the two-stage soaking is preferably a pre-soaking and a main soaking. In this invention, the pre-soaking is preferably performed by mixing the salted fur, water, and EM solution. The mixing method of this invention preferably includes: first mixing the fur with water to obtain a first fur-water mixture, and then mixing the EM solution with the first fur-water mixture. When mixing water with fur in this invention, the temperature of the water is preferably 18–28°C, more preferably 20–26°C, and more preferably 24°C; the amount of water added is preferably 100%–300% of the fur's mass, and more preferably 150%. After mixing the fur and water, the pH value of the first fur-water mixture is preferably adjusted; the pH value is preferably 6.0-7.2, more preferably 6.5. After obtaining the first fur-water mixture, the present invention preferably mixes EM bacterial solution with the first fur-water mixture, more preferably adding EM bacterial solution to the first fur-water mixture for mixing. In the present invention, the amount of EM bacterial solution added is preferably 0.1%-1.1% of the fur mass, more preferably 0.1%-0.32%, more preferably 0.28%. The present invention pre-soaks the fur, water, and EM bacterial solution after mixing. In the present invention, the pre-soaking process preferably includes a continuous rotation reaction stage and an intermittent rotation reaction stage sequentially. In the present invention, the rotation speed is preferably 2-10 rpm, more preferably 5-6 rpm. In the present invention, the duration of the continuous rotation reaction stage is preferably 180 min. After the continuous rotation reaction stage, the present invention preferably performs an intermittent rotation reaction stage. In this invention, the intermittent rotation reaction stage is preferably performed by rotating for 10-20 minutes per hour, followed by a pause of 40-50 minutes, more preferably by rotating for 10 minutes per hour, followed by a pause of 50 minutes. In this invention, the pre-soaking time is preferably 10-18 hours, more preferably 14-18 hours, and more preferably 16 hours. After pre-soaking, this invention preferably collects the pre-soaked fur to obtain pre-soaked fur. After obtaining the pre-soaked fur, this invention preferably further includes de-fleshing the pre-soaked fur to obtain de-fleshed fur. This invention does not specifically limit the de-fleshing method; any conventional de-fleshing method in the art can be used. After obtaining the de-fleshed fur, this invention preferably weighs the de-fleshed fur. Weighing the de-fleshed fur facilitates comparison of the effectiveness of EM bacterial solution in replacing the soaking agent and degreasing agent in traditional processes.

[0104] After obtaining the de-fleshed fur, the present invention preferably performs a primary soaking in water. In the present invention, the primary soaking is preferably performed by mixing the de-fleshed fur, water, and EM (Effective Microorganisms) solution. The present invention preferably mixes the de-fleshed fur and water to obtain a second fur-water mixture. When mixing water with the de-fleshed fur, the temperature of the water is preferably 18–28°C, more preferably 20–26°C, and even more preferably 24°C; the amount of water added is preferably 100%–300% of the fur mass, and even more preferably 150%. After mixing the de-fleshed fur and water, the present invention preferably adjusts the pH value of the second fur-water mixture; the pH value is preferably 8.8–10.5, and even more preferably 9.4–9.6. After obtaining the second fur-water mixture, the present invention preferably mixes the EM solution with the second fur-water mixture, and even more preferably adds the EM solution to the second fur-water mixture for mixing. In this invention, the amount of EM bacterial solution added is preferably 0.1% to 1.1% of the fur's mass, more preferably 0.1% to 0.32%, and even more preferably 0.32%. In this invention, the de-fleshed fur, water, and EM bacterial solution are mixed and then subjected to primary soaking. In this invention, the primary soaking process preferably includes a continuous rotation reaction stage and an intermittent rotation reaction stage sequentially. In this invention, the rotation speed is preferably 2 to 10 rpm, more preferably 5 to 6 rpm. In this invention, the duration of the continuous rotation reaction stage is preferably 180 min. After the continuous rotation reaction stage, the intermittent rotation reaction stage is preferably performed. In this invention, the intermittent rotation reaction stage preferably involves rotation for 10 to 20 min per hour, followed by a pause for 40 to 50 min, more preferably 10 min per hour, followed by a pause for 50 min. In this invention, the primary soaking time is preferably 10 to 18 h, more preferably 14 to 18 h, and even more preferably 16 h. After the primary soaking is completed, in this invention, the fur that has undergone primary soaking is preferably collected to obtain primary soaked fur. In this invention, the soaked fur can also be referred to as soaked fur. In the leather-making process, this invention replaces the soaking agent and degreasing agent in the traditional leather-making process with EM (Effective Microorganisms) solution. The EM solution has excellent wetting, penetrating, and moisturizing effects, effectively increasing the water content of the fur and facilitating subsequent processes. The EM solution also has excellent degreasing effects, efficiently removing grease from the fur.

[0105] After obtaining the soaked fur, the present invention further limes the soaked fur to obtain limed fur. Preferably, the present invention uses a conventional liming process on the soaked fur, or mixes the soaked fur, water, lime, sodium hydrosulfide, sodium sulfide, and EM bacterial solution for liming to obtain limed fur. More preferably, the present invention uses a mixture of the soaked fur, water, lime, sodium hydrosulfide, sodium sulfide, and EM bacterial solution for liming to obtain limed fur. The mixing process in the present invention preferably involves first mixing the soaked fur with water. Preferably, the present invention mixes the soaked fur and water to obtain a soaked fur-water mixture. In the present invention, the amount of water added is preferably 100% to 300% of the fur's mass, more preferably 200%. When mixing water and fur, the temperature of the water is preferably 18 to 28°C, more preferably 20 to 26°C, and more preferably 24°C. After obtaining the fur-soaked liquid mixture, the present invention preferably mixes the EM bacterial solution with the fur-soaked liquid mixture, more preferably by adding the EM bacterial solution to the fur-soaked liquid mixture for mixing, to obtain a fur fermentation liquid mixture. In the present invention, the amount of EM bacterial solution added is preferably 0.1% to 1.1% of the fur mass, more preferably 0.1% to 0.32%, and more preferably 0.2%. After obtaining the fur fermentation liquid mixture, the present invention preferably mixes the fur fermentation liquid mixture with lime, sodium hydrosulfide, and sodium sulfide in sequence, more preferably by adding lime, sodium hydrosulfide, and sodium sulfide in sequence to the fur fermentation liquid mixture. In the present invention, the amount of lime added is preferably 2.8% to 4.3% of the fur mass, more preferably 3.5%; the amount of sodium hydrosulfide added is preferably 0.6% to 1.0% of the fur mass, more preferably 0.8%; and the amount of sodium sulfide added is preferably 0.3% to 0.8% of the fur mass, more preferably 0.5%. The liming process described in this invention is preferably carried out for 10–18 hours, more preferably 12–18 hours, and even more preferably 15–18 hours. In this invention, the liming process is preferably accompanied by intermittent rotation. In this invention, the rotation speed is preferably 2–10 rpm, more preferably 5–6 rpm. In this invention, the intermittent rotation preferably includes rotating for 10–20 minutes per hour, then stopping for 40–50 minutes, more preferably rotating for 20 minutes per hour, then stopping for 40 minutes. The purpose of rotating the drum during liming in this invention is mainly to prevent lime from settling at the bottom of the drum, allowing it to slowly dissolve and take effect. After the liming reaction is completed, this invention preferably yields limed fur.

[0106] After obtaining the ash-soaked fur, the present invention preferably separates the ash-soaked fur into layers; the layers can be separated into top-grain fur, second-grain fur, and / or third-grain fur. The present invention does not have special requirements on the thickness of the layers, and any thickness conventional in the art can be used. The present invention does not have special limitations on the layering method, and any conventional layering method in the art can be used. The present invention preferably performs subsequent processes such as deashing on the top-grain fur, and temporarily collects the second-grain fur and / or third-grain fur.

