Complex microbial inoculant for promoting lignocellulose degradation and humus generation in mulberry twig cow dung composting process and application of complex microbial inoculant

Abstract

The invention belongs to the technical field of microorganisms, and particularly relates to a complex microbial inoculant for promoting lignocellulose degradation and humus generation in the mulberry twig cow dung composting process and application of the complex microbial inoculant. The complex microbial inoculant is formed by mixing a bacterial strain B1, a bacterial strain F1 and a bacterial strain F2, and the ratio of effective viable counts in the bacterial strain B1, the bacterial strain F1 and the bacterial strain F2 is 1: 1: 1; wherein the preservation number of the bacterial strain B1 is GDMCC No: 65049; the preservation number of the strain F1 is GDMCC No: 65050; the preservation number of the bacterial strain F2 is GDMCC No: 65051. The bacillus cereus B1, the phanerochaete chrysosporium F1 and the smokeless fungi F2 in the microbial composite inoculant are effective microorganisms for promoting the decay of the fertilizer, and the three microorganisms can cooperate with one another in the aerobic composting process, so that the conversion and degradation of raw material substances are fully realized, and a high-quality organic fertilizer is produced. In addition, the composite microbial inoculant can promote the degradation of lignocellulose and the generation of humus in the composting process.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and particularly relates to a composite bacterial agent that promotes the degradation of lignocellulose and the generation of humus in the process of composting mulberry twigs and cow dung, and application thereof. Background Art

[0002] It is reported that in 2022, the Guangxi Zhuang Autonomous Region will have 1.4282 million cattle slaughtered, an increase of 6.3% over the previous year; silkworm breeding in the region produces about 3 million tons of dry mulberry branches and more than 4 million tons of silkworm feces each year. How to efficiently degrade and transform mulberry branch straw is not only an urgent problem facing modern agriculture, but also the focus of many scholars. In the past, most of the cut mulberry branch straw was burned as firewood or directly abandoned in the field, resulting in a large amount of resource waste and environmental pollution; only a small part of mulberry branch straw was used as a resource, including the production of health foods, preparation of medicines and cultivation of edible fungi (utilization rate of about 5%). Therefore, in order to realize the resource utilization of mulberry branch waste, mulberry branches and cow dung can be mixed in a certain proportion through composting technology, and the waste can be degraded and converted into useful and mature organic products under the action of microorganisms. However, traditional composting has a long fermentation cycle, slow degradation of lignocellulose, and low humus content. It also produces greenhouse gases such as CO2, CH4, and N2O, resulting in carbon and nitrogen losses and reduced quality of compost products. Therefore, in-depth research on the technology to improve the efficiency of mulberry twig and cow dung composting is of great significance to solving the technical bottleneck of mulberry twig and cow dung fertilizer utilization.

[0003] As a byproduct of composting, humus is a key indicator for evaluating the stability and quality of compost. In addition, humus can also improve soil quality, absorb heavy metals and increase crop yields. Converting more organic matter into humus is very important for improving compost quality and environmental benefits. High-temperature composting is an effective way to achieve harmless utilization of cow dung and mulberry branches. However, cow dung and mulberry branches contain a large amount of complex and difficult-to-degrade lignocellulose components, which cause low composting efficiency, long cycle and incomplete degradation, which seriously restricts the resource utilization efficiency of mulberry and silkworm waste. Based on this, it is very meaningful to promote the degradation of lignocellulose for humus synthesis.

[0004] Bioaugmentation technology can improve the synthesis of humus and has attracted widespread attention. Inoculation of microorganisms with specific functions can promote the synthesis of humus. Several studies have shown that adding lignocellulose-degrading microorganisms to compost can increase the degradation rate of lignocellulose and the content of humus. Bacteria tend to degrade cellulose, while fungi tend to decompose hemicellulose and lignin. Different strains have different degradation effects on different components, and studies have also shown that different strains can degrade the same substance through synergy. However, the formation of humus is regulated by a complex microbial network. The interactions between these microorganisms may affect the bacterial community and lead to bacterial community succession. During the composting process, microorganisms decompose organic matter and convert it into humus through community succession. Changes in physical and chemical indicators such as temperature, pH and EC can cause changes in the structure of the microbial community, thereby affecting the quality of compost. Changes in environmental factors can affect the succession of microbial communities. When the microbial community changes, its metabolic function will also change, thus affecting cellulose degradation and humus synthesis.

