Preparation method and application of solid microbial inoculum for fiber extraction

Abstract

The invention discloses a preparation method and application of a solid microbial inoculum for fiber extraction, and the preparation method comprises the following steps: inoculating activated DCE-01 and BE-91 seed solutions into a fermentation culture solution for propagation fermentation to obtain a mature fermentation solution, concentrating the mature fermentation solution, then adding a protective agent onto the concentrated fermentation solution, and uniformly mixing to obtain wet bacterial powder; and finally, flatly paving the wet bacterial powder, and drying at 25-30 DEG C to obtain the product. According to the invention, two excellent microorganisms are selected to prepare the complex microbial inoculant, so that the fiber extraction effect is enhanced; the corn steep liquor dry powder and the peanut cake powder are used for replacing most peptone to prepare the fermentation culture solution, so that the production cost is reduced, and a flocculation effect is achieved; the sterilized bran and the cottonseed meal are selected as protective agents, the thallus adsorption capacity is large, the subsequent drying load is reduced, and meanwhile, the bran and the cottonseed meal contained in the fungicide can provide nutrient substances needed by strain growth for subsequent retting of the fungicide; by adopting a cold air normal pressure drying method, DCE-01 and BE-91 strains are protected from being damaged to the maximum extent, energy is saved, and theoretical and practical significance is great.

Description

Technical Field

[0001] The present invention relates to the technical field of plant fiber raw material processing, and in particular to a preparation method and application of a solid bacterial agent for fiber extraction. Background Art

[0002] Plants are one of the world's most important sources of natural fiber. To obtain plant fibers that meet industrial requirements, fiber extraction processes are necessary to remove non-cellulosic substances (commonly known as "colloids") such as pectin, hemicellulose, and lignin. Traditional chemical extraction, using caustic soda as a core, suffers from significant pollution and fiber damage. Bioextraction, using microorganisms as a core, offers advantages of being "green, environmentally friendly, and highly efficient," and is the trend in fiber extraction.

[0003] The core of implementing fiber biological extraction is to obtain efficient strains. The applicant's team previously selected and bred the highly efficient strain D.dadantii DCE-01 for hemp degumming, which can simultaneously and efficiently process a variety of plant fiber raw materials including kenaf, jute, flax, industrial hemp, etc. This single strain of DCE-01 is suitable for pure cultivation in a fermentation workshop to complete factory-scale fiber extraction of plant raw materials. In addition, the DCE-01 strain is a thermosensitive Gram-negative bacterium, and its strain preparation technology is relatively difficult. In particular, the technical problem of easy degradation and mutation of the strain restricts its further expansion of application in kenaf / kenaf and flax / flax retting. B.subtilis BE-91 is a strain that our team screened in the early stage that can efficiently degrade hemicellulose, but it lacks pectinase and ligninase, and cannot remove pectin and lignin from fiber raw materials. Therefore, it cannot be used alone for fiber extraction.

[0004] The invention prepares a high-efficiency mixed solid microbial agent by drying D. dadantii DCE-01 and B. subtilis BE-91 under the condition of cold air, thereby solving the problems of low activity, incomplete enzyme system and high cost of the existing fiber biological extraction microbial agent. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention provides a method for preparing and applying a solid-state inoculant for fiber extraction. This method utilizes the synergistic effects of DCE-01 and BE-91 to improve fiber extraction efficiency. Furthermore, by adjusting the preparation method, a microbial inoculant with a higher viable count is obtained.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A preparation method and application of a solid bacterial agent for fiber extraction comprises the following steps: mixing activated DCE-01 and BE-91 seed liquid and inoculating the mixture into a fermentation culture medium for expansion and fermentation; concentrating the obtained mature fermentation liquid; adding a protective agent to the concentrated fermentation liquid and mixing the mixture uniformly to obtain a wet bacterial powder; and finally spreading the wet bacterial powder flatly and drying it at 25-30°C.

[0008] Specifically, the fermentation culture solution has a mass ratio formula of: glucose 0.5-1.5% + corn steep liquor powder 1.0-2.0% + peanut cake powder 1.0-2.0% + peptone 0.5% + NaCl 0.5%, and the balance is water.

[0009] In the above technical solution, the expansion fermentation method is as follows: the DCE-01 and BE-91 seed solution mixture and the fermentation culture medium are placed in a sealed fermentation tank at a volume ratio of 1:40-50, the filling volume is controlled to be 40-60% of the fermentation tank volume, and the pH value is controlled to 6.5-7.0 by adding NH3·H2O, 32-35°C, and the stirring speed is 200-220r / min, corresponding to a ventilation rate of 0.3-0.5m per liter of seed solution. 3 / h, and ferment for 12-14h until the pH value remains constant or increases.

