Organic matrix preparation process based on synergistic fermentation of complex microbial inoculants

Abstract

The invention belongs to the technical field of organic substrates, and particularly relates to an organic substrate preparation process based on complex microbial inoculant synergistic fermentation, which comprises the following steps: selecting agricultural wastes, livestock and poultry manure and food industry byproducts, and carrying out staged fermentation by adopting complex microorganisms such as bacillus, streptomyces, clostridium and bacteroides; the decomposition efficiency of degradation-resistant substances such as cellulose and lignin is obviously improved. By combining precise temperature control and oxygen concentration adjustment strategies, the stability of the fermentation process is enhanced, nitrogen volatilization is reduced, and the total nitrogen content is stabilized at 1.2-1.5%. Nitrogen-fixing bacteria and phosphate solubilizing bacteria are introduced in the after-ripening stage, the biological activity of the matrix is improved, the screening process ensures that the finished product is uniform in particle size and few in impurities, the content of organic matter reaches 45% or above, the pH value is stabilized at 6.5-7.5, excellent agricultural performance is achieved, and efficient resource utilization of organic waste is achieved; the problems that in the prior art, organic matter degradation is not thorough, the controllability of the fermentation process is poor, nutrient loss is serious, and the quality of a finished product is unstable are effectively solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of organic matrix, and particularly relates to a preparation process of an organic matrix based on synergistic fermentation of a composite microbial agent. BACKGROUND

[0002] In the field of agricultural production and ecological restoration, the preparation process of the organic matrix as an important component of soil improvement materials and biological fertilizers has attracted widespread attention. Traditional preparation of the organic matrix is usually carried out by using single bacterial species or natural composting. The raw materials are mainly agricultural waste or livestock manure, supplemented with a small amount of household organic waste. In the prior art, the common process includes: simply mixing raw materials such as straw and livestock manure, and then stacking, and carrying out aerobic fermentation under natural or semi-controlled conditions, and finally obtaining the finished product through drying, crushing and screening.

[0003] However, this kind of traditional method has obvious limitations, mainly including low organic matter degradation efficiency, long fermentation period, poor product stability, and serious nutrient loss. Due to the lack of effective regulation of microbial synergistic effect, temperature fluctuation, low humification degree, and serious nitrogen volatilization often occur during the fermentation process, and the fertility and biological activity of the obtained organic matrix are difficult to meet the application requirements of modern agriculture and ecological engineering. SUMMARY

[0004] The purpose of the present application is to provide a preparation process of an organic matrix based on synergistic fermentation of a composite microbial agent, which effectively improves the degradation efficiency of organic matter and the stability and functionality of the product by controlling the ratio of raw materials, introducing a composite microbial flora with complementary functions, and controlling the fermentation environmental conditions in stages, so as to solve the problems raised in the background art.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical scheme: a preparation process of an organic matrix based on synergistic fermentation of a composite microbial agent, comprising the following steps:

[0006] Raw material pretreatment: mixing agricultural waste, livestock manure and food industry by-products according to the mass ratio, wherein the agricultural waste accounts for 40% to 50%, the livestock manure accounts for 30% to 40%, and the food industry by-products account for 10% to 20%;

[0007] Primary fermentation: aerobic fermentation is carried out by using Bacillus and Streptomyces at a temperature of 50℃ to 60℃ for 10 to 15 days, so that the temperature of the stack is maintained at 50℃ to 60℃;

[0008] Secondary fermentation: sealed stacking and intermittent micro-aerobic supply, oxygen concentration is controlled below 2%, temperature is maintained at 35℃ to 40℃, anaerobic fermentation is carried out by using Clostridium and Bacteroides for 15 to 20 days;

[0009] Maturation stabilization: ventilated cultivation for 7-10 days at 25-30°C, inoculation of nitrogen-fixing and phosphorus-dissolving bacteria;

[0010] Finished product screening: removal of impurities by a vibrating screening system, with a 10 mm and 2 mm mesh size, to obtain an organic substrate with a particle size of 0.5-2 mm.

[0011] Preferably, the raw material pretreatment comprises: using a combination of mechanical crushing and physical crushing to crush the raw material to a particle size of less than 2 cm, and adjusting the moisture content to 60-70%; the crushing equipment is a hammer crusher or a shredder.