[0005] The inventors have constructed a composite bacterial agent with efficient fermentation function by screening existing microorganisms. By adding the composite bacterial agent, the composting process is optimized, thereby accelerating the maturity of the compost and increasing the humus content of the compost, which can provide scientific and technological support for promoting the resource utilization of agricultural solid waste and the production of new bio-organic fertilizers.

[0006] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0007] The object of the present invention is to provide a composite bacterial agent for promoting the degradation of lignocellulose and the generation of humus in the process of mulberry twig cow dung composting and its application, so as to solve the problems of long fermentation cycle, slow degradation of lignocellulose and low humus content in traditional composting in the background technology.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A composite bacterial agent, the composite bacterial agent is mixed with strain B1, strain F1 and strain F2, the ratio of effective live bacteria counts in strain B1, strain F1 and strain F2 is 1:1:1; wherein the taxonomic name of strain B1 is Bacillus cereus, which was deposited in Guangdong Microbiological Culture Collection Center on August 23, 2024, with the deposit number: GDMCC No: 65049;

[0010] The strain F1 has a taxonomic name of Phanerochaete chrysosporium and was deposited in Guangdong Microbiological Culture Collection Center on August 23, 2024, with a deposit number of GDMCC No: 65050.

[0011] The taxonomic name of the strain F2 is Bjerkandera adusta, and it was deposited in the Guangdong Provincial Microbiological Culture Collection Center on August 23, 2024, with the collection number: GDMCC No: 65051.

[0012] More specifically, the effective viable count of strain B1, strain F1 and strain F2 is 1.0×10 8 spore / mL.

[0013] The present invention also provides the use of the composite bacterial agent in promoting the degradation of lignocellulose and the generation of humus in the process of mulberry twig and cow dung composting.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] (1) In the microbial composite agent of the present invention, Bacillus cereus B1, Phanerochaete chrysosporium F1 and Pseudomonas aeruginosa F2 are all effective microorganisms for promoting fertilizer composting. The three microorganisms can cooperate with each other in the aerobic composting process to fully realize the conversion and degradation of raw materials and produce high-quality organic fertilizer.

[0016] (2) The microbial composite agent of the present invention can achieve rapid temperature rise of compost, the high temperature period lasts for more than 15 days, and can effectively kill pathogens and weed seeds, the total carbon content reaches 35.51%, and the total nitrogen content can reach 2.75%, which meets the national industry standard for organic fertilizers, and can improve the seed germination index, lignin degradation rate, cellulose degradation rate, hemicellulose degradation rate and humus content. It can be seen that the microbial composite agent of the present invention can promote the degradation of lignocellulose and the generation of humus during composting.

[0017] Storage Information

[0018] The taxonomic name of strain B1 is Bacillus cereus, and it was deposited in Guangdong Microbiological Culture Collection Center on August 23, 2024. The deposit address is: 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou, Institute of Microbiology, Guangdong Academy of Sciences, deposit number: GDMCC No: 65049;

[0019] The taxonomic name of strain F1 is Phanerochaete chrysosporium, and it was deposited in Guangdong Microbiological Culture Collection Center on August 23, 2024. The deposit address is: 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou, Institute of Microbiology, Guangdong Academy of Sciences, deposit number: GDMCC No: 65050;

[0020] The taxonomic name of strain F2 is Bjerkandera adusta. It was deposited in the Guangdong Microbial Culture Collection Center on August 23, 2024. The deposit address is: 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou, Institute of Microbiology, Guangdong Academy of Sciences, Deposit number: GDMCC No: 65051. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 For strain screening and plate confrontation;

[0022] Figure 2 Phylogenetic tree of the strain and its growth in culture medium;

[0023] Figure 3 The degradation of mulberry straw by the composite microbial agent;