[0010] In the above technical solution, before being used for expansion and fermentation, the fermentation culture medium is sterilized at 121° C. for 20-30 min, and the pH value is adjusted to 7.0-7.5 with NH 3 ·H 2 O before sterilization.

[0011] Furthermore, in the above technical solution, the concentration of DCE-01 bacteria in the mature fermentation broth is greater than 1×10 9 cfu / mL, the concentration of BE-91 bacteria was greater than 1×10 10 cfu / mL.

[0012] In detail, in actual application, the mature fermentation liquid is usually subjected to a degumming experiment to verify its bacterial activity. The specific method is as follows: 2 wt% of the mature fermentation liquid is added to tap water preheated at 35°C to form a bacterial suspension, and the kenaf bast and the bacterial suspension are soaked in a bath ratio of 1:10; the kenaf bast is allowed to stand for degumming at 35°C for 10-12 hours, and the kenaf bast becomes soft and the fiber dispersion is good, indicating that the mixed strains of DCE-01 and BE-01 have high activity.

[0013] In the above technical solution, the concentrated fermentation broth is collected by centrifugation at a speed of 3000-5000 r / min for 20-30 min. In actual application, 1 / 5-1 / 4 of the supernatant is usually retained and remixed to obtain the concentrated fermentation broth.

[0014] Specifically, the presence of corn steep liquor and peanut meal in the fermentation broth significantly increased its sedimentation coefficient, resulting in a favorable sedimentation effect. Furthermore, the supernatant after centrifugation was subjected to lens testing, stained with crystal violet, and observed for bacterial counts under an oil immersion lens (40×100 magnification). Fewer than 10 bacterial cells were observed in each field of view, demonstrating favorable centrifugation results.

[0015] Furthermore, in the above technical solution, the protective agent is a mixture of sterilized bran and cottonseed powder. Preferably, the mass ratio of the sterilized bran to the cottonseed powder is 1:1, and the mass ratio of the concentrated fermentation liquid to the mixture of sterilized bran and peanut cake powder is 1:5-8.

[0016] In the above technical solution, the drying method of the wet bacterial powder is: spreading the wet bacterial powder on a stainless steel mesh screen with a thickness of 1-2 cm, and drying it with cold air at 25-30° C. for 25-40 minutes until the moisture content is 6-8%.

[0017] Furthermore, in the above technical solution, the content of the finished microbial agent in the vacuum package after crushing is greater than 1×10 9 cfu / g, the content of BE-91 bacteria is greater than 1×10 10 cfu / g.

[0018] Furthermore, in the above technical solution, the solid inoculum obtained by mixing the DCE-01 and BE-91 strains can be directly used in the field of fiber extraction such as kenaf / jute and hemp / flax retting.

[0019] Advantages of the present invention:

[0020] (1) The preparation method and application of the solid bacterial agent for fiber extraction provided by the present invention are to prepare a composite bacterial agent by mixed culture of DCE-01 and BE-01 strains, enrich the colloid-degrading enzyme system of plant fiber raw materials, enhance the degradation ability of non-cellulose substances, and improve the fiber preparation efficiency.

[0021] (2) The preparation method and application of the solid bacterial agent for fiber extraction provided by the present invention greatly reduces production costs by adjusting the formula of the fermentation culture medium and replacing most of the peptone with corn steep liquor powder and peanut cake powder. In addition, these two new nitrogen sources can change the overall properties of the culture medium and promote the subsequent growth and reproduction of mixed bacteria. The two coarse-grained fermentation medium components also enhance the adsorption and sedimentation of bacteria in the mature fermentation liquid, achieving the effect of immobilization and flocculation.

[0022] (3) The preparation method and application of the solid microbial agent for fiber extraction provided by the present invention, by selecting sterilized bran and cottonseed powder as a composite protective agent, the adsorption capacity of the microorganism is large, and the fluffy nature of the sterilized bran reduces the load of subsequent drying, and the actual application effect is excellent; at the same time, the bran and peanut cake powder contained in the microbial agent can provide the nutrients required for the growth of the microorganisms for the subsequent retting of the microbial agent, which is convenient for direct feeding;

[0023] (4) The preparation method and application of the solid bacterial agent for fiber extraction provided by the present invention, by adopting the cold air normal pressure drying method, can protect the DCE-01 and BE-91 strains from damage to the greatest extent and save energy; the process is simple, the cost is low, and it is easy to promote and apply, with broad practical application prospects and great theoretical and practical significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a process flow chart of the preparation method and application of the solid bacterial agent for fiber extraction provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The specific implementation of the present invention is further described in detail below with reference to the accompanying drawings and specific examples.

