Brevibacillus thermophilus with strong fiber degradation function and application of brevibacillus thermophilus

Abstract

The invention provides brevibacillus thermophilus with a strong fiber degradation function and application of the brevibacillus thermophilus. The brevibacillus soil thermophilus is named as brevibacillus soil (Brevibacillus agri) GZAUS211024 and is preserved in the Guangdong Microbial Culture Collection Center, and the preservation number of the brevibacillus soil thermophilus is GDMCC (Guangdong Microbial Culture Collection Center) 65171. The brevibacillus soilis GZAUS211024 has relatively strong cellulase, amylase and lipase enzyme activities at the temperature of 45 DEG C, has relatively high degradation efficiency on pure lignin, has a relatively high direct degradation rate on straw stalks with a relatively high lignification degree under the same condition, has an obvious effect of weakening a fiber structure, and has a good application prospect. The defects of the microbial resources can be made up to a certain extent.

Description

Technical Field

[0001] The present invention relates to the field of microbial technology, and particularly relates to a thermophilic soil Brevibacillus brevis with strong fiber degradation function and its application. Background Art

[0002] In China, about 30% of crop straw is burned in place or randomly piled in the fields every year. However, the degradation of lignocellulose is an important component of many crop straws. It is cross-linked by three polymers, namely cellulose, hemicellulose, and lignin. Its cross-linked structure is complex, which makes the degradation of lignocellulose one of the major obstacles in the utilization of agricultural straw.

[0003] Among various lignocellulose degradation methods, the use of microorganisms for degradation has become the primary method for lignocellulose degradation due to its environmental protection characteristics. Some microorganisms in nature have varying degrees of lignocellulose degradation ability, mainly fungi. For example, wood-decaying fungi such as white rot fungi and brown rot fungi have the ability to secrete a large amount of lignin-degrading enzymes and are the most concerned lignin-degrading microorganisms. However, during the lignin degradation process by fungi, there are many limiting factors. Some studies have shown that under high-temperature conditions, the degradation efficiency of lignocellulose will be improved to a certain extent, but most microorganisms often cannot achieve high efficiency under high-temperature conditions. Bacteria, such as Sphingomonas and Bacillus, can also produce specific enzymes to degrade lignocellulose, and there is a rich variety of bacteria, which can adapt to more environmental conditions. However, compared with fungi, the efficiency of their degradation of lignocellulose is relatively low.

[0004] Therefore, developing microbial resources and screening bacterial resources that are more suitable for lignocellulose degradation conditions are crucial for using the microbial degradation method to overcome the difficulties in lignocellulose degradation and increase the efficiency and ways of high-value utilization of agricultural waste. At the same time, in actual applications, during the process of microbial degradation of lignocellulose, the degradation of other substances is often accompanied, such as other polysaccharides and fats. The presence of these related substances also restricts the selection and application effect of microbial strains to a certain extent. Therefore, under actual conditions, there is a relative lack of strains with strong comprehensive degradation ability for common energy substances in the environment.

[0005] The strain Brevibacillus brevis GZAUS211024 involved in this application has strong cellulase, amylase, and lipase activities at 45°C. At the same time, it has a high degradation efficiency for pure lignin, and has a high direct degradation rate for straw with a relatively high degree of lignification under the same conditions, and has an obvious effect of weakening the fiber structure, which can make up for the deficiency of the above-mentioned microbial resources to a certain extent. Summary of the Invention

[0006] The object of the present invention is to provide a thermophilic soil Brevibacillus with strong fiber degradation function and its application. This strain has the ability to strongly degrade lignin, cellulose, starch, and fat at a high temperature of 45°C, and can be used to prepare lignin, cellulose, starch, and fat degrading agents; at the same time, it has a high degradation efficiency for pure lignin, and has a relatively high direct degradation rate for rice straw with a relatively high degree of lignification under the same conditions, with an obvious effect of weakening the fiber structure, which can make up for the deficiency of the above-mentioned microbial resources to a certain extent; and it solves the problem that most microorganisms often cannot achieve a high degradation efficiency of lignocellulose under high temperature conditions, resulting in a relatively low degradation efficiency of lignocellulose.

