Enzymolysis method for efficiently preparing seaweed oligosaccharide from kelp
By using alginate degradation enzymes, pectinases and cellulase compositions to perform enzymatic reactions on kelp and optimize the enzymatic conditions, the problems of insufficient deep degradation efficiency and oligooligosaccharide yield in the prior art are solved, and the problem of insufficient yield of kelp in the prior art is achieved. Efficient preparation of seaweed oligosaccharides, improving biological activity and production efficiency.
Patent Information
- Application Number
- CN202411526073.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-30
- Publication Date
- 2024-12-17
AI Technical Summary
There has not been a method for effectively and deeply degrading kelp and improving the yield of oligosaccharides of oligosaccharides in the prior art. The existing enzymatic methods have insufficient degradation efficiency and product yield.
The enzyme composition composed of alginate degradation enzyme, pectin enzyme and cellulase was used to carry out enzymatic reaction on dry kelp. The enzymatic decomposition ratio and process conditions were optimized through the response surface method to achieve the enzymatic decomposition rate of kelp solids reaching 67. More than % and the proportion of highly active oligosaccharides in the enzymatic solution reaches 78%.
The kelp enzymatic degradation technology process has been greatly simplified, the yield and biological activity of oligosaccharides of oligomers have been improved, the enzyme dosage and cost are reduced, and the process flow has been simplified.
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Figure CN119144682A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of high-value utilization of kelp, and in particular relates to an enzymatic hydrolysis method for efficiently preparing seaweed oligosaccharides from kelp. Background Art
[0002] Seaweed polysaccharides in kelp are important marine active substances. Seaweed polysaccharides are the main components of algae cell walls and membrane matrix. Seaweed polysaccharides have good biological activities in inhibiting bacterial growth, anti-oxidation, anti-virus, and promoting body development, but their easy coagulation characteristics have hindered their application. Degrading seaweed polysaccharides into seaweed oligosaccharides composed of monosaccharides with a degree of polymerization of 2-20 can improve their solubility and make them easier to be absorbed and utilized by the body, which is more conducive to their application in food, medicine, military industry, and agriculture.
[0003] With the development of the enzyme preparation industry, highly active seaweed-degrading enzymes have been developed and applied, providing technical support for the preparation of high-concentration seaweed oligosaccharides by enzymatic hydrolysis of kelp through biodegradation. Compared with the traditional chemical method, the enzymatic method for preparing seaweed oligosaccharides can better maintain the biological activity of oligosaccharides and is more environmentally friendly, so it has better application prospects.
[0004] Using kelp as raw material, the preparation of brown algae oligosaccharides by bioenzymatic method mostly adopts multi-enzyme composite degradation technology supplemented by physical crushing technology, such as CN110637920A discloses "a method for enzymatic hydrolysis of kelp", which adopts a physical crushing step to crush the kelp to 20-60 mesh, and uses pectinase and cellulase to enzymatic hydrolyze the kelp, and the reducing sugar content in the enzymatic hydrolyzate is 8.0-12.5g / 100g. This technology breaks the cell wall of kelp cells by adding cellulase on the basis of decomposing kelp cells into single dispersed cells by pectinase. Although this method increases the content of reducing sugar in kelp enzymatic hydrolyzate, it does not mention the content of deep cracking brown algae oligosaccharides. CN110301601A uses alginate lyase and cellulase to crack fresh kelp to prepare soluble kelp powder, but its brown algae oligosaccharide content is only 40-50%. Therefore, a more feasible method that can effectively degrade kelp in depth and simultaneously increase the yield of the obtained oligomeric brown algae oligosaccharides has not been proposed in the prior art. Summary of the invention
[0005] The present invention provides an enzymatic hydrolysis method for efficiently preparing seaweed oligosaccharides from kelp. The method greatly simplifies the existing technical process of enzymatic degradation of kelp, so that the enzymatic hydrolysis rate of kelp solids reaches more than 67%. At the same time, the proportion of highly active brown algae oligosaccharides in the enzymatic hydrolyzate reaches about 78%, effectively improving the yield of brown algae oligosaccharides.
[0006] In order to achieve the above-mentioned object, the present invention provides an enzymatic hydrolysis method for efficiently preparing algal oligosaccharides from kelp, using an enzyme composition composed of alginate degrading enzyme, pectinase and cellulase to perform enzymatic hydrolysis reaction on ultrafine powder of dry kelp, the enzymatic hydrolysis rate of the obtained kelp solid reaches more than 67%, and the proportion of highly active oligosaccharides of brown algae in the enzymatic hydrolysis liquid reaches 78%.
