An aerobic composting method for wood ear mushroom residue

Abstract

A method for aerobic composting of Auricularia auricula-judae mushroom residue, relating to the field of Auricularia auricula-judae mushroom residue treatment, is disclosed to address the problems of slow temperature rise, insufficient composting, and unstable product quality associated with existing methods. The method comprises: 1. Mixing Auricularia auricula-judae mushroom residue, cow dung, and chicken dung to obtain a mixture; 2. Inoculating the mixture with lignocellulose-degrading bacteria; 3. Performing aerobic composting fermentation on the mixture after inoculation with lignocellulose-degrading bacteria, employing a staged intermittent composting process. This method promotes the composting and lignocellulose degradation of Auricularia auricula-judae mushroom residue, significantly increasing the composting rate, promoting the biotransformation of Auricularia auricula-judae mushroom residue, improving composting efficiency, and resulting in higher product quality stability. This invention is for the aerobic composting of Auricularia auricula-judae mushroom residue.

Description

Technical Field

[0001] This invention relates to the field of mushroom residue treatment, specifically to an aerobic composting method for mushroom residue. Background Technology

[0002] Black fungus is one of the most important edible fungi in my country, and its large-scale production generates a large amount of fungal residue. This residue, typically formed from sawdust, wheat bran, and other substrate materials after fungal cultivation, still contains high levels of organic matter, cellulose, hemicellulose, lignin, and certain amounts of nutrients such as nitrogen, phosphorus, and potassium, giving it high resource utilization value. Proper treatment and high-value utilization of this residue can not only reduce the waste disposal pressure of the edible fungi industry but also achieve the recycling of agricultural organic waste, resulting in significant ecological, economic, and social benefits.

[0003] However, the lignocellulose content in mushroom residue is high and its structure is complex. Directly returning it to the field or natural composting results in slow decomposition, long maturation periods, poor stability, and easy nutrient waste. Furthermore, improper disposal of large quantities of residue can pose environmental pollution risks, hindering the green and sustainable development of the edible fungi industry. While existing composting technologies can be used for organic waste treatment, they generally suffer from slow temperature rise, insufficient maturation, and unstable product quality when applied to high-lignocellulose raw materials like mushroom residue, making it difficult to fully realize the resource utilization potential of the residue. Summary of the Invention

[0004] The present invention aims to address the problems of slow temperature rise, insufficient composting, and unstable product quality in existing methods for processing Auricularia auricula-judae residue, and to provide a highly efficient aerobic composting method for Auricularia auricula-judae residue.

[0005] The present invention provides a method for aerobic composting of wood ear mushroom residue, comprising the following steps:

[0006] Step 1: Mix the wood ear mushroom residue, cow dung, and chicken dung to obtain a mixture;

[0007] Step 2: Inoculate the mixture obtained in Step 1 with lignocellulose-degrading bacteria and mix thoroughly; the lignocellulose-degrading bacteria is Geobacillus sp. DKC0303, which is deposited at Guangdong Microbial Culture Collection Center on November 12, 2024, with accession number GDMCC No: 65469.

[0008] Step 3: The mixture inoculated with lignocellulose-degrading bacteria is then subjected to aerobic composting fermentation. The aeration method used in the composting process is as follows:

[0009] In the initial stage of fermentation: aeration intensity of 3~5 L / min, 1~2 times a day, 30 min each time;

[0010] High-temperature fermentation stage: aeration intensity of 10 L / min, 1-2 times a day, 30 min each time;

[0011] Cooling and composting stage: Aeration intensity 3 L / min, 1-2 times a day, 30 min each time.

[0012] Furthermore, in step one, the mass ratio of the fungus residue, cow dung, and chicken dung is (8~9):(2~3):1.

[0013] Furthermore, the effective viable count of the lignocellulose-degrading bacteria solution inoculated in step two was 3.0 × 10⁻⁶. 8 ~4.0×10 8 CFU / mL.

[0014] Furthermore, in step two, the bacterial culture is inoculated at 1.0% (v / w) of the total wet weight of the mixture.

[0015] Furthermore, the aerobic composting fermentation time in step three is 56-64 days.

[0016] Furthermore, during step three of the composting process, the moisture content of the compost pile is maintained at 42.6% to 58.9%.