[0024] Figure 4 This is a temperature change diagram during aerobic composting of cow dung and mulberry branches;

[0025] Figure 5 This is the pH change diagram during aerobic composting of cow dung and mulberry branches;

[0026] Figure 6 This is the total carbon change diagram during aerobic composting of cow dung and mulberry branches;

[0027] Figure 7 This is the change of total nitrogen during aerobic composting of cow dung and mulberry branches;

[0028] Figure 8 This is the carbon-nitrogen ratio change during aerobic composting of cow dung and mulberry branches;

[0029] Fig. 9 This is a graph showing the changes in seed germination index during aerobic composting of cow dung and mulberry branches;

[0030] Fig.10 This is a diagram showing the changes in lignocellulose components during aerobic composting of cow dung and mulberry branches;

[0031] Fig.11 This is a diagram showing the changes in humus components during aerobic composting of cow dung and mulberry branches.

[0032] Description of main reference numerals:

[0033] Figure 1 In the figure, (a) shows the fading of different strains in aniline blue medium; (b) shows the fading of different strains in Congo red medium; (c) shows the antagonism between strains, from left to right, the antagonism between bacteria and bacteria, fungi and fungi, and bacteria and fungi;

[0034] exist Figure 4-11 In the table, Control is the control group, and SynCom is the inoculated group;

[0035] exist Figure 5-Figure 11 In the composting process, IPP is the initial stage, MEP is the temperature rise stage, THP is the high temperature stage, and MAP is the maturity stage. DETAILED DESCRIPTION

[0036] The following is a clear and complete description of the technical solution of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by technicians in this field without creative work are within the scope of protection of the present invention.

[0037] 1. Screening of strains

[0038] Weigh 5g of silkworm excrement and mulberry branch compost sample and dissolve it in 95mL sterile water, and shake it at 30℃ and 180rpm for 30min. Take 5mL of bacterial suspension and place it in a triangular flask containing 95mL of enrichment medium, shake it at 30℃ and 180rpm for 72h, perform 10-fold gradient dilution, take a small amount of bacterial suspension and evenly apply it on the primary screening medium (aniline blue medium and Congo red medium), and place it at 28℃ and 37℃ for constant temperature culture for 24h-48h. Observe the growth of the colony, determine whether there is a hydrolysis circle, select the strains in the degradation circle and pick the bacteria (bacteria are streaked, fungi are gradient diluted and coated) to purify the strains, and store them at 4℃ for use.

[0039] Bacterial cakes with a diameter of 1 cm of each strain were inoculated onto CMC-Na plate culture medium and cultured for 24-72 hours. A blank control (CK) was used without adding any strain. The culture was stained with 0.1% Congo red aqueous solution for 30 minutes, and the staining solution was discarded.

[0040] Dp=(D / d) 2 , D is the diameter of the hydrolysis zone, d is the diameter of the colony, and the average value is taken from four measurements from different directions. Two bacteria and two fungi were selected according to the size of the hydrolysis zone. The results are shown in Tables 1 and Figure 1 .

[0041] Table 1 Dp values ​​of cellulose-degrading bacteria

[0042]

[0043] Note: The data in the column represent the mean ± standard error

[0044] 2. Strain Antagonism

[0045] The different strains isolated were inoculated on carboxymethyl cellulose solid culture medium plates, and the bacteria were crossed in pairs. The antagonism between bacteria and fungi was first coated with bacteria and then inoculated with fungi. The fungi were punched and connected to each other. Three parallel tests were set up. The strains were cultured in a constant temperature incubator at the corresponding temperature to observe whether the strains had antagonism, inhibition of spore formation, etc. during their growth. The strains with antagonistic effects could not be combined. Strains without antagonistic effects were selected to construct composite bacterial agents. The results are shown in Table 2 and Figure 1 shown.

[0046] Table 2 Direct antagonistic relationship between strains

[0047]

[0048] Note: + indicates antagonism, - indicates no antagonism

[0049] As shown in Table 2, there is no antagonism between bacteria B1 and the two fungal strains F1 and F2.