[0026] The following examples are used to illustrate the present invention but are not used to limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0027] Unless otherwise specified, the experimental reagents and materials used in the examples of the present invention are commercially available. Unless otherwise specified, the technical means used in the examples of the present invention are conventional means well known to those skilled in the art.

[0028] Example 1 Preparation method and application of a solid bacterial agent for fiber extraction

[0029] A loop of DCE-01 strain was picked from the slant original strain moss preserved by the Plant Fiber Functional Materials Innovation Team of the Institute of Hemp, Chinese Academy of Agricultural Sciences and inoculated into 5 mL of modified broth culture medium (i.e., GR culture medium, whose mass ratio formula is: 1% glucose + 0.5% beef extract + 0.5% peptone + 0.5% NaCl, adjusted to pH 7.5), fully suspended, and cultured at 35°C for 6 hours; after dilution, spread on YQ nutrient agar plate, cultured at 35°C for 20 hours, and single colonies were isolated; typical colonies were selected and streaked on a fresh slant, cultured at 35°C for 20 hours, vacuum-packed, and stored at room temperature; 1 mL of sterilized improved broth culture medium was poured into one of the above-mentioned slant strains, and the surface moss was gently scraped with an inoculation loop to ensure that all the moss was mixed into the culture medium.

[0030] A loop of BE-91 strain was picked from the slant original strain moss preserved by the Plant Fiber Functional Materials Innovation Team of the Institute of Hemp, Chinese Academy of Agricultural Sciences and inoculated into 5 mL of improved broth culture medium (i.e., GR culture medium, whose mass ratio formula is: 1% glucose + 0.5% beef extract + 0.5% peptone + 0.5% NaCl, adjusted to pH 7.5), fully suspended and cultured at 35°C for 6 hours; after dilution, spread on YQ nutrient agar plate, cultured at 35°C for 20 hours, and single colonies were isolated; typical colonies were selected and streaked on a fresh slant, cultured at 35°C for 20 hours, vacuum-packed, and stored at room temperature; 1 mL of sterilized improved broth culture medium was poured into one of the above-mentioned slant strains, and the surface moss was gently scraped with an inoculation loop to ensure that all the moss was mixed into the culture medium.

[0031] The liquid mixed with the bacterial moss was inoculated into a 100 mL Erlenmeyer flask containing 40 mL of GR culture medium, mixed thoroughly, and cultured in a water bath shaker at 35°C and 180 r / min for 5 h to obtain the first-level seed liquid; the first-level seed liquid was then inoculated into a 3500 mL Erlenmeyer flask containing 1000 mL of GR culture medium, mixed thoroughly, and cultured in a water bath shaker at 35°C and 180 r / min for 6 h to obtain the second-level seed liquid.

[0032] DCE-01 and BE-91 secondary seed liquid were mixed in a ratio of 1:40-50, and 0.6-0.8 L of the mixed liquid was inoculated into a 50 L fermenter (Bio, Germany) containing 30 L of fermentation culture medium. NH3·H2O was added automatically and continuously to maintain the pH at 6.7. The ventilation volume was 0.7 m 3 / h, 34℃, 180r / min for 10h, i.e., until the pH slightly rises, fermentation is terminated and the mature fermentation broth is harvested.

[0033] Specifically, the mass ratio formula of the fermentation culture medium is: glucose 0.5-1.5% + corn steep liquor powder 1.0-2.0% + peanut cake powder 1.0-2.0% + peptone 0.5% + NaCl 0.5%, and the balance is water.

[0034] According to the standard "Test Method for Lactic Acid Bacteria in Import and Export Food" (SN / T 1941.1-2017), the viable bacteria of DCE-01 and BE-91 in the mature fermentation broth were separated and counted by gradient dilution method. The viable bacteria counts were 1.2×10 9 cfu / mL and 2.2×10 10 cfu / mL.