[0017] The beneficial effects of this invention are:

[0018] This invention provides a highly efficient composting method for treating Auricularia auricula-judae mushroom residue. Using Auricularia auricula-judae mushroom residue as the main raw material, combined with cow and chicken manure, and inoculated with the highly efficient lignocellulose-degrading bacterium Geobacillus sp. DKC0303 for aerobic composting fermentation, this method can promote the maturation and lignocellulose degradation of the Auricularia auricula-judae mushroom residue, significantly increasing the maturation rate, promoting the biotransformation of the residue, improving composting efficiency, and resulting in more stable product quality.

[0019] This invention is of great significance for promoting the conversion of recalcitrant organic components in Auricularia auricula-judae mushroom residue, improving composting efficiency, shortening the composting cycle, and enhancing the quality of compost products. In particular, the construction of a targeted composting system by combining highly efficient lignocellulose-degrading functional bacteria is expected to further improve the resource utilization efficiency of Auricularia auricula-judae mushroom residue, providing technical support for the reduction, harmlessness, and resource utilization of edible fungi waste, and has good application prospects.

[0020] Instruction manual illustrations

[0021] Figure 1 Photograph of the aerobic composting reactor used in this embodiment;

[0022] Figure 2 Temperature changes during the composting of wood ear mushroom residue, as illustrated in this example;

[0023] Figure 3The change in moisture content during the composting of wood ear fungus residue is illustrated in this example.

[0024] Figure 4 The change in organic matter content during the composting of wood ear fungus residue, as illustrated in the example.

[0025] Figure 5 The change in humic acid (HS) content during the composting of Auricularia auricula-judae residue, as an example;

[0026] Figure 6 The change in humic acid (HA) content during the composting of Auricularia auricula-judae residue, as an example;

[0027] Figure 7 The change in fulvic acid (FA) content during the composting of Auricularia auricula-judae residue in the example. Detailed Implementation

[0028] The embodiments of the present invention will be described in detail below. The following embodiments are implemented based on the technical solution of the present invention, and detailed implementation schemes and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments.

[0029] Example: Experiment on composting of fungal residue from wood ear mushroom cultivation

[0030] This experiment was conducted in Greenhouse No. 1 of the Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences. An aerobic composting reactor was used, with a total volume of 30 L, an inner diameter of 0.32 m, and a height of 0.40 m. The reactor was a double-layered stainless steel structure with a polyurethane insulation layer between the layers. A removable sealing cover was installed on the top of the reactor, along with aeration inlets, gas sampling / release inlets, and temperature measuring ports. The aeration system was connected to the bottom of the reactor via perforated air distribution pipes and operated intermittently under timer control. The compost temperature was continuously monitored using an automatic temperature recorder. Photos of the actual reactor are shown below. Figure 1 As shown.

[0031] The experiment in this embodiment is set up with two treatments, T1 and T2.

[0032] T1 treatment: Mix mushroom substrate, cow dung, and chicken dung in a mass ratio of 8:3:1 to obtain a mixture; inoculate the mixture with an effective viable count of 3.0 × 10⁻⁶ bacteria. 8 A lignocellulose-degrading bacterial solution of CFU / mL was inoculated at 1.0% (v / w) of the total wet weight of the mixture, i.e., 1 L of bacterial solution was added to every 100 kg of mixture. After thorough mixing, aerobic composting fermentation was carried out. The initial C / N ratio was 23.38 and the initial moisture content was 45.21%.

[0033] T2 treatment: Mix mushroom substrate, cow dung, and chicken dung in a mass ratio of 9:2:1 to obtain a mixture; inoculate the mixture with an effective viable count of 3.0 × 10⁻⁶ bacteria. 8A lignocellulose-degrading bacterial solution of CFU / mL was inoculated at 1.0% (v / w) of the total wet weight of the mixture, i.e., 1 L of bacterial solution was added to every 100 kg of mixture. After thorough mixing, aerobic composting fermentation was carried out. The initial C / N ratio was 20.35 and the initial moisture content was 44.82%.

[0034] The lignocellulose-degrading bacterium is Geobacillus sp. DKC0303, which is deposited at the Guangdong Microbial Culture Collection Center on November 12, 2024, with accession number GDMCC No: 65469.