[0012] Preferably, the primary fermentation comprises: oxygen supply is achieved by forced ventilation combined with regular turning, with ventilation once every 24 hours in the early stage and once every 48 hours in the middle stage; the pH value increases from 6.0-6.5 to 7.5-8.5 during the fermentation process.

[0013] Preferably, the secondary fermentation comprises: oxygen concentration control is achieved by sealed stacking combined with intermittent micro-oxygen supply, with short-term ventilation for 30 minutes every 48 hours; temperature adjustment uses an external insulation layer to adjust the ambient temperature.

[0014] Preferably, the maturation stabilization comprises: ventilated cultivation uses a periodic ventilation mode, with ventilation for 60 minutes every 72 hours, and the height and density of the pile are adjusted to ensure uniform air penetration; when inoculating nitrogen-fixing and phosphorus-dissolving bacteria, microbial inoculants are sprayed to evenly distribute the bacterial population inside the pile.

[0015] Preferably, the finished product screening comprises: using a double-layer vibrating screen, with a 10 mm mesh size on the upper layer and a 2 mm mesh size on the lower layer; when removing impurities, combine manual screening with magnetic impurity removal technology, and use a magnetic selection device to remove metal contaminants.

[0016] Preferably, the raw material pretreatment comprises: food industry by-products include fruit and vegetable residues and bean dregs, with a mass fraction of 10-20%.

[0017] Preferably, the primary fermentation comprises: the metabolic products of Bacillus and Streptomyces make the volatile solid loss rate 35.2%, and the lignocellulose degradation rate 28.5%.

[0018] Preferably, the secondary fermentation comprises: the humic acid content increases by 27.8% in the maturation stabilization stage, and the lignocellulose degradation rate is 42.6%; the pH value decreases to 5.5-6.0 during the fermentation process, and then rises to 6.5-7.5.

[0019] Preferably, the total organic matter content of the finished organic substrate is more than 45%, the total nitrogen content is 1.2% to 1.5%, the total phosphorus content is 0.5% to 0.8%, and the total potassium content is 1.0% to 1.3%; the pH value is stable at 6.5 to 7.5, and the conductivity is less than 2.0 mS / cm.

[0020] The technical effects and advantages of the present application: the organic substrate preparation process based on composite microbial agent synergistic fermentation provided by the present application has the following advantages compared with the prior art:

[0021] The present application selects agricultural waste, livestock and poultry manure and food industry by-products, and adopts composite microbial flora such as bacillus, streptomyces, clostridium and bacteroides for stage-by-stage fermentation, which significantly improves the decomposition efficiency of cellulose, lignin and other difficult-to-degrade substances. Combined with precise temperature control and oxygen concentration regulation strategy, the stability of the fermentation process is enhanced, and the nitrogen volatilization is reduced, and the total nitrogen content is stable at 1.2% to 1.5%. The introduction of nitrogen-fixing bacteria and phosphorus-solubilizing bacteria in the maturation stage improves the biological activity of the substrate, and the screening process ensures that the finished product has uniform particle size, less impurities, organic matter content of more than 45%, pH value stable at 6.5 to 7.5, and excellent agricultural performance, realizing efficient resource utilization of organic waste; effectively solving the problems of incomplete degradation of organic matter, poor controllability of fermentation process, serious nutrient loss and unstable quality of finished product in the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The flow chart of the organic substrate preparation process based on composite microbial agent synergistic fermentation of the present application. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. The specific embodiments described herein are only used to explain the present application, and are not used to limit the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0024] Embodiment one

[0025] The present application provides an organic substrate preparation process based on composite microbial agent synergistic fermentation as shown in Figure 1 The present application provides an organic substrate preparation process based on composite microbial agent synergistic fermentation as shown in

[0026] Firstly, in the raw material pretreatment stage, agricultural waste (such as straw, livestock and poultry manure), landscaping waste (such as fallen leaves, pruned branches) and food industry by-products (such as vegetable residues, bean dregs) are mixed in a certain proportion, and the carbon-nitrogen ratio is adjusted to a suitable range. Subsequently, a combination of mechanical crushing and physical breaking is used to reduce the particle size of the material to a suitable level for fermentation, and an appropriate amount of water is added to maintain a proper moisture content. After pretreatment, the raw material enters the first fermentation stage, where high-temperature resistant aerobic bacteria (such as Bacillus and Streptomyces) are used to carry out preliminary degradation, causing the cleavage of macromolecular organic matter and the release of some soluble nutrients.

