Sargassum fermentation product as well as preparation method and application thereof

Abstract

The invention discloses a gulfweed fermentation product and a preparation method and application thereof, and the gulfweed fermentation product is prepared by the following steps: pretreating fresh gulfweed to obtain cured gulfweed powder, adding a mixed culture solution, inoculating a compound bacteria seed solution into the mixture, and carrying out solid aerobic fermentation to obtain the gulfweed fermentation product. And performing high-pressure sterilization and freeze-drying on the fermentation product, and then performing cryopreservation to obtain the sargassum fermentation product. According to the method for efficiently fermenting the gulfweed, provided by the invention, the content of macromolecular polysaccharide is remarkably reduced, and the degradation efficiency of the gulfweed is improved; the obtained gulfweed leavening can promote the proliferation of probiotics and inhibit the proliferation of harmful bacteria, and can also improve the intestinal health of groupers.

Description

Technical Field

[0001] The invention belongs to the technical field of Sargassum, and in particular relates to a Sargassum fermentation product and a preparation method and application thereof. Background Art

[0002] Sargassum spp. belongs to the Phaeophyceae and is an important economic seaweed in China's coastal areas. There are about 60 species of Sargassum in my country, mainly distributed in the coastal areas of Guangdong, Hainan and Guangxi, with high economic output. However, the macromolecular polysaccharides in Sargassum, due to their viscosity and low water solubility, limit the release of nutrients and bioactive substances. Therefore, it is urgent to develop efficient fermentation technology to effectively degrade the macromolecular polysaccharides in Sargassum that are difficult to utilize and improve their nutrient utilization.

[0003] Solid-state fermentation is a process in which microorganisms use solid substrates to grow and metabolize in an environment with little or no water. This process has the advantages of simple process, low investment cost and low energy consumption, and is widely used in feed production. Commonly used microbial strains include molds, yeasts, lactic acid bacteria and Bacillus subtilis, among which Bacillus can produce a variety of extracellular enzymes to effectively decompose complex organic matter such as alginate, cellulose, protein and starch, showing good application potential.

[0004] Although various fermentation methods of Sargassum are disclosed in the prior art, the fermentation effects and the quality of the obtained products vary greatly due to the different methods, and the uses are also different. Summary of the invention

[0005] The object of the present invention is to provide a Sargassum fermentation product and a preparation method thereof.

[0006] The present invention also aims to provide the use of the above-mentioned Sargassum fermentation product in the preparation of products for promoting the proliferation of probiotics or in the preparation of products for inhibiting the proliferation of harmful bacteria or in the preparation of products for improving the intestinal health of grouper.

[0007] The first object of the present invention can be achieved by the following technical solution: A method for preparing a fermented Sargassum, comprising the following steps: (1) Wash the fresh Sargassum to remove impurities and surface salt, dry it, grind it into powder, and sieve it; (2) pre-freezing the sieved Sargassum in step (1) with liquid nitrogen and then grinding the ground product, repeatedly freezing and thawing the ground product several times in a low temperature environment to obtain Sargassum powder; (3) curing the Sargassum powder obtained in step (2) in a high temperature environment; (4) adding the mixed culture solution to the Sargassum powder matured in step (3), mixing well and allowing to stand to obtain a mixture; (5) inoculating a composite bacterial seed liquid into the mixture for solid-state aerobic fermentation, and stirring the mixture during the fermentation process to obtain a fermentation product, wherein the composite bacterial seed liquid is a composite bacterial seed liquid of Bacillus subtilis, Saccharomyces cerevisiae, Lactobacillus rhamnosus, and a recombinant yeast DH5α producing alginate lyase; (6) The fermentation product obtained in step (5) is sterilized by high pressure, freeze-dried and then frozen for storage, thereby obtaining the Sargassum fermentation product.

[0008] In the preparation method of the above-mentioned Sargassum fermented product: Preferably, during sieving in step (1), the mesh size of the sieve is 60-100.