[0035] Table 1 Experimental scheme for composting black fungus residue

[0036]

[0037] After all raw materials were mixed, they were loaded into the reactor for 64 days of aerobic composting. The composting process employed a phased, intermittent forced aeration strategy: In the initial fermentation stage, low-intensity aeration of 5 L / min was used, once daily for 30 minutes each time, to meet the oxygen requirements of the microorganisms during the initiation phase and promote temperature rise; during the high-temperature fermentation stage, the aeration intensity was increased to 10 L / min according to temperature changes, twice daily for 30 minutes each time, to maintain the aerobic state of the compost pile and prevent localized anaerobic conditions; during the cooling and maturation stage, low-intensity intermittent aeration was restored to 3 L / min, once daily for 30 minutes each time, with manual turning or loosening of the materials as needed, and water added as necessary to maintain the moisture content of the compost pile within a suitable range. During composting, samples were periodically taken to measure physicochemical properties, maturity, and stability-related indicators.

[0038] The results showed that all treatments could complete the aerobic composting fermentation of the mushroom residue, with the highest temperature of the pile reaching 72.5℃. Among them, treatment T1 was better in terms of heating rate, high temperature maintenance and composting maturity.

[0039] Depend on Figure 2 and Figure 3It is evident that after aerobic composting of *Auricularia auricula-judae* residue using the method of this invention, all treated piles rapidly increased in temperature and entered the high-temperature fermentation stage. This indicates that the present invention, through synergistic regulation of the ratio of *Auricularia auricula-judae* residue to livestock and poultry manure, inoculant inoculation, and aeration conditions, can significantly improve the microbial activity of the pile, enhance the organic matter degradation capacity, and promote the efficient biotransformation of *Auricularia auricula-judae* residue. Among these, the temperature rise rate of treatment T1 was significantly faster than that of treatment T2, reaching a high temperature level rapidly in the early stages of fermentation, with a maximum temperature of 72.5 ℃ and a longer duration of high temperature maintenance. This suggests that treatment T1 is more effective in promoting the decomposition of organic matter in the pile, increasing the composting rate, and maintaining a stable aerobic fermentation environment. Compared to treatment T2, treatment T1 can form and maintain a high-temperature environment conducive to the degradation of lignocellulose in a shorter time, thereby helping to accelerate the composting process of *Auricularia auricula-judae* residue and improve composting efficiency.

[0040] Meanwhile, the moisture content changes show that the moisture content of both treatments continuously decreased during the composting process, indicating vigorous microbial metabolism and sufficient heat release within the compost pile. This resulted in continuous evaporation of moisture from the material, accompanied by the continuous decomposition of organic components. The moisture content decrease in treatment T1 was significantly greater than that in treatment T2, and even lower at the end of fermentation. This suggests that treatment T1 resulted in higher fermentation intensity, better material stabilization, and more complete composting. These results further demonstrate that the raw material combination and process parameter settings employed in this invention can effectively improve the aeration, hydrothermal conditions, and nutrient structure matching during the composting of *Auricularia auricula-judae* residue, thereby enhancing the overall fermentation performance of the compost pile.

[0041] In the implementation of this invention, a CS-T10R-PT temperature recorder was used to continuously monitor the temperature of the pile. The pile height was divided into three equal parts, and samples were periodically collected from the upper, middle, and lower parts using a sampler for measurement. Moisture content was measured according to GB / T 8576. Experimental results show that the method of this invention can achieve rapid heating of the mushroom residue pile, maintain a high-temperature fermentation state for a longer period, effectively reduce moisture content, and accelerate material maturation. It has advantages such as high composting efficiency, stable fermentation process, good maturation effect, and strong resource utilization capacity. Specifically, treatment T1 is superior to treatment T2 in terms of heating rate, maximum temperature, high-temperature maintenance capacity, and moisture content reduction effect. This indicates that when mushroom residue, cow manure, and chicken manure are mixed in a mass ratio of 8:3:1 and inoculated with 1% high-efficiency lignocellulose-degrading bacteria, a better composting fermentation effect can be obtained, providing reliable technical support for the efficient and harmless treatment and resource utilization of mushroom residue.