[0035] A bacterial suspension was prepared by adding 2% DCE-01 mature fermentation broth to preheated tap water at 35°C. 20g of kenaf was then soaked in 200ml of this suspension. Degumming at 35°C revealed that the kenaf bast began to soften after 10 hours and was completely softened after 11.5 hours. The fibers showed good fiber dispersion, confirming the high activity of the DCE-01 and BE-01 mixed strains.

[0036] The mature fermentation broth was centrifuged at 5000 rpm for 20 minutes to collect the cells. The supernatant was then used for lens examination, stained with crystal violet, and the cells were counted under an oil immersion lens (40 × 100 magnification). Five to eight cells were observed per field of view, indicating good centrifugation.

[0037] Take 30L of mature fermentation broth, concentrate it to 5-6L, add 25kg of sterilized bran and cottonseed meal, mix thoroughly, and spread the wet bacterial powder on a stainless steel mesh screen to a thickness of 1cm. Dry in a tea dryer with cold air blowing at 28°C for approximately 30 minutes (mix and spread the powder every 10 minutes). Use a grinder to grind the bacterial powder through a 100-mesh sieve and vacuum-pack it to obtain the finished solid inoculum. Using a moisture meter, the finished solid inoculum contains approximately 8-10% moisture. The viable bacterial counts of DCE-01 and BE-91, measured by gradient dilution, are 8.1×10, respectively. 9 cfu / g and 9.09×10 10 cfu / g.

[0038] After calculation, the total recovery rate of DCE-01 and BE-91 live bacteria prepared by the solid bacterial powder in the example was 24.5%.

[0039] Comparative Example 1

[0040] The difference from Example 1 is:

[0041] The mass ratio formula of the fermentation culture liquid is: glucose 0.5-1.5%+corn steep liquor dry powder 1.0-2.0%+soybean meal 1.0-2.0%+peptone 0.5%+NaCl 0.5%, and the balance is water.

[0042] The rest of the preparation method is the same as that in Example 1.

[0043] According to the standard "Test Method for Lactic Acid Bacteria in Import and Export Food" (SN / T 1941.1-2017), the viable bacteria of DCE-01 and BE-91 in the mature fermentation broth were separated and counted by gradient dilution method. The viable bacteria counts were 5.2×10 8 cfu / mL and 1.4×10 9 cfu / mL.

[0044] The activity of the fermentation liquid was verified by the kenaf degumming test. The kenaf began to soften after 14 hours and the fiber dispersion was poor, which verified that the activity of the mixed strains of DCE-01 and BE-01 was basically qualified.

[0045] The moisture content of the finished solid microbial agent was about 8-10% when tested with a moisture meter. The viable bacterial counts of DCE-01 were 2.2×10 8 cfu / g and 8.4×10 8 cfu / g.

[0046] After calculation, the total recovery rate of DCE-01 and BE-91 live bacteria in the solid bacterial powder prepared by the preparation method of Comparative Example 1 was 15.1%.

[0047] Comparative Example 2

[0048] The mass ratio formula of the fermentation culture medium is: glucose 1%+beef extract 2.0%+peptone 0.5%+NaCl 0.5%, and the balance is water.

[0049] The rest of the preparation method is the same as that in Example 1.

[0050] According to the standard "Test Method for Lactic Acid Bacteria in Food for Import and Export" (SN / T 1941.1-2017), the viable bacteria of DCE-01 and BE-91 in the mature fermentation broth were separated and counted by gradient dilution method. The viable bacteria counts were 1.04×10 8 cfu / mL and 1.38×10 9 cfu / mL.

[0051] The activity of the fermentation liquid was verified by the kenaf degumming test. The kenaf became soft after 14 hours and the fiber dispersion was good, which verified that the activity of the mixed strains of DCE-01 and BE-01 was basically qualified.

[0052] The moisture content of the finished solid microbial agent was about 8-10% when the moisture meter was used. The viable bacterial counts of DCE-01 were 8.02×10 7 cfu / g and 9.4×10 8 cfu / g.

[0053] After calculation, the total recovery rate of DCE-01 and BE-91 live bacteria in the solid bacterial powder prepared by the preparation method of Comparative Example 2 was 8.1%.

[0054] Comparative Example 3

[0055] The rest is the same as in Example 1.