[0027] After the completion of the first fermentation, the material enters the second fermentation stage, where anaerobic bacteria (such as Clostridium and Bacteroides) are introduced to further degrade the remaining complex organic matter in a micro-aerobic or anaerobic environment, while promoting the generation of humic acid substances. The key to this stage is to regulate the environmental conditions to allow aerobic and anaerobic bacteria to function in an orderly manner, thereby improving the overall degradation efficiency.

[0028] Finally, in the post-ripening stabilization stage, the material after the second fermentation is placed in a well-ventilated environment to allow it to oxidize slowly and stabilize, while adding beneficial microorganisms such as nitrogen-fixing bacteria and phosphorus-solubilizing bacteria to enhance the nutrient release capacity of the finished product.

[0029] After the completion of fermentation and stabilization, the material is screened to remove incompletely degraded large particle impurities, obtaining the final organic substrate product. This process not only effectively improves the resource utilization rate of organic waste, but also enhances the fertility and ecological adaptability of the obtained substrate, providing high-quality soil improvement materials for subsequent agricultural production applications.

[0030] In this embodiment, the selected raw materials need to meet certain carbon-nitrogen ratio (C / N) requirements, controlled between 25:1 and 30:1. Specifically, agricultural waste (such as corn straw, wheat straw), livestock and poultry manure (such as cow dung, chicken manure) and food industry by-products (such as bean dregs, bean dregs) are used as the main raw materials, and mixed in the following mass proportions: agricultural waste accounts for 40%~50%, livestock and poultry manure accounts for 30%~40%, and food industry by-products accounts for 10%~20%.

[0031] Among them, agricultural waste mainly provides abundant cellulose and hemicellulose components, livestock and poultry manure is rich in nitrogen source and trace elements, and food industry by-products supplement easily degradable sugars and proteins, so that the raw material system has a relatively balanced nutrient structure.

[0032] After the raw material ratio is completed, because the original material often contains large particles, which is not conducive to the uniform adhesion and degradation of microorganisms, it is necessary to use mechanical crushing equipment (such as hammer crusher or shredder) to crush it into small particles with a particle size of less than 2 centimeters. In addition, for straw materials with high lignification, physical crushing techniques such as steam explosion or ultrasonic assisted crushing can also be used to destroy their dense structure and increase the accessible area of microorganisms in the subsequent fermentation process. The crushed material should be kept loose to facilitate air circulation and uniform distribution of moisture.

[0033] After the crushing operation is completed, the material needs to be adjusted for moisture to reach the appropriate moisture content range (60% to 70%). If the initial raw material moisture content is too low, it needs to be sprayed with an appropriate amount of water or recycled fermentation liquid for water replenishment; otherwise, if the moisture content is too high, it can be adjusted by drying or adding dry additives such as sawdust and rice husk.

[0034] After the above pretreatment steps, the raw material has the appropriate carbon-nitrogen ratio, particle size and moisture content, which lays a good foundation for the subsequent primary fermentation. The technical effects of this stage mainly lie in three aspects: first, through reasonable raw material ratio, the carbon source and nitrogen source are balanced to provide sufficient nutrition for microbial growth; second, the use of crushing and breaking means increases the surface area of the material and improves the efficiency of microbial adhesion; third, through moisture adjustment, the fermentation environment is optimized to ensure that the microorganisms can quickly start metabolic activity. These measures work together to make the raw material more easily degraded by the subsequent fermentation bacteria, thereby improving the overall process efficiency.

[0035] After the raw material pretreatment is completed, the material enters the primary fermentation stage. The core goal of this stage is to use aerobic bacteria to efficiently degrade the organic matter in the raw material under suitable environmental conditions, causing it to be preliminarily decomposed and releasing soluble nutrients.

[0036] The main bacteria used in this example are Bacillus and Streptomyces, which have strong cellulase, protease and amylase activity, can rapidly decompose complex organic matter in the raw material, and produce a large amount of heat in the metabolic process, causing the temperature of the pile to rise above 50°C, thereby promoting the inactivation of pathogenic bacteria and weed seeds.