[0009] Preferably, in step (2), the grinding time is 5-10 min, the low temperature environment is -20 to -80°C, and the number of freeze-thaw cycles is 3-5 times.

[0010] Preferably, the high temperature environment in step (3) is 90-100°C and the aging time is 1-3 h.

[0011] Preferably, the mixed culture medium in step (4) comprises a mixed culture medium of YPD culture medium, LB culture medium and MRS culture medium, and the volume ratio of the YPD culture medium, LB culture medium and MRS culture medium is 1:2:1.

[0012] Preferably, the formula of 1L of the YPD culture medium is: 10 g / L yeast extract powder, 20 g / L glucose, 20 g / L sodium chloride, and 20 g / L soy peptone.

[0013] Preferably, the formula of 1L of the LB culture medium is: 10 g / L tryptone, 10 g / L sodium chloride, and 5 g / L yeast extract.

[0014] Preferably, the formula of 1L of the MRS culture medium is: 10 g / L beef extract, 10 g / L tryptone, 20 g / L glucose, 5 g / L yeast powder, 2 g / L dipotassium hydrogen phosphate, 2 g / L diammonium hydrogen citrate, 5 g / L sodium acetate, 0.1% Tween 80, 0.58 g / L magnesium sulfate, and 0.25 g / L manganese sulfate.

[0015] Preferably, in step (4), the dosage of the Sargassum powder and the mixed culture solution is 1 g: 0.3-0.8 L, the mixing time is 10-20 min, and the standing time is 1-3 h.

[0016] Preferably, in step (5), the Bacillus subtilis ( Bacillus subtilis ) is inoculated at a ratio of 1% to 3%, v / v, and the brewer's yeast ( Saccharomyces cerevisiae) is inoculated at a ratio of 1% to 4%, v / v, and the Lactobacillus rhamnosus ( Lactobacillus rhamnosus The inoculation ratio of the recombinant yeast DH5α producing alginate lyase is 1%-4%, v / v.

[0017] Preferably, the inoculation density of Bacillus subtilis in step (5) is (2-6)×10 7 / mL, the inoculation density of the brewer's yeast is (2-5)×10 7 / mL, the inoculation density of Lactobacillus rhamnosus is (4-8)×10 7 / mL, the inoculation density of the recombinant yeast DH5α producing alginate lyase is (1-3)×10 8 Pieces / mL.

[0018] Preferably, in step (5), the temperature of the solid aerobic fermentation is 30-42°C, the fermentation period is 60-96 h, and the stirring period is 20-26 h.

[0019] The invention also provides application of the method in improving the degradation efficiency of Sargassum.

[0020] Optionally, the improving the degradation efficiency of Sargassum includes reducing the content of cellulose and hemicellulose, and increasing the content of polysaccharides, alginic acid and algal oligosaccharides calculated as glucose.

[0021] The present invention further provides Sargassum fermentation product prepared by the method.

[0022] The above-mentioned second object of the present invention can be achieved by the following technical scheme: the use of the fermented Sargassum in preparing a product that promotes the proliferation of probiotics or in preparing a product that inhibits the proliferation of harmful bacteria.

[0023] Preferably, the probiotics include beneficial bacteria Bacillus subtilis, Saccharomyces cerevisiae and Lactobacillus rhamnosus.

[0024] Preferably, the harmful bacteria include Staphylococcus aureus and Aeromonas hydrophila.

[0025] The following tests were conducted to verify the effectiveness of Sargassum fermentation in promoting the proliferation of probiotics or inhibiting the proliferation of harmful bacteria: The aqueous solution of the fermented Sargassum was added to YPD culture medium, LB culture medium, MRS culture medium, BP culture medium or TSA culture medium, and beneficial bacteria Bacillus subtilis, Saccharomyces cerevisiae or Lactobacillus rhamnosus, and harmful bacteria Staphylococcus aureus or Aeromonas hydrophila were inoculated respectively to observe the dynamic proliferation of these bacteria.