[0107] After obtaining the top-grain fur, the present invention performs a de-ashing and softening treatment on the top-grain fur to obtain de-ashed and softened fur. Preferably, the present invention performs a traditional de-ashing and softening treatment on the top-grain fur, or mixes the top-grain fur, water, de-ashing agent, and EM bacterial solution for de-ashing followed by softening to obtain de-ashed and softened fur. More preferably, the present invention mixes the top-grain fur, water, de-ashing agent, and EM bacterial solution for de-ashing followed by softening to obtain de-ashed and softened fur. The mixing process in the present invention preferably involves first mixing the top-grain fur with water. Preferably, the present invention mixes the top-grain fur and water to obtain a top-grain fur-water mixture. In the present invention, the amount of water added is preferably 80% to 150% of the fur mass, more preferably 100%. When mixing water with the top-grain fur, the temperature of the water is preferably 26 to 35°C, more preferably 28 to 33°C, and more preferably 32°C. After obtaining the top-grain fur-water mixture, the present invention preferably mixes the top-grain fur-water mixture with a de-ashing agent. In this invention, the mixing preferably involves adding a deliming agent to the top-grain fur water mixture. The amount of the deliming agent added is preferably 1.0% to 2.0% of the fur's weight, more preferably 1.2%. After adding the deliming agent, the present invention preferably adds EM (Effective Microorganisms) solution to the top-grain fur water mixture. The amount of EM solution added is preferably 0.1% to 1.1% of the fur's weight, more preferably 0.1% to 0.32%, more preferably 0.1%. The present invention involves mixing the top-grain fur, water, deliming agent, and EM solution for deliming. The deliming time is preferably 50 to 100 minutes, more preferably 60 minutes. The deliming process is preferably accompanied by rotation, with the rotation speed preferably 2 to 10 rpm, more preferably 5 to 6 rpm. The deliming agent is preferably sourced from Qihe Lihou Chemical Co., Ltd. (KAISTER BK). After deliming, the present invention preferably yields delimed fur. After obtaining the de-ashed fur, the present invention preferably mixes the de-ashed fur with a softening enzyme for softening. In the present invention, the amount of the softening enzyme added is preferably 0.5% to 1.2% of the fur's mass, more preferably 0.6%. In the present invention, the softening enzyme preferably includes trypsin and sodium sulfate. In the present invention, the softening enzyme is preferably KORUTASO from Qihe Lihou Chemical Co., Ltd. After mixing the de-ashed fur with the softening enzyme, the present invention preferably further includes pH adjustment; the pH is preferably adjusted to 8.0 to 8.8, more preferably to 8.2 to 8.5. In the present invention, the softening time is preferably 100 to 180 minutes, more preferably 120 minutes. In the present invention, the softening is preferably accompanied by rotation, the rotation speed is preferably 2 to 10 rpm, more preferably 5 to 6 rpm. After softening, the present invention preferably performs controlled-water washing or rinsing on the obtained fur to obtain de-ashed and softened fur.

[0108] After obtaining the deashed and softened fur, the present invention will further process the deashed and softened fur by pickling and tanning to obtain leather.

[0109] This invention does not impose any particular limitation on the methods of pickling and tanning; conventional pickling and tanning methods in the art can be used.

[0110] In this invention, the acid soaking step preferably includes mixing the delimed and softened fur with water to obtain a delimed and softened fur aqueous mixture. In this invention, the amount of water added is preferably 50% to 120% of the fur's mass, more preferably 70%. When mixing water with the delimed and softened fur, the temperature of the water is preferably 16 to 26°C, more preferably 18 to 24°C, and more preferably 22°C. After obtaining the delimed and softened fur aqueous mixture, this invention preferably mixes the delimed and softened fur aqueous mixture with salt and then performs a rotational treatment to obtain a fur salt mixture. In this invention, the amount of salt added is preferably 6% to 9% of the fur's mass, more preferably 7%. After mixing the delimed and softened fur aqueous mixture with salt, this invention preferably performs a rotational treatment for 10 to 60 minutes, more preferably 30 minutes. In this invention, the rotational speed of the rotational treatment is preferably 2 to 10 rpm, more preferably 5 to 6 rpm. After the rotational treatment is completed, this invention preferably mixes the fur salt mixture with formic acid for a first acidification treatment to obtain a first acidified fur. In this invention, the amount of formic acid added is preferably 0.6-0.9% of the fur mass, more preferably 0.7%. In this invention, the first acidification treatment time is preferably 30-60 minutes, more preferably 45 minutes. In this invention, the formic acid is preferably added to the fur salt mixture in several portions, more preferably in two portions. This invention does not specifically limit the amount added in the two portions, but more preferably the amounts added in both portions are the same. In this invention, the two additions of formic acid preferably include a first addition and a second addition. In this invention, the time interval between the first and second additions of formic acid is preferably 10-20 minutes, more preferably 15 minutes. In this invention, it is preferred that after the first addition of formic acid, the mixture is rotated at 2-10 rpm for 10-20 minutes, followed by the second addition of formic acid; after the second addition of formic acid, the mixture is rotated at 2-10 rpm for 30 minutes to obtain the first acidified fur. After obtaining the first acidified fur, this invention preferably mixes sulfuric acid with the first acidified fur and then performs a second acidification treatment to obtain the second acidified fur. In this invention, the amount of sulfuric acid added is preferably 0.9% to 1.3% of the fur's mass, more preferably 1.0%. In this invention, the second acidification treatment time is preferably 150 to 220 minutes, more preferably 165 minutes. In this invention, the sulfuric acid is preferably added to the first acidified fur in several stages, more preferably in three stages. This invention does not specifically limit the amount added in the three stages, but preferably the amounts added in all three stages are the same. In this invention, the three additions of sulfuric acid preferably include a first addition, a second addition, and a third addition. In this invention, the time interval between the first and second additions of sulfuric acid is preferably 15 minutes; the time interval between the second and third additions of sulfuric acid is preferably 15 minutes.In this invention, after the first addition of sulfuric acid, the rotation is preferably performed at 2-10 rpm for 15 minutes, followed by a second addition of sulfuric acid. After the second addition, the rotation is preferably performed at 2-10 rpm for 15 minutes, followed by a third addition of sulfuric acid. After the third addition, the rotation is preferably performed at 2-10 rpm for 15 minutes. After the third addition of sulfuric acid, the rotation is preferably performed again at 2-10 rpm for 105-175 minutes, more preferably for 120 minutes. In this invention, after the rotation is completed, the rotation is preferably stopped, and the pH of the second acidified fur is adjusted to 2.8 to obtain the second acidified fur. After obtaining the second acidified fur, the acid-treated fur is obtained.

[0111] After obtaining the acid-tanned fur, the present invention preferably tanns the acid-tanned fur to obtain leather. In the present invention, the tanning preferably includes chrome tanning by mixing the acid-tanned fur with chrome powder. In the present invention, the chrome tanning preferably includes two chrome tanning processes, namely a first chrome tanning and a second chrome tanning. In the present invention, the first chrome tanning preferably involves mixing the acid-tanned fur with chrome powder, more preferably by adding chrome powder to the acid-tanned fur. In the present invention, the amount of chrome powder added is preferably 2.5% to 4.5% of the fur mass, more preferably 3%. In the present invention, the first chrome tanning time is preferably 30 to 150 minutes, more preferably 60 minutes. After the first chrome tanning is completed, the present invention preferably performs a second chrome tanning. In the present invention, the second chrome tanning preferably includes mixing the first chrome tanning product with chrome powder, more preferably by adding chrome powder to the first chrome tanning product. In the present invention, the amount of chrome powder added is preferably 2.5% to 5% of the fur mass, more preferably 3.5%. In the present invention, the second chrome tanning time is preferably 30 to 150 minutes, more preferably 60 minutes. After the second chrome tanning is completed, the present invention preferably mixes the second chrome tanned product with magnesium oxide to carry out a basicity adjustment reaction. In the present invention, the mixing preferably involves adding magnesium oxide to the second chrome tanned product. In the present invention, the amount of magnesium oxide added is preferably 0.4% to 0.7% of the fur weight, more preferably 0.5%. In the present invention, the basicity adjustment reaction time is preferably 250 to 600 min, more preferably 300 min. In the present invention, the first chrome tanning, the second chrome tanning, and the basicity adjustment reaction are preferably all accompanied by rotation, the rotation speed is preferably 2 to 10 rpm, more preferably 5 to 6 rpm. After the basicity adjustment reaction is completed, the present invention preferably mixes the product after the basicity adjustment reaction with water and carries out a rotational reaction to obtain leather. In the present invention, the mixing preferably involves adding water to the product after the basicity adjustment reaction. In the present invention, the amount of water added is preferably 80% to 150% of the fur weight, more preferably 100%. When the product after the reaction is mixed with water, the temperature of the water is preferably 25 to 70°C, more preferably 65°C. After mixing the reaction product with water, the rotational reaction time of the present invention is preferably 80-200 min, more preferably 120 min. After the rotational reaction is completed, the reaction product is preferably left to stand overnight. In the present invention, the overnight standing time is preferably 10-18 h, more preferably 16 h. After the overnight standing is completed, the obtained fur is preferably separated to obtain leather. In the present invention, the leather is also referred to as wet blue leather, or tanned wet blue leather.

