Animal coccus az288 and straw decomposition complex microbial inoculant containing same and application thereof

Abstract

The application discloses an animal coccus AZ288, a straw-decomposing composite microbial inoculum containing the animal coccus AZ288 and application, and belongs to the technical field of microorganisms. The animal coccus AZ288 has a preservation number of CGMCC No. 32177, can effectively inhibit the interference of other microorganisms on straw-decomposing strains under the condition of applying nitrogen fertilizer, and maintains the activity of the straw-decomposing strains. The application further provides a composite microbial inoculum composed of the animal coccus AZ288 and bacillus with strong straw-decomposing ability. The composite microbial inoculum can maintain high straw-decomposing ability under the interference of other strains with weak straw-decomposing ability, can resist the inhibiting effect of external microorganisms on the function of the composite microbial inoculum, maintains the growth and function of the strain with strong decomposing ability, and thus significantly promotes straw decomposition under the application of nitrogen, and has a good application prospect in the field of reducing the application of chemical fertilizer and straw returning.

Description

Technical Field

[0001] This invention relates to the field of microbial technology, and in particular to a strain of Zoococcus AZ288 and a straw-decomposing compound microbial agent containing it and its application. Background Technology

[0002] Efficient fertilization is a crucial measure to ensure high and stable crop yields and sustainable agricultural development. However, long-term irrational fertilization has led to a series of soil degradation problems, such as soil compaction, acidification, and microbial imbalance. Returning crop straw to the field is one of the important ways to reduce fertilizer application and increase efficiency. Crop straw resources contain a large amount of nitrogen, phosphorus, and potassium nutrients, which have great potential to replace chemical fertilizers. However, efficient straw return to the field faces many technical bottlenecks, including an imbalance in the soil's carbon-nitrogen ratio after straw return, resulting in slow straw decomposition, affecting crop growth, and severely restricting the efficient utilization of straw resources. Generally speaking, applying straw in combination with composting microbial agents is an effective strategy to solve this problem in current agricultural production.

[0003] Currently, research on straw-decomposing bacteria mainly focuses on the screening and application of single-function strains. For example, reported strains include Bacillus subtilis, which produces cellulase at low temperatures, yeast, and straw-decomposing bacteria with heavy metal passivation capabilities. However, these studies are limited to the functional development of single strains and do not fully consider the synergistic effects between microorganisms. In actual agricultural production, when single straw-decomposing bacteria are applied to the soil, they easily antagonize native microorganisms, leading to inhibited or inactivated activity. This is a significant reason for the unstable effectiveness of straw-decomposing bacteria. In contrast, microbial communities composed of multiple species have richer metabolic capabilities and stronger environmental adaptability, enabling them to colonize the soil more stably and perform their functions more efficiently.

[0004] Current research on straw compound microbial agents mainly focuses on the interactions between different straw-decomposing bacteria, neglecting the potential synergistic effects of non-decomposing bacteria in the straw decomposition process. In fact, non-decomposing bacteria may indirectly improve straw decomposition efficiency by improving the microenvironment, providing growth factors, or promoting the colonization of decomposing bacteria. Therefore, systematically identifying functional microbial communities related to straw decomposition and exploring the synergistic mechanisms between non-decomposing and decomposing bacteria, combined with strain isolation and culture and bioinformatics analysis, is crucial for constructing highly efficient and stable straw compound microbial agents. This research will provide important technical support for efficient straw return to the field and sustainable agricultural development. Summary of the Invention

[0005] The purpose of this invention is to provide a strain of *Zoococcus* AZ288, a compound microbial agent containing it for straw decomposition, and its application, to solve the problems existing in the prior art. The *Zoococcus* AZ288 provided by this invention can effectively inhibit the interference of other microorganisms on straw-decomposing strains under nitrogen fertilizer application conditions, maintaining the activity of the straw-decomposing strains. The compound microbial agent composed of *Bacillus* AZ103 and *Bacillus* AZ290 can maintain a high straw decomposition capacity even in the presence of other strains with weak straw decomposition capabilities.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] This invention provides a strain of animal coccus (Mammaliicoccus sp.) AZ288, which is deposited at the China General Microbiological Culture Collection Center, with accession number CGMCC No.32177.

