Microbial culture medium prepared from plant wastes

Abstract

The present invention discloses a microbial culture medium prepared from plant waste, and relates to the technical field of microbial culture media, the microbial culture medium comprises a Chinese cabbage leaf extract, an inorganic salt and water, and the weight ratio of the Chinese cabbage leaf extract to the water is 3: 1: (40-50); the Chinese cabbage leaf waste is used as a preparation raw material of the microbial culture medium, Chinese cabbage leaves are extracted to obtain the Chinese cabbage extract, the Chinese cabbage extract contains rich protein, saccharides, vitamins and a small amount of fat and mineral substances, sufficient carbon sources and carbon sources can be provided for the culture medium, and a good culture effect is achieved; an excellent enrichment effect on bacteria and fungi in microorganisms is achieved, the enrichment time can be shortened, the enrichment quantity can be increased, and a good enrichment promotion effect is achieved; meanwhile, the Chinese cabbage leaf waste can be recycled, environmental pollution caused by the Chinese cabbage leaf waste is prevented, the production cost of the culture medium is reduced, the Chinese cabbage leaf waste can bring economic benefits, and the commercial value is improved.

Description

Technical Field

[0001] The invention relates to the technical field of microbial culture medium, in particular to a microbial culture medium prepared from plant waste. Background Art

[0002] As a common vegetable, cabbage is widely grown. However, a large amount of cabbage leaf waste is generated during the harvesting, processing and transportation of cabbage. These wastes are often regarded as useless and are discarded or burned, which not only wastes resources but also may pollute the environment.

[0003] Cabbage leaves are rich in nutrients such as cellulose, hemicellulose, pectin, protein and minerals, which are all nutrients required for the growth of microorganisms. At present, the utilization of cabbage leaf waste is mainly focused on composting, feed and biomass energy. However, these utilization methods often have problems such as low efficiency and low added value.

[0004] At the same time, the preparation of microbial culture medium requires a large amount of organic matter as carbon and nitrogen sources, and traditionally, grain raw materials are mostly used, which is costly. Although there have been some studies on the use of agricultural waste to prepare microbial culture medium, there are relatively few studies specifically on cabbage leaf waste, and there are problems such as unbalanced nutrients in the culture medium and poor microbial growth effect.

[0005] Therefore, how to effectively utilize cabbage leaf waste and convert it into valuable microbial culture medium has become an urgent problem to be solved. Summary of the invention

[0006] The purpose of the present invention is to provide a microbial culture medium prepared from plant waste to solve the following technical problems:

[0007] How to prepare efficient biological culture medium from cabbage leaf waste.

[0008] The purpose of the present invention can be achieved through the following technical solutions:

[0009] The invention discloses a microbial culture medium prepared from plant waste. The components of the microbial culture medium include cabbage leaf extract, inorganic salt and water. The weight ratio of the cabbage leaf extract to water is 3:1:(40-50); preferably, the weight ratio of the cabbage leaf extract to water is 3:1:45.

[0010] The cabbage leaves contain proteins, carbohydrates, vitamins (vitamin A, vitamin C, carotene) and a small amount of fat and minerals (calcium, phosphorus, potassium, iron, etc.), which can provide sufficient nitrogen and carbon sources for the culture medium and provide energy for microbial reproduction. The protein contains a large amount of superoxide dismutase, which plays an important role in the growth of microorganisms. Therefore, the cabbage leaf extract contains a large amount of nutrients required for the microbial culture medium. After a large number of experiments, the present invention has determined that it can be used as a good choice for the culture medium raw material.