[0112] This invention provides a method for rehydrating leather, comprising the following steps:

[0113] The fur is acidified to obtain acidified fur.

[0114] The acidified fur was mixed with EM bacterial solution and degreased and rehydrated to obtain rehydrated fur.

[0115] The acidification treatment described in this invention preferably includes:

[0116] After mixing fur, water, and oxalic acid, a third acidification treatment is carried out to obtain third acidified fur.

[0117] After mixing the third-acid-treated fur with formic acid, a fourth-acid-treated fur is obtained, also known as acid-treated fur.

[0118] This invention involves mixing fur, water, and oxalic acid, followed by a third acidification treatment. Preferably, the fur and water are mixed first, then the oxalic acid is added. The fur preferably includes wet blue fur. The source of the wet blue fur is not specifically limited; wet blue fur prepared using the method described above or conventionally purchased wet blue fur is acceptable. The amount of water added is preferably 80%–200% of the fur's mass, more preferably 100%. When mixing the fur and water, the water temperature is preferably 40–50°C, more preferably 45°C. When mixing with oxalic acid, the oxalic acid is preferably added to the fur and water mixture. The amount of oxalic acid added is preferably 0.4%–0.7% of the fur's mass, more preferably 0.5%. The third acidification treatment time is preferably 20–60 minutes, more preferably 30 minutes. After the third acidification treatment, the invention preferably yields a third-acidified fur. After obtaining the third acid-treated fur, the present invention preferably mixes the third acid-treated fur with formic acid and then performs a fourth acid treatment. In the present invention, the mixing preferably involves adding formic acid to the third acid-treated fur. In the present invention, the amount of formic acid added is preferably 0.45% to 0.6% of the fur's mass, more preferably 0.5%. After mixing the third acid-treated fur with formic acid, the present invention preferably further includes adjusting the pH of the reaction system; the pH is preferably adjusted to 3.2 to 3.8, more preferably 3.4 to 3.6. After adjusting the pH of the reaction system, the present invention preferably performs a fourth acid treatment. In the present invention, the fourth acid treatment time is preferably 20 to 60 minutes, more preferably 30 minutes. After the fourth acid treatment is completed, the present invention preferably obtains a fourth acid-treated fur.

[0119] After obtaining the fourth acid-treated fur, the present invention preferably mixes the fourth acid-treated fur with EM bacterial solution for degreasing and rehydration to obtain rehydrated fur. In the present invention, the amount of EM bacterial solution added is preferably 0.1% to 1.1% of the fur mass. In the present invention, when using EM bacterial solution as an EM fermentation liquid as a leather auxiliary agent, the amount of EM fermentation liquid added is preferably 0.5% to 1.1%, more preferably 1.1%; when using EM bacterial solution as an EM stock solution as a leather auxiliary agent, the amount of EM stock solution added is preferably 0.1% to 0.5%, more preferably 0.11%. In the present invention, the degreasing and rehydration time is preferably ≥180 min, more preferably 180 min. The degreasing and rehydration process of the present invention preferably involves rotation. In the present invention, the rotation speed is preferably 2 to 10 rpm. In the present invention, during the degreasing and rehydration process, the degree of rehydration is preferably detected when the degreasing and rehydration time is ≥180 min. When the degree of rehydration is qualified, the rehydration step of the fur is completed, and the rehydrated fur is obtained; if the degree of rehydration is not qualified, the degreasing and rehydration process continues until the degree of rehydration is qualified, and the rehydrated fur is obtained.

[0120] The method for preparing leather using EM (Effective Microorganisms) solution as a leather auxiliary agent provided by the above-mentioned technical solution of the present invention has good wetting, penetration, and moisturizing effects. Compared with traditional soaking agents, it can efficiently increase the water content of fur, which is beneficial to subsequent processes when applied to leather soaking. In the present invention, the EM solution as a leather auxiliary agent has a good degreasing effect. When applied to fur degreasing, the degreasing effect of using EM solution is better than that of using traditional degreasing agents. In the present invention, the EM solution as a leather auxiliary agent can be used as a rehumidifying agent to rehumidify fur. Compared with the rehumidifying agents in traditional leather tanning processes, the rehumidification effect of EM solution as a leather auxiliary agent in the present invention is better, and the resulting rehumidified fur is softer. The EM solution as a leather auxiliary agent in the present invention can better protect the collagen in fur, and can effectively reduce the loss of collagen in various processing steps, especially in the liming step. Meanwhile, the EM (Effective Microorganisms) solution used in this invention can be used as a leather auxiliary agent to promote the tanning effect of chromium powder on leather and reduce the chromium trioxide content in wastewater. Furthermore, the EM solution used in this invention can effectively reduce the solids, COD, and ammonia nitrogen content in wastewater generated during various stages of leather production. In summary, the EM solution provided by this invention, compared to using traditional chemical raw materials as leather auxiliary agents, can produce higher quality leather while reducing the pollutant content in wastewater.

[0121] This invention provides an EM (Effective Microorganisms) stock solution as a leather auxiliary agent, comprising: photosynthetic bacteria, actinomycetes, yeast, compound lactic acid bacteria, and Bacillus; the compound lactic acid bacteria include Lactobacillus brevis, Lactobacillus bifidum, Lactobacillus plantarum, Bifidobacterium lactis, and Lactobacillus acidophilus; the Bacillus includes one or more of Bacillus subtilis, Bacillus licheniformis, Bacillus cereus, Bacillus megaterium, Bacillus mucilaginosus, Bacillus azotocinus, Bacillus spheroidosa, and Bacillus laterosporus brevis; the yeast includes one or more of Saccharomyces cerevisiae, Saccharomyces grape juice, Candida albicans, Pasteurella multocida, Saccharomyces rouxii, Hansenula polymorpha, and Schizosoma fissicola. The specific composition of the EM stock solution of this invention is the same as that of the EM stock solution described in the above-mentioned technical solutions, and will not be repeated here.

[0122] This invention provides a method for preparing the EM stock solution described in the above technical solution, comprising the following steps:

[0123] Photosynthetic bacteria, actinomycetes, yeast, compound lactic acid bacteria and Bacillus were inoculated into a culture medium and fermented together to obtain EM stock solution.

[0124] In this invention, the preparation method of the EM stock solution is preferably the same as the preparation method of the EM stock solution described in the above technical solution, and will not be repeated here.

[0125] This invention provides an EM (Effective Microorganisms) fermentation broth, comprising the following components by mass percentage: 1%–10% EM stock solution, 10%–70% fermentation broth, and the remainder water;

[0126] The fermentation broth comprises the following components by mass percentage:

[0127] It contains 3%–15% collagen hydrolysate or leather tanning waste, 5%–15% sugar, 0.5%–1% inorganic salts, 0%–1% organic acids, and 68%–89.5% water.

[0128] In this invention, the specific composition of the EM fermentation broth is the same as that of the EM fermentation broth described in the above technical solution, and will not be repeated here.

[0129] This invention also provides a method for preparing the EM bacteria fermentation broth described in the above technical solution, comprising the following steps:

[0130] The EM bacteria stock solution, fermentation broth and water are mixed and fermented to obtain the EM bacteria fermentation broth.

[0131] In this invention, the preparation method of the EM bacteria fermentation broth is the same as that of the EM bacteria fermentation broth described in the above technical solution, and will not be repeated here.