[0008] The animal cocci AZ288 does not have the ability to decompose straw, but under nitrogen fertilizer application conditions, it can promote the growth of other strains with strong straw decomposition ability and effectively inhibit the growth of strains with weak decomposition ability, thereby maintaining the high straw decomposition efficiency of the microbial community.

[0009] The present invention also provides the application of the aforementioned animal cocci AZ288 in improving the ability of Bacillus to degrade straw, wherein the animal cocci AZ288 can improve the ability of Bacillus to degrade straw in the presence of other straw-degrading strains.

[0010] Optionally, the Bacillus includes Bacillus sp. AZ103 and / or Bacillus sp. AZ290;

[0011] The Bacillus AZ103 has the accession number CGMCC No. 33001;

[0012] The Bacillus AZ290 has the accession number CGMCC No.32178.

[0013] Optionally, the animal cocci AZ288 can enhance the ability of the Bacillus to degrade straw under nitrogen application conditions.

[0014] The Bacillus AZ103 and Bacillus AZ290 have strong straw decomposition capabilities, but they are easily interfered with by other straw decomposition bacteria, leading to a decrease in their straw decomposition capabilities. The Zoococcus AZ288 can effectively alleviate the inhibitory effect of Bacillus strains with weak straw decomposition capabilities under nitrogen fertilizer application conditions, promote the growth of Bacillus AZ103 and Bacillus AZ290 with strong straw decomposition capabilities in the compound microbial system, and maintain the high-efficiency straw decomposition capability of the compound microbial system.

[0015] The present invention also provides the application of the aforementioned animal cocci AZ288 in the preparation of Bacillus inoculum containing straw decomposition ability.

[0016] The present invention also provides a compound microbial agent comprising the aforementioned animal cocci AZ288 and Bacillus; wherein the Bacillus is the aforementioned Bacillus AZ103 and / or Bacillus AZ290.

[0017] Optionally, the ratio of the effective viable counts of the animal cocci AZ288, the Bacillus AZ103, and the Bacillus AZ290 is 1:1:1.

[0018] The present invention also provides an application of the aforementioned compound microbial agent in promoting straw decomposition.

[0019] Optionally, the compound microbial agent promotes rapid decomposition of straw under nitrogen application conditions.

[0020] The present invention also provides an application of the aforementioned compound microbial agent in improving the efficiency of straw return to the field.

[0021] The present invention discloses the following technical effects:

[0022] This invention yielded a strain of Zoococcus AZ288, which, under nitrogen fertilizer application conditions, can effectively inhibit the interference of other microorganisms on straw-decomposing strains and maintain the straw-decomposing ability of straw-decomposing strains.

[0023] This invention involves the microbial isolation of straw residue after nitrogen fertilizer application, combined with bioinformatics analysis, to simplify and recombine the straw microbial community, resulting in one strain of *Zoococcus* AZ288 and two strains of *Bacillus* AZ103 and *Bacillus* AZ290 with strong straw-decomposing abilities. *Zoococcus* AZ288 is combined with the two highly decomposing *Bacillus* strains to form a nitrogen-efficient straw-decomposing complex microbial system. Experiments have demonstrated that, even with interference from other strains with weaker straw-decomposing abilities, *Zoococcus* AZ288 can effectively inhibit the growth of these strains, mitigating their interference with the two highly decomposing *Bacillus* strains. This improves the straw-decomposing ability of the complex microbial system under nitrogen application conditions, demonstrating its promising application prospects in areas such as fertilizer reduction and straw return to the field. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 The relative abundance of Zoococcus and Bacillus under nitrogen-free, low-nitrogen, and high-nitrogen treatments;

[0026] Figure 2 The straw decomposition rate was 10 days after inoculation with the strain; different letters indicate significant differences between treatments (P<0.05).