[0007] To achieve the above object, the technical scheme adopted by the present invention is as follows:

[0008] A thermophilic soil Brevibacillus with strong fiber degradation function described in the present invention, this strain is named Brevibacillus agri GZAUS211024, and is preserved in the Guangdong Provincial Microbial Culture Collection Center, with the preservation number GDMCC 65171 and the preservation date of December 13, 2024.

[0009] The application of the thermophilic soil Brevibacillus described in the present invention in the preparation of lignin, cellulose, starch, and fat degrading agents.

[0010] The application of the thermophilic soil Brevibacillus described in the present invention in the preparation of lignin, cellulose, starch, and fat degrading agents that simultaneously have the ability at high temperature.

[0011] The high temperature described in the present invention is 45°C.

[0012] The application of the thermophilic soil Brevibacillus described in the present invention in the preparation of pure lignin degrading agents.

[0013] The application of the thermophilic soil Brevibacillus described in the present invention in the degradation of rice straw.

[0014] The beneficial effects of the present invention:

[0015] 1. Through the detection of the enzyme activity tests of cellulase, amylase, lipase, and filter paper enzyme of Brevibacillus agri GZAUS211024 of the present invention, it is confirmed that Brevibacillus agri GZAUS211024 has relatively high cellulase, lipase, and amylase at high temperature. Under the condition of 45°C, its cellulase activity reaches 154.41±4.95 U / mL, lipase activity reaches 100.77±9.84 U / mL, amylase activity reaches 90.10±3.55 U / mL, and filter paper enzyme activity reaches 40.68±2.99 U / mL, indicating that the strain GZAUS211024 has good and stable degradation ability for polysaccharide and lipid substances at high temperature.

[0016] 2. The lignin degradation test of the present invention confirms that the degradation efficiency of strain GZAUS211024 on pure lignin is 40.87±3.86%, indicating that strain GZAUS211024 is a bacterium capable of efficiently degrading lignin at high temperatures.

[0017] 3. The test on the degradation of rice straw by Bacillus brevis GZAUS211024 in soil of the present invention confirms that under the high temperature condition of 45°C, the degradation rate of rice straw reaches 39.10% within 15 days. The observation result of the structure of rice straw shows that when treated with this single strain under high temperature conditions for 15 days, it can significantly weaken the robust fiber network structure in rice straw, achieving the effect of substantially degrading lignocellulose components. Description of the Drawings

[0018] Figure 1 It is the colony morphology of GZAUS211024.

[0019] Figure 2 It is the cell morphology of GZAUS211024.

[0020] Figure 3 It is the phylogenetic tree of GZAUS211024.

[0021] Figure 4 It is the growth curve of Bacillus brevis GZAUS211024 in soil at different temperatures.

[0022] Figure 5 It is the glucose standard curve of Bacillus brevis GZAUS211024 in soil.

[0023] Figure 6 It is the maltose standard curve of Bacillus brevis GZAUS211024 in soil.

[0024] Figure 7 It is the lignin standard curve of Bacillus brevis GZAUS211024 in soil.

[0025] Figure 8 It is the determination of the activity of the substance degrading enzyme and the lignin degradation rate of GZAUS211024.

[0026] Figure 9 It is the effect of GZAUS211024 on degrading rice straw (a is the microscopic morphology of the straw before degradation treatment, b is the microscopic morphology of the straw after degradation treatment). Detailed Embodiments

[0027] The technical solutions of the present invention will be described in detail below in combination with specific embodiments. The following embodiments are only for explanation and illustration, and do not constitute a limitation to the technical solutions of the present invention.

[0028] Example 1 Isolation and screening method of strong soil degradation Brevibacillus

[0029] (1) Sample collection: Soil was collected near the hot spring water source in Guizhou Province, and the surface dead branches and leaves were removed. Soil samples with a depth of 0-5 cm were collected and stored at room temperature;

[0030] (2) Weigh 10 g of the preserved soil, add 100 mL of PBS buffer (pH 7.2), shake thoroughly, and incubate at 85°C for 1 h.