[0132] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0133] Example 1-1

[0134] An EM (Effective Microorganisms) stock solution is prepared as follows:

[0135] Add 100 kg of purified water and 2 kg of molasses to the fermentation tank, stir until fully dissolved, then add 0.06 kg of photosynthetic bacteria, 0.02 kg of actinomycetes, 0.12 kg of yeast, 0.13 kg of compound lactic acid bacteria, and 0.022 kg of Bacillus. Maintain the temperature at 36℃ and run the circulating pump at 3500 rpm for 10 days, yielding a bacterial count of 4.5 × 10⁻⁶ per unit volume. 9 EM stock solution with CFU / mL.

[0136] Among them, the photosynthetic bacteria were sourced from Qingdao Genyuan Biotechnology Group Co., Ltd., the actinomycetes from Qingdao Genyuan Biotechnology Group Co., Ltd., the yeast from Angel Yeast Co., Ltd., the compound lactic acid bacteria from Jining Jinyijun Biotechnology Co., Ltd., and the Bacillus from Jining Jinyijun Biotechnology Co., Ltd.

[0137] The composition of the obtained EM stock solution is as follows:

[0138] The bacteria include photosynthetic bacteria, actinomycetes, yeast, compound lactic acid bacteria, and Bacillus; the compound lactic acid bacteria include Lactobacillus brevis, Lactobacillus bifidum, Lactobacillus plantarum, Bifidobacterium lactis, and Lactobacillus acidophilus; the Bacillus is Bacillus subtilis and Bacillus licheniformis; and the yeast is Grape Juice Yeast.

[0139] The photosynthetic bacteria activity in the EM stock solution was 7 × 10⁻⁶. 8 CFU / mL; Actinomycete viability was 1×10⁻⁶. 9 CFU / mL; yeast activity was 1×10⁻⁶. 9 CFU / mL; the activity level of the compound lactic acid bacteria was 1.1 × 10⁻⁶. 9 CFU / mL; Bacillus viability was 7 × 10⁻⁶. 8 CFU / mL; the activity level of *Lactobacillus brevis* in the compound lactic acid bacteria is 1×10⁻⁶. 8 CFU / mL, Bifidobacterium viability was 1×10⁻⁶. 8 CFU / mL, the bacterial activity of Lactobacillus plantarum was 2×10⁻⁶. 8 CFU / mL, Bifidobacterium lactis activity was 4×10⁻⁶. 8 CFU / mL and Lactobacillus acidophilus activity were 3×10⁻⁶. 8CFU / mL; of the Bacillus species, the bacterial activity of Bacillus subtilis was 3.5 × 10⁻⁶. 8 CFU / mL; Bacillus licheniformis viability was 3.5 × 10⁻⁶. 8 CFU / mL.

[0140] Examples 1-2

[0141] An EM (Effective Microorganisms) stock solution, composed of:

[0142] The bacterial count of photosynthetic bacteria was 1×10⁻⁶. 8 CFU / mL; Actinomycete viability was 1×10⁻⁶. 8 CFU / mL; yeast activity was 3×10⁻⁶. 8 CFU / mL; the activity level of *Lactobacillus brevis* in the compound lactic acid bacteria is 1×10⁻⁶. 8 CFU / mL, Bifidobacterium viability was 1×10⁻⁶. 8 CFU / mL, the bacterial activity of Lactobacillus plantarum was 2×10⁻⁶. 8 CFU / mL, Bifidobacterium lactis activity was 4×10⁻⁶. 8 CFU / mL and Lactobacillus acidophilus activity were 3×10⁻⁶. 8 CFU / mL; among the Bacillus species, the bacterial activity of Bacillus cereus was 3 × 10⁻⁶. 8 CFU / mL; Bacillus megaterium viability was 4 × 10⁻⁶. 8 CFU / mL. The yeast strain is brewer's yeast.

[0143] Examples 1-3

[0144] An EM (Effective Microorganisms) stock solution, composed of:

[0145] The bacterial activity of photosynthetic bacteria was 2×10⁻⁶. 9 CFU / mL; Actinomycete viability was 1.8 × 10⁻⁶. 9 CFU / mL; yeast activity was 1.0 × 10⁻⁶. 9 CFU / mL; the activity level of *Lactobacillus brevis* in the compound lactic acid bacteria is 1×10⁻⁶. 8 CFU / mL, Bifidobacterium viability was 1×10⁻⁶. 8 CFU / mL, the bacterial activity of Lactobacillus plantarum was 2×10⁻⁶. 8 CFU / mL, Bifidobacterium lactis activity was 4×10⁻⁶. 8 CFU / mL and Lactobacillus acidophilus activity were 3×10⁻⁶. 8 CFU / mL; among the Bacillus species, the viability of Bacillus mucilaginosus, Bacillus azotocinus, Bacillus spheroidosa, and Bacillus brevis lateralis were 1.3 × 10⁻⁶ CFU / mL. 8 CFU / mL, 3.0 × 10 8 CFU / mL, 1.6 × 108 CFU / mL, 1.1×10 8 CFU / mL. The yeast strains included *Candida*, *Pasteurella*, and *Rhodotorula*, with cell viability of 3 × 10⁻⁶. 8 CFU / mL, 4×10 8 CFU / mL, 3×10 8 CFU / mL.

[0146] Example 2

[0147] A collagen hydrolysate, the specific preparation method of which is as follows:

[0148] Weigh 20 kg of leather scraps and add them to a drum. Add 40 kg of purified water and 0.2 kg of the decomposing enzyme preparation KORUTAGF-2. Heat the drum to 57°C and rotate at 60 rpm for 5 hours. Check for any obvious solids to obtain collagen hydrolysate.

[0149] The degrading enzyme preparation comprises alkaline protease and lipase, wherein the mass ratio of alkaline protease to lipase is 2.5:1; the enzyme activity of the alkaline protease is 200,000 U / g; and the enzyme activity of the lipase is 80,000 U / g. The degrading enzyme preparation KORUTAGF-2 used in this example was purchased from Qihe Lihou Chemical Co., Ltd.

[0150] Example 3

[0151] A fermentation culture medium, comprising:

[0152] Example 2 contained 3 kg (10%) of collagen hydrolysate, 3 kg (10%) of molasses, 0.15 kg (0.5%) of sodium chloride, 0.3 kg (1%) of lactic acid, and 23.55 kg (78.5%) of purified water.

[0153] The preparation method is as follows: Collagen hydrolysate, molasses, sodium chloride, lactic acid and purified water are mixed and stirred evenly.

[0154] Example 4

[0155] A fermentation culture medium, comprising:

[0156] 1 kg of grey leather scraps, 3 kg of brown sugar, 0.15 kg of disodium hydrogen phosphate, 0.3 kg of formic acid, and 25.55 kg of purified water.

[0157] The preparation method is the same as in Example 3.

[0158] Example 5

[0159] EM fermentation broth consists of the following components:

[0160] The fermentation culture consisted of 30 kg (30%) of collagen hydrolysate, 3 kg (3%) of molasses, 0.15 kg (0.15 kg) of sodium chloride, 0.3 kg (0.3 kg) of lactic acid and 23.55 kg (23.55 kg) of purified water, 2 kg (2%) of EM stock solution from Example 1-1 and 68 kg (68%) of purified water.

[0161] A method for preparing EM (Effective Microorganisms) fermentation broth, comprising the following steps:

[0162] Add collagen hydrolysate, molasses, sodium chloride, lactic acid, and purified water to the fermentation tank, stir well, add EM stock solution, and then add 68 kg of purified water. Maintain the temperature at 42℃, start the circulation pump, and ferment for 10 days. During the fermentation process, control the pH of the fermentation broth to be <4.0. The resulting bacterial count per unit volume is 1.3 × 10⁻⁶. 8 EM bacteria fermentation broth at CFU / mL.

[0163] Application Example 1

[0164] The COD of the EM stock solution in Examples 1-1, the EM fermentation broth in Example 5, and commonly used tanning agents such as soaking agents, degreasing agents, liming agents, and rehumidifying agents were tested. The COD test results are shown in Table 1.

[0165] Among them, the water-soaking agent FRUCTYC, the degreasing agent FRUCTYFB, the ash-soaking agent FRUCTYLH, and the rehumidifying agent FRUCTY TLA were all purchased from Qihe Lihou Chemical Co., Ltd.

