Method for solid state fermentation of bagasse by using white rot fungi

Abstract

The invention relates to the technical field of biology, in particular to a method for solid state fermentation of bagasse by using white rot fungi, which comprises the following steps: (1) activation and propagation of strains: pouring the white rot fungi into a PDA culture medium for activation and propagation; (2) raw material preparation: air-drying fresh bagasse, adding water to adjust the water content of the bagasse to 60-70%, and adjusting the pH to 4-6 with glacial acetic acid; and (3) preparing the bagasse feed, namely mixing the white rot fungi subjected to expanding culture according to 1-5% of the weight of an air-dried substance with bagasse of which the initial pH is adjusted to be 4-6, adding 1-5% of soluble sugar, and fermenting for 10-45 days to obtain the fermented bagasse feed. According to the white rot fungus fermented bagasse prepared by the method disclosed by the invention, the hemicellulose content of the bagasse can be reduced to 26.62%-22.45%, the lignin content can be reduced to 10.67%-8.66%, the crude protein content of the bagasse can be increased to 1.61%-2.12%, the lactic acid content can be increased to 26.57 mg / L-181.69 mg / L, and high-quality feed application of the bagasse can be realized.

Description

Technical Field

[0001] The invention relates to the technical field of microbial fermentation, in particular to a method for solid-state fermentation of bagasse by utilizing white rot fungi. Background Art

[0002] Bagasse has the characteristics of high fiber and low protein, and has typical straw-like characteristics. Straw feed has a good prospect and can be used as roughage for ruminants. It contains a large amount of crude fiber, which can promote rumination and saliva secretion to maintain the normal physiological function of the rumen. However, the digestible cellulose and hemicellulose in the roughage combine with lignin to form a stable and complex lignin-hemicellulose-cellulose complex, and the rumen of ruminants lacks microorganisms and enzymes that can degrade lignin, resulting in the complex hindering the decomposition of roughage by proteases, cellulases, amylases and rumen microorganisms. If the sugarcane bagasse can be fermented by microorganisms to reduce lignocellulose, promote lactic acid and beneficial microorganisms to inhibit the reproduction of harmful bacteria, the fermentation quality of the sugarcane bagasse will be improved, the storage time will be extended, and the shortage of resource feed will be alleviated, which is of great significance for the application of sugarcane bagasse as a special biological feed. "Study on the Impact of White-rot Fungi and Aspergillus niger on the Degradation of Sugarcane Bagasse" discloses a method for fermenting sugarcane bagasse with white-rot fungi, but it does not consider adding some substances to improve the fermentation ability of the white-rot fungi themselves and thereby improve the nutritional value and fermentation quality of the fermented sugarcane bagasse. The present invention creatively adds soluble sugars and acetic acid to promote the fermentation of sugarcane bagasse with white-rot fungi, improves the nutritional value and fermentation quality of sugarcane bagasse, and conducts a more in-depth study on the fermentation of sugarcane bagasse with white-rot fungi. Summary of the invention

[0003] The present invention aims to solve the shortcomings of bagasse as a feed with high fiber content and low feeding value, improve the nutritional value and fermentation quality of bagasse, and provide a method for solid-state fermentation of bagasse using white rot fungi, thereby increasing the microbial richness of bagasse, reducing the relative abundance of caproic acid-producing bacteria, reducing the content of hemicellulose and lignin, increasing the crude protein content, and increasing the lactic acid content.

[0004] To achieve the above object, the technical solution of the present invention is: a method for solid-state fermentation of sugarcane bagasse using white rot fungi, wherein the fermented sugarcane bagasse is prepared by fermenting sugarcane bagasse and white rot fungi.

[0005] The bagasse is fresh bagasse produced after sugar cane is squeezed, and the bagasse is air-dried to obtain air-dried bagasse, and water is added to the bagasse after air-drying to adjust the water content to 60% to 70%.