[0050] 3. Identification of strains

[0051] The genomic DNA of the strain was extracted according to the kit method, and PCR amplification was performed using universal primers for fungi and bacteria, with the genomic DNA of the strain as a template, and the amplification results were sequenced. The nucleotide sequences of each strain were analyzed for homology in NCBI, and the phylogenetic tree was constructed using MEGA11.0 software.

[0052] According to the morphological identification of the strains and combined with the phylogenetic tree, the results are as follows Figure 2 shown.

[0053] After identification, the taxonomic name of strain B1 is Bacillus cereus, the taxonomic name of strain F1 is Phanerochaete chrysosporium, and the taxonomic name of strain F2 is Bjerkandera adusta. The sequences of strain B1, strain F1 and strain F2 are shown in Table SEQ ID No.1-3.

[0054] 4. Construction of composite bacterial agents

[0055] The single-factor method was used to compare the efficiency of single strains B1, F1, F2 and composite bacterial agents in degrading lignocellulose under the same conditions, so as to optimize and construct the composite bacterial agent.

[0056] The selected bacteria and fungi were inoculated into Erlenmeyer flasks containing LB and PDA liquid culture media, respectively, and the culture conditions were as follows: initial pH range of 5.0-6.0, shaker speed of 180 rpm / min, culture temperature of 37°C or 28°C, and the strains were used as spare after 48h or 72h of culture.

[0057] The strain (effective viable count 1×10 8 spore / mL) were mixed according to Table 3 to construct a composite bacterial agent and the filter paper strip disintegration experiment and mulberry straw degradation experiment were carried out.

[0058] Filter paper strip disintegration experiment: The single strain and the composite strain were inoculated into a conical flask containing 50 mL of filter paper strip disintegration medium, and the group without bacterial solution was set as the control group. The culture was carried out at 30°C and 130 rpm / min. The filter paper strip disintegration was observed and recorded regularly. The results are shown in Table 3.

[0059] Table 3 Degradation effect of lignocellulose-degrading bacteria on filter paper strips (3d)

[0060]

[0061] Note: “0” - almost no change in the filter paper; “+” - the edge of the filter paper swells; “++” - the filter paper as a whole swells; “+++” - the filter paper swells in larger pieces; “++++” - the filter paper is in a paste-like state with small pieces; and “+++++” - the filter paper is in a paste-like state and dispersed.

[0062] As shown in Table 3, strains B1, F1, F2 and their composite bacterial agents can all degrade filter paper strips, among which composite bacterial agents M1, M2, M4 and M5 are better than other groups; among them, after M4 and M5 degraded the filter paper strips, the filter paper became paste-like and dispersed, which was better than M1 and M2.

[0063] Mulberry straw degradation experiment: The M1, M2, M4 and M5 strain combinations in Table 3 were inoculated at 6% into mulberry liquid enzyme production culture medium (10 g / L crushed 20-mesh mulberry straw, 1 g / L (NH4)2·SO4, 1 g / L KH2PO4, 0.1 g / L yeast extract, 0.5 g / LMgSO4·7H2O, 0.1 g / L CaCl2), and the group without bacterial solution was set as the control group. The culture was carried out at 30°C, 130 rpm / min in the dark for 7 days. After the culture, the residual mycelium and calcium carbonate were removed with a mixture of hydrochloric acid and nitric acid, and the culture was repeatedly rinsed with sterile water. The culture was centrifuged at 5000 rpm for 10 min, and the precipitate was dried in a drying oven to constant weight, and the weight loss rate of the mulberry straw was measured. Results Figure 3 .

[0064] Depend on Figure 3It can be seen that the combination of strains M1, M2, M4 and M5 can degrade mulberry straw, among which M4 and M5 have more significant degradation rates on mulberry straw, with mulberry straw weight loss rates of 33.60% and 32.33% respectively. M4 was subsequently used as a microbial composite agent.