[0026] The results show that the proliferation rate of Bacillus subtilis, Saccharomyces cerevisiae and Lactobacillus rhamnosus is accelerated and the abundance is higher. Further comparison shows that compared with the comparative example, the Sargassum culture solution in all embodiments can more significantly promote the proliferation of probiotics, especially in Example 2. At the same time, the Sargassum culture solution in all embodiments showed an inhibitory effect on the proliferation of harmful bacteria Staphylococcus aureus or Aeromonas hydrophila. These results show that Sargassum fermentation can not only promote the proliferation of probiotics, but also inhibit the proliferation of harmful bacteria, showing its potential as a prebiotic.

[0027] The present invention also provides the use of the fermented Sargassum in preparing a product for improving the intestinal health of grouper.

[0028] The method for improving the intestinal health of grouper includes increasing the activity of digestive enzymes in the intestinal tract of grouper, improving the diversity of intestinal flora of grouper, reducing the content of inflammatory factors IL1β and TNFα in the intestinal tract of grouper, and increasing the content of intestinal structural proteins. zo-1 and occludin expression level.

[0029] The following experiments were conducted to verify the effect of Sargassum fermented products on improving the intestinal health of grouper: The obtained Sargassum fermentation product was dissolved in double distilled water, fully soaked and stirred to obtain an aqueous solution of Sargassum fermentation product. The Sargassum aqueous solution was intraperitoneally injected into pearl gentian grouper to measure the activity of intestinal digestive enzymes of grouper, including trypsin, lipase and amylase; the diversity index of intestinal flora of grouper, including Shannon index and Simpson index, was evaluated; and the intestinal inflammatory response and structural integrity of grouper, including inflammatory factors and structural proteins, were measured.

[0030] The results showed that Sargassum fermented products can increase the activity of digestive enzymes in the intestine of grouper, improve the diversity of intestinal flora of grouper, significantly reduce the content of inflammatory factors IL1β and TNFα in the intestine of grouper, and significantly increase the content of intestinal structural proteins. zo-1 and occludin These results indicate that Sargassum fermented with composite bacteria can significantly improve the intestinal health of grouper.

[0031] Compared with the prior art, the present invention has the following advantages: (1) The method for efficiently fermenting Sargassum provided by the present invention significantly reduces the content of macromolecular polysaccharides and improves the degradation efficiency of Sargassum; (2) The fermented Sargassum obtained by the present invention can promote the proliferation of probiotics and inhibit the proliferation of harmful bacteria, and can also improve the intestinal health of grouper. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1The effect of the fermented Sargassum on the proliferation of probiotics and harmful bacteria in Experimental Example 2; Figure 2 The effect of the fermented Sargassum on the digestive enzyme activity of grouper in the test example 3; Figure 3 The effect of fermented Sargassum on the diversity of intestinal flora of grouper in Experimental Example 4; Figure 4 This is the effect of Sargassum fermentation product in Experimental Example 5 on the expression of inflammatory factors and structural proteins in the intestine of grouper. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments and drawings of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] In the following examples, unless otherwise specified, all conventional methods are used, and the raw materials used in the following examples are commercially available products unless otherwise specified.

[0035] The following examples are recommended but not limited to: The recommended formula for 1L of YPD culture medium is: 10 g / L yeast extract powder, 20 g / L glucose, 20 g / L sodium chloride, and 20 g / L soy peptone.

[0036] The recommended formula for 1L of LB culture medium is: 10 g / L tryptone, 10 g / L sodium chloride, and 5 g / L yeast extract.

[0037] The recommended formula for 1L of MRS culture medium is: 10 g / L beef extract, 10 g / L tryptone, 20 g / L glucose, 5 g / L yeast powder, 2 g / L dipotassium hydrogen phosphate, 2 g / L diammonium hydrogen citrate, 5 g / L sodium acetate, 0.1% Tween 80, 0.58 g / L magnesium sulfate, and 0.25 g / L manganese sulfate.