[0037] During the fermentation process, temperature control is one of the key factors affecting microbial activity. In this example, the internal temperature of the pile is monitored regularly, and turning measures are taken to maintain the appropriate fermentation temperature.

[0038] During the initial stage of fermentation, the pile temperature rapidly rises to 50-60°C and remains within this range for 5-7 days to ensure the effective propagation and metabolism of thermophilic microorganisms. When the temperature exceeds 65°C, the oxygen supply should be appropriately reduced or the moisture supply should be increased to prevent excessive temperature rise, which can lead to a decrease in microbial activity. Secondly, oxygen supply is the basis for ensuring the normal metabolism of aerobic bacteria. In this embodiment, forced ventilation combined with regular turning of the pile is used to maintain the oxygen concentration in the pile above 10% to support the aerobic respiration of microorganisms. The ventilation frequency is adjusted according to the temperature change of the pile, generally once every 24 hours in the initial stage, once every 48 hours in the middle stage, and the ventilation frequency can be gradually reduced in the later stage.

[0039] During the primary fermentation process, the pH value in the pile fluctuates as organic matter is degraded. In the initial stage, due to the accumulation of organic acids produced by microbial metabolism, the pH value may drop to 6.0-6.5. However, with the release of ammonia nitrogen, the pH value gradually rises to 7.5-8.5. In this embodiment, the pH value is regularly detected, and lime powder or calcium carbonate adjuster is added as necessary to maintain a suitable environment for microbial growth.

[0040] In terms of fermentation time, the primary fermentation stage usually lasts for 10-15 days. During this period, the color of the material gradually changes from the initial yellow-brown to dark brown, the volume significantly decreases, and a typical rotten smell is emitted. Through regular sampling analysis, it can be observed that the volatile solid content significantly decreases, indicating that organic matter has been effectively degraded. In addition, the microbial community structure inside the pile is also changing, with an increase in the abundance of aerobic bacteria and a significant reduction in the number of potential pathogenic microorganisms.

[0041] After the completion of the primary fermentation, the material enters the secondary fermentation stage. The main goal of this stage is to utilize anaerobic bacteria to further degrade residual complex organic matter and promote the formation of humic substances, thereby improving the stability and nutrient release capacity of the organic substrate. Compared to the aerobic bacteria in the primary fermentation stage, anaerobic bacteria (such as Clostridium and Bacteroides) can survive in low-oxygen or anaerobic environments and degrade lignocellulose, hemicellulose, and some difficult-to-degrade aromatic compounds through anaerobic metabolic pathways.

[0042] During the secondary fermentation process, the oxygen concentration, temperature, and pH value need to be controlled. Since anaerobic bacteria cannot survive in a high-oxygen environment, this embodiment uses a sealed stacking method combined with intermittent micro-oxygen supply to maintain the oxygen concentration in the stack below 2%. Specifically, after the first-stage fermentation is completed, the material is transferred to a closed fermentation bin and covered with a plastic film with low air permeability to reduce the infiltration of external oxygen. At the same time, short-term micro-oxygen ventilation is performed every 48 hours during the fermentation process (not more than 30 minutes each time) to avoid the accumulation of harmful gases such as hydrogen sulfide in a completely anaerobic environment, while promoting the oxidative conversion of some intermediate metabolites.

[0043] During the initial stage of secondary fermentation, the heat accumulated during the first-stage fermentation has not yet been completely dissipated, and the stack temperature remains between 45°C and 55°C. As the fermentation process progresses, the metabolic rate gradually slows down, and the temperature slowly drops to 35°C to 40°C.

[0044] In addition, the change in pH value has a direct impact on the metabolic efficiency of anaerobic bacteria. During the secondary fermentation process, due to the further decomposition of organic acids, the pH value in the stack will experience a process of first decreasing and then increasing. In the initial stage, the pH value may drop to 5.5 to 6.0, which is caused by the accumulation of short-chain fatty acids produced during the degradation process of anaerobic bacteria. However, with the release of ammonia nitrogen and the conversion of some organic acids, the pH value gradually rises to 6.5 to 7.5, which is beneficial to the stable growth of anaerobic bacteria. To prevent drastic fluctuations in pH value, this embodiment regularly detects the acidity and alkalinity inside the stack and adds an appropriate amount of calcium carbonate or phosphate buffer for adjustment when necessary.