[0166] Table 1 COD Test Results

[0167] raw material COD concentration (mg / L) EM stock solution 81320 Re-fermentation liquid 61256 FRUCTYC (water-absorbing agent) 521980 FRUCTYFB degreasing agent 543660 FRUCTYLH impregnation agent 541810 FRUCTYTLA dehumidifier 286500

[0168] As shown in Table 1, the COD of the EM fermentation broth or EM stock solution provided by this invention is much lower than that of petrochemical raw materials. When used in leather making, it can reduce the wastewater treatment load, which is beneficial to reducing production costs and protecting the environment.

[0169] Example 6

[0170] The EM fermentation broth from Example 5 was used in the tanning process, from soaking to tanning, and compared with the traditional tanning process using petrochemical raw materials. The test was conducted at a tanning enterprise in Shandong Province. 15 tons of salted hides were weighed and added to the drum. The hides were sourced from domestically fattened cattle, including mixed bull and cow hides, and were processed according to the described process. The steps are shown in Table 2 (the amounts of the corresponding substances added in Table 2 are based on salted hides). The specific steps are as follows:

[0171] (1) Weigh 15 tons of salted fur and put it into a rotary drum. Then add water at 24°C, with the amount of water being 150% of the weight of the salted fur. At the same time, adjust the pH of the mixture to 6.5 and add 0.28% of the weight of the salted fur with EM fermentation liquid to carry out the pre-soaking process. During the pre-soaking process, the drum is rotated at 5 rpm for 180 minutes, then rotated for 10 minutes every hour, and stopped for 50 minutes. The next morning, the fur is removed from the drum, demineralized, and weighed. The pre-soaking time is 16 hours.

[0172] (2) The pre-soaked fur is placed into a rotating drum, and then water at 24°C is added. The amount of water added is 150% of the weight of the salted fur. At the same time, the pH of the mixture is adjusted to 9.4-9.6. Simultaneously, 0.32% of the weight of the salted fur is added to the EM fermentation liquid for the main soaking process. During the main soaking process, the drum is rotated at 5 rpm for 180 minutes, then rotated for 10 minutes every hour, and stopped for 50 minutes. The fur is removed from the drum the next morning. The main soaking time is 16 hours.

[0173] (3) After soaking in water, the fur is placed into a rotating drum, and then water at 24°C is added. The amount of water added is 200% of the weight of the salted fur. 0.2% of the weight of the salted fur is added to EM fermentation liquid, 3.5% of the weight of the salted fur is added to lime, 0.8% of the weight of the salted fur is added to sodium hydrosulfide, and 0.5% of the weight of the salted fur is added to carry out the liming process. During the liming process, the drum is rotated at 5 rpm for 20 minutes per hour and stopped for 40 minutes. The next morning (16 hours), the drum skin is washed out with water, and the fur is separated into layers. The first layer is weighed and enters the deliming process, and the second layer is collected in the warehouse for sale.

[0174] (4) Place the top-grain fur into a rotating drum, then add water at 32°C, the amount of water being 100% of the weight of the salted fur. Then add 1.2% of the weight of the salted fur's deashing agent KAISTER BK, and 0.1% of the weight of the salted fur's EM fermentation broth for deashing for 60 minutes. The deashing process is carried out by rotating the drum at 5 rpm. After deashing, add 0.6% of the weight of the salted fur's softening enzyme KORUTA SO to the reaction system, adjust the pH to 8.2-8.5, and soften for 120 minutes at 5 rpm. After softening, wash the fur with drained water to obtain the final deashed and softened fur.

[0175] (5) Place the de-ashed and softened fur into a rotating drum, then add water at 22°C, the amount of water being 70% of the weight of the salted fur, and add salt accounting for 7% of the weight of the salted fur. Rotate at 5 rpm for 30 minutes. Then, add formic acid in two batches at 15-minute intervals, the total mass of formic acid being 0.7% of the weight of the salted fur. After the formic acid is added, rotate at 5 rpm for 30 minutes. After reacting for 45 minutes from the first addition of sulfuric acid, add sulfuric acid in three batches at 15-minute intervals, the total mass of sulfuric acid being 1.0% of the weight of the salted fur. After the sulfuric acid is added, adjust the pH to 2.8 and rotate at 5 rpm for 120 minutes. The reaction time is 165 minutes from the first addition of sulfuric acid, completing the fur pickling process.

[0176] (6) After the pickling is completed, the pickled fur is obtained. Then, 3% of the weight of the salted fur chromium powder is added to the pickled fur and rotated at 5 rpm for 60 min. Then, 3.5% of the weight of the salted fur chromium powder is added and rotated at 5 rpm for 60 min. Then, 0.5% of the weight of the salted fur magnesium oxide is added and rotated at 5 rpm for 300 min. Finally, 100% of the weight of the salted fur water is added and rotated at 5 rpm for 120 min at 65°C. After the reaction is completed, it is left to stand overnight (16 h) to complete the tanning step. The fur is then removed from the drum and aged to obtain leather (wet blue leather).

[0177] Comparative Example 1

[0178] Traditional leather tanning using petrochemical raw materials: The experiment was conducted at a leather tanning enterprise in Shandong Province. 15 tons of salted hides were weighed and added to a rotary drum. The hides were sourced from domestically fattened cattle, a mixture of bull and cow hides, etc., and the process was carried out according to the described application process. The steps are shown in Table 2, and the specific steps are as follows:

[0179] (1) Weigh 15 tons of salted fur and put it into a rotary drum. Then add water at 24°C, with the amount of water being 150% of the weight of the salted fur. At the same time, adjust the pH of the mixture to 6.5. Simultaneously add 0.2% FRUCTYC (soaking agent) and 0.08% FRUCTYFB (degreasing agent) by weight of the salted fur to carry out the pre-soaking process. During the pre-soaking process, the drum is rotated at 5 rpm for 180 minutes, then rotated for 10 minutes every hour, and stopped for 50 minutes. The fur is removed from the drum the next morning, demineralized, and weighed. The pre-soaking time is 16 hours.

[0180] (2) The pre-soaked fur is placed in a rotating drum, and then water at 24°C is added. The amount of water added is 150% of the weight of the salted fur. At the same time, the pH of the mixture is adjusted to 9.4-9.6. 0.2% of the weight of the salted fur is added as a soaking agent FRUCTY C and 0.12% as a degreasing agent FRUCTYFB. The main soaking process is carried out. During the main soaking process, the drum is rotated at 5 rpm for 180 minutes, then rotated for 10 minutes every hour, and stopped for 50 minutes. The fur is removed from the drum the next morning. The main soaking time is 16 hours.

[0181] (3) After soaking in water, the fur is placed into a rotating drum, and then water at 24°C is added. The amount of water added is 200% of the weight of the salted fur. 0.2% of the weight of the salted fur is added as fructy LH liming agent, 3.5% of the weight of the salted fur is added as lime, 0.8% of the weight of the salted fur is added as sodium hydrosulfide, and 0.5% of the weight of the salted fur is added as sodium sulfide. The liming process is carried out. During the liming process, the drum is rotated at 5 rpm for 20 minutes per hour, and then stopped for 40 minutes. The next morning (16 hours), the drum skin is washed out with water. The fur is then separated into layers. The first layer is weighed and sent to the deliming process, while the second layer is collected and stored in the warehouse for sale.

[0182] (4) Place the top-grain fur into a rotating drum, then add water at 32°C, the amount of water being 100% of the weight of the salted fur. Then add 1.2% of the weight of the salted fur's deliming agent KAISTER BK and 0.1% of the weight of the salted fur's degreasing agent FRUCTYFB for deliming for 60 minutes. The drum rotates at 5 rpm during the deliming process. After deliming, add 0.6% of the weight of the salted fur's softening enzyme KORUTA SO to the reaction system, adjust the pH to 8.2-8.5, and soften for 120 minutes at 5 rpm. After softening, wash the fur with drained water to obtain the delimed and softened fur.

[0183] (5) Place the de-ashed and softened fur into a rotating drum, then add water at 22°C, the amount of water being 70% of the weight of the salted fur, and add salt accounting for 7% of the weight of the salted fur. Rotate at 5 rpm for 30 minutes. Then, add formic acid in two batches at 15-minute intervals, the total mass of formic acid being 0.7% of the weight of the salted fur. After the formic acid is added, rotate at 5 rpm for 30 minutes. After reacting for 45 minutes after the first addition of formic acid, add sulfuric acid in three batches at 15-minute intervals, the total mass of sulfuric acid being 1.0% of the weight of the salted fur. After the sulfuric acid is added, adjust the pH to 2.8 and rotate at 5 rpm for 120 minutes. After reacting for 165 minutes after the first addition of sulfuric acid, the fur pickling process is complete.