[0011] Furthermore, the preparation method of the cabbage leaf extract is:

[0012] The first step is to naturally air-dry the cleaned cabbage leaf waste and mix it with deionized water. In order to facilitate mixing, the cabbage leaves can be preliminarily broken into pieces, and the ratio of cabbage leaves to deionized water is 1:3; then add it to a freezing grinder under an ice bath for grinding, so that the active ingredients are separated from the dissolved deionized water to obtain a slurry, transfer the slurry to an ultrasonic mixer, and ultrasonically vibrate at 60-80 Hz at 50-65° C. for 15-20 minutes, then drop sodium hydroxide to adjust the pH to 7.5-8, and stand for 5-10 minutes to obtain a crude extract;

[0013] The second step is to transfer the crude extract to a centrifuge for centrifugal treatment for 15-20 minutes, and then filter it through a nanofiltration membrane with a pore size of 5000D to remove a large amount of impurities and fungi to obtain an extract fine liquid. A small amount of water can be added to the extract fine liquid to maintain fluidity, and then spray drying is performed. The powder particles collected at the bottom of the tower are the cabbage leaf extract.

[0014] Furthermore, in the first step, the cabbage leaves are waste generated during the processing or transportation of cabbage.

[0015] For example, Chinese cabbage is widely used in the food industry, for example, to make various types of pickles, pickles, instant noodle vegetable packs, etc. Before Chinese cabbage is put into use, in order to ensure the quality of Chinese cabbage, it is usually necessary to peel off the outermost petals of Chinese cabbage, because the cabbage raw material is inevitably damaged by impact during transportation, or it is in contact with air for a long time and loses water, which affects the quality of the Chinese cabbage raw material. For manufacturers, the amount of the Chinese cabbage leaf waste removed is large, and usually it is directly discarded, so it will have a negative impact on the environment, and it can also be used as feed to feed livestock, but the utilization rate is not high. Therefore, the present invention uses the Chinese cabbage leaf waste generated in the food processing process as the preparation raw material of the culture medium, which can not only reduce the pollution to the environment, but also improve the utilization rate of resources.

[0016] Furthermore, the inorganic salt is a combination of any one or more of sodium chloride, potassium phosphate, sodium phosphate, and magnesium sulfate; preferably, the inorganic salt is sodium chloride.

[0017] Furthermore, the preparation method of the microbial culture medium is:

[0018] Step 1, the cabbage leaf extract, inorganic salt and water are mixed evenly in a weight ratio of 3:1:(10-15), and then water is added to make the weight ratio of the three to be 3:1:(40-50), and the culture solution is obtained after stirring evenly;

[0019] Step 2: sterilize the culture solution to obtain the microbial culture medium.

[0020] Furthermore, the sterilization methods include ultraviolet sterilization, chemical sterilization, filtration sterilization and high-pressure steam sterilization; preferably, ultraviolet sterilization is selected.

[0021] Furthermore, the microbial culture medium is used to culture bacteria or fungi; preferably, the bacteria is any one of lactic acid streptococci, bifidobacterium and Helicobacter pylori.

[0022] Beneficial effects of the present invention:

[0023] The present invention uses cabbage leaf waste generated during processing or transportation as a raw material for preparing a microbial culture medium, and obtains cabbage extract by extracting the cabbage leaves. The cabbage extract contains rich proteins, sugars, vitamins and a small amount of fat and minerals, and can provide sufficient carbon sources and carbon sources for the culture medium. No other nitrogen sources and carbon sources need to be added to achieve a good culture effect. The cabbage extract has an excellent bacterial growth effect on bacteria and fungi in microorganisms, can shorten the bacterial growth time and increase the number of bacterial growth, and achieve a benign bacterial growth promotion effect. At the same time, the cabbage leaf waste can be reused to prevent environmental pollution caused by cabbage leaf waste, and also improve the commercial reuse rate of cabbage leaves, reduce the production cost of the culture medium, so that the cabbage leaf waste can bring economic benefits and enhance commercial value. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0025] The experimental methods in the following examples, unless otherwise specified, are all conventional methods, and are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial channels.