[0007] Preferably, the addition amount of alginate degrading enzyme is 350-400U / g kelp powder, the addition amount of pectinase is 4500-5500U / g kelp powder, and the addition amount of cellulase is 250-300U / g kelp powder.
[0008] Preferably, the addition amount of alginate degrading enzyme is 360 U / g kelp powder, the addition amount of pectinase is 5000 U / g kelp powder, and the addition amount of cellulase is 280 U / g kelp powder.
[0009] Preferably, the temperature of the enzymatic hydrolysis reaction is 45-50°C, the pH is 5.0-6.0, and the enzymatic hydrolysis time is 6-10 hours.
[0010] Preferably, the temperature of the enzymatic hydrolysis reaction is 49° C., the pH is 5.2, and the enzymatic hydrolysis time is 8 h.
[0011] Preferably, the ultrafine powder of dried kelp is ultrafine powder below 300 mesh.
[0012] It is understandable that in the above scheme, the key of the present application is to carry out deep enzymolysis reaction to kelp under specific conditions by the enzyme composition composed of three enzymes to achieve the expected effect. The reason is that the kelp cell wall and intercellular matrix contain multiple components. In theory, according to its chemical composition, the deep degradation of kelp can be achieved by using multiple enzymes to work together. However, enzyme is a kind of biocatalyst, and each enzyme has its own suitable action temperature and pH conditions. To achieve different enzymes to work together under the same action conditions, it is necessary to weigh the activity retention rate of multiple enzymes under different conditions and explore a condition suitable for multiple enzymes to work. The present invention has established such a process condition that can make 3 kinds of lyases play a synergistic role in the same reaction system to the greatest extent through a large number of experimental explorations. This is compared with the prior art considering the maintenance of enzyme activity, some choose to use 2 key enzymes, and some use step-by-step enzymolysis (steps are more complicated), such as using enzyme A to enzymolyze 6h under a condition, then changing enzymolysis condition b, adding enzyme B to continue enzymolyze 8h and other technologies, not only simplifying cumbersome steps, but also obtaining better technical effects.
[0013] Preferably, the highly active oligosaccharide is an oligosaccharide with a molecular weight of less than 2000 Da.
[0014] Preferably, the highly active brown algae oligosaccharide is mainly composed of brown algae oligosaccharide with a polymerization degree of 2-saccharide, 3-saccharide and 4-saccharide.
[0015] As a preference, the method comprises the following steps:
[0016] The dried kelp ultrafine powder crushed to 300 mesh, alginate lyase, pectinase and cellulase are weighed and put into a centrifuge tube for mixing, a buffer solution is added, the mixture is mixed, and the mixture is put into a metal bath at a preset temperature for heat preservation and enzymolysis;
[0017] During the enzymatic hydrolysis process, the enzymatic hydrolysis system is shaken every 20-40 minutes to allow the kelp powder to be fully enzymatically hydrolyzed. After the enzymatic hydrolysis is completed, the metal bath temperature is immediately adjusted to 90-100°C for 10-20 minutes to inactivate the enzyme in the reaction system, and then the system is taken out and naturally cooled to room temperature;
[0018] Centrifuge the enzymatically hydrolyzed kelp solution at 4000-5000×g for 15-20 minutes and repeat the separation twice.
[0019] Preferably, the mass ratio of the added kelp powder to the buffer solution is 1:10.
[0020] Preferably, the preset temperature of the metal bath is 40-60°C.
[0021] Compared with the prior art, the advantages and positive effects of the present invention are:
[0022] 1. The enzymatic hydrolysis method provided by the present invention selects three kinds of lyases (a combination of alginate degrading enzyme, cellulase and pectinase) to enzymatically hydrolyze kelp, and optimizes the enzymatic hydrolysis compound ratio and enzymatic hydrolysis process conditions by using the response surface methodology, thereby achieving deep enzymatic hydrolysis of kelp and obtaining oligosaccharides with a degree of polymerization mainly consisting of 2-sugar, 3-sugar and 4-sugar.