[0065] 5. Aerobic composting experiment of cow dung and mulberry branches

[0066] 5.1 Strain culture

[0067] Bacillus cereus B1 was inoculated into a triangular flask (1L capacity) containing 500mL beef extract peptone medium. The culture conditions were: initial pH range of 5.0-6.0, shaker speed of 180rpm / min, culture temperature of 37°C, and cultured for 48 days for standby use. The beef extract peptone medium preparation method is as follows: take the preparation of 1L as an example: weigh 5g beef extract, 10g peptone, 5g NaCl, dissolve them all, add distilled water to make up to 1L, and sterilize at 115°C for 20min.

[0068] Phanerochaete chrysosporium F1 and F2 were inoculated into a triangular flask (1L capacity) containing 500mL of PDA medium, and the culture conditions were: initial pH range of 5.0-6.0, shaker speed of 180rpm / min, culture temperature of 28℃, and cultured for 72 days as a strain. The preparation method of PDA medium is as follows: take 1L of the amount as an example: weigh 200g of peeled potatoes, cut them into small pieces, put them into 1L of boiling deionized water and cook for 30min, add 20g of glucose to the filtrate after passing through four layers of gauze, make the volume to 1L, and sterilize at 115℃ for 20min.

[0069] 5.2 Preparation of composite bacterial agent

[0070] The fermentation broth of Bacillus cereus B1, Phanerochaete chrysosporium F1 and F2 was adjusted to 1×10 8 spore / mL. The adjusted bacterial solution was mixed evenly according to the effective colony count ratio of Bacillus cereus B1, Phanerochaete chrysosporium F1 and F2 in a ratio of 1:1:1, and then the bacterial strain adsorbent rice bran was mixed and adsorbed in a blender in a volume mass ratio of 1:10, and dried at room temperature until the water content was less than 20%, thereby obtaining a microbial composite bacterial agent, which was stored in a cool and dry place for use.

[0071] 5.3 Aerobic composting test

[0072] Fresh cow dung and mulberry branches were collected from farmers in Dacai Township, Huanjiang Maonan Autonomous County, Hechi City, Guangxi Zhuang Autonomous Region. Their basic physical and chemical properties are shown in Table 4.

[0073] Table 4 Basic physical and chemical properties of composting materials

[0074]

[0075] Air-dry the fresh cow dung and mulberry branches naturally, crush the air-dried mulberry branches and pass through a 10-mesh sieve. Mix the cow dung and mulberry branches in a ratio of 8:2 by dry weight, adjust the moisture content to about 60%, and build a pile with a size of 1.5m×1.5m×1.2m in length×width×height.

[0076] An inoculation group and a control group were set up to compare the composting effects of the inoculation group and the control group; the inoculation group was inoculated with the prepared microbial composite agent, and the control group was added with an equal amount of adsorbent rice bran. The total fresh weight of each pile at the initial stage of composting was about 1000kg, and the ratio of inoculation amount to pile mass was 6%. The pile was turned once on the 1st, 3rd, 5th, 10th and 15th day after the pile was built; during the period of 15-60 days, the pile was turned and ventilated every 7 days to ensure the homogenization of the pile. After 50 days of composting, the compost was piled in a ventilated and cool place for 40 days to enter the post-ripening stage until the compost was fully decomposed. During the composting process, the temperature was measured at 3 pm every day, and the temperature changes and morphological appearance changes of the pile for 60 days were recorded.

[0077] After the cow dung and mulberry branches were piled up, samples were collected on the 1st, 3rd, 5th, 10th, 15th, 22nd, 29th, 36th, 45th, 52nd and 60th days. The collection method is as follows: the pile is evenly divided into three parts: front, middle and back. A section is selected from each part, and the section multi-height equal sampling method is adopted, that is, the pile is divided into multiple sections, and equal samples are collected at multiple heights in each section (upper layer: 0.05m-0.1m; middle layer: 0.5m-0.6m; lower layer 0.8m-1.2m), and then the samples are mixed, and the samples are taken three times by the quartering method to make the samples representative. One part is stored in a 4℃ refrigerator, and the other part is naturally air-dried for the determination of physical and chemical indicators and fertilizer maturity analysis.

[0078] Determination of carbon-nitrogen ratio during composting: A carbon-nitrogen element analyzer was used to determine the total carbon, total nitrogen and carbon-nitrogen ratio in the air-dried samples.