[0026] Preparation Example 1

[0027] Preparation of cabbage leaf extract: Cabbage leaf waste (purchased from a supermarket, obtained by peeling off the outermost 3-5 petals) was washed with clean water and naturally air-dried until there were no droplets on the surface, then 100 g was weighed, torn into small pieces and added to a freeze grinder, and then 300 g of deionized water was added, and then ground under ice bath conditions for 1 hour to obtain a slurry, which was transferred to an ultrasonic mixer and ultrasonically oscillated at 70 Hz for 18 minutes at 55°C, and then sodium hydroxide was added dropwise to adjust the pH to 7.8. After standing for 8 minutes, a crude extract was obtained, which was transferred to a centrifuge and centrifuged for 18 minutes. The centrifuge was filtered through a nanofiltration membrane with a pore size of 5000D to obtain a fine extract, 50 mL of deionized water was added to the fine extract and stirred evenly, and then spray-dried, and the powder particles at the bottom of the tower were collected, which was the cabbage leaf extract. After weighing, the obtained cabbage leaf extract was 12.14 g.

[0028] Example 1

[0029] Preparation of culture medium: Take 3g of the cabbage leaf extract prepared in Preparation Example 1, 1g of sodium chloride and 13g of water, add them into a beaker and stir evenly, then slowly add 32g of water while stirring, and after stirring evenly, place it in an ultraviolet sterilization box and sterilize it with ultraviolet rays with a wavelength of 253.7nm for 1h to obtain a microbial culture medium.

[0030] Example 2

[0031] Preparation of culture medium: Take 3g of the cabbage leaf extract prepared in Preparation Example 1, 1g of sodium chloride and 10g of water, add them into a beaker and stir evenly, then slowly add 30g of water while stirring, and after stirring evenly, place it in an ultraviolet sterilization box and sterilize it with ultraviolet rays with a wavelength of 253.7nm for 1h to obtain a microbial culture medium.

[0032] Example 3

[0033] Preparation of culture medium: Take 3g of the cabbage leaf extract prepared in Preparation Example 1, 1g of sodium chloride and 15g of water, add them into a beaker and stir evenly, then slowly add 45g of water while stirring, and after stirring evenly, place it in an ultraviolet sterilization box and sterilize it with ultraviolet rays with a wavelength of 253.7nm for 1h to obtain a microbial culture medium.

[0034] Comparative Example 1

[0035] Tryptone soy agar medium (purchased from Beijing Luqiao Technology Co., Ltd.) was used as a comparison, and its main components include tryptone, soytone, sodium chloride and agar.

[0036] Comparative Example 2

[0037] Nutrient agar medium (purchased from Guangdong Huankai Microbiological Technology Co., Ltd.) was used as a comparison, and its main components include peptone, beef extract, sodium chloride and agar.

[0038] Comparative Example 3

[0039] Potato glucose agar medium (purchased from Guangdong Huankai Microbiological Technology Co., Ltd.) was used as a comparison, and its main components included potato extract, glucose and agar.

[0040] Comparative Example 4

[0041] Preparation of culture medium: Take 3g of the cabbage leaf extract prepared in Preparation Example 1, 1g of sodium chloride and 13g of water, add them into a beaker and stir evenly, then slowly add 26g of water while stirring, and after stirring evenly, place it in an ultraviolet sterilization box and sterilize it with ultraviolet rays with a wavelength of 253.7nm for 1h to obtain a microbial culture medium.

[0042] Comparative Example 5

[0043] Preparation of culture medium: Take 3g of the cabbage leaf extract prepared in Preparation Example 1, 1g of sodium chloride and 13g of water, add them into a beaker and stir evenly, then slowly add 38g of water while stirring, and after stirring evenly, place it in an ultraviolet sterilization box and sterilize it with ultraviolet rays with a wavelength of 253.7nm for 1h to obtain a microbial culture medium.

[0044] Next, the microbial culture medium of Examples 1-3 and Comparative Examples 1-5 was tested to determine the bacterial growth effect on microorganisms. The three bacterial groups of lactic acid streptococci, bifidobacteria and Helicobacter pylori were used as test objects, and the specific test method was as follows:

[0045] Test the bacterial growth effect of lactic acid streptococcus: take 8 test tubes, numbered S1, S2, S3, D1, D2, D3, D4, D5, add 10mL of the microbial culture medium of Examples 1-3 and Comparative Examples 1-5 to each test tube, and then add 1mL of a lactic acid streptococcus suspension with a concentration of 20CUF / mL, shake well, and then draw 200uL into a sterile well plate, set the temperature of the microplate reader to 35°C, and read the OD every 2h 550nm The OD value (OD value is the energy difference before and after the light passes through the microbial culture medium. This difference is the energy absorbed by the microorganisms in the culture medium. During the microbial culture process, as the microorganisms grow and multiply, the number of cells in the culture medium increases, and the absorption of light also increases, resulting in an increase in the OD value. The growth of the bacterial flora can be judged by the increase in the OD value) is measured until the culture is cultured for 24 hours.