[0038] Bacillus subtilis was purchased from the official website of CGMCC with the item number CGMCC 1.1086, Saccharomyces cerevisiae was purchased from the China Industrial Microbiological Culture Collection Center with the item number CICC1251, and Lactobacillus rhamnosus was purchased from the official website of CGMCC with the item number CGMCC 1.577. The recombinant yeast DH5α producing alginate lyase was prepared by mutating yeast DH5α, namely H71K. The preparation method was based on previous research doi: 10.3389 / fbioe.2022.1011273. Example 1

[0039] The method for preparing the fermented Sargassum provided in this embodiment comprises the following steps: (1) Wash fresh Sargassum with water of decreasing salinity, dry it, grind it into powder, and sieve it through 80 mesh; (2) The sieved Sargassum was pre-frozen in liquid nitrogen and then ground for 8 min, and then repeatedly frozen and thawed five times at -80°C; (3) Curing the Sargassum powder at 95 °C for 2 h; (4) preparing a mixed culture medium of YPD culture medium, LB culture medium and MRS culture medium in a ratio of 1:2:1 (v / v / v), adjusting the material-liquid ratio of Sargassum powder to the mixed culture medium to 1 g:0.5 L, adding the mixed culture medium to the Sargassum powder matured in step (3), mixing thoroughly for 20 min, and letting it stand for 2 h; (5) Inoculation density of 1% (volume percentage, accounting for the total volume of mixed culture solution, the same below) is 4×10 7 Bacillus subtilis of 1% (volume percentage, accounting for the total volume of mixed culture solution, the same below) has a density of 3×10 7 / mL of Saccharomyces cerevisiae, 1% (volume percentage, accounting for the total volume of the mixed culture, the same below) density is 6×10 7 Lactobacillus rhamnosus, 1% (volume percentage, accounting for the total volume of the mixed culture, the same below) density is 2×10 8 The recombinant yeast DH5α seed solution producing alginate lyase was prepared by solid-state aerobic fermentation at 30℃ for 60 h, with stirring once every 24 h. (6) sterilizing by high pressure, freeze-drying and then storing in a frozen state to obtain the fermented Sargassum. Example 2

[0040] The method for preparing the fermented Sargassum provided in this embodiment comprises the following steps: (1) Wash fresh Sargassum with water of decreasing salinity, dry it, grind it into powder, and sieve it through 80 mesh; (2) Pre-freeze in liquid nitrogen and grind for 8 min, then freeze and thaw 5 times at -80°C; (3) Curing the Sargassum powder at 95 °C for 2 h; (4) Prepare a mixed culture medium of YPD culture medium, LB culture medium and MRS culture medium in a ratio of 1:2:1 (v / v / v), adjust the material-liquid ratio of Sargassum powder to the mixed culture medium to 1 g:0.5 L, add the mixed culture medium to the Sargassum powder matured in step (3), mix thoroughly for 20 min, and let stand for 2 h; (5) The inoculation volume percentage is 2% and the density is 4×10 7Bacillus subtilis of 10 / mL, with a volume percentage of 2% and a density of 3×10 7 / mL of brewer's yeast, with a volume percentage of 2% and a density of 6×10 7 Lactobacillus rhamnosus, with a volume percentage of 3% and a density of 2×10 8 The recombinant yeast DH5α seed solution producing alginate lyase was prepared by solid-state aerobic fermentation at 37℃ for 72 h, with stirring once every 24 h. (6) sterilizing by high pressure, freeze-drying and then storing in a frozen state to obtain the fermented Sargassum. Example 3