[0184] (6) After the pickling is completed, the pickled fur is obtained. Then, 3% of the weight of the pickled fur is salted and treated with chromium powder at 5 rpm for 60 min. Then, 3.5% of the weight of the salted fur is added and treated with chromium powder at 5 rpm for 60 min. Then, 0.5% of the weight of the salted fur is added and treated with magnesia at 5 rpm for 300 min. Finally, 100% of the weight of the salted fur is added and treated with magnesia at 5 rpm for 120 min at 65°C. After the reaction is completed, the drum is stopped and left overnight (16 h) to complete the tanning step. The fur is removed from the drum and aged to obtain leather (wet blue leather).

[0185] The soaking agent, degreasing agent, liming agent, deliming agent, and softening enzyme are FRUCTY C, FRUCTYFB, FRUCTYLH, KAISTER BK, and KORUTA SO, respectively, produced by Qihe Lihou Chemical Co., Ltd. FRUCTY C's main components are fatty alcohol polyoxyethylene ether surfactants and sodium thiram bactericide, with an effective content of 40% by mass. FRUCTY FB's main components are fatty alcohol polyoxyethylene ether and isomeric alcohol polyoxyethylene ether surfactants, with an effective content of 40% by mass. FRUCTY LH's main component is an aqueous solution of alcoholic amines, with an effective content of 40% by mass. KAISTER BK's main component is an organic carboxylic acid, and KORUTA SO's main components are trypsin and sodium sulfate.

[0186] Table 2. Leather Process from Soaking to Tanning

[0187]

[0188]

[0189] Note: Temperature conditions not specified in the table are for room temperature fermentation. For conditions where pH is not specified, no pH adjustment is necessary. The fermentation broth in Table 2 refers to EM (Effective Microorganisms) fermentation broth.

[0190] Comparative Example 2

[0191] The leather-making method is the same as in Example 6, except that a commercially available EM bacterial solution is used instead of the EM stock solution in Example 5. The commercially available EM bacterial solution is sourced from Zhengzhou Yuqifu Agricultural Technology Co., Ltd.

[0192] Application Example 2

[0193] 1. In Example 6, Comparative Example 1 and Comparative Example 2, the meat was removed by pre-soaking in water and then weighed.

[0194] The fur prepared using the process in Comparative Example 1 weighed 14326 kg, the fur prepared using the process in Comparative Example 2 weighed 15280 kg, and the fur prepared using the process in Example 8 weighed 16100 kg. This indicates that the EM fermentation liquid, when used for soaking leather in water, has excellent wetting, penetration, and moisturizing effects, thus increasing the water content of the fur and making it more conducive to subsequent processes. The EM fermentation liquid prepared from the EM stock solution provided by this invention has a significantly better effect on fur soaking than commercially available EM fermentation liquid prepared from EM stock solution.

[0195] 2. Samples of pre-soaked and fleshed leather, main-soaked leather, limed leather, tanned leather, and corresponding wastewater were retained for testing. Samples of leather and wastewater from each process are as follows: Figures 1-14 As shown.

[0196] in Figure 1 This is the fur obtained after pre-soaking in water and removing the flesh, as in Comparative Example 1. Figure 2 The fur obtained after pre-soaking in water and removing the flesh in Example 8; Figure 3 The fur obtained after soaking in water in Comparative Example 1; Figure 4 The fur obtained after soaking in water in Example 8; Figure 5 The fur obtained after soaking in ash in Comparative Example 1; Figure 6 The fur obtained after ash soaking in Example 8; Figure 7 The blue wet leather prepared by the method in Comparative Example 1: Figure 8 The blue wet leather was prepared by the method in Example 8. Figure 9 The waste liquid before pre-soaking in the preparation process of Example 8 and Comparative Example 1 refers to a water sample taken after the material has been pre-soaked in water and the drum has been running for 5 to 10 minutes to completely dissolve and homogenize the material. Figure 10 The waste liquid after pre-soaking in water in the preparation process of Example 8 and Comparative Example 1; Figure 11 The waste liquid before the main immersion in the preparation process of Example 8 and Comparative Example 1 refers to a water sample taken after the material for the main immersion has been added and the drum has been running for 5 to 10 minutes to completely dissolve and homogenize the material. Figure 12 The waste liquid after the main immersion in water during the preparation process of Example 8 and Comparative Example 1; Figure 13 The waste liquid after liming in the preparation process of Example 8 and Comparative Example 1; Figure 14 The waste liquid after tanning in the preparation process of Example 8 and Comparative Example 1.

[0197] 3. The pH value, solid content, COD, and ammonia nitrogen concentration of the waste liquid collected from each process in Example 8 and Comparative Examples 1 and 2 were tested. The chromium trioxide content of the tanning waste liquid was also measured. The results are shown in Table 3. In Table 3, "normal" corresponds to the preparation process corresponding to Comparative Example 1; "commercially available EM bacteria" corresponds to the preparation process corresponding to Comparative Example 2; and "bio-based" corresponds to the preparation process corresponding to Example 6.

[0198] Table 3. Results of determination of relevant indicators in waste liquid

[0199] waste liquid sample pH value Solid content % COD (mg / L) Ammonia nitrogen (mg / L) Chromium trioxide % Before normal pre-soaking 9.95 7.05 7170 After normal pre-soaking 8.88 11.57 13584 107.07 Before pre-soaking commercially available EM bacteria in water 9.78 7.38 5495 Commercially available EM bacteria pre-soaked in water 8.80 10.88 10462 101.26 Bio-based pre-soaking 9.76 7.71 5282 Bio-based pre-soaking 8.75 10.62 9812 100.71 Before normal main immersion 13.13 2.26 7546 After normal main immersion 10.05 4.85 13210 158.12 Before soaking commercially available EM bacteria in water 12.91 2.37 5311 Commercially available EM bacteria, after soaking in water 9.96 4.59 10892 133.18 Before bio-based main immersion 12.88 2.39 4962 Bio-based main immersion after water 9.91 4.46 9485 127.10 After normal ash impregnation 13.58 6.45 25660 1049.40 Commercially available EM bacteria soaked in ash 13.58 5.77 22530 961.22 After bio-based impregnation 13.61 4.66 19260 846.12 After normal tanning 3.25 7.09 6226 0.27 Commercially available EM bacteria tanning 3.26 6.80 4684 0.23 Bio-based tanning 3.26 6.69 4528.5 0.19

[0200] Note: If the specific content is not specified in the table, it means that the relevant substance was not detected.

[0201] Table 3 shows that using bio-based EM (Effective Microorganisms) fermentation broth and commercially available EM fermentation broth for leather tanning results in lower levels of solid waste, COD, and ammonia nitrogen in the wastewater from each process compared to normal processes. The concentration of chromium trioxide in the tanning wastewater is also lower, indicating that the EM fermentation broth provides better protection for leather collagen, resulting in less collagen loss after liming. This leads to lower COD and ammonia nitrogen levels in the wastewater and also promotes the tanning effect of chromium powder on the leather, thus reducing the residual chromium trioxide in the wastewater. Compared to commercially available EM fermentation broth, the bio-based EM fermentation broth provided by this invention is more effective in reducing the levels of solid waste, COD, and ammonia nitrogen in wastewater and is also more conducive to promoting the tanning effect of chromium powder on the leather.

[0202] 4. The oil content of leather samples collected from each process in Example 6, Comparative Examples 1 and 2 was determined according to the industry standard QB / T2718-2005 "Leather Chemical Tests - Dichloromethane Extract". The results are shown in Table 4. In Table 4, "normal" corresponds to the preparation process corresponding to Comparative Example 1; "commercially available EM bacteria" corresponds to the preparation process corresponding to Comparative Example 2; and "bio-based" corresponds to the preparation process corresponding to Example 6.