[0031] (3) Take 1 mL of the incubated suspension and add it to 100 mL of LB liquid medium. Incubate the culture at 45°C for 24 h.

[0032] (4) Take the bacterial solution and add PBS buffer incubated at 45℃ for 1 hour, dilute 10 5 , 10 6 , 10 7 times;

[0033] (5) Take 100 μL of the above bacterial dilution and spread it on the NA plate, with three replicates for each treatment;

[0034] (6) After culturing at 45°C for 1 day, single colonies with different phenotypes were picked and streaked onto LB medium for purification.

[0035] Example 2 Identification method of soil Brevibacillus

[0036] (1) Morphological identification

[0037] The Bacillus GZAUS211024 strain was inoculated into LB medium and cultured at 45°C for 48 hours. Yellow-white colonies were visible on the LB medium. The colonies were round with neat edges. After 3-5 days of culture, the color of the strain gradually turned brown.

[0038] (2) Molecular Biological Identification

[0039] The Bacillus GZAUS211024 strain was cultured in LB medium for 48 h and then sent to Guangzhou Aiki Biotechnology Co., Ltd. for sequencing. The length of the sequence was about 1400 bp and the sequence number was SEQ ID NO.1;

[0040] Sequencing primer DNA sequence:

[0041] 27F:5-AGAGTTTGATCCTGGCTCAG-3

[0042] 1492R:5-GGTTACCTTGTTACGACTT-3

[0043] In the GenBank database of NCBI, the 16S rDNA sequence of strain GZAUS211024 was retrieved and identified by BLAST.

[0044] Example 3 Detection of Temperature Tolerance of Brevibacillus agri GZAUS211024

[0045] (1) Inoculate into LB liquid medium at an inoculum size of 1%, and culture with shaking at 180 rpm at 30 °C, 35 °C, 40 °C, 45 °C, and 50 °C respectively. Measure the OD value every 4 h. 600 value.

[0046] (2) Plot the growth curve of Brevibacillus agri GZAUS211024 at different temperatures.

[0047] Example 4 Determination of Substance Degradation Properties of Brevibacillus agri GZAUS211024

[0048] (1) Determination of cellulase activity

[0049] Inoculate into LB liquid medium at an inoculum size of 1%, culture at 45 °C and 180 rpm for 24 h, take the culture solution and centrifuge at 12000 rpm for 3 min to obtain the enzyme solution to be measured. Prepare a 2 mg / mL glucose solution and plot the standard curve according to Table 1 below:

[0050] Table 1 Parameter values set for preparing glucose solution

[0051]

[0052] Take 1 ml of the enzyme solution, incubate in a water bath at 40 °C for 5 min, add 1 ml of 2% carboxymethyl cellulose sodium solution (pre-warmed to 40 °C), incubate in a water bath at 40 °C for 10 min, add 2 ml of DNS solution, boil in a water bath for 5 min, cool to room temperature and make up the volume to 25 ml, and measure the OD value at a wavelength of 540 nm.

[0053] Convert the enzyme activity according to the following formula: U = [(milligrams of glucose × N) / 10] × 1000

[0054] (2) Determination of filter paper enzyme activity

[0055] Prepare a phosphate buffer with pH = 6 and plot the glucose standard curve according to the method for determining cellulase activity.

[0056] Inoculate at an inoculum size of 1% into the starch-producing liquid medium, culture at 30 °C and 180 r / min for 48 h, take the culture solution and centrifuge at 12000 r for 3 min to obtain the enzyme solution to be measured.

[0057] Cut the filter paper into strips of 1 × 6 cm (about 50 mg), and then cut them into pieces for later use.

[0058] Add a filter paper strip fragment, 1 mL of the enzyme solution to be tested, and 1 mL of buffer solution into a test tube.