[0023] 2. The enzymatic hydrolysis method established by the present invention has undergone two rounds of optimization processes, one of which is the optimization of the compound ratio of enzymes, so that the solid enzymatic hydrolysis rate reaches about 54%, and the other is the further optimization of the enzymatic hydrolysis conditions, so that the solid enzymatic hydrolysis rate is increased to about 67%. Through two rounds of optimization, the synergistic effect of three lysing enzymes in the same reaction system is achieved, the enzyme dosage and cost are reduced, and the technical process of kelp enzymatic degradation is greatly simplified. While the kelp solid enzymatic hydrolysis rate reaches more than 67%, the proportion of highly active brown algae oligosaccharides in the enzymatic hydrolyzate reaches about 78%, effectively improving the yield of brown algae oligosaccharides. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 This is a high pressure liquid phase analysis spectrum of the kelp enzymatic hydrolysate provided in an embodiment of the present invention. DETAILED DESCRIPTION
[0025] The technical solutions in the embodiments of the present invention are described clearly and completely below. 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.
[0026] Example 1 Optimization of the ratio of multiple enzymes for kelp enzymolysis by response surface methodology
[0027] 1.1 Experimental materials and enzymatic hydrolysis steps:
[0028] Alginate lyase 10000U / g; Pectinase 100000U / g; Cellulase 8000U / g; Kelp powder 300 mesh; Enzyme buffer: citric acid-disodium hydrogen phosphate buffer
[0029] Weigh 0.5g of dried kelp ultrafine powder (300 mesh) and alginate lyase, pectinase, and cellulase into a 10mL centrifuge tube and mix well. Add 5mL of buffer solution, mix well, and put it into a metal bath with a pre-set temperature for enzymolysis. During the enzymolysis process, the enzymolysis system should be shaken every 30 minutes to fully enzymolyze the seaweed powder and fully leached the reducing sugar. After the enzymolysis is completed, immediately adjust the metal bath temperature to 100℃ and react for 10 minutes to inactivate the enzyme in the reaction system, take it out and cool it down naturally to room temperature. Centrifuge the enzymolyzed kelp enzymolysis solution at 4000×g for 15 minutes and repeat the separation twice. The DNS colorimetric method is used to determine the reducing sugar content in the supernatant enzymolysis solution to determine the enzymolysis efficiency.
[0030] 1.2 Response surface experimental design and results analysis
[0031] The Box-Behnken design (BBD) design was adopted, with the reducing sugar content of the supernatant in the system after enzymatic hydrolysis as the response value. This optimization experiment designed a set of 17 BBD experiments, of which the number of factorial experiments was 12 and the number of central point repeated experiments was 5. There were 3 factors (i.e., the amount of alginate lyase added, the amount of pectinase added, and the amount of cellulase added). During the experiment, pH = 7, seaweed powder / buffer 1:10, enzymatic hydrolysis time 8h, and enzymatic hydrolysis temperature 50℃. Table 1 is the BBD response surface experimental scheme designed for the enzymatic hydrolysis of kelp powder based on the three factors of alginate lyase addition, pectinase addition, and cellulase addition, and the measurement results of the reducing sugar content of the supernatant after enzymatic hydrolysis.
[0032] Table 1 Multi-enzyme complex ratio BBD response surface experimental scheme and results
[0033]
[0034]
[0035] The response surface analysis method was used to analyze the above experimental results. It can be seen that the model is significant and the lack of fit term is not significant. Therefore, the model is established, and the experimental plan and experimental results are reliable (Table 2). From the numerical values, it can be seen that "Prob>F"<0.05 means that the factors have significant effects, so the amount of alginate lyase added has an extremely significant effect on the enzymatic efficiency, the amount of pectinase added has an extremely significant effect on the enzymatic efficiency, and the effect of cellulase is relatively small. The factors that affect the enzymatic efficiency are pectinase addition> alginate lyase addition> cellulase addition. In addition, CV=3.8%, which proves that the experimental credibility and precision are high; R-Squared=0.9623, with high correlation. However, the interaction between the factors is weak.
[0036] Table 2 Response surface design table results analysis of three factors and three levels of kelp powder enzymatic hydrolysis (BBD)
[0037]
[0038]
[0039] The optimal conditions obtained by optimization according to the model are: alginate lyase addition amount A = 3.61%, pectinase addition amount B = 5.00%, cellulase addition amount C = 2.84%, the predicted maximum reducing sugar content is 19.22 mg / mL, and Desirability = 0.906.