[0006] The white rot fungus is Phanerochaete chrysosporium, 1% to 5% of the white rot fungus and 1% to 5% of the soluble sugar are contained in the air-dried matter by weight, the fermentation time is 10 to 45 days, the initial pH is 4 to 6,

[0007] The hemicellulose content of sugarcane bagasse fermented by white rot fungi is reduced to 26.62% to 22.45%, the lignin content is reduced to 10.61% to 8.66%, the crude protein content of bagasse is increased to 1.67% to 2.12%, and the lactic acid content is increased to 26.57 mg / L to 181.69 mg / L;

[0008] The white rot fungus fermented bagasse is prepared as follows:

[0009] (1) Activation and expansion of strains: Pour the white rot fungus (CHCC336258) into PDA medium for activation and expansion. After 2-3 generations of expansion by the 4-zone line method, the strain is transferred to PDB medium. The shaking speed is set at 140 r / min and the temperature is 27°C. Glass beads are added to prevent the strain from agglomerating into bacterial clumps. After culturing for 2-3 days, the bacterial solution becomes turbid. The expanded strain is counted by the plate count method and the resulting bacterial solution is placed in a 4°C refrigerator for later use.

[0010] (2) Raw material preparation: Spread fresh sugarcane bagasse evenly on the ground and air dry it naturally. Add distilled water to adjust the pH to 60% to 70% and measure the original pH. Then use glacial acetic acid to adjust the pH to 4 to 6.

[0011] (3) Preparing bagasse feed: mixing the white rot fungi cultured in step (1) at a ratio of 1% to 5% by weight of dry matter with the bagasse adjusted to pH 4 to 6 by glacial acetic acid in step (2) in a uniform manner, adding 1% to 5% by weight of sucrose, placing the mixture in a sealed can, compacting the mixture and sealing the can with plastic wrap, and fermenting the mixture in the dark at room temperature for 15 to 45 days to obtain fermented bagasse feed.

[0012] The PDB culture medium in step (1) is composed of: 6 g / L potato flour, 20 g / L glucose, 3.0 g / L KH2PO4, 1.5 g / L MgSO4·7H2O, trace vitamin B, 20.0 g / L agar, pH 6.0±0.2, and is prepared with distilled water and placed in an autoclave for sterilization at 121°C for 20 min.

[0013] The total number of colonies obtained by plate counting after the white rot fungus is expanded in step (1) is greater than 1.5*10^8 CFU / ml.

[0014] The white rot fungus is Phanerochaete chrysosporium, which is purchased from Beijing Zhongjian Beacon Metrology Technology Co., Ltd. (CHCC336258).

[0015] In step (2), the initial pH is adjusted to pH 4-6 using analytical grade glacial acetic acid.

[0016] In step (3), the fermentation is stored in a sealed manner.

[0017] 16srRNA sequencing analysis revealed that it can reduce the relative abundance of caproic acid-producing bacteria.

[0018] The outstanding beneficial effects of the present invention are:

[0019] 1. The present invention utilizes white rot fungi to solid-state ferment sugarcane bagasse. Through the strong degradation ability of white rot fungi on lignin, the extracellular lignin-degrading enzyme system is secreted to destroy the plant cell wall, thereby changing the internal structure of sugarcane bagasse and degrading lignin and hemicellulose into glucose.

[0020] 2. The produced carbohydrates and added carbohydrates can be used by beneficial microorganisms such as lactobacillus, and white rot fungi are aerobic bacteria. They consume oxygen in the early stage of fermentation, create an anaerobic environment, promote the reproduction of lactic acid bacteria, and then promote the accumulation of lactic acid content, inhibiting the reproduction of harmful bacteria.