[0045] In terms of fermentation time, the secondary fermentation stage usually lasts 15 to 20 days. During this period, the color of the material further darkens, gradually changing from dark brown to black brown, and the texture becomes more soft and has obvious signs of decomposition. Through regular sampling analysis, it can be observed that the lignocellulose content is significantly reduced, while the content of humic acid substances is significantly increased, indicating that the process of deep degradation and stabilization of organic matter is progressing smoothly. In addition, the microbial community structure inside the stack also changes, with the abundance of anaerobic bacteria increasing and the number of some aerobic bacteria gradually decreasing, which indicates that the fermentation environment has changed from aerobic to anaerobic, consistent with the expected process design.

[0046] After the completion of the secondary fermentation, the material enters the post-ripening stabilization stage. The main goal of this stage is to further stabilize the organic substrate and enhance its nutrient release capacity and microbial activity by optimizing environmental conditions. Although most of the easily and hardly degradable organic matter has been degraded through primary and secondary fermentation, there are still a small amount of active microorganisms inside the pile, and their metabolic activities continue. Therefore, this embodiment uses ventilation control, temperature regulation, and microbial inoculation to ensure that the organic substrate is fully matured and its biological activity and stability are improved.

[0047] In terms of environmental regulation, this embodiment adopts a progressive ventilation management strategy to promote the slow oxidation of the organic substrate and reduce energy consumption. Compared with the micro-aerobic environment in the secondary fermentation stage, the post-ripening stabilization stage requires a moderate increase in oxygen supply to maintain a low-oxygen to moderate-oxygen state (oxygen concentration of about 5% to 8%) inside the pile.

[0048] Specifically, this embodiment adopts a periodic ventilation mode, i.e., ventilation is performed every 72 hours, and each lasts for 60 minutes, to ensure gas exchange inside the pile while avoiding excessive ventilation that leads to loss of organic matter. In addition, this embodiment adjusts the height and density of the pile to ensure that air can uniformly penetrate into the pile, thereby ensuring that the stabilization process of the entire material system proceeds synchronously.

[0049] At the end of the secondary fermentation, the temperature of the pile has gradually decreased from 50°C to 55°C at the peak to 35°C to 40°C. In order to maintain the metabolic activity of microorganisms while avoiding nutrient loss due to excessive heating, this embodiment uses natural ventilation combined with shading and insulation to stabilize the temperature of the pile at 25°C to 30°C.

[0050] In terms of microbial inoculation, this embodiment introduces nitrogen-fixing bacteria (such as rhizobium) and phosphorus-dissolving bacteria (such as bacillus), to enhance the nutrient release capacity of the organic substrate. These functional bacterial groups can continue to play a role in the post-ripening stabilization stage, converting nitrogen in the soil into ammonium nitrogen that can be absorbed by plants, and converting insoluble phosphorus into soluble phosphate, thereby improving the fertility of the substrate. Specifically, this embodiment sprays microbial inoculants during ventilation to ensure uniform distribution of the bacterial groups inside the pile. The inoculated material is cultured at 25°C to 30°C for 7 to 10 days to ensure that the functional bacterial groups are fully colonized and a stable microbial ecosystem is established.

[0051] After the post-maturation stabilization treatment, the physicochemical properties of the organic substrate changed significantly. First, the pH value tended to be stable, maintaining between 6.5 and 7.5, indicating that the acid-base balance inside the pile had reached an ideal state. Second, the organic matter content decreased slightly, but the proportion of humic acid substances increased significantly, indicating that the mineralization and humification process of organic matter had been completed. In addition, through regular detection of microbial activity, it was found that the number of nitrogen-fixing bacteria and phosphorus-dissolving bacteria was steadily increasing, indicating that the functional bacterial flora had successfully colonized the substrate.

[0052] After completing the post-maturation stabilization, the organic substrate enters the final product screening stage. The main task of this stage is to remove incompletely degraded impurities, ensure the uniformity and applicability of the finished product substrate, and conduct quality assessment to verify whether it meets the agricultural application standards. This embodiment uses a vibrating screening system, combined with manual screening and magnetic impurity removal technology, to efficiently separate coarse particles, metal impurities, and other non-degradable substances.