[0027] Figure 3 The straw decomposition rate on day 10 of the nitrogen-efficient straw decomposition compound microbial agent induced by zoococci; among them, different letters represent significant differences between treatments (P<0.05);

[0028] Figure 4 The straw decomposition rate after adding compound microbial strains SC1 and MSC1 on day 10 under nitrogen-applied and nitrogen-free treatments was calculated; different letters indicate significant differences between treatments (P<0.05).

[0029] Figure 5 The community composition of the combined bacterial strains SC1 and MSC1 on day 10 under nitrogen treatment; asterisks indicate significant differences between treatments (P<0.05). Detailed Implementation

[0030] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0031] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0032] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0033] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0034] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0035] Example 1: Test of bacterial strain isolation and decomposition ability of straw residue

[0036] 1. Isolation and Identification of Strains

[0037] 1) Sampling

[0038] The combined application of nitrogen fertilizer and crop straw is an effective strategy for balancing the carbon-nitrogen ratio required for microbial decomposition and crop growth. Therefore, the inventors collected data from Yuanyang City, Henan Province (34.78°N, 113.67°E) in the North China Plain, using a nitrogen-free and low-nitrogen (180 kg / hm²) soil sample. -2 ) and high nitrogen (240 kg hm -2 The wheat straw bale samples were processed on day 7, placed in a resealable bag, and brought back to the laboratory on ice.

[0039] 2) Isolation of strains

[0040] In a clean bench, using sterilized scissors, the residue from the wheat straw bales was chopped into small pieces. 1g of the straw residue was transferred to an Erlenmeyer flask containing 200mL of sterile water and shaken at 28℃ and 180rpm for 1 hour to form a suspension. The straw residue suspension was then serially diluted to 10-1. -6 ~10 -1 Concentration gradients were used, with 100 μL of the diluted solution spread onto six different culture media: CMC, LB, TSB, R2A, TSA-YE, and CBA, and incubated at 28°C for 3–4 days. Based on the differences in colony morphology and color, single colonies were obtained through three purification processes and stored at -70°C in 30% glycerol.

[0041] CMC medium contains the following components: dipotassium hydrogen phosphate 2.50 g·L⁻¹ -1 2.50 g·L disodium hydrogen phosphate -1 Sodium carboxymethyl cellulose 20.00 g·L -1 2.00 g / L of peptone -1 Yeast extract 0.50 g·L -1 20.00 g / L agar -1 Congo Red 0.20 g·L -1 .

[0042] LB medium contains the following components: 10.00 g / L tryptone. -1 Yeast extract 5.00 g·L -1 Sodium chloride 10.00 g·L -1 and agar 20.00g·L -1 .

[0043] TSB solid culture medium contains the following components: yeast extract 17.0 g·L⁻¹ -1 Sodium chloride 5.0 g·L -1 3.0 g / L of peptone -1 2.5 g·L⁻¹ dipotassium hydrogen phosphate -1 2.5 g / L glucose -1 and 20g·L of agar -1 .

[0044] R2A medium contains the following components: yeast extract 0.50 g·L⁻¹ -1 Peptone No. 30.50 g / L -1 Casein amino acids 0.5 g·L -1 0.5 g / L glucose -1 0.5 g / L of soluble starch -1 Sodium pyruvate 0.30 g·L -1 0.30 g·L⁻¹ dipotassium hydrogen phosphate -1 Magnesium sulfate 0.50 g·L -1 and agar 15.00g·L -1 .

[0045] TSA-YE medium contains the following components: 15.00 g / L casein trypsin digest. -1 5.00 g / L of soybean papain digest. -1 Sodium chloride 5.00 g·L -1 and agar 15.00g·L -1 .

[0046] CBA medium contains the following components: 10.00 g / L casein trypsin digest. -1 5.00 g / L of meat digested by gastric enzymes -1 3.00 g / L of beef heart digest -1 Yeast extract 5.00 g·L -1 Sodium chloride 5.00 g·L -1 1.00 g / L of corn starch -1 and agar 15.00g·L -1 Additionally, 70.00 mL of fresh, sterile, defibrinated sheep blood needs to be added.