[0203] Table 4 Results of oil content determination in leather samples

[0204] Leather sample Oil content % (samples taken from the same part of different hides, with several pieces of leather tested together). Unsoaked fur 4.26 Remove the meat after pre-soaking in water (normal). 3.15 Pre-soak in water and remove meat (using commercially available EM bacteria). 3.01 Pre-soaked in water and then de-fleshed (bio-based) 2.83 After immersion in water (normal). 2.91 After soaking in water (using commercially available EM bacteria) 2.79 After primary immersion in water (bio-based) 2.58 Lime soaking (normal) 1.51 Lime soaking (commercially available EM bacteria) 1.34 Lime impregnation (bio-based) 1.13 Blue wet skin (normal) 2.48 Blue wet skin (commercially available EM bacteria) 2.29 Blue wet skin (bio-based) 2.05

[0205] As shown in Table 4, when using bio-based EM fermentation liquid for leather making, the oil content in leather samples from each process is slightly lower than that of the normal process and the commercially available EM fermentation liquid leather making process, indicating that it has better penetration and degreasing effect. Moreover, the COD concentration in the waste liquid is lower than that of the normal process and the commercially available EM fermentation liquid leather making process, indicating that it has a good decomposition and consumption effect on oil and other organic matter in the wastewater. Therefore, although the amount of oil removed from the leather is slightly more than that of the normal process, the COD concentration is actually lower.

[0206] Example 7

[0207] The EM fermentation broth from Example 5 was used in the wet blue leather rewetting process and compared with the traditional leather-making process using petrochemical raw materials. The test was conducted at the application laboratory of Qihe Lihou Chemical Co., Ltd., and the test steps are shown in Table 5.

[0208] Five wet blue hides were selected, dried, and weighed a total of 52.5 kg. They were split in half along the spine, and the edges were trimmed so that the total weight of the left and right halves of the wet blue hides was 25 kg. Half of the wet blue hides were put into the drum and processed according to the following application process. The wet blue hides were purchased from Dezhou Xinglong Leather Products Co., Ltd.

[0209] Add wet blue hides to the drum, add water at 45°C (100% of the hides' weight), and then add 0.5% oxalic acid (hash rate of the hides' weight). React for 30 minutes. Next, add 0.5% formic acid (hash rate of the hides' weight of the hides) to adjust the pH to 3.4–3.6, and react for another 30 minutes. Finally, add 1.1% EM (Effective Microorganisms) fermentation broth (hash rate of the hides' weight of the hides), and react at 2–10 rpm for 180 minutes. After 180 minutes, check the degree of rewetting. If it passes, proceed to the retanning process; otherwise, continue the process.

[0210] Note: The reason for using the same wet blue leather for comparative testing is that the oil content of different leathers may vary greatly, while the oil content of the same leather in the same location may vary little.

[0211] Comparative Example 3

[0212] The other half of the blue wet skin from Example 7 was put into the drum and the application process was carried out as follows.

[0213] The wet blue hides are placed in a rotating drum, and water at 45°C (100% of the hide's weight) is added. Then, 0.5% oxalic acid (based on the hide's weight) is added, and the reaction is allowed to proceed for 30 minutes. Next, 0.5% formic acid (based on the hide's weight) is added to adjust the pH to 3.4–3.6, and the reaction is allowed to continue for 30 minutes. Finally, 0.3% of the degreasing agent FRUCTY FB and 0.8% of the rehumidifying agent FRUCTYTLA (based on the hide's weight) are added, and the reaction is carried out at 2–10 rpm for 180 minutes. After 180 minutes, the degree of rehumidification is checked. If it passes the test, the retanning process is carried out; otherwise, the drum continues to rotate.

[0214] FRUCTYFB's main components are fatty alcohol polyoxyethylene ether and isomeric alcohol polyoxyethylene ether surfactants, with an effective content of 40% by mass; FRUCTYTLA's main components are fatty amine polyoxyethylene ether and isopropanol, with an effective content of 20% by mass. FRUCTYFB and FRUCTYTLA were purchased from Qihe Lihou Chemical Co., Ltd.

[0215] Table 5. Rewetting process of wet blue leather in Example 7 and Comparative Example 3.

[0216]

[0217] Note: Temperature conditions not specified in the table are assumed to be at room temperature. If the pH value is not specified, no pH adjustment is required.

[0218] Example 8

[0219] The EM stock solution from Example 1-1 was used in the rewetting process of wet blue leather tanning, and a comparative experiment was conducted with the traditional tanning process using petrochemical raw materials. The experiment was conducted at the application laboratory of Qihe Lihou Chemical Co., Ltd., and the experimental steps are shown in Table 6.

[0220] Three wet blue hides were selected, dried, and weighed a total of 30.8 kg. They were split in half along the spine, and the edges were trimmed so that the total weight of the left and right halves of the wet blue hides was 15 kg. Half of the wet blue hides were put into the drum and processed according to the following application process. The wet blue hides were purchased from Dezhou Xinglong Leather Products Co., Ltd.

[0221] Add wet blue hides to the drum, add water at 45°C (100% of the hide's weight), and add 0.5% oxalic acid (based on the hide's weight). React for 30 minutes. Then add 0.5% formic acid (based on the hide's weight) to adjust the pH to 3.4–3.6 and react for another 30 minutes. Finally, add 1.1% EM stock solution (0.11% of the hide's weight, diluted 10 times with water before adding to the mixture). React at 2–10 rpm and 45°C for 180 minutes. After 180 minutes, check the degree of rewetting. If it passes, proceed to the retanning process; otherwise, continue the process.

[0222] Comparative Example 4

[0223] The other half of the blue wet skin from Example 8 was put into the drum and the application process was carried out as follows.

[0224] The wet blue hides are placed in a rotating drum, and water at 45°C (100% of the hide's weight) is added. Then, 0.5% oxalic acid (based on the hide's weight) is added, and the reaction is allowed to proceed for 30 minutes. Next, 0.5% formic acid (based on the hide's weight) is added to adjust the pH to 3.4–3.6, and the reaction is allowed to continue for another 30 minutes. Finally, 0.3% of the degreasing agent FRUCTYFB and 0.8% of the rehumidifying agent FRUCTYTLA (based on the hide's weight) are added, and the reaction is carried out at 2–10 rpm for 180 minutes. After 180 minutes, the degree of rehumidification is checked. If it passes the test, the retanning process is carried out; otherwise, the process continues.

[0225] The information related to FRUCTYFB and FRUCTYTLA is the same as that in comparison 2.

[0226] Table 6. Rewetting process of wet blue leather in Example 8 and Comparative Example 4.

[0227]

[0228]

[0229] Example 9

[0230] The wet blue leather rewetting process is the same as in Example 7, specifically: select 5 pieces of wet blue cowhide, dry them, with a total weight of 51.8 kg, cut them in half from the back, trim the corners so that the total weight of the left and right halves of the wet blue leather is 25 kg, put half of the wet blue leather into the drum, and carry out the process according to Example 7. The wet blue leather was purchased from Dezhou Xinglong Leather Products Co., Ltd.

[0231] Comparative Example 5

[0232] The other half of the wet blue skin from Example 9 was added to the drum and processed according to the application process of Example 9, except that the EM stock solution in the EM fermentation broth of Example 5 was replaced with commercially available EM stock solution. The commercially available EM stock solution was purchased from Zhengzhou Yuqifu Agricultural Technology Co., Ltd.

[0233] Application Example 3

[0234] Samples were taken from the leathers prepared by the processes described in Examples 7-9 and Comparative Examples 3-5, and the oil content was determined according to the industry standard QB / T2718-2005 "Leather Chemical Tests - Dichloromethane Extract". The results are shown in Table 7.

[0235] Table 7. Results of Oil and Fat Testing

[0236]

[0237] The purpose of checking the oil content of wet blue leather after tanning is to ensure that high natural oil content prevents spoilage, rancidity, and mold growth during aging and storage, thus affecting the quality of the wet blue leather. Therefore, the lower the oil content in the preparation of wet blue leather, the better. Table 7 shows that using the EM fermentation broth or EM stock solution provided by this invention in the rewetting process, instead of a degreasing agent, yields better degreasing effects than degreasing agents formulated with traditional petrochemical raw materials. This indicates that the EM fermentation broth or EM stock solution provided by this invention can be used in place of a degreasing agent in the wet blue leather rewetting process. Using the EM fermentation broth provided by this invention in the rewetting process results in better degreasing effects compared to using commercially available EM fermentation broth. This demonstrates that the EM fermentation broth provided by this invention has a greater advantage in degreasing.