[0059] Place the test tube in a constant temperature water bath at 50 °C for 1 h, then add 1.5 mL of DNS reagent, heat in a boiling water bath for 5 min and then cool it. After that, make up the volume to 25 mL, let it stand for 20 min and then measure the absorbance at a wavelength of 540 nm.

[0060] Calculate the glucose content within the standard curve and substitute it into the following formula for enzyme activity calculation:

[0061] U (U / mL) = glucose content / (volume of enzyme solution × 60)

[0062] (3) Determination of amylase activity

[0063] Inoculate according to an inoculum size of 1% into a starch-producing liquid medium, culture at 30 °C and 180 r / min for 48 h, and centrifuge the culture solution at 12000 r for 3 min to obtain the enzyme solution to be tested.

[0064] Prepare a 2 g / ml maltose solution and establish a standard curve according to Table 2 below.

[0065] Table 2 Parameter values set for preparing the maltose solution

[0066]

[0067] Take 1 ml of the enzyme solution, place it in a water bath at 40 °C for 5 min, add 1 ml of 1% starch solution (pre-warmed to 40 °C), keep it in a water bath at 40 °C for 10 min, add 2 ml of DNS solution, heat in a boiling water bath for 5 min, cool to room temperature and make up the volume to 25 ml, and measure the OD value at a wavelength of 540 nm.

[0068] Perform enzyme activity conversion according to the following formula: U = [(milligrams of maltose × N) / 10] × 1000

[0069] (4) Determination of lignin degradation rate

[0070] Strain culture: Add alkaline lignin to the LB liquid medium to make the final concentration 50 μg / mL, inoculate the strain according to an inoculum size of 1%, and culture at 30 °C for 48 h.

[0071] Reagent preparation: Take alkaline lignin powder, prepare a 40 μg / mL solution with distilled water. If the solubility of lignin in distilled water is low, adjust the pH to 12 to help dissolve and prepare a lignin standard solution; prepare an 8 mM potassium ferricyanide solution and a 0.1 M ferric chloride solution.

[0072] Establish a standard curve: Take 9 test tubes and operate according to Table 3 below:

[0073] Table 3 Parameter values ​​for preparing lignin solution

[0074]

[0075] The test tube was shaken for 5 min, incubated at 30°C for 10 min, and the OD700 value was measured. A standard curve was established based on the lignin concentration and absorbance value.

[0076] Determination: Take 1.5 mL of bacterial solution, add 100 μL of potassium ferrocyanide, and then immediately add 100 μL of ferric chloride, shake the test tube for 5 minutes, incubate at 30°C for 10 minutes, use blank LB medium as a control, and determine the OD700 absorbance value.

[0077] Calculation: Substitute the sample absorbance value into the standard curve, check the value, and calculate the degradation rate according to the following formula:

[0078] Degradation rate (%) = [(50-X) / 50]*100, where X is the value of the sample in the standard curve.

[0079] Example 4 Determination of the ability of soil Brevibacillus GZAUS211024 to degrade rice straw

[0080] (1) Activate Brevibacillus sp. GZAUS211024 in LB liquid culture medium, culture with shaking at 45° C. and 180 rpm for 18 h, and set aside.

[0081] (2) Dry the rice straw, cut it into small pieces about 5 cm in length, weigh 10 g, and wrap it in gauze.

[0082] (3) Use a spray bottle to evenly spray the bacterial solution on the small pieces of rice straw. Put the straw pieces sprayed with the bacterial solution into a ziplock bag and place it at 45°C for 15 days.

[0083] (4) Take out the rice straw segments and dry them at 60°C until constant weight.

[0084] (5) Calculate the straw degradation rate using the weight difference as an indicator.

[0085] In order to further verify the reliability of the present invention and screen out the best solution, the inventor conducted a series of experiments, as follows:

[0086] 1. Isolation and screening methods of Bacillus

[0087] (1) Sample collection

[0088] Soil was collected near the hot spring water source in Guizhou Province, and the surface dead branches and leaves were removed. Soil samples with a depth of 0-5 cm were taken and stored at room temperature.