[0047] Unless otherwise specified, all culture media should be autoclaved at 121°C for 15 minutes before use.

[0048] 167 single bacteria were obtained from straw residue on day 7 by 16S rRNA sequence analysis.

[0049] 2. Bioinformatics analysis and identification of the straw decomposition ability of the strain

[0050] 1) Bioinformatics analysis

[0051] Using FastDNA TM DNA was extracted from straw residue samples under nitrogen application, low nitrogen, and high nitrogen treatments using the SPIN Kit for Soil. The V3-V4 regions of the bacterial 16S rRNA gene were amplified using primers 338F (5'-ACTCCTACGGGAGGCAGCA-3') and 806R (5'-GGACTACHVGGGTWTCTAAT-3'). The concentration of PCR products was measured and equal volumes were mixed. Sequencing libraries were constructed using the Illumina TruSeq DNAPCR-Free Library Preparation Kit, and amplicon sequencing was performed on the NovaSeq-PE250 platform. The OTUs obtained from the amplicon sequencing were compared with the 16S rRNA V3-V4 regions of 167 bacterial strains using UCLUST software at a 98.65% threshold to identify the abundance of the 167 strains under different nitrogen application conditions, thus obtaining the main microbial species under straw return and nitrogen fertilizer application.

[0052] The results showed that among the 167 identified strains, *Mammaliicoccus* and *Bacillus* had relatively high abundance under nitrogen application conditions (see [link to study]). Figure 1 Upon identification, the genus *Mammaliicoccus* included one strain, *Mammaliicoccus sp.* AZ288. The genus *Bacillus* included two representative strains, *Bacillus sp.* AZ103 and *Bacillus sp.* AZ290.

[0053] Mammaliicoccus sp. AZ288 was deposited on October 11, 2024, at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, with accession number CGMCC No. 32177.

[0054] Bacillus sp. AZ103 was deposited on December 10, 2024, at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, with accession number CGMCCNo.33001.

[0055] Bacillus sp. AZ290 was deposited on October 11, 2024, at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, with accession number CGMCCNo.32178.

[0056] 2) Identification of the straw decomposition ability of the strain

[0057] The straw decomposition ability of *Animal Cocci* AZ288, *Bacillus* AZ103, *Bacillus* AZ290, and two reference strains obtained in this invention was determined using a straw decomposition test. The reference strains were two *Bacillus* strains (strain numbers ACCC 64376 and ACCC 64377), both purchased from the China Agricultural Microbiological Culture Collection Center. The specific methods are as follows:

[0058] Animal cocci AZ288, Bacillus AZ290, Bacillus AZ103, Bacillus ACCC 64376, and Bacillus ACCC 64377 were activated on TSB solid medium. Single colonies of these strains were then picked and inoculated into TSB liquid medium and cultured overnight at 30°C and 280 rpm for 14-16 h. The overnight culture was centrifuged at 4°C and 5000 × g for 10 min, and the supernatant was removed. The cells were resuspended twice in an equal volume of 0.9% physiological saline and centrifuged for 10 min under the same conditions to remove residual culture medium and bacterial metabolites, obtaining a bacterial precipitate. The OD of the washed bacterial solution was... 600 Adjusted to version 1.0 for future use.

[0059] Wheat straw was soaked in 1% NaOH (w / v) solution for 24 hours, rinsed with distilled water until neutral, and dried in a 70℃ oven. The dried wheat straw was then cut into 0.5–1 cm pieces. 1.2 g of straw was added to a 100 mL Erlenmeyer flask and autoclaved at 121℃ for 15 min. 57 mL of inorganic salt liquid culture medium (0.1 g / L yeast extract) was then added. -1 0.1 g / L of peptone -1 Potassium dihydrogen phosphate 2.0 g·L -1 Magnesium sulfate heptahydrate 0.3 g·L -1 and ammonium sulfate 6.37 g·L -1 (pH=7) and 3 mL OD 600The bacterial culture for testing was 1.0 μL. Aseptic addition served as a control group. Each treatment was performed in triplicate. All samples were incubated at 30°C and 180 rpm for 10 days. After incubation, the remaining wheat straw residue was collected using a 100-mesh stainless steel filter, washed three times with water, and dried in a 70°C oven. The wheat straw decomposition rate was calculated.