[0056] Take 30L of mature fermentation broth, concentrate it to 5-6L, add 25kg of sterilized cottonseed powder, mix thoroughly, and spread the wet powder on a stainless steel mesh screen to a thickness of 1cm. Dry in a tea dryer with cold air blowing at 28°C for approximately 30 minutes (mix and spread the powder every 10 minutes). Use a grinder to grind the powder through a 100-mesh sieve and vacuum-pack it to obtain the finished solid inoculum. Using a moisture meter, the moisture content of the finished solid inoculum is approximately 12%. The viable bacterial counts of DCE-01 and BE-91, measured by gradient dilution, are 3.7×10 8 cfu / g and 9.09×10 7 cfu / g.

[0057] After calculation, the total recovery rate of live bacteria of DCE-01 and BE-91 in the solid bacterial powder prepared by the preparation method of Comparative Example 3 was 1.4%.

[0058] Comparative Example 4

[0059] The rest is the same as Example 1.

[0060] Take 30L of mature fermentation broth, concentrate it to 5-6L, add 25kg of sterilized bran, mix thoroughly, and spread the wet bacterial powder on a stainless steel mesh screen to a thickness of 1cm. Dry in a tea dryer with cold air blowing at 28°C for approximately 30 minutes (mix and spread the powder every 10 minutes). Use a grinder to grind the bacterial powder through a 100-mesh sieve and vacuum-pack it to obtain the finished solid bacterial inoculant. Using a moisture meter, the moisture content of the finished solid bacterial inoculant is approximately 8-9%. The viable bacterial counts of DCE-01 and BE-91, measured by gradient dilution, are 2.37×10 8 cfu / g and 3.09×10 8 cfu / g.

[0061] After calculation, the total recovery rate of DCE-01 and BE-91 live bacteria prepared by the solid bacterial powder of Comparative Example 4 was 4.5%.

[0062] Comparative Example 5

[0063] 0.6-0.8 L of DCE-01 secondary seeds were inoculated into a 50 L fermenter (Biotech, Germany) containing 30 L of fermentation broth. NH3·H2O was added automatically to maintain the pH at 6.7. The ventilation volume was 0.7 m 3 / h, 34℃, 180r / min for 10h, i.e., until the pH slightly rises, the fermentation is terminated and the mature fermentation broth is harvested.

[0064] The rest is the same as Example 1.

[0065] According to the standard "Test Method for Lactic Acid Bacteria in Food for Import and Export" (SN / T 1941.1-2017), the DCE-01 viable bacteria in the mature fermentation broth were separated and counted by gradient dilution method, and the viable bacteria counts were 6.74×10 9 cfu / mL.

[0066] The activity of the fermentation liquid was verified by the kenaf degumming test. The kenaf began to soften after 14 hours and the fiber dispersion was poor, which verified that the DCE-01 strain was not active enough.

[0067] The moisture content of the finished solid microbial agent was about 8-10% when tested with a moisture meter. The viable bacterial counts of DCE-01 were 3.02×10 9 cfu / g.

[0068] After calculation, the total recovery rate of DCE-01 live bacteria prepared by the solid bacterial powder of Comparative Example 5 was 10.2%.

[0069] Comparative Example 6

[0070] 0.6-0.8 L of BE-91 secondary seeds were inoculated into a 50 L fermenter (Biotech, Germany) containing 30 L of fermentation broth. NH3·H2O was added automatically to maintain the pH at 6.7. The ventilation volume was 0.7 m 3 / h, 34℃, 180r / min for 10h, i.e., until the pH slightly rises, the fermentation is terminated and the mature fermentation broth is harvested.

[0071] The rest is the same as Example 1.

[0072] According to the standard "Test Method for Lactic Acid Bacteria in Import and Export Food" (SN / T 1941.1-2017), the BE-91 viable bacteria in the mature fermentation broth were separated and counted by gradient dilution method, and the viable bacteria counts were 1.38×10 9 cfu / mL.

[0073] The kenaf degumming test was used to verify the activity of the fermentation liquid. The kenaf did not become soft and the fibers did not disperse, which verified that the BE-01 strain had basically no independent degumming ability.

[0074] The moisture content of the finished solid microbial agent was about 8-10% when tested with a moisture meter. The viable bacterial counts of BE-01 were 3.4×10 9 cfu / g.

[0075] After calculation, the total recovery rate of BE-91 live bacteria prepared by the solid bacterial powder of Comparative Example 6 was 6.2%.