[0041] The method for preparing the fermented Sargassum provided in this embodiment comprises the following steps: (1) Wash fresh Sargassum with water of decreasing salinity, dry it, grind it into powder, and sieve it through 80 mesh; (2) Pre-freeze in liquid nitrogen and grind for 8 min, then freeze and thaw 5 times at -80°C; (3) Curing the Sargassum powder at 95 °C for 2 h; (4) Prepare a mixed culture medium of YPD culture medium, LB culture medium and MRS culture medium in a ratio of 1:2:1 (v / v / v), adjust the material-liquid ratio of Sargassum powder to the mixed culture medium to 1 g:0.5 L, add the mixed culture medium to the Sargassum powder matured in step (3), mix thoroughly for 20 min, and let stand for 2 h; (5) The inoculation volume percentage is 3% and the density is 4×10 7 Bacillus subtilis of 10 / mL, with a volume percentage of 4% and a density of 3×10 7 / mL of brewer's yeast, with a volume percentage of 3% and a density of 6×10 7 Lactobacillus rhamnosus, with a volume percentage of 4% and a density of 2×10 8 The recombinant yeast DH5α seed solution producing alginate lyase was fermented in solid state aerobic conditions at 42°C for 96 h, with stirring once every 24 h. (6) sterilizing by high pressure, freeze-drying and then storing in a frozen state to obtain the fermented Sargassum.

[0042] Comparative Example 1 (1) Wash fresh Sargassum with water of decreasing salinity, dry it, grind it into powder, and sieve it through 80 mesh; (2) Pre-freeze in liquid nitrogen and grind for 8 min, then freeze and thaw 5 times at -80°C; (3) Curing the Sargassum powder at 95 °C for 2 h; (4) preparing a mixed culture medium of YPD culture medium, LB culture medium and MRS culture medium in a ratio of 1:2:1, adjusting the material-liquid ratio of Sargassum powder to the mixed culture medium to 1 g:0.5 L, adding the mixed culture medium to the Sargassum powder matured in step (3), mixing thoroughly for 20 min, and letting it stand for 2 h; (5) The inoculation volume percentage is 2% and the density is 4×10 7 / mL of Bacillus subtilis, 2% by volume and 3×10 7 / mL of brewer's yeast, with a volume percentage of 2% and a density of 6×10 7 Lactobacillus rhamnosus was fermented aerobically at 37℃ for 72 h, with stirring once every 24 h. (6) sterilizing by high pressure, freeze-drying and then storing in a frozen state to obtain the fermented Sargassum.

[0043] Blank example 1 Sterile phosphate buffered saline (PBS) was used as blank example 1.

[0044] Test Example 1 The contents of lignin, hemicellulose and cellulose were measured by a series of specific testing techniques, which were strictly carried out according to the detailed procedures described in FUT-SOP(L)-37.1. The polysaccharide content (in terms of glucose) was determined using the method specified in the SN / T 4260-2015 standard. The content of alginic acid was determined according to the HG / T 5050-2016 standard, while the content of seaweed oligosaccharides was determined according to the Q / 371083WX002-2016 standard. All test results have been summarized in Table 1 for further analysis and discussion.

[0045] Table 1 Distribution of sugars in Sargassum

[0046] Sargassum is rich in dense and poorly water-soluble components such as lignin, hemicellulose and cellulose. The high viscosity of these components limits the effective utilization of nutrients and active ingredients. The present invention effectively degrades these components into substances such as seaweed oligosaccharides with better water solubility through innovative fermentation technology. In particular, in Example 2, the degradation efficiency of Sargassum reaches the best level.