[0053] First, the screening equipment uses a double-layer vibrating screen, with the upper layer screen aperture set to 10 millimeters, used to remove large-diameter undegraded fibers, tree bark fragments, plastic debris, and other impurities; the lower layer screen aperture is 2 millimeters, used to further screen small particles to ensure the uniform particle size of the finished product substrate. After screening, the particle size of the substrate is controlled within the range of 0.5 to 2 millimeters, which ensures good permeability and avoids the problem of hardening caused by excessively fine particles. In addition, to prevent metal impurities from mixing into the finished product, this embodiment adds a magnetic separation device during screening to screen for metal contaminants, ensuring the safety of the final product.

[0054] After screening is completed, the finished product substrate is subjected to quality assessment, focusing on detecting key indicators such as nutrient content, pH value, electrical conductivity (EC value), and microbial activity. The test results of this embodiment show that the total organic matter content of the finished product substrate reaches more than 45%, the total nitrogen content is 1.2% to 1.5%, the total phosphorus content is 0.5% to 0.8%, and the total potassium content is 1.0% to 1.3%, all of which meet the high-quality organic fertilizer standards. In addition, the pH value is stable between 6.5 and 7.5, and the EC value is less than 2.0 mS / cm, indicating that the salt content of the substrate is moderate and will not negatively affect crop growth. The microbial activity test results show that the survival rate of functional bacterial flora (such as nitrogen-fixing bacteria and phosphorus-dissolving bacteria) reaches more than 10 6 CFU / g, indicating that the substrate has strong biological activity and helps to improve the soil microbial environment.

[0055] After screening and quality evaluation, the finished substrate can be used for various agricultural purposes such as soil improvement, seedling substrate, potting substrate, and organic fertilizer production. The organic substrate provided in this embodiment has good water retention, air permeability, and nutrient release capacity, and is suitable for planting various crops, especially showing excellent application potential in facility agriculture and horticultural cultivation. Through strict screening control and quality detection, this embodiment ensures the stability and functionality of the final product, providing a reliable technical path for the resource utilization of organic waste.

[0056] To verify the actual effect of the organic substrate preparation process based on composite microbial agent synergistic fermentation provided in this embodiment, a plurality of comparative experiments are conducted to compare and analyze different microbial population combinations, fermentation parameters, and raw material ratios. Through statistical comparison of the experimental data of each group, the comprehensive performance of the process in terms of organic matter degradation efficiency, nutrient retention capacity, and microbial activity is evaluated.

[0057] Comparative Example 1: Single microbial population fermentation vs. composite microbial population synergistic fermentation

[0058] In the first comparative experiment, the control group only uses a single microbial population (such as Bacillus or Clostridium) for fermentation, while the experimental group uses the composite microbial population synergistic fermentation process described in this embodiment (including Bacillus, Streptomyces, Clostridium, and Bacteroides, etc.). Both groups use the same raw material ratio (40% agricultural waste, 40% livestock and poultry manure, and 20% food industry by-products) and fermentation conditions (10 days of primary fermentation and 20 days of secondary fermentation), and sample analysis is performed at the same time nodes.

[0059] The experimental data shows that the organic matter degradation rate of the experimental group is about 18.5% higher than that of the control group. In the primary fermentation stage, the volatile solids (VS) loss rate of the experimental group is 35.2%, while that of the control group is only 29.7%. In the secondary fermentation stage, the lignocellulose degradation rate of the experimental group reaches 42.6%, while that of the control group is only 34.1%. In addition, the humic acid content of the experimental group increases by 27.8% in the post-maturation stabilization stage, while that of the control group only increases by 19.3%. These data indicate that the synergistic effect of the composite microbial population can more efficiently degrade complex organic matter and promote the formation of humic substances, thereby improving the stability and fertility of the organic substrate.

[0060] Comparative Example 2: Effect of different carbon-nitrogen ratios on fermentation efficiency

[0061] In the second comparative example experiment, the effect of different carbon-nitrogen ratios (C / N) on fermentation efficiency was studied. The control group used the traditionally recommended carbon-nitrogen ratio of 20:1, while the experimental group used the optimized carbon-nitrogen ratio (25:1 to 30:1) of the present embodiment. Both groups used the same microbial flora combination (Bacillus, Streptomyces, Clostridium, and Bacteroides) and fermentation conditions, and samples were taken and analyzed at the same time nodes.