[0021] 3. The hemicellulose content of the sugarcane bagasse fermented by the white rot fungus of the present invention is reduced to 26.62%-22.45%, the lignin content is reduced to 10.67%-8.66%, the crude protein content of the sugarcane bagasse is increased to 1.67%-2.12%, and the lactic acid content is increased to 26.57mg / L-181.69mg / L; thereby, the microbial richness of the sugarcane bagasse is improved, the relative abundance of caproic acid-producing bacteria is reduced, the hemicellulose and lignin contents are reduced, the crude protein content is increased, and the lactic acid content is increased.

[0022] 4. During the anaerobic fermentation process, the initial colony content, fermentation time, initial pH value and soluble sugar will affect the activity of the fermentation bacteria, thereby affecting the fermentation index. Therefore, the present invention has found through a large number of experimental studies that the fermented sugarcane bagasse index is optimal when the white rot fungi (total colony count> 1.5*10^8CFU / ml), the fermentation time is 30d, the initial pH is 4, and the soluble sugar is 5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Composition of bacterial genus level in fermentation broth at different fermentation ratios.

[0024] Figure 2 Comparative example of bacterial genus level distribution.

[0025] Figure 3 Example 1 Distribution of bacterial genus levels.

[0026] Figure 4 Example 2 Distribution of bacterial genus levels. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further described in detail below through examples.

[0028] Example 1

[0029] This embodiment is an example of the method for solid-state fermentation of bagasse using white rot fungi according to the present invention, comprising the following steps:

[0030] (1) Activation and expansion of strains: The white rot fungus (CHCC336258) purchased from Beijing Zhongjian Navigation Marking Metrology Technology Co., Ltd. was poured into PDA medium for activation and expansion. After 2-3 generations of vigorous expansion by the 4-zone line drawing method, it was transferred to PDB medium. The shaking speed was set to 140r / min and the temperature was 27°C. Glass beads were added to prevent it from condensing into bacterial clumps. After 2-3 days of cultivation, when the bacterial solution became turbid, the expanded strains were counted by the plate counting method. The obtained bacterial solution was placed in a 4°C refrigerator for later use;

[0031] Use a pipette to take 0.2 ml of the bacterial solution prepared above and pour it into a 2 ml centrifuge tube and then pour it into 1.8 ml of normal saline to prepare a 10-fold dilution. The 100-fold and 1000-fold dilution steps are carried out in the same way as the 10-fold dilution. After dilution, pour it into PDA agar for plate counting;

[0032] (2) Raw material preparation: Spread fresh bagasse evenly on the ground, air-dry and dry naturally. Use the four-point sampling method to take 20g of bagasse, add 66ml of distilled water to make its water content reach 70%, and then mix it evenly with 180mL of Ringer's solution. Let it stand for 5min, stir for 30s, filter with double-layer gauze, and collect the extract in a 200mL beaker. Use the standard solution to calibrate the pH meter (model: FE28) and insert it under the liquid surface of the extract to directly measure, read and record. According to the initial pH of the bagasse, adjust the pH to 4 with analytical grade glacial acetic acid;

[0033] (3) Preparation of bagasse feed: The cultured white rot fungi are added at a dry matter ratio of 3%, mixed with bagasse adjusted to pH 4 with glacial acetic acid, and 5% soluble sugar is added. The mixed bagasse is adjusted to a moisture content of 70% with distilled water, placed in a sealed can, compacted and sealed with plastic wrap, and fermented at room temperature in the dark for 30 days to obtain fermented bagasse feed.

[0034] The fermented bagasse feed was tested for nutritional components and fermentation index changes in the laboratory according to the methods for determination of neutral detergent fiber (NDF) in feed (GB / T20806-2006), determination of acid detergent fiber (ADF) in feed (NY / T 1459-2007), determination of acid detergent lignin (ADL) in feed (GB / T20805-2006), determination of crude ash in feed (GB / T6438-2007), pH in feed (pH meter model: FE28), determination of lactic acid in feed (p-hydroxybiphenyl method), determination of ammonia nitrogen in feed (phenol-sodium hypochlorite colorimetric method) and determination of volatile fatty acids in feed (gas chromatography), and the test results are listed in Tables 1 and 2.