[0060] Straw decomposition rate = (initial straw dry weight - straw dry weight after decomposition) / initial straw dry weight × 100%.

[0061] The straw decomposition abilities of different strains are shown in Table 1 and Figure 2 As shown.

[0062] Table 1 Straw decomposition capacity of the strains

[0063] Serial Number strains 10-day straw decomposition rate % variance 1 Aseptic control group <![CDATA[7.28 d ]]> 0.96 2 Animal cocci AZ288 <![CDATA[8.05 d ]]> 0.48 3 Bacillus AZ103 <![CDATA[48.61 a ]]> 0.96 4 Bacillus AZ290 <![CDATA[49.17 a ]]> 2.20 5 Bacillus ACCC64376 <![CDATA[37.22 b ]]> 0.96 6 Bacillus ACCC64377 <![CDATA[31.95 c ]]> 2.10

[0064] Note: Different lowercase letters in the same column indicate significant differences.

[0065] From Table 1 and Figure 2 As can be seen, *Zoococcus* AZ288 lacks the ability to decompose straw and is therefore a non-decomposing bacterium. All four *Bacillus* strains possess the ability to decompose straw, with *Bacillus* AZ290 and AZ103 exhibiting the strongest decomposition capabilities, classifying them as highly efficient decomposing bacteria. Their straw decomposition rates are 31.34% and 53.04% higher than those of *Bacillus* ACCC 64376 and ACCC 64377, respectively.

[0066] Example 2: Construction and Efficacy Verification of a Nitrogen-Efficient Straw-Decomposing Compound Microbial System Induced by Zoococcus

[0067] 1. Construction of a composite microbial system for straw decomposition

[0068] Based on the results of straw decomposition ability of Zoococcus AZ288, Bacillus AZ103, Bacillus AZ290 and two reference strains in Example 1, a total of 12 composite strains were constructed in this example. The strain composition and ratio of the composite strains are shown in Table 2.

[0069] Table 2. Grouping Explanation for the Validation Test of Straw Decomposition Capacity of Compound Microbial Strains

[0070]

[0071]

[0072] 2. Verification of the decomposition effect of the straw decomposition compound microbial system

[0073] 1) Preparation of liquid compound bacterial culture

[0074] Animalococcus AZ288, Bacillus AZ290, Bacillus AZ103, and Bacillus ACCC 64376 and ACCC 64377 were activated on TSB solid medium. Single colonies of these strains were then inoculated into TSB liquid medium and cultured overnight at 30°C and 280 rpm for 14-16 h. The overnight culture was centrifuged at 4°C and 5000×g for 10 min, and the supernatant was removed. The bacterial pellet was resuspended twice in an equal volume of 0.9% physiological saline and centrifuged for 10 min under the same conditions to remove residual culture medium and bacterial metabolites. The OD of the washed bacterial culture was then calculated. 600 Adjust to 1.0. Mix the OD in equal proportions according to the ratio of the compound bacterial strains in Table 2. 600 For bacterial suspensions equal to 1.0, the final volume of the compound bacterial system is 3 mL.

[0075] 2) Wheat straw decomposition experiment

[0076] Wheat straw was soaked in 1% NaOH (w / v) solution for 24 hours, rinsed with distilled water until neutral, and dried in a 70℃ oven. The dried wheat straw was then cut into 0.5–1 cm pieces. 1.2 g of straw was added to a 100 mL Erlenmeyer flask, autoclaved, and 57 mL of inorganic salt liquid culture medium and 3 mL of a compound bacterial culture solution were added respectively. Strong decomposition strains AZ103 and AZ290 were used as controls. Each treatment was repeated four times. All samples were incubated at 30℃ and 180 rpm for 10 days. After incubation, the remaining wheat straw residue was collected through a stainless steel filter (100 mesh), washed three times with water, and dried in a 70℃ oven. The wheat straw decomposition rate was calculated, and the results are shown in Table 3. Figure 3 As shown.