[0089] (2) Culture medium

[0090] LB liquid medium: Tryptone 10 g / L, Yeast extract powder 5.0 g / L, NaCl 10 g / L.

[0091] Starch-producing liquid medium: Soluble starch 10 g / L, Sodium chloride 5 g / L, Potassium dihydrogen phosphate 2 g / L, Calcium chloride 0.5 g / L, Magnesium sulfate 0.5 g / L, Ferrous sulfate heptahydrate 0.5 g / L, Agar 20 g / L.

[0092] (3) Isolation and screening of strains

[0093] Collect the soil near the hot spring water source: Remove the surface layer of dead branches and leaves, dig out the finer soil, and store it at room temperature.

[0094] Weigh 10 g of the stored soil, add 100 mL of PBS buffer (pH 7.2), shake well, and incubate at 85 °C for 1 h.

[0095] Take 1 mL of the incubated suspension and add it to 100 mL of LB liquid medium, shake the bacteria at 45 °C for 24 h. Take the bacterial liquid and add it to the PBS buffer incubated at 45 °C for 1 h, and dilute it 105, 106, and 107 times; Take 100 μL of the above-mentioned bacterial dilution and spread it on the NA plate, with three replicates for each treatment; After culturing at 45 °C for 1 d, pick the single colonies with phenotypic differences and streak them on the LB medium for purification culture; All treatments are cultured at 45 °C for 2 d to obtain Bacillus.

[0096] II. Identification methods

[0097] Including morphological identification and biological identification, specifically as follows:

[0098] (1) Morphological identification

[0099] Inoculate the Bacillus GZAUS211024 strain into the LB medium and culture it at 45 °C for 48 h. After that, yellowish-white colonies can be seen on the LB medium. The colonies are round with neat edges. During the later stage of culturing for 3 - 5 d, the color of the strain gradually turns brown (see Figure 1 ). Gram-positive staining, the bacterial cells are rod-shaped and arranged singly (see Figure 2 ).

[0100] (2) Molecular biological identification

[0101] After culturing the Bacillus GZAUS211024 strain in the LB medium for 48 h, send it to Guangzhou Aiji Biotechnology Co., Ltd. for sequencing. The length of the sequencing sequence is about 1400 bp, and the sequence number is SEQ ID NO.1;

[0102] Sequencing primer DNA sequence:

[0103] 27F rDNA (Forward primer): TACGGYTACCTTGTTACGACTT;

[0104] 1492R rDNA (Reverse primer): AGAGTTTGATCMTGGCTCAG;

[0105] In the GenBank database of NCBI, the 16S rDNA sequence of strain GZAUS211024 was retrieved and identified using BLAST.

[0106] The results showed that it had the closest genetic relationship with Brevibacillus agri (see Figure 3 ).

[0107] SEQ ID NO.1:

[0108]

[0109] III. Functional verification of the strain Brevibacillus agri GZAUS211024

[0110] 1. Detection of the temperature tolerance of Brevibacillus agri GZAUS211024

[0111] Inoculate into LB liquid medium at an inoculation amount of 1%, and culture with shaking at 180 rpm at 30 °C, 35 °C, 40 °C, 45 °C, and 50 °C respectively. Detect the OD 600 value every 4 h.

[0112] Draw the growth curve of Brevibacillus agri GZAUS211024 at different temperatures.

[0113] The results are shown in Figure 4 . Below 45 °C, the OD600 value of the strain is less than 0.5 within 24 h. Above 45 °C, the strain enters the exponential growth phase 4 h after growth and reaches the stationary phase 20 h later, and the OD600 value stabilizes at about 2.0. This indicates that there is a direct relationship between the growth state of the strain and temperature, and there is obvious thermophilia.