[0042] Depend on Figure 4It can be seen that in the aerobic composting process of the fungus residue of this invention, the organic matter content of both treatments gradually decreased with the extension of fermentation time, indicating that the microbial metabolic activity in the compost was vigorous and could continuously decompose and transform the organic components in the fungus residue and livestock and poultry manure. In the early stage of composting, as the temperature of the compost pile rose rapidly, the activity of microorganisms, especially thermophilic bacteria, was significantly enhanced, and the rate of organic matter degradation accelerated, so the organic matter content decreased significantly. After entering the high-temperature fermentation stage, a large amount of easily degradable organic matter in the compost pile was consumed, and the organic matter degradation was at a relatively fast level. As the temperature gradually decreased in the later stage of fermentation, the microbial activity tended to stabilize, and the remaining organic matter gradually stabilized after continuous degradation and humification transformation, indicating that the composting system gradually entered the maturation stage.

[0043] Among the treatments, the decrease in organic matter content in treatment T1 was significantly greater than that in treatment T2, indicating that the microbial degradation of the compost pile was stronger and the decomposition of organic matter was more complete under treatment T1, resulting in higher bioconversion efficiency of the mushroom residue. Combined with the aforementioned temperature change results, it can be seen that treatment T1 heated up faster, reached a higher maximum temperature, and maintained the high temperature for a longer period, thus creating more favorable reaction conditions for the continuous degradation of organic matter. Therefore, its organic matter degradation effect was superior to that of treatment T2. At the end of fermentation, the organic matter content in treatment T1 tended to stabilize, indicating a higher degree of material maturity and a more complete composting process; although treatment T2 also achieved organic matter degradation, its overall degradation rate and degree were lower than those of treatment T1.

[0044] In this embodiment, the organic matter content was determined according to the national standard NY / T 525—2021. The results show that the method of this invention can effectively promote the degradation and transformation of organic matter during the composting process of *Auricularia auricula-judae* residue, accelerate the maturation process, and improve composting efficiency. Simultaneously, the product maintains a high level of organic matter after fermentation, meeting the requirement of NY / T 525—2021 that the organic matter content should not be less than 30%. This indicates that while achieving the reduction and harmless treatment of *Auricularia auricula-judae* residue, this invention also ensures that the compost product has good fertilizer value and resource utilization potential. In comprehensive comparison, treatment T1 is superior to treatment T2 in both organic matter degradation efficiency and maturation effect. This indicates that mixing *Auricularia auricula-judae* residue, cow manure, and chicken manure in a mass ratio of 8:3:1 and inoculating with 1% high-efficiency lignocellulose-degrading bacteria is more conducive to improving the composting reaction intensity and organic matter transformation effect, fully demonstrating the advantages of this invention in the efficient composting utilization of *Auricularia auricula-judae* residue.

[0045] Depend on Figures 5 to 7It is evident that during the aerobic composting process of *Auricularia auricula-judae* residue in this invention, the contents of humic acid (HS), humic acid (HA), and fulvic acid (FA) all changed significantly with the fermentation process. This indicates that the organic matter in the compost continuously undergoes degradation, transformation, and resynthesis under the action of microorganisms, and the degree of humification of the compost system continuously increases. As composting progresses, the contents of HA and FA both show an upward trend and gradually stabilize in the later stage of fermentation, indicating that the organic components in the *Auricularia auricula-judae* residue and its supporting raw materials further transform into humic components and gradually complete stabilization after high-temperature degradation. Among them, HA, as an important component with high stability in humic matter, can well reflect the degree of compost maturity and humification level; HS represents the total amount of HA and FA, and its increase indicates that the humic content in the compost product is increased, and the product stability and fertilizer utilization value are enhanced.

[0046] Comparing the two treatments, treatment T1 showed a significant advantage in humus accumulation. At the end of composting, treatment T1 had HA content of 39.3 g / kg, FA content of 18.7 g / kg, and HS content of 58.0 g / kg; while treatment T2 had HA content of 23.5 g / kg, FA content of 21.9 g / kg, and HS content of 45.4 g / kg. This indicates that treatment T1 had HS content 12.6 g / kg higher and HA content 15.8 g / kg higher than treatment T2, suggesting that treatment T1 was more conducive to the formation and accumulation of stable humic components during the composting process of mushroom residue. Although treatment T2 ultimately had a slightly higher FA content than treatment T1, FA is a humic component with a small molecular weight, high activity, and relatively weak stability; its higher content usually indicates a greater accumulation of intermediate conversion products. In contrast, treatment T1 showed higher HA content and higher HS accumulation levels, indicating that it was more conducive to the conversion of small-molecule organic matter into large-molecule, stable humic matter, resulting in a higher degree of compost maturity and better product stability.