[0077] Table 3. Straw decomposition capacity of different compound microbial strains

[0078] Serial Number strain / lineage 10-day straw decomposition rate % variance 1 Bacillus AZ103 <![CDATA[45.21 a ]]> 1.43 2 Bacillus AZ290 <![CDATA[44.58 a ]]> 1.08 3 SC0 <![CDATA[44.96 a ]]> 1.75 4 MSC0 <![CDATA[44.50 a ]]> 1.21 5 SC1 <![CDATA[37.29 b ]]> 1.05 6 SC2 <![CDATA[36.49 b ]]> 0.63 7 SC3 <![CDATA[36.54 b ]]> 1.58 8 SC4 <![CDATA[37.09 b ]]> 1.74 9 SC5 <![CDATA[36.84 b ]]> 1.38 10 MSC1 <![CDATA[43.54 a ]]> 1.25 11 MSC2 <![CDATA[42.97 a ]]> 1.19 12 MSC3 <![CDATA[43.72 a ]]> 1.52 13 MSC4 <![CDATA[42.38 a ]]> 0.84 14 MSC5 <![CDATA[41.88 a ]]> 1.42

[0079] Note: Different lowercase letters in the same column indicate significant differences.

[0080] From Table 3 and Figure 3As can be seen, either the highly decomposing Bacillus AZ103 or AZ290 strains, whether used alone or in combination, exhibit high straw decomposition capabilities. Even with the introduction of Zoococcus AZ288, the composite strains constructed from these highly decomposing strains maintain their high and stable decomposition efficiency (i.e., MSC0). When a single Bacillus AZ103, Bacillus AZ290, or a composite strain of both is used in conjunction with weakly decomposing strains, the straw decomposition rate of the highly decomposing strains is significantly interfered with by the weakly decomposing strains, decreasing by approximately 22.08% (i.e., SC1, SC2, SC3, SC4, and SC5). However, when the non-degrading bacterium Zoococcus AZ288 was added to the compound microbial strains SC1, SC2, SC3, SC4, and SC5, the straw decomposition rate of the compound microbial strains recovered to the same level as that treated with only the strong degrading strains. This indicates that the non-degrading bacterium Zoococcus AZ288 can effectively inhibit the interference of other microorganisms on the straw degrading strains and maintain the degradation ability of the strong degrading strains (i.e., MSC1, MSC2, MSC3, MSC4, and MSC5).

[0081] Example 3: Verification of straw decomposition rate and the effect of Zoococcus AZ288 on the growth of strains in the complex microbial system under nitrogen application conditions.

[0082] The composite bacterial strain SC1 containing four Bacillus strains and the composite bacterial strain MSC1 containing Zoococcus AZ288 and four Bacillus strains were selected from Example 2. Straw decomposition experiments were conducted using two liquid culture media (nitrogen-containing inorganic salt liquid culture medium and nitrogen-free inorganic salt liquid culture medium).

[0083] The nitrogen-containing inorganic salt liquid culture medium consists of: yeast extract 0.1 g·L⁻¹ -1 0.1 g / L of peptone -1 Potassium dihydrogen phosphate 2.0 g·L -1 Magnesium sulfate heptahydrate 0.3 g·L -1 and ammonium sulfate 6.37 g·L -1 pH=7.

[0084] The nitrogen-free inorganic salt liquid culture medium consists of: yeast extract 0.1 g·L⁻¹ -1 0.1 g / L of peptone -1 Potassium dihydrogen phosphate 2.0 g·L -1 Magnesium sulfate heptahydrate 0.3 g·L -1 pH=7.