[0035] Table 1 Effect of Example 1 Fermentation of Bagasse on Its Chemical Composition

[0036]

[0037]

[0038] Table 2 Effect of fermented bagasse on its fermentation index in Example 1

[0039]

[0040] According to the test data in Table 1 and Table 2, it can be seen that the hemicellulose content of Example 1 is 26.62%, and the hemicellulose content of Comparative Example 1 is 29.19%. It is 8.8% lower than that of Comparative Example 1. The lignin content of Example 1 is 8.66%, and the lignin content of Comparative Example 1 is 9.47%, which is 8.6% lower than that of Comparative Example 1. The crude protein content of Example 1 is 1.67%, and the crude protein content of Comparative Example 1 is 1.58%. It is 5.7% higher than that of Comparative Example 1. The lactic acid content of Example 1 is 181.69 mg / L, and the lactic acid content of Comparative Example 1 is 22.69 mg / L, which is 700.8% higher than that of Comparative Example 1. The acetic acid content of Example 1 is 22.92 mmol / L, and the acetic acid content of Comparative Example 1 is 6.07 mmol / L, which is 277.6% higher than that of Comparative Example 1.

[0041] Example 2

[0042] This embodiment is another example of the method for solid-state fermentation of bagasse using white rot fungi according to the present invention, comprising the following steps:

[0043] (1) fermenting bagasse under horizontal factor conditions of 5% white rot fungi (total colony count>1.5*10^8 CFU / g) based on the weight percentage of air-dried matter (% DM), 1% soluble sugar, fermentation time of 30 days, and initial pH of 6, and the operation steps are the same as step 1 in Example 1;

[0044] (2) Raw material preparation: Spread fresh bagasse evenly on the ground, air-dry and dry naturally. Use the four-point sampling method to take 20g of bagasse, add 66ml of distilled water to make its water content reach 70%, and then mix it evenly with 180mL of Ringer's solution. Let it stand for 5min, stir for 30s, filter with double-layer gauze, and collect the extract in a 200mL beaker. Use the standard solution to calibrate the pH meter (model: FE28) and insert it under the liquid surface of the extract to directly measure, read and record. According to the initial pH of the bagasse, adjust the pH to 6 with analytical grade glacial acetic acid;

[0045] (3) Preparation of bagasse feed: Add the expanded white rot fungi at a dry matter ratio of 5% and mix with bagasse adjusted to pH 6 with glacial acetic acid, add 1% soluble sugar, adjust the mixed bagasse to a moisture content of 70% with distilled water, place in a sealed can, compact and seal with plastic wrap, and ferment at room temperature in the dark for 30 days to obtain fermented bagasse feed.

[0046] The fermented bagasse feed was tested for nutritional components and fermentation index changes in the laboratory according to the methods of determination of neutral detergent fiber (NDF) in feed (GB / T20806-2006), determination of acid detergent fiber (ADF) in feed (NY / T 1459-2007), determination of acid detergent lignin (ADL) in feed (GB / T20805-2006), determination of crude ash in feed (GB / T6438-2007), pH in feed (pH meter model: FE28), determination of lactic acid in feed (p-hydroxybiphenyl method), determination of ammonia nitrogen in feed (phenol-sodium hypochlorite colorimetric method) and determination of volatile fatty acids in feed (gas chromatography), and the results are listed in Tables 3 and 4.