[0047] Further analysis revealed that the HA / FA value of treatment T1 was 2.10, significantly higher than the 1.07 of treatment T2. The HA / FA value is a crucial indicator for evaluating the degree of humification and maturity of compost; a higher value indicates a higher degree of humification and more complete formation of stable humic matter. Therefore, treatment T1 not only outperformed treatment T2 in terms of total HS content but also showed a more favorable structure for the formation of stable humic acid components in the humic matter composition, indicating that the compost product obtained under the optimized formulation conditions of this invention has higher maturity and better quality. In this embodiment, humic acid was determined using the alkaline extraction-acid precipitation method. Specifically, 2.5 g of the air-dried and pulverized sample was weighed and placed in an Erlenmeyer flask. 0.1 mol / L NaOH solution was added, and extraction was performed at a solid-liquid ratio of 1:10. The extract was filtered through filter paper, and the filtrate was retained. The pH was adjusted to 1-2 using hydrochloric acid to precipitate humic acid. The precipitate was filtered, dried, and weighed to obtain the humic acid (HA) content. Fulvic acid (FA) was further determined, and its content, along with the total HA, constituted the humic acid (HS) content. The results showed that the method of this invention can effectively promote the formation of humic substances, especially stable humic acid, during the composting process of Auricularia auricula-judae residue, improving the maturity, stability, and fertilizer utilization value of the compost products. Among these, the T1 treatment, inoculated with 1% highly efficient lignocellulose-degrading bacteria after mixing Auricularia auricula-judae residue, cow manure, and chicken manure in a mass ratio of 8:3:1, showed the best results, fully demonstrating the technical advantages of this invention in the efficient composting, rapid maturation, and preparation of high-quality organic fertilizer from Auricularia auricula-judae residue.

Claims

1. A method for aerobic composting of wood ear mushroom residue, characterized in that, The method includes the following steps: Step 1: Mix the wood ear mushroom residue, cow dung, and chicken dung to obtain a mixture; Step 2: Inoculate the mixture obtained in Step 1 with lignocellulose-degrading bacteria; the lignocellulose-degrading bacteria is Geobacillus sp. DKC0303, which is deposited at Guangdong Microbial Culture Collection Center on November 12, 2024, with accession number GDMCC No: 65469; Step 3: The mixture inoculated with lignocellulose-degrading bacteria is then subjected to aerobic composting fermentation. The aeration method used in the composting process is as follows: In the initial stage of fermentation: aeration intensity of 3~5 L / min, 1~2 times a day, 30 min each time; High-temperature fermentation stage: aeration intensity of 10 L / min, 1-2 times a day, 30 min each time; Cooling and composting stage: Aeration intensity 3L / min, 1-2 times a day, 30 min each time.

2. The method for aerobic composting of wood ear mushroom residue according to claim 1, characterized in that, In step one, the mass ratio of fungus residue, cow dung, and chicken dung is (8~9):(2~3):

1.

3. The method for aerobic composting of wood ear mushroom residue according to claim 2, characterized in that, The effective viable count of the lignocellulose-degrading bacteria solution inoculated in step two was 3.0 × 10⁻⁶. 8 ~4.0×10 8 CFU / mL.

4. The method for aerobic composting of wood ear mushroom residue according to claim 3, characterized in that, In step two, inoculate the bacterial solution at 1.0% (v / w) of the total wet weight of the mixture.

5. The method for aerobic composting of wood ear mushroom residue according to claim 1, characterized in that, The aerobic composting fermentation time in step three is 56-64 days.

6. The method for aerobic composting of wood ear mushroom residue according to claim 1, characterized in that, Step 3: During the composting process, maintain the moisture content of the compost pile at 42.6% to 58.9%.

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