[0040] 1.3 Experimental verification of the optimal compounding ratio
[0041] Using 0.5 g of ultrafine kelp powder and 5 mL of pH = 7 buffer solution, enzymatic hydrolysis was performed at 50 ° C for 8 h. The enzymatic hydrolysis was repeated 3 times with the above-mentioned optimal compounding ratio (algin lyase addition amount = 3.61%, pectinase addition amount = 5.00%, cellulase addition amount = 2.84%). The average reducing sugar content was 20.69 mg / mL, which was slightly higher than the predicted value. Therefore, the conditions of the compounding ratio of multiple feed enzymes optimized by response surface analysis are feasible.
[0042] Example 2 Optimization of kelp enzymatic hydrolysis process conditions by response surface methodology
[0043] 2.1 Experimental plan and result analysis of optimization of enzymatic hydrolysis conditions by response surface methodology
[0044] The BBD design with the reducing sugar content of the supernatant in the system after enzymatic hydrolysis as the response value was adopted, and a total of 17 BBD experiments were designed for the optimization experiment, of which the number of factorial experiments was 12 times, the number of central point repeated experiments was 5 times, and there were 3 factors (enzymatic hydrolysis temperature, enzymatic hydrolysis time, pH). The results of the response surface experiment of the composite ratio of kelp lyase were applied in the experiment, that is, the addition amount of alginate lyase = 3.61%, the addition amount of pectinase = 5.00%, and the addition amount of cellulase = 2.84%. The experimental design and results are shown in Table 3.
[0045] Table 3 BBD response surface experiment scheme and results of kelp enzymatic digestion conditions
[0046]
[0047]
[0048] Table 4 is the experimental results of BBD design. It can be seen that the model is significant and the lack of fit term is not significant. Therefore, the model is established, and the experimental plan and experimental results are reliable. From the numerical values, it can be seen that "Prob>F"<0.05 means that the factors have significant effects, the effect of enzymatic hydrolysis time on enzymatic hydrolysis efficiency is not significant, the effect of pH on enzymatic hydrolysis efficiency is the most significant, and the effect of temperature is not significant. The factors that affect the enzymatic hydrolysis efficiency are pH>enzymatic hydrolysis time>enzymatic hydrolysis temperature. In addition, there is a strong interaction between AC, that is, there is a certain interaction between temperature and buffer solution pH. In addition, CV=6.61%, which proves that the experimental credibility and precision are high; R-Squared=0.8835, with high correlation. However, the interaction between factors is weak.
[0049] Table 4 Response surface design table results analysis of three factors and three levels of kelp enzymatic hydrolysis conditions (BBD)
[0050]
[0051] The optimal conditions obtained by optimization according to the model are: A (temperature) = 49.39°C, B (enzymatic hydrolysis time) = 8h, C (pH) = 5.18, the predicted maximum reducing sugar content is 26.245mg / mL, and Desirability = 0.861.
[0052] 2.2 Verification of the optimal enzymatic hydrolysis conditions for kelp
[0053] The optimal enzymatic hydrolysis conditions obtained by the optimal solution were used to conduct a verification experiment on the enzymatic hydrolysis of kelp powder. Similarly, 0.5g of kelp powder was used, and the above-mentioned optimal conditions, i.e., enzymatic hydrolysis temperature = 49°C, enzymatic hydrolysis solution pH = 5.2, and enzymatic hydrolysis time = 8h, were used for enzymatic hydrolysis of kelp powder under the conditions of alginate lyase addition = 3.61%, pectinase addition = 5.00%, and cellulase addition = 2.84%. The concentration of reducing sugar in the enzymatic hydrolysis solution was close to the central point extraction rate, and the average reducing sugar content obtained was 25.268mg / mL, which shows that the enzymatic digestion conditions optimized by response surface analysis are feasible.
[0054] Example 3 Kelp Powder Solid Enzyme Hydrolysis Rate
[0055] Solid enzymatic hydrolysis rate, this indicator is generally expressed as seaweed degradation rate (solid enzymatic hydrolysis rate), which is the solid content of the enzymatic hydrolysis part. The specific operation is to first take 0.5g of dry kelp ultrafine powder and put it into an oven at 80℃ to dry to constant weight, and weigh it. Then wash and centrifuge the precipitate after centrifugation of the enzymatic hydrolysis sample tube twice, put it into an oven at 80℃ to dry to constant weight, and weigh it. Solid enzymatic hydrolysis rate (%) = (weight of original kelp powder after drying - weight of enzymatic hydrolysis precipitate after drying) / weight of original kelp powder after drying × 100.