[0047] Table 3 Effect of fermentation of sugarcane bagasse on its chemical composition

[0048]

[0049] Table 4 Effect of fermented bagasse on its fermentation index in Example 2

[0050]

[0051]

[0052] According to the test data in Table 3 and Table 4, it can be seen that the hemicellulose content of Example 2 is 22.45%, and the hemicellulose content of Comparative Example 1 is 29.19%. It is 23.1% lower than that of Comparative Example 1. The lignin content of Example 2 is 10.67%, and the lignin content of Comparative Example 1 is 9.47%, which is 12.7% higher than that of Comparative Example 1. The crude protein content of Example 2 is 2.12%, and the crude protein content of Comparative Example 1 is 1.58%. It is 34.2% higher than that of Comparative Example 1. The lactic acid content of Example 2 is 26.57 mg / L, and the lactic acid content of Comparative Example 1 is 22.69 mg / L, which is 17.1% higher than that of Comparative Example 1. The acetic acid content of Example 2 is 12.50 mmol / L, and the acetic acid content of Comparative Example 1 is 6.07 mmol / L, which is 105.9% higher than that of Comparative Example 1.

[0053] Example 3

[0054] This embodiment is another example of the method for solid-state fermentation of bagasse using white rot fungi according to the present invention, comprising the following steps:

[0055] (1) fermenting bagasse under horizontal factor conditions of 1% white rot fungi (total colony count>1.5*10^8 CFU / g) based on the weight percentage of air-dried matter (% DM), 1% soluble sugar, fermentation time of 30 days, and initial pH of 4, and the operation steps are the same as step 1 in Example 1;

[0056] (2) Raw material preparation: Spread fresh bagasse evenly on the ground, air-dry and dry naturally. Use the four-point sampling method to take 20g of bagasse, add 66ml of distilled water to make its water content reach 70%, and then mix it evenly with 180mL of Ringer's solution. Let it stand for 5min, stir for 30s, filter with double-layer gauze, and collect the extract in a 200mL beaker. Use the standard solution to calibrate the pH meter (model: FE28) and insert it under the liquid surface of the extract to directly measure, read and record. According to the initial pH of the bagasse, adjust the pH to 6 with analytical grade glacial acetic acid;

[0057] (3) Preparation of bagasse feed: The cultured white rot fungi are added at a dry matter ratio of 1% and mixed with bagasse adjusted to pH 4 with glacial acetic acid, 1% soluble sugar is added, and the mixed bagasse is adjusted to a moisture content of 70% with distilled water. The mixture is placed in a sealed can, compacted and sealed with plastic wrap, and fermented at room temperature in the dark for 15 days to obtain fermented bagasse feed.

[0058] The fermented bagasse feed was tested for nutritional components and fermentation index changes in the laboratory according to the methods of determination of neutral detergent fiber (NDF) in feed (GB / T20806-2006), determination of acid detergent fiber (ADF) in feed (NY / T 1459-2007), determination of acid detergent lignin (ADL) in feed (GB / T20805-2006), determination of crude ash in feed (GB / T6438-2007), pH in feed (pH meter model: FE28), determination of lactic acid in feed (p-hydroxybiphenyl method), determination of ammonia nitrogen in feed (phenol-sodium hypochlorite colorimetric method) and determination of volatile fatty acids in feed (gas chromatography), and the results are listed in Tables 5 and 6.

[0059] Table 5 Effect of fermentation of sugarcane bagasse on its chemical composition

[0060]

[0061] Table 6 Effect of fermented bagasse on fermentation indexes in Example 3

[0062]

[0063]

[0064] According to the test data in Table 5 and Table 6, it can be seen that the hemicellulose content of Example 3 is 26.46%, and the hemicellulose content of Comparative Example 1 is 29.19%. It is 9.4% lower than that of Comparative Example 1. The lignin content of Example 3 is 9.07%, and the lignin content of Comparative Example 1 is 9.47%, which is 4.2% lower than that of Comparative Example 1. The crude protein content of Example 3 is 1.61%, and the crude protein content of Comparative Example 1 is 1.58%. It is 1.9% higher than that of Comparative Example 1. The lactic acid content of Example 3 is 52.59 mg / L, and the lactic acid content of Comparative Example 1 is 22.69 mg / L, which is 131.8% higher than that of Comparative Example 1. The acetic acid content of Example 3 is 10.17 mmol / L, and the acetic acid content of Comparative Example 1 is 6.07 mmol / L, which is 67.6% higher than that of Comparative Example 1.