[0114] 2. Determination of the substance degradation ability of Brevibacillus agri GZAUS211024

[0115] 2.1 Determination of cellulase activity

[0116] Inoculate into LB liquid medium at an inoculation amount of 1%, culture at 45 °C and 180 rpm for 24 h, take the culture solution and centrifuge at 12000 rpm for 3 min to obtain the enzyme solution to be measured. Prepare a 2 mg / mL glucose solution and draw a standard curve according to Table 4:

[0117] Table 4 Parameter values set for preparing glucose solution

[0118]

[0119] Take 1 ml of the enzyme solution, water bath at 40 °C for 5 min, add 1 ml of 2% carboxymethyl cellulose sodium solution (pre-warmed at 40 °C), water bath at 40 °C for 10 min, add 2 ml of DNS solution, boil in a water bath for 5 min, cool to room temperature and make up the volume to 25 ml, and measure the OD value at a wavelength of 540 nm.

[0120] Perform enzyme activity conversion according to the following formula: U = [(milligrams of glucose × N) / 10] × 1000

[0121] The standard curve is as shown in Figure 5 , and the enzyme activity is shown in Figure 8 .

[0122] 2.2 Determination of filter paper enzyme activity

[0123] Prepare a phosphate buffer solution with pH = 6 and draw a glucose standard curve according to the cellulase activity determination method.

[0124] Inoculate at an inoculum size of 1% into LB liquid medium and culture at 30 °C and 180 r / min for 48 h. Take 12000 r of the culture solution and centrifuge for 3 min to obtain the enzyme solution to be measured.

[0125] Cut the filter paper into strips of 1×6 cm (about 50 mg), and then cut them into pieces for later use.

[0126] Add a piece of filter paper fragment, 1 mL of the enzyme solution to be measured, and 1 mL of buffer solution into a test tube.

[0127] Place the test tube in a constant temperature water bath at 50 °C for 1 h, then add 1.5 mL of DNS reagent, boil in a water bath for 5 min and then cool, and then make up the volume to 25 mL. After standing for 20 min, measure the absorbance at a wavelength of 540 nm.

[0128] Calculate the glucose content within the standard curve and substitute it into the following formula for enzyme activity calculation:

[0129] U (U / mL) = glucose content / (enzyme solution volume × 60)

[0130] Result: Under the condition of 45 °C, the filter paper enzyme activity of strain GZAUS211024 reached 40.68 U / mL.

[0131] 2.3 Determination of amylase activity

[0132] Inoculate at an inoculum size of 1% into starch-producing liquid medium and culture at 30 °C and 180 r / min for 48 h. Take 12000 r of the culture solution and centrifuge for 3 min to obtain the enzyme solution to be measured.

[0133] Prepare a 2 g / ml maltose solution and establish a standard curve according to Table 5 below.

[0134] Table 5 Parameter values set for preparing maltose solution

[0135]

[0136] Take 1 ml of the enzyme solution and place it in a water bath at 40 °C for 5 min, add 1 ml of 1% starch solution (pre-warmed at 40 °C), place it in a water bath at 40 °C for 10 min, add 2 ml of DNS solution, boil in a water bath for 5 min, cool to room temperature and make up the volume to 25 ml, and measure the OD value at a wavelength of 540 nm.

[0137] Perform enzyme activity conversion according to the following formula: U = [(maltose milligram number × N) / 10] × 1000

[0138] The standard curve is as Figure 6As shown, the enzyme activity is shown Figure 8 .

[0139] 2.4 Determination of lignin degradation rate

[0140] Strain culture: add alkaline lignin to LB liquid medium to make the final concentration of 50 μg / mL, inoculate the strain at a 1% inoculation amount, and culture at 30° C. for 48 h.

[0141] Reagent preparation: Take alkaline lignin powder and prepare it into a 40 μg / mL solution with distilled water. If the solubility of lignin in distilled water is low, the pH can be adjusted to 12 to help dissolution and prepare a lignin standard solution; prepare 8mM potassium ferrocyanide solution and 0.1M ferric chloride solution.

[0142] Standard curve establishment: Take 9 test tubes and follow the steps in Table 6 below:

[0143] Table 6 Parameter values ​​for preparing lignin solution

[0144]

[0145] The test tube was shaken for 5 min, incubated at 30°C for 10 min, and the OD700 value was measured. A standard curve was established based on the lignin concentration and absorbance value.