[0056] Using the above optimized compound enzyme ratio and enzymatic hydrolysis reaction conditions, three enzymatic hydrolysis experiments were carried out on kelp powder, and the average enzymatic hydrolysis rate of kelp solids was 67.1%.
[0057] Example 4 Determination of oligosaccharide composition in kelp hydrolysate
[0058] GPC gel chromatography was used to determine the molecular weight distribution of polysaccharides in the hydrolyzate. The results showed that the polysaccharides with a molecular weight of less than 1000 Da accounted for 66.95% of the hydrolyzate, and the polysaccharides with a molecular weight between 1000-2000 Da accounted for 11.74%. It can be seen that more than 78% (less than 2000 Da) of the polysaccharides have been deeply hydrolyzed into low-polymer oligosaccharides with higher biological activity.
[0059] Table 5 Sugar molecular weight distribution of kelp hydrolysate
[0060]
[0061]
[0062] The oligosaccharide composition in the hydrolyzate was determined by high pressure liquid chromatography (HPLC). The kelp hydrolyzate was prepared into a 10 mg / mL solution, and a SuperdexTM Peptide column G10 / 300 column was used, with 0.1 M ammonium bicarbonate solution as the mobile phase, flow rate: 0.4 mL / min, and UV detector (detection wavelength 235 nm) for detection. The results are as follows Figure 1As shown, after comparison with the HPLC spectrum of brown algae oligosaccharide standard, it can be seen that the peak at 37min is disaccharide, the absorption peak at 39min is trisaccharide, and the absorption peak at 42min is tetrasaccharide. It can be seen that the main components of the enzymatic hydrolysate are oligosaccharides such as disaccharides, trisaccharides, and tetrasaccharides.
[0063] Comparative Example 1
[0064] The experimental materials and enzymatic hydrolysis steps were the same as those in Example 1, except that no alginate lyase was added to the combined enzymes. In this manner, the enzymatic hydrolysis rate of the obtained kelp solids was 35.54%, and the proportion of highly active brown algae oligosaccharides in the enzymatic hydrolyzate was 34.22%.
[0065] Comparative Example 2
[0066] The experimental materials and enzymatic hydrolysis steps were the same as those in Example 1, except that pectinase was not added to the combined enzymes. In this manner, the enzymatic hydrolysis rate of the obtained kelp solids was 38.65%, and the proportion of highly active brown algae oligosaccharides in the enzymatic hydrolyzate was 42.80%.
[0067] Comparative Example 3
[0068] The experimental materials and enzymatic hydrolysis steps were the same as those in Example 1, except that no cellulase was added to the combined enzymes. In this manner, the enzymatic hydrolysis rate of the obtained kelp solids was 42.16%, and the proportion of highly active brown algae oligosaccharides in the enzymatic hydrolyzate was 32.55%.
[0069] Comparative Example 4
[0070] The experimental materials and enzymatic hydrolysis steps are the same as those in Example 2, except that the pH value during enzymatic hydrolysis is less than 5.0, and 4.8 is used as an example. In this way, the enzymatic hydrolysis rate of the obtained kelp solids is 45.20%, and the proportion of highly active brown algae oligosaccharides in the enzymatic hydrolyzate is 33.21%.
[0071] Comparative Example 5
[0072] The experimental materials and enzymatic hydrolysis steps are the same as those in Example 2, except that the pH during enzymatic hydrolysis is greater than 6.0, with 6.2 being used as an example. In this manner, the enzymatic hydrolysis rate of the obtained kelp solids is 41.02%, and the proportion of highly active brown algae oligosaccharides in the enzymatic hydrolyzate is 43.76%.
[0073] Comparative Example 6
[0074] The experimental materials and enzymatic hydrolysis steps are the same as those in Example 2, except that the enzymatic hydrolysis time is less than 6 hours, and 5 hours is taken as an example. In this way, the enzymatic hydrolysis rate of the obtained kelp solids is 56.80%, and the proportion of highly active brown algae oligosaccharides in the enzymatic hydrolyzate is 65.50%.