[0065] Table 7 Comparison of three embodiments

[0066]

[0067]

[0068] Combined with the conventional nutrients and fermentation indicators of the three embodiments, two representative groups of embodiments, namely, embodiment 1 and embodiment 2, were selected, and 16srRNA sequencing was performed, with a total of 3 groups and 3 replicates in each group, i.e., 9 samples. From Table 6, Chao1 and ACE are richness indexes, Shannon and Simpson are diversity indexes, and the embodiments increase the microbial richness of sugarcane bagasse and reduce the microbial diversity of sugarcane bagasse.

[0069] Table 8: Alpha diversity index analysis table

[0070]

[0071]

[0072] like Figure 1 As shown, from the genus level, the dominant bacterial groups at the genus level in each group of fermentation broth are different. The genus with the highest relative abundance in Comparative Example 1 is Caproiciproducens; the genus with the highest relative abundance in Example 1 is Liquorilactobacillus; and the genus with the highest relative abundance in Example 2 is Clostridium.

[0073] At the bacterial genus level, Figure 1 and Figure 2 It can be seen that compared with Comparative Example 1, the abundance of caproic acid-producing bacteria in Example 1 and Example 2 is significantly reduced, indicating that white rot fungi have an inhibitory effect on them. The carbohydrates produced by the selective degradation of lignocellulose by white rot fungi are utilized by some acetic acid-producing and lactic acid bacteria, producing acetic acid and lactic acid to lower the pH, thereby inhibiting the growth of harmful bacteria and the relative abundance of caproic acid-producing bacteria.

[0074] From the perspective of conventional nutrients, it can be seen from Table 1, Table 3, and Table 5 that compared with the comparative example, the addition of 1% white rot fungi reduced hemicellulose by 9.4%, acid-insoluble lignin by 4.2%, and crude protein by 1.9%; the addition of 3% white rot fungi reduced hemicellulose by 8.8%, acid-insoluble lignin by 8.6%, and crude protein by 5.7%; the addition of 5% white rot fungi reduced hemicellulose by 23.1%, and crude protein by 34.2%. This may be because the white rot fungi use hyphae to adsorb lignin, and then secrete lignin peroxidase to destroy the complex and difficult-to-break ester bonds or ether bonds in lignin, thereby decomposing lignin into low molecular weight fragments, destroying the spatial structure, and then decomposing hemicellulose. At the same time, the decrease in organic matter increases the relative content of crude protein. From Table 7, it can be seen that the hemicellulose content of the white rot fungi with 5% and 3% additions gradually decreases with the increase of the addition amount compared with the addition of 1% white rot fungi. This shows that increasing the concentration of white rot fungi is effective in the degradation of hemicellulose, but at the same time, the exploration of lignin content showed that the lignin content increased when 5% white rot fungi were added. From the perspective of organic matter content, the lowest content was found when 5% white rot fungi were added. This shows that the reason for the increase in lignin content when 5% white rot fungi were added may be that the large amount of white rot fungi caused more consumption of the original organic matter in the feed, resulting in an increase in the relative content of lignin. Therefore, although white rot fungi can degrade lignin, excessive white rot fungi will instead cause an increase in the relative content of lignin.

[0075] From the fermentation index, it can be seen from Table 2, Table 4 and Table 6 that compared with the comparative example, the lactic acid content of the white rot fungi with 3% addition significantly increased by 700.8%, the lactic acid content of the white rot fungi with 5% addition significantly increased by 17.1%, and the lactic acid content of the white rot fungi with 1% addition significantly increased by 131.8%. It shows that the addition of white rot fungi to degrade lignocellulose provides a carbon source for beneficial bacteria such as lactic acid bacteria and lactobacillus, while reducing the decomposition of lactic acid by harmful bacteria, thereby promoting the accumulation of lactic acid content. However, the results show that the biggest factor affecting the lactic acid content is the initial pH. The effects of the two embodiments with an initial pH of 4 are significantly higher than those of the embodiments with an initial pH of 6, indicating that an increase in acetic acid content can promote the enrichment of lactic acid bacteria.