[0079] Determination of fertilizer germination index during composting: Add 5g of fresh compost sample to 50mL of deionized water, shake on a shaker for 24h, and filter. Add 5mL of filtrate to a culture dish covered with filter paper, add 20 plump cucumber seeds to the culture dish, spread them evenly, and culture them in a 25℃ incubator away from light for 3d. Set up a control (add 5mL of sterile water to the control group), and replicate each sample three times. Count the number of germinated seeds and measure the length of seed roots to analyze the maturity of the compost material and the quality of the organic fertilizer. Calculation formula:

[0080] GI (%) = (seed germination rate of compost extract × seed root length) / (seed germination rate of distilled water × seed root length) × 100.

[0081] Determination of humus content during composting: The compost sample was extracted with a mixed solution of 0.1M Na4P2O7·10H2O and NaOH at 1:10 (w:v), then shaken at 25°C for 24h and centrifuged at 11000rpm for 5min to obtain the supernatant. The solution was then filtered with a 0.45μm microporous membrane and humus was obtained. The pH of the humus solution was adjusted to 1.5 with 6M HCl and allowed to stand at 4°C for 12h. The acidic solution was centrifuged at 11000rpm for 15min, the supernatant was FA, and the precipitate was HA. HA was washed alternately twice with 0.1M HCl and deionized water. Finally, the precipitate was dissolved with 0.05M NaHCO3. The concentrations of humus, HA, and FA were determined by Shimadzu TOC-Vcph analyzer. All processes were repeated in triplicate, and the average value for each case was calculated.

[0082] Determination of lignocellulose content during composting: The contents of lignin, cellulose and hemicellulose were determined using the Paradigm washing method using an FT12 automatic fiber analyzer.

[0083] 5.2 Results and Analysis

[0084] 5.2.1 Temperature changes during aerobic composting of cow dung and mulberry branches

[0085] Results Figure 4 .

[0086] Depend on Figure 4 It can be seen that the composting treatment of the inoculated group has a faster heating speed and a higher temperature than the composting treatment of the control group, indicating that the microbial composite agent of the present invention can effectively accelerate the start of composting. At the same time, the temperature in the compost of the inoculated group drops to room temperature faster than that of the control group, and room temperature indicates that the composting process stops, indicating that the inoculated group improves the composting efficiency by accelerating the high temperature period and shortening the composting cycle.

[0087] 5.2.2 pH changes during aerobic composting of cow dung and mulberry branches

[0088] Results Figure 5 .

[0089] Depend on Figure 5 It can be seen that the pH values ​​of the control group and the inoculated group showed a similar pattern, increasing rapidly during the warming period, decreasing during the high temperature period, and slightly recovering during the maturity period, reaching 8.60 and 8.67 respectively. The control group fluctuated more significantly than the inoculated group, which indicates that the inoculated group can effectively improve the synthesis of organic acids during the composting process.

[0090] 5.2.3 Changes in total carbon during aerobic composting of cow dung and mulberry branches

[0091] Results Figure 6 .

[0092] Depend on Figure 6 It can be seen that the total carbon content of the control group and the inoculated group showed a downward trend during the entire composting process, and the total carbon degradation rate of the inoculated group was higher than that of the control group, indicating that the mineralization effect of organic matter in the inoculated group was higher than that in the control group. The decrease in total carbon content in the inoculated group may be the result of enhanced interactions between microorganisms after inoculation of the synthetic flora.

[0093] 5.2.4 Changes in total nitrogen during aerobic composting of cow dung and mulberry branches

[0094] Results Figure 7 .

[0095] Depend on Figure 7 It can be seen that the total nitrogen content of the inoculated group and the treated group showed an overall upward trend during the entire composting process, and the total nitrogen content of the inoculated group increased significantly during the warming period, indicating that the inoculation of synthetic flora can reduce a certain amount of nitrogen loss.

[0096] 5.2.5 Changes in carbon-nitrogen ratio during aerobic composting of cow dung and mulberry branches

[0097] Results Figure 8 .