[0075] Comparative Example 7
[0076] The experimental materials and enzymolysis steps are the same as those in Example 2, except that the enzymolysis time is greater than 10 hours, with 12.5 hours being taken as an example. In this way, the enzymolysis rate of the obtained kelp solids is 66.80%, and the proportion of highly active brown algae oligosaccharides in the enzymolysis solution is 79.10%. It is understandable that, in theory, the longer the enzymolysis time, the more thorough the enzymolysis will be. However, in fact, the enzymolysis rate and product yield are not improved accordingly by extending the enzymolysis time, which means an increase in production costs and a waste of resources, so this condition is not suitable.
[0077] Comparative Example 8
[0078] The experimental materials and enzymatic hydrolysis steps are the same as those in Example 1, except that the amount of pectinase added in the combined enzyme is less than 4500 U / g, and 4000 U / g is taken as an example. In this way, the enzymatic hydrolysis rate of the obtained kelp solids is 45.33%, and the proportion of highly active brown algae oligosaccharides in the enzymatic hydrolyzate is 67.30%.
[0079] Comparative Example 9
[0080] The experimental materials and enzymolysis steps are the same as those in Example 1, except that the amount of pectinase added in the combined enzyme is greater than 5500U / g, with 6000U / g as an example. In this way, the enzymolysis rate of the obtained kelp solids is 67.10%, and the proportion of highly active oligosaccharides of brown algae in the enzymolysis solution is 79.02%. It is understandable that, in theory, the greater the amount of enzyme used, the more thorough the enzymolysis may be. But in fact, the increase in the amount of enzyme used does not increase the enzymolysis rate and product yield accordingly, which means an increase in cost and a waste of resources, so this condition is not suitable.
Claims
1. An enzymatic hydrolysis method for efficiently preparing seaweed oligosaccharides from kelp, characterized in that: The ultrafine powder of dried kelp was enzymatically hydrolyzed by an enzyme composition consisting of alginate degrading enzyme, pectinase and cellulase. The enzymatic hydrolysis rate of the obtained kelp solids reached more than 67%, and the proportion of highly active oligosaccharides of brown algae in the enzymatic hydrolyzate reached 78%.
2. The enzymatic hydrolysis method according to claim 1, characterized in that The added amount of alginate degrading enzyme is 350-400U / g kelp powder, the added amount of pectinase is 4500-5500U / g kelp powder, and the added amount of cellulase is 250-300U / g kelp powder.
3. The enzymatic hydrolysis method according to claim 2, characterized in that The addition amount of alginate degrading enzyme was 360U / g kelp powder, the addition amount of pectinase was 5000U / g kelp powder, and the addition amount of cellulase was 280U / g kelp powder.
4. The enzymatic hydrolysis method according to claim 1, characterized in that The temperature of the enzymatic hydrolysis reaction is 45-50°C, the pH is 5.0-6.0, and the enzymatic hydrolysis time is 6-10h.
5. The enzymatic hydrolysis method according to claim 4, characterized in that The temperature of the enzymatic hydrolysis reaction was 49°C, the pH was 5.2, and the enzymatic hydrolysis time was 8 h.
6. The enzymatic hydrolysis method according to claim 1, characterized in that Highly active oligosaccharides are oligosaccharides with a molecular weight of less than 2000 Da.
7. The enzymatic hydrolysis method according to claim 1, characterized in that Highly active brown algae oligosaccharides are mainly composed of brown algae oligosaccharides with a degree of polymerization of 2-saccharides, 3-saccharides, and 4-saccharides.
8. The enzymatic hydrolysis method according to any one of claims 1 to 7, characterized in that: The following steps are involved: Ultrafine powder of dried kelp crushed to 300 mesh, alginate lyase, pectinase and cellulase are weighed and put into a centrifuge tube for mixing, a buffer solution is added, mixed, and put into a metal bath at a preset temperature for heat preservation and enzymolysis; During the enzymatic hydrolysis process, the enzymatic hydrolysis system is shaken every 20-40 minutes to allow the kelp powder to be fully enzymatically hydrolyzed. After the enzymatic hydrolysis is completed, the metal bath temperature is immediately adjusted to 90-100°C for 10-20 minutes to inactivate the enzyme in the reaction system, and then the system is taken out and naturally cooled to room temperature; Centrifuge the enzymatically hydrolyzed kelp solution at 4000-5000×g for 15-20 minutes and repeat the separation twice.
9. The enzymatic hydrolysis method according to claim 8, characterized in that The mass ratio of the added kelp powder to the buffer solution is 1:
10.
10. The enzymatic hydrolysis method according to claim 8, characterized in that: The preset temperature of the metal bath is 40-60°C.