[0076] As can be seen from this, using kenaf retting effectiveness as a measure of bacterial strain activity, the kenaf retting effectiveness of the strains in the mature fermentation broths produced in Examples and Comparative Examples 1-6, from strongest to weakest, is: Example 1 > Comparative Example 2 > Comparative Example 1 > Comparative Example 3 = Comparative Example 4 > Comparative Example 5 > Comparative Example 6; the effectiveness of the bacterial inoculants produced in Examples and Comparative Examples 1-6, from strongest to weakest, is: Example 1 > Comparative Example 1 > Comparative Example 5 > Comparative Example 2 > Comparative Example 6 > Comparative Example 4 > Comparative Example 3. Comparative Examples 5 and 6 show that while BE-91 lacks independent degumming capabilities, its combination with DCE-01 significantly improves degumming effectiveness, demonstrating the synergistic effect of DCE-01 and BE-91 in the present invention. Comparative Examples 1 and 2 show that using soybean meal or beef extract as a nitrogen source in the fermentation broth affects bacterial viability and recovery in the inoculum. It can be seen from Comparative Examples 3 and 4 that when cottonseed powder and sterilized bran are used alone as protective agents, the bacterial count and recovery rate in the inoculum are greatly reduced; this indicates that cottonseed powder and sterilized bran used together as protective agents in this application can improve the bacterial count and recovery rate of the inoculum in this application.

[0077] Finally, the above is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a solid bacterial agent for fiber extraction, characterized in that: The activated Dickeya dandantii DCE-01 and Bacillus subtilis BE-91 seed liquid is inoculated into the fermentation medium and mixed and fermented. The mature fermentation liquid is concentrated, and then a protective agent is added to the concentrated fermentation liquid and mixed uniformly to obtain a wet bacterial powder. Finally, the wet bacterial powder is spread evenly and dried at 25-30°C. The fermentation culture solution has a mass ratio formula of: glucose 0.5-1.5% + corn steep liquor powder 1.0-2.0% + peanut powder 1.0-2.0% + peptone 0.5% + NaCl 0.5%, and the balance is water.

2. The preparation method according to claim 1, characterized in that The method of the expansion fermentation is as follows: the mixed solution of the DCE-01 and BE-91 seed solutions and the fermentation culture solution are placed in a sealed fermentation tank at a volume ratio of 1:40-50, the filling volume is controlled to be 40-60% of the volume of the fermentation tank, and the pH value is controlled to be 6.5-7.0 and 32-35° C. by adding NH 3 · H 2 O, the stirring speed is 200-220 r / min, and the ventilation volume per liter of seed solution is 0.3-0.5 m 3 / h, fermentation culture for 12-14h until the pH value remains constant or increases; The final concentration of DCE-01 inoculated into the fermentation tank culture medium was 1-5×10 5 cfu / ml, and the final inoculum concentration of BE-91 was 1×10 4 cfu / ml.

3. The preparation method according to claim 1, characterized in that Before being used for expansion and fermentation, the fermentation broth is sterilized at 121° C. for 20-30 min, and the pH value is adjusted to 7.0-7.5 with NH 3 ·H 2 O before sterilization.

4. The preparation method according to any one of claims 1 to 3, characterized in that The concentration of DCE-01 bacteria in the mature fermentation broth is greater than 1×10 9 cfu / mL, the concentration of BE-91 bacteria was greater than 1×10 10 cfu / mL.

5. The preparation method according to claim 1, characterized in that The concentrated fermentation liquid is collected by centrifugal separation, with a centrifugal speed of 3000-5000 r / min and a centrifugal time of 20-30 min.

6. The preparation method according to claim 1, characterized in that The protective agent is a mixture of sterilized bran and cottonseed powder.

7. The preparation method according to claim 6, characterized in that The mass ratio of the sterilized bran to the peanut cake powder is 1:1, and the mass ratio of the concentrated fermentation liquid to the mixture of the sterilized bran and cottonseed powder is 1:5-8.

8. The preparation method according to claim 1, characterized in that The drying method of the wet bacterial powder is as follows: the wet bacterial powder is fully mixed, spread on a stainless steel mesh screen to a thickness of 1-2 cm, and dried with cold air at 25-30° C. for 25-40 minutes until the moisture content is less than 10%; after crushing, vacuum packaging is performed to obtain the finished bacterial agent, wherein the content of DCE-01 bacteria is greater than 1×10 9 cfu / g, the content of BE-91 bacteria is greater than 1×10 10 cfu / g.

9. A solid bacterial agent for fiber extraction prepared by the preparation method according to any one of claims 1 to 7.

10. Use of the solid microbial agent for fiber extraction according to claim 9 in the retting process of jute, kenaf, hemp, ramie or flax.

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