[0085] The combined bacterial strains SC1 and MSC1 were added to nitrogen-containing and nitrogen-free inorganic salt liquid media, respectively, for straw decomposition experiments. The experimental methods were the same as in Example 2, except that the straw alkalization method, the amount of liquid medium added, and the preparation and addition amount of the combined bacterial strains were consistent with those in Example 2. Each treatment was repeated three times. All samples were cultured at 30℃ and 180rpm for 10 days. After the culture was completed, the remaining wheat straw residue was collected using a stainless steel filter (100 mesh), washed three times with water, dried in a 70℃ oven, and the wheat straw decomposition rate was calculated. The liquid culture was transferred to a 50mL sterile centrifuge tube, centrifuged at 5000×g for 10min, and the bacterial pellet was collected for amplicon sequencing.

[0086] wheat straw decomposition as follows Figure 4 As shown, under nitrogen application conditions, the straw decomposition rate was significantly higher than that under non-nitrogen application conditions, regardless of whether the compound microbial strain SC1 or MSC1 was used.

[0087] Further bioinformatics analysis was used to obtain the abundance information of each strain in the nitrogen-treated bacterial cultures SC1 and MSC1. The results are as follows: Figure 5 As shown, under nitrogen application conditions, 93.17% of the strains in the compound bacterial strain SC1 belonged to the weakly decomposing strain Bacillus ACCC 64376. However, in the compound bacterial strain MSC1 with added Zoococcus AZ288, the strong decomposing strains Bacillus AZ103 (53.65%) and Bacillus AZ290 (19.93%) were dominant. The results indicate that under nitrogen application conditions, Zoococcus AZ288 can inhibit the growth of weakly decomposing strains, reshape the decomposing bacterial community dominated by strong decomposing strains, and thus maintain the efficient straw decomposition capacity of the microbial community.

[0088] The above results indicate that the zoococcal-induced nitrogen-efficient straw-decomposing compound microbial agent of the present invention can resist the inhibitory effect of external microorganisms on the function of the compound microbial agent, maintain the growth and function of strains with strong decomposition ability, and thus significantly promote straw decomposition under nitrogen application. It has good application prospects in the fields of fertilizer reduction and straw return to the field.

[0089] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A strain of Mammaliicoccus sp. AZ288, characterized in that, It is preserved in China General Microbiological Culture Collection Center, and the preservation number is CGMCC No.32177.

2. The use of the animal coccus AZ288 according to claim 1 in improving the ability of Bacillus to degrade straw, characterized in that, The animal coccus AZ288 can improve the ability of the Bacillus to degrade straw in the presence of other straw-degrading strains. The Bacillus is Bacillus sp. AZ103 and / or Bacillus sp. AZ290. The preservation number of the Bacillus AZ103 is CGMCC No.33001. The preservation number of the Bacillus AZ290 is CGMCC No.32178. The other straw-degrading strains are Bacillus ACCC 64376 and / or Bacillus ACCC 64377.

3. Use according to claim 2, characterized in that, The animal coccus AZ288 can improve the ability of the Bacillus to degrade straw under the condition of nitrogen application.

4. Use of the animal coccus AZ288 of claim 1 in the preparation of a Bacillus bacterial agent containing straw-degrading ability.

5. A complex microbial agent, characterized in that, The animal coccus AZ288 of claim 1 and the Bacillus; the Bacillus is Bacillus sp. AZ103 and / or Bacillus sp. AZ290 as described in claim 2. 6.The complex bacterial agent according to claim 5, characterized in that, The ratio of the effective viable cell number of the animal coccus AZ288, the Bacillus AZ103 and the Bacillus AZ290 is 1:1:

1.

7. Use of the complex bacterial agent of claim 5 or 6 in promoting straw degradation.

8. Use according to claim 7, characterized in that, The complex bacterial agent promotes rapid degradation of straw under the condition of nitrogen application.

9. Use of the complex bacterial agent of claim 5 or 6 in improving the efficiency of straw returning to farmland.

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