[0047] Test Example 2 The Sargassum fermented products in Examples 1-3, Comparative Example 1 and Blank Example 1 were dissolved in double distilled water, the mass of which was 5 times the total mass of the Sargassum fermented products, and fully soaked and stirred. The magnetic stirring speed was 500 rpm, and the soaking time was 4 h to obtain an aqueous solution of the Sargassum fermented products. The aqueous solution was filtered and sterilized, and the filter membrane was 0.22 μm. The sterilized Sargassum aqueous solution was added to YPD culture medium, LB culture medium and MRS culture medium, respectively, to prepare 3% Sargassum YPD culture medium, 3% Sargassum LB culture medium and 3% Sargassum MRS culture medium. The Sargassum culture medium was inoculated with probiotics Bacillus subtilis, Saccharomyces cerevisiae and Lactobacillus rhamnosus, as well as harmful bacteria Staphylococcus aureus and Aeromonas hydrophila, and the dynamic proliferation of these bacteria within 0-12 h was determined.

[0048] from Figure 1 It can be seen that compared with Blank Example 1, the Sargassum culture solution in Comparative Example 1 can promote the proliferation of probiotics, which is specifically manifested as the accelerated proliferation rate of Bacillus subtilis, Saccharomyces cerevisiae and Lactobacillus rhamnosus, and the higher abundance. Further comparison found that compared with Comparative Example 1, the Sargassum culture solution in all embodiments can more significantly promote the proliferation of probiotics, especially in Example 2. The effect is particularly prominent. At the same time, the Sargassum culture solution in all embodiments showed an inhibitory effect on the proliferation of harmful bacteria. These results show that Sargassum fermentation can not only promote the proliferation of probiotics, but also inhibit the proliferation of harmful bacteria, showing its potential as a prebiotic.

[0049] Test Example 3 100 μL of the sterilized Sargassum aqueous solution (prepared in the same way as in Test Example 2) was injected intraperitoneally into a pearl grouper weighing about 100 g. The effect lasted for 7 days (168 hours) after injection, after which the digestive enzyme activity in the grouper's intestine was measured. The activities of trypsin, lipase, and amylase were measured using commercial kits. The results are shown in Table 1. Figure 2 shown.

[0050] Figure 2 The data showed that compared with Blank Example 1 or Comparative Example 1, the Sargassum aqueous solution injection treatment in Example 1, Example 2 and Example 3 significantly increased the activity of digestive enzymes in the grouper intestine, including trypsin, lipase and amylase. In particular, in Example 2, the digestive enzymes showed the highest activity level overall.

[0051] Test Example 4 100 μL of sterilized Sargassum aqueous solution (prepared in the same way as in Experiment 2) was administered intraperitoneally to pearl grouper weighing about 100 g for 7 days (168 hours). After 168 hours, the diversity of the grouper's intestinal flora was determined. The results were analyzed using 16S rRNA sequencing technology. Figure 3 shown.

[0052] Figure 3 It is shown that the injection of Sargassum aqueous solution in Example 1, Example 2 and Example 3 significantly improved the diversity of the intestinal flora of grouper compared with Blank Example 1 or Comparative Example 1. Compared with Blank Example 1, this improvement is reflected in the significant increase of Shannon Index and Simpson Index.

[0053] Test Example 5 100 μL of sterilized Sargassum aqueous solution (preparation method is the same as in Test Example 2) was administered to pearl grouper weighing about 100 g by intraperitoneal injection for 7 days (168 hours). After 168 hours, the intestinal health indicators of grouper were measured. The content of inflammatory factors IL1β and TNFα in the intestine was measured using ELISA commercial kits, and intestinal structural proteins, including tight junction proteins, were measured using qPCR technology. zo-1 and occludin occludin The expression of Figure 4 shown.

[0054] Figure 4 The results showed that compared with Blank Example 1 or Comparative Example 1, the injection of Sargassum aqueous solution in Example 1, Example 2 and Example 3 significantly reduced the content of inflammatory factors IL1β and TNFα in the intestine of grouper. In addition, compared with Blank Example 1, these treatments significantly increased the content of intestinal structural proteins zo-1 and occludin These results indicate that Sargassum fermented with composite bacteria can significantly improve the intestinal health of grouper.

[0055] It should be pointed out that the above embodiments are only further explanations of the present invention rather than limitations, and any adjustments or changes by those skilled in the art within the meaning and scope equivalent to the technical solution of the present invention should be deemed to be included in the protection scope of the present invention.