[0146] Determination: Take 1.5 mL of bacterial solution, add 100 μL of potassium ferrocyanide, and then immediately add 100 μL of ferric chloride, shake the test tube for 5 minutes, incubate at 30°C for 10 minutes, use blank LB medium as a control, and determine the OD700 absorbance value.

[0147] Calculation: Substitute the sample absorbance value into the standard curve, check the value, and calculate the degradation rate according to the following formula:

[0148] Degradation rate (%) = [(50-X) / 50]*100, where X is the value of the sample in the standard curve.

[0149] The standard curve is as follows Figure 7 shown.

[0150] 2.5 Lipase activity assay

[0151] The lipase activity test was performed using a lipase-LPS test kit, catalog number: YX-C-B402, which was sourced from Hefei Lyle Biotechnology Co., Ltd.

[0152] Results: At 45℃, the lipase activity reached 100.77±9.84U / mL.

[0153] In summary, through the cellulase activity test of Brevibacillus agri GZAUS211024, it is confirmed that Brevibacillus agri GZAUS211024 has relatively high cellulase, lipase, and amylase activities under the high temperature condition of 45°C. At 45°C, its cellulase activity reaches 154.41±4.95 U / mL, lipase activity reaches 100.77±9.84 U / mL, amylase activity reaches 90.10±3.55 U / mL, and filter paper enzyme activity reaches 40.68±2.99 U / mL, indicating that strain GZAUS211024 has good and stable degradation ability for polysaccharides and fats at high temperature (see Figure 8 ).

[0154] 3. Determination of the ability of Brevibacillus agri GZAUS211024 to degrade rice straw

[0155] 1) Activate Brevibacillus agri GZAUS211024 in LB liquid medium and shake culture at 45°C and 180 rpm for 18 h for standby.

[0156] 2) Dry the rice straw and cut it into small sections about 5 cm in length. Weigh 10 g and wrap it with gauze.

[0157] 3) Use a spray bottle to evenly spray the bacterial solution on the small rice straw sections. Put the rice straw sections sprayed with the bacterial solution into a self-sealing bag and place it at 45°C for 15 d.

[0158] 4) Take out the rice straw sections and dry them at 60°C to constant weight.

[0159] Calculate the straw degradation rate with the weight difference as the index. See Table 7.

[0160] Table 7 Determination of the ability of Brevibacillus agri GZAUS211024 to degrade rice straw

[0161]

[0162] Results: Through the experiment on the degradation of rice straw by Brevibacillus agri GZAUS211024, it is confirmed that under the high temperature condition of 45°C, the degradation rate of rice straw reaches 39.10% within 15 days. The observation results of the rice straw structure show that when treated with a single strain at high temperature for 15 days, it can significantly weaken the stable fiber network structure in the rice straw and achieve the effect of substantially degrading the lignocellulose component. See Figure 9 .

[0163] Although the present invention has been described in detail above with general descriptions and specific embodiments, some modifications or improvements can be made based on the present invention, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. A thermophilic soil brevis bacillus with strong fiber degradation function, characterized in that: The strain was named Brevibacillus agri GZAUS211024, deposited in Guangdong Provincial Microbiological Culture Collection Center, with the deposit number GDMCC 65171 and the deposit date of December 13, 2024.

2. Use of the thermophilic soil brevis bacillus according to claim 1 in the preparation of lignin, cellulose, starch and fat degrading bacterial agents.

3. The use according to claim 2, characterized in that The thermophilic soil brevis bacillus is used in preparing a bacterial agent capable of simultaneously degrading lignin, cellulose, starch and fat at high temperature.

4. The use according to claim 3, characterized in that The high temperature is 45°C.

5. Use of the thermophilic soil brevis bacillus according to claim 1 in preparing a pure lignin-degrading bacterial agent.

6. Use of the thermophilic soil brevis bacillus according to claim 1 in degrading rice straw.

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