[0062] The experimental results showed that the fermentation rate and nutrient retention rate of the experimental group were better than those of the control group. In the primary fermentation stage, the peak temperature of the experimental group reached 58°C, higher than the 53°C of the control group, and the high-temperature period lasted for 2-3 days longer, indicating that the microbial metabolism was more active. In addition, in the secondary fermentation stage, the loss rate of ammonia nitrogen (NH4 + -N) of the experimental group was only 12.4%, while that of the control group reached 18.7%. This shows that a higher carbon-nitrogen ratio helps to reduce nitrogen loss and improve nutrient retention capacity. In the post-ripening stabilization stage, the total nitrogen content of the experimental group was 1.42%, while that of the control group was only 1.25%, further verifying the positive effect of optimizing the carbon-nitrogen ratio on nutrient retention.

[0063] Comparative Example Three: Effect of Different Raw Material Ratios on Substrate Performance

[0064] In the third comparative example experiment, the effect of different raw material ratios on the performance of the final organic substrate was studied. The control group used the traditional agricultural waste (60%) and livestock and poultry manure (40%) ratio, while the experimental group used the recommended agricultural waste (40%-50%), livestock and poultry manure (30%-40%), and food industry by-products (10%-20%) ratio of the present embodiment. Both groups used the same microbial flora combination and fermentation conditions, and the quality was evaluated after the finished product was screened.

[0065] The experimental data showed that the organic matter content of the experimental group reached 46.3%, which was 4.8 percentage points higher than the 41.5% of the control group. In addition, the total phosphorus content of the experimental group was 0.68%, and the total potassium content was 1.25%, both of which were better than the 0.52% and 1.08% of the control group. In terms of microbial activity, the survival rate of functional flora (such as nitrogen-fixing bacteria and phosphorus-solubilizing bacteria) of the experimental group reached 1.2×10 6 CFU / g, while that of the control group was only 8.5×10 5 CFU / g. These results show that a reasonable raw material ratio not only improves the nutrient content of the organic substrate, but also enhances its biological activity, making it more suitable for agricultural production.

[0066] Through comprehensive analysis of the data of the above three comparative examples, it can be seen that the composite microbial agent synergistic fermentation process provided in the embodiment is superior to the traditional method in many aspects. First, the synergistic effect of the composite microbial flora can significantly improve the degradation efficiency of organic matter, increasing the loss rate of volatile solids and lignocellulose by 18.5% and 25%, respectively. Second, the optimized carbon-nitrogen ratio (25:1 to 30:1) can effectively reduce nitrogen loss and improve nutrient retention, increasing total nitrogen content by 13.6%. In addition, reasonable raw material ratio (agricultural waste 40%-50%, livestock and poultry manure 30%-40%, food industry by-products 10%-20%) not only increases the organic matter content, but also enhances the microbial activity, making the survival rate of functional flora increase by more than 40%.

[0067] In summary, the organic substrate preparation process based on composite microbial agent synergistic fermentation provided in the embodiment has significant advantages in organic matter degradation, nutrient retention, and microbial activity. By scientifically regulating the combination of microbial flora, carbon-nitrogen ratio, and raw material ratio, this process can effectively improve the quality of organic substrate, making it more suitable for agricultural production and soil improvement, and providing a feasible technical solution for the resource utilization of organic waste.

[0068] Finally, it should be noted that: the above only for the preferred embodiments of the present application, and not for the limitation of the present application, although the present application is described in detail with reference to the foregoing embodiments, for those skilled in the art, it still can modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features, any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application, should be included in the protection scope of the present application.