[0098] Depend on Figure 8 It can be seen that the carbon-nitrogen ratio of the control group and the inoculated group showed an overall downward trend during the composting process, and decreased rapidly during the warming period and the maturity period. At the end of fermentation, the carbon-nitrogen ratios of the control group and the inoculated group were 13.38 and 12.91, respectively. This is because the mineralization of total carbon is stronger than that of total nitrogen.

[0099] 5.2.6 Changes in seed germination index during aerobic composting of cow dung and mulberry branches

[0100] Results Fig. 9 .

[0101] Depend on Fig. 9 It can be seen that the seed germination index of the control group and the inoculated group showed an upward trend during the composting process, but the seed germination index of the inoculated group was 51.32% higher than that of the control group during the mature stage. This shows that the inoculated group has high biological activity in the entire composting process, can effectively degrade organic acids, reduce the toxicity of the compost, and increase the germination index.

[0102] 5.2.7 Changes in lignocellulose components during aerobic composting of cow dung and mulberry branches

[0103] Results Fig.10 .

[0104] Depend on Fig.10It can be seen that the lignocellulose content of the control group and the inoculated group continued to decrease during the composting process, and there was a significant difference between the two inoculated groups during the high temperature period. The lignocellulose degradation rate of the inoculated group in the later stage of composting was significantly higher than that of the control group. In contrast, the lignin degradation rate of the inoculated group increased by 19.21%, the cellulose degradation rate increased by 7.89%, and the hemicellulose degradation rate increased by 11.96%. These results show that the inoculated group can accelerate the stability and maturity of compost through the conversion of lignocellulose.

[0105] 5.2.8 Changes in humus components during aerobic composting of cow dung and mulberry branches

[0106] Results Fig.11 .

[0107] Depend on Fig.11 It can be seen that the humus content of the control group and the inoculated group showed a trend of first decreasing and then increasing during the composting process. This is because the organic matter that can be directly used in the early stage of composting is quickly decomposed. When the available organic matter is insufficient, the humus will be decomposed and used by microorganisms. The humus content of the inoculated group increased to 117.05 mg / g in the late stage of composting, which was significantly higher than that of the control group (94.30 mg / g), and increased by 24.13% over the control group. During the composting process, the humic acid content of the control group and the inoculated group showed an upward trend, and the fulvic acid content showed a trend of first decreasing and then increasing. In addition, the humic acid content of the inoculated group increased by 6.23% compared with the control group. These results show that the inoculated group can accelerate the stability and maturity of compost by promoting the conversion of fulvic acid to humic acid.

[0108] In summary, Bacillus cereus B1, Phanerochaete chrysosporium F1 and Bacillus fusca F2 in the microbial composite agent of the invention are all effective microorganisms for promoting fertilizer composting. The three microorganisms can cooperate with each other in the aerobic composting process to fully realize the transformation and degradation of raw materials and produce high-quality organic fertilizer.

[0109] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A composite bacterial agent, characterized in that: The composite bacterial agent is formed by mixing strain B1, strain F1 and strain F2, and the ratio of effective live bacteria counts in strain B1, strain F1 and strain F2 is 1:1:1; Among them, the taxonomic name of the strain B1 is Bacillus cereus ( Bacillus cereus ), deposited in Guangdong Microbiological Culture Collection Center on August 23, 2024, with the deposit number: GDMCC No: 65049; The strain F1 is taxonomically named Phanerochaete chrysosporium ( Phanerochaete chrysosporium ), deposited in Guangdong Microbiological Culture Collection Center on August 23, 2024, with the deposit number: GDMCC No: 65050; The taxonomic name of the strain F2 is Add a comment ), deposited in Guangdong Microbiological Culture Collection Center on August 23, 2024, with the deposit number: GDMCC No: 65051.

2. The composite bacterial agent according to claim 1, characterized in that The effective viable count of strain B1, strain F1 and strain F2 is 1.0×10 8 spore / mL.

3. Use of the composite bacterial agent according to claim 1 in promoting the degradation of lignocellulose and the generation of humus during the composting of mulberry twigs and cow dung.

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