Claims

1. A method for preparing a fermented product of Sargassum, characterized in that: The following steps are involved: (1) Wash the fresh Sargassum to remove impurities and surface salt, dry it, grind it into powder, and sieve it; (2) pre-freezing the sieved Sargassum in step (1) with liquid nitrogen and then grinding the ground product, repeatedly freezing and thawing the ground product several times in a low temperature environment to obtain Sargassum powder; (3) curing the Sargassum powder obtained in step (2) in a high temperature environment; (4) adding the mixed culture solution to the Sargassum powder matured in step (3), mixing well and allowing to stand to obtain a mixture; (5) inoculating a composite bacterial seed liquid into the mixture for solid-state aerobic fermentation, and stirring the mixture during the fermentation process to obtain a fermentation product, wherein the composite bacterial seed liquid is a composite bacterial seed liquid of Bacillus subtilis, Saccharomyces cerevisiae, Lactobacillus rhamnosus, and a recombinant yeast DH5α producing alginate lyase; (6) The fermentation product obtained in step (5) is sterilized by high pressure, freeze-dried and then frozen for storage, thereby obtaining the Sargassum fermentation product.

2. The method for preparing the fermented Sargassum according to claim 1, characterized in that: The mixed culture solution in step (4) includes a mixed culture solution of YPD culture solution, LB culture solution and MRS culture solution, and the volume ratio of the YPD culture solution, LB culture solution and MRS culture solution is 1:2:1; the dosage relationship of the Sargassum powder and the mixed culture solution in step (4) is 1g:0.3-0.8L, the mixing time is 10-20 min, and the standing time is 1-3 h.

3. The method for preparing the fermented Sargassum according to claim 1, characterized in that: The inoculation ratio of Bacillus subtilis in step (5) is 1%-3%, v / v, the inoculation ratio of Saccharomyces cerevisiae is 1%-4%, v / v, the inoculation ratio of Lactobacillus rhamnosus is 1%-3%, v / v, and the inoculation ratio of the recombinant yeast DH5α producing alginate lyase is 1%-4%, v / v; the inoculation density of Bacillus subtilis in step (5) is 2×10 7 -6×10 7 The inoculation density of the brewer's yeast was 2×10 7 -5×10 7 / mL, and the inoculation density of Lactobacillus rhamnosus is 4×10 7 -8×10 7 The inoculation density of the recombinant yeast DH5α producing alginate lyase was 1×10 8 -3×10 8 Pieces / mL.

4. The method for preparing the fermented Sargassum according to claim 1, characterized in that: In step (5), the temperature of the solid aerobic fermentation is 30-42°C, the fermentation period is 60-96 h, and the stirring period is 20-26 h.

5. Use of the method according to any one of claims 1 to 4 in improving the degradation efficiency of Sargassum.

6. A fermented product of Sargassum, characterized in that: The method is prepared by any one of claims 1 to 4.

7. Use of the fermented Sargassum according to claim 6 in preparing products for promoting the proliferation of probiotics or inhibiting the proliferation of harmful bacteria.

8. The use according to claim 7, characterized in that: The probiotics include beneficial bacteria Bacillus subtilis, Saccharomyces cerevisiae and Lactobacillus rhamnosus; the harmful bacteria include Staphylococcus aureus and Aeromonas hydrophila.

9. Use of the fermented Sargassum according to claim 6 in preparing a product for improving the intestinal health of grouper.

10. The use according to claim 9, characterized in that: The method for improving the intestinal health of grouper includes increasing the activity of digestive enzymes in the intestinal tract of grouper, improving the diversity of intestinal flora of grouper, reducing the content of inflammatory factors IL1β and TNFα in the intestinal tract of grouper, or increasing the content of structural proteins in the intestinal tract of grouper. zo-1 and occludin expression level.

Images