[0076] The above results show that the addition of white rot fungi can selectively remove lignin and hemicellulose, change the microbial community structure during the fermentation process, reduce the relative abundance of caproic acid-producing bacteria, reduce the decomposition of nutrients such as lactic acid and crude protein by harmful bacteria, produce short-chain fatty acids, promote the degradation of lignocellulose, and increase the lactic acid content.

[0077] In summary, solid-state fermentation of bagasse by white rot fungi can effectively improve its nutritional value and fermentation quality, prolong storage time, realize high-quality feed application of bagasse, reduce feed costs, and provide a reference for the application of bagasse as special feed.

Claims

1. A method for solid-state fermentation of bagasse using white rot fungi, characterized in that: Fermented bagasse is made by fermenting bagasse with white rot fungi, and glacial acetic acid and soluble sugar are used for auxiliary fermentation, according to the following steps: (1) Activation and expansion of strains: Pour the white rot fungus into PDA medium for activation and expansion. After 2-3 generations of expansion by the 4-zone line method, the strain is transferred to PDB medium. The shaking speed is set at 140 r / min and the temperature is 27°C. Glass beads are added to prevent the strain from agglomerating into bacterial clumps. After culturing for 2-3 days, the bacterial solution becomes turbid. The expanded strain is counted by the plate count method and the resulting bacterial solution is placed in a 4°C refrigerator for later use. (2) Raw material preparation: fresh bagasse is air-dried and then water is added to adjust the water content of the bagasse to 60% to 70%, and the pH is adjusted to 4 to 6 with glacial acetic acid; (3) Preparation of bagasse feed: The cultured white rot fungi are mixed with the pH-adjusted bagasse at a ratio of 1% to 5% dry matter, soluble sugar is added at 1% to 5% dry matter, and fermented for 15 to 45 days to obtain fermented bagasse feed.

2. The method according to claim 1, characterized in that Fermented bagasse is made by fermenting bagasse and white rot fungi with the assistance of sucrose and glacial acetic acid.

3. The method according to claim 1, characterized in that The bagasse is fresh bagasse produced after sugarcane is extracted, and is air-dried bagasse obtained by air-drying.

4. The method according to claim 1, characterized in that The white rot fungus is Phanerochaete chrysosporium, and the total colony count of Phanerochaete chrysosporium is greater than 1.5*10^8 CFU / ml.

5. The method according to claim 1, characterized in that The PDB culture medium is composed of: 6 g / L potato flour, 20 g / L glucose, 3.0 g / L KH2PO4, 1.5 g / L MgSO4·7H2O, trace vitamin B, 20.0 g / L agar, pH 6.0±0.2, and is prepared with distilled water and placed in a high pressure sterilizer for sterilization at 121° C. for 20 min.

6. The method according to claim 1, characterized in that The hemicellulose content of the fermented bagasse is reduced to 26.62%-22.45%, the lignin content is reduced to 10.67%-8.66%, the crude protein content of the bagasse is increased to 1.61%-2.12%, and the lactic acid content is increased to 26.57mg / L-181.69mg / L.

7. The method according to claim 1, characterized in that During the fermentation process, the initial pH value is 4-6, and the fermentation time is 15-45 days.

8. The method according to claim 1, characterized in that 16srRNA sequencing analysis showed that it can reduce the relative abundance of caproic acid-producing bacteria in fermented sugarcane bagasse.

9. The method according to claim 1, characterized in that: The fermented bagasse has the best index when the white rot fungi (total colony count>1.5*10^8 CFU / ml) are present at 3%, the fermentation time is 30 days, the initial pH is 4, and the soluble sugar is 5%.

10. A fermented bagasse feed prepared by the method according to any one of claims 1 to 9.

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