Claims

1. A process for preparing an organic substrate based on synergistic fermentation of a complex bacterial agent, characterized in that, The method comprises the following steps: Raw material pretreatment: mixing agricultural waste, livestock and poultry manure and food industry by-products according to the mass ratio, the agricultural waste accounts for 40%-50%, the livestock and poultry manure accounts for 30%-40%, and the food industry by-products accounts for 10%-20%; Primary fermentation: aerobic fermentation is carried out by using Bacillus and Streptomyces at a temperature of 50-60 DEG C for 10-15 days, so that the temperature of the heap is maintained at 50-60 DEG C; Secondary fermentation: sealed stacking and intermittent micro-oxygen supply, the oxygen concentration is controlled below 2%, the temperature is maintained at 35-40 DEG C, anaerobic fermentation is carried out by using Clostridium and Bacteroides for 15-20 days; Post-mature stabilization: ventilation culture at 25-30 DEG C for 7-10 days, inoculating nitrogen-fixing bacteria and phosphorus-solubilizing bacteria; Finished product screening: removing impurities through a vibrating screening system, the screen mesh aperture is 10 mm and 2 mm, and the organic substrate with a particle size of 0.5-2 mm is obtained.

2. The process for preparing an organic substrate based on the synergistic fermentation of a complex bacterial agent according to claim 1, characterized in that, The raw material pretreatment comprises: The raw material is crushed to a particle size less than 2 cm by using a mechanical crushing and physical crushing combination mode, and the moisture content is adjusted to 60%-70%; The crushing equipment is a hammer crusher or a shredder.

3. The process for preparing an organic substrate based on the synergic fermentation of a complex bacterial agent according to claim 1, characterized in that, The primary fermentation comprises: The oxygen supply is achieved by forced ventilation combined with regular turning over, the ventilation is carried out once every 24 hours in the early stage and once every 48 hours in the middle stage; The pH value is increased from 6.0-6.5 to 7.5-8.5 during the fermentation process.

4. The process for preparing an organic substrate based on the synergic fermentation of a complex bacterial agent according to claim 1, characterized in that, The secondary fermentation comprises: The oxygen concentration control is achieved by sealed stacking combined with intermittent micro-oxygen supply, the ventilation is carried out for 30 minutes every 48 hours for a short time; The temperature adjustment is achieved by using an external heat preservation layer to adjust the environmental temperature.

5. The process for preparing an organic substrate based on the synergic fermentation of a complex bacterial agent according to claim 1, characterized in that, The post-mature stabilization comprises: The ventilation culture adopts a periodic ventilation mode, the ventilation is carried out for 60 minutes every 72 hours, and the height and density of the heap are adjusted to ensure that the air is uniformly penetrated; When the nitrogen-fixing bacteria and phosphorus-solubilizing bacteria are inoculated, the microbial inoculum is sprayed to uniformly distribute the bacterial flora in the interior of the heap.

6. The process for preparing an organic substrate based on the synergic fermentation of a complex bacterial agent according to claim 1, characterized in that, The finished product screening comprises: A double-layer vibrating screening is used, the upper layer screen mesh aperture is 10 mm, and the lower layer screen mesh aperture is 2 mm; The impurities are removed by combining manual screening with magnetic impurity removal technology, and a magnetic selection device is used to remove metal contaminants.

7. The process for preparing an organic substrate based on the synergic fermentation of a complex bacterial agent according to claim 1, characterized in that, The raw material pretreatment comprises: The food industry by-products include fruit and vegetable residues and bean dregs, and the mass ratio is 10%-20%. 8.The process for preparing organic substrate based on synergic fermentation of composite bacterial agent according to claim 1, characterized in that, The primary fermentation comprises: The metabolic products of Bacillus and Streptomyces make the volatile solid loss rate 35.2%, and the lignocellulose degradation rate 28.5%. 9.The process for preparing organic substrate based on synergic fermentation of composite bacterial agent according to claim 1, characterized in that, The secondary fermentation comprises: The humic acid content is increased by 27.8% in the post-mature stabilization stage, and the lignocellulose degradation rate is 42.6%; the pH value is first decreased to 5.5-6.0 during the fermentation process, and then increased to 6.5-7.

5.

10. The process for preparing an organic substrate based on the synergic fermentation of a complex bacterial agent according to claim 1, characterized in that, The total organic matter content of the finished product organic substrate is more than 45%, the total nitrogen content is 1.2%-1.5%, the total phosphorus content is 0.5%-0.8%, and the total potassium content is 1.0%-1.3%; the pH value is stable at 6.5-7.5, and the conductivity is lower than 2.0 mS / cm.

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