[0238] Furthermore, the rehydrated blue wet skins prepared using the processes described in Examples 7-9 and Comparative Examples 3-4 were examined. The results showed that the blue wet skins prepared using the normal process (Comparative Examples 3-4) were harder, while those obtained using the bio-based EM fermentation broth or EM stock solution (Examples 7-9) were softer, had better water absorption, and a slightly astringent surface. The blue wet skins obtained using commercially available EM bacteria (Comparative Example 5) were slightly less soft than those of Examples 7-9, and had a slightly slippery surface. This indicates that the EM fermentation broth or EM stock solution provided by this invention can be used in place of a rehydration agent in the blue wet skin rehydration process, and has advantages over commercially available EM products.

[0239] Example 10

[0240] EM fermentation broth consists of the following components:

[0241] The fermentation culture broth in Example 4 was 30 kg (30%), the EM stock solution in Examples 1-2 was 2 kg (2%), and the purified water was 68 kg (68%).

[0242] The preparation method of EM bacteria fermentation broth is the same as in Example 5.

[0243] Example 11

[0244] The EM fermentation liquid from Example 10 was used in the wet blue leather rewetting process. The wet blue leather rewetting process was the same as in Example 7, specifically: five cow wet blue hides were selected, dried, and weighed a total of 52.1 kg. They were split in half from the back, and the edges were trimmed so that the total weight of the left and right halves of the wet blue hides was 25 kg. Half of the wet blue hides were put into the drum and processed according to the application process in Example 7. The wet blue hides were purchased from Dezhou Xinglong Leather Products Co., Ltd.

[0245] Comparative Example 6

[0246] The other half of the blue wet skin from Example 11 was added to the drum and processed according to the application process of Example 11, except that the EM stock solution in the EM fermentation broth of Example 10 was replaced with commercially available EM stock solution. The commercially available EM stock solution was purchased from Zhengzhou Yuqifu Agricultural Technology Co., Ltd.

[0247] Application Example 4

[0248] The leathers prepared by the processes described in Example 11 and Comparative Example 6 were sampled, and the oil content was determined in accordance with the industry standard QB / T2718-2005 "Leather Chemical Tests - Dichloromethane Extract". The results are shown in Table 8.

[0249] Table 8. Results of Oil and Fat Testing

[0250]

[0251] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. An EM (Effective Microorganisms) stock solution for use as a leather auxiliary agent, characterized in that, include: Photosynthetic bacteria, actinomycetes, yeast, complex lactic acid bacteria, and Bacillus; The bacterial activity of the photosynthetic bacteria was 1×10⁻⁶. 8 ~2×10 9 CFU / mL; the bacterial activity of the actinomycetes was 1×10⁻⁶. 8 ~1.8×10 9 CFU / mL; the activity of the yeast was 3 × 10⁻⁶. 8 ~1.2×10 9 CFU / mL; the bacterial activity of the compound lactic acid bacteria is 5×10⁻⁶. 8 ~1.7×10 9 CFU / mL; the bacterial activity of the Bacillus was 1×10⁻⁶. 8 ~7×10 8 CFU / mL; the compound lactic acid bacteria include Lactobacillus brevis, Lactobacillus bifidum, Lactobacillus plantarum, Bifidobacterium lactis, and Lactobacillus acidophilus; the Bacillus species include any one or more of Bacillus subtilis, Bacillus licheniformis, Bacillus cereus, Bacillus megaterium, Bacillus mucilaginosus, Bacillus azotocinus, Bacillus spheroidosa, and Bacillus brevis; the yeast species include any one or more of Saccharomyces cerevisiae, Saccharomyces grape juice, Candida albicans, Pasteurella multocida, Rhus oryzae, Hansenula polymorpha, and Schizosoma fissicola. The EM stock solution is prepared by adding 0.05-0.07 kg of photosynthetic bacteria, 0.02-0.04 kg of actinomycetes, 0.1-0.12 kg of yeast, 0.12-0.15 kg of compound lactic acid bacteria, and 0.01-0.03 kg of Bacillus to a molasses water culture medium for co-fermentation; the molasses water culture medium includes 100 kg of purified water and 1.5-2 kg of molasses.

2. The EM stock solution according to claim 1, characterized in that, In the compound lactic acid bacteria, the live bacteria ratio of Lactobacillus brevis, Lactobacillus bifidum, Lactobacillus plantarum, Bifidobacterium lactis, and Lactobacillus acidophilus is 0.5–1.5:0.5–1:0.5–2:1–4:1–3.

3. An EM (Effective Microorganisms) fermentation broth, characterized in that, It comprises the following components by weight percentage: 1% to 10% of the EM bacterial stock solution as described in claim 1 or 2, 10% to 70% of the fermentation broth, and the balance being water; The fermentation broth comprises the following components by mass percentage: The composition consists of 3%–15% collagen hydrolysate or leather tanning waste, 5%–15% sugar, 0.5%–1% inorganic salts, 0%–1% organic acids, and 68%–89.5% water.

4. The EM fermentation broth according to claim 3, characterized in that, The preparation method of the collagen hydrolysate includes the following steps: Tanning waste, decomposing enzyme preparation and water are mixed and then enzymatically hydrolyzed to obtain collagen hydrolysate. The mass ratio of the tanning waste to water is (1-2):(2-10); the amount of the decomposing enzyme preparation added is 1%-5% of the mass of the tanning waste. The decomposing enzyme preparation includes alkaline protease and lipase; the mass ratio of alkaline protease to lipase is (2-8):(1-2); the enzyme activity of alkaline protease is 50,000-200,000 U / g; the enzyme activity of lipase is 50,000-100,000 U / g.

5. The method for preparing the EM bacteria fermentation broth according to claim 3 or 4, characterized in that, Includes the following steps: The EM bacteria stock solution, fermentation broth and water are mixed and fermented to obtain the EM bacteria fermentation broth.

6. The application of EM bacterial solution in the preparation of leather, wherein the application includes any one or more of the following (1) to (4): the EM bacterial solution is the EM bacterial stock solution of claim 1 or 2, the EM bacterial fermentation broth of claim 3 or 4, or the EM bacterial fermentation broth prepared by the preparation method of claim 5; (1) Application in soaking fur in water; (2) Application in liming fur; (3) Application in deliming and softening fur; (4) Application in fur rehydration.

7. A method for preparing leather using EM bacterial solution as a leather auxiliary agent, characterized in that, Includes the following steps: After mixing fur, water, and EM bacterial solution, the mixture is soaked in water to obtain soaked fur. The water-soaked fur is then subjected to an ash-soaking treatment to obtain ash-soaked fur; The ash-soaked fur is layered to obtain the top layer fur; The top-grain fur is subjected to a de-ashing and softening treatment to obtain de-ashed and softened fur. The deashed and softened fur is then pickled and tanned to obtain leather. The EM bacterial solution is the EM bacterial stock solution according to claim 1 or 2, the EM bacterial fermentation broth according to claim 3 or 4, or the EM bacterial fermentation broth prepared by the preparation method according to claim 5.

8. The method according to claim 7, characterized in that, The liming process includes: mixing the soaked fur, water, lime, sodium hydrosulfide, sodium sulfide and EM bacterial solution for liming to obtain limed fur; The deashing and softening treatment includes: mixing the top layer of fur, water, deashing agent and EM bacterial solution for deashing and then softening to obtain deashed and softened fur.

9. A method for rehydrating leather, characterized in that, Includes the following steps: The fur is acidified to obtain acidified fur. The acidified fur was mixed with EM bacterial solution, and then degreased and rehydrated to obtain rehydrated fur. The EM bacterial solution is the EM bacterial stock solution according to claim 1 or 2, the EM bacterial fermentation broth according to claim 3 or 4, or the EM bacterial fermentation broth prepared by the preparation method according to claim 5.

10. The method according to any one of claims 7 to 9, characterized in that, The amount of EM bacterial solution added is 0.1% to 1.1% of the fur weight.

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