[0046] Test the effect of enriching bifidobacteria: Same as the above method, only need to replace the bacterial suspension of lactic streptococcus with the bacterial suspension of bifidobacteria.

[0047] Test the bacterial growth effect of Helicobacter pylori: Same as the above method, only need to replace the bacterial suspension of lactic streptococcus with the bacterial suspension of Helicobacter pylori.

[0048] The test results for three bacterial groups, namely, lactic acid streptococci, bifidobacteria and Helicobacter pylori, are listed in Tables 1-3, as follows.

[0049] Table 1 Effect of different microbial culture media on the enrichment of lactic acid streptococci

[0050]

[0051]

[0052] By analyzing the data in Table 1, it can be learned that the microbial culture medium of Example 1-3 has a significantly better bacterial growth effect on Streptococcus lactis than that of Comparative Example 1-5, and the time for the start of bacterial growth is only 8 hours, which is about 12 hours earlier than that of Comparative Example 1-3. It can be seen that compared with the existing basic culture medium, the culture effect of Streptococcus lactis has been greatly improved, while the effect of Comparative Example 4-5 is significantly reduced compared with Example 1-3, but the effect is better than that of Comparative Example 1-3. This is because the concentration of the cabbage leaf extract in the culture medium affects it, indicating that the optimal concentration range of the cabbage leaf extract should be the dosage range in Example 1-3.

[0053] Table 2 Effect of different microbial culture media on the enrichment of Bifidobacterium

[0054]

[0055]

[0056] By analyzing the data in Table 2, it can be learned that the microbial culture medium of Examples 1-3 has a significantly better bacterial growth effect on bifidobacteria than that of Comparative Examples 1-5, and the start time of bacterial growth is only 10 hours, which is about 8 hours earlier than that of Comparative Examples 1-3. It can be seen that compared with the existing basic culture medium, the culture effect of bifidobacteria has been greatly improved, while the effect of Comparative Examples 4-5 is significantly reduced compared with Examples 1-3, but the effect is better than that of Comparative Examples 1-3. This is because the concentration of the cabbage leaf extract in the culture medium affects it, indicating that the optimal concentration range of the cabbage leaf extract should be the dosage range in Examples 1-3.

[0057] Table 3 Effects of different microbial culture media on the growth of Helicobacter pylori

[0058]

[0059] By analyzing the data in Table 2, it can be learned that the microbial culture medium of Examples 1-3 has a significantly better effect on the growth of Helicobacter pylori than that of Comparative Examples 1-5, and the start time of its growth is only 12 hours, which is about 10 hours earlier than that of Comparative Examples 1-3. It can be seen that compared with the existing basic culture medium, the culture effect of Helicobacter pylori has been greatly improved, while the effect of Comparative Examples 4-5 is significantly reduced compared with that of Examples 1-3, but the effect is better than that of Comparative Examples 1-3. This is because the concentration of the cabbage leaf extract in the culture medium affects it, indicating that the optimal concentration range of the cabbage leaf extract should be the dosage range in Examples 1-3.

[0060] In summary, the microbial culture medium prepared with the cabbage leaf extract of the present invention has excellent bacterial enrichment effects on lactic acid streptococci, bifidobacteria and Helicobacter pylori, especially the best culture effect on lactic acid streptococci.

[0061] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A microbial culture medium prepared from plant waste, It is characterized in that The components of the microbial culture medium include cabbage leaf extract, inorganic salt and water, and the weight ratio of the cabbage leaf extract to water is 3:1:(40-50).

2. The microbial culture medium prepared from plant waste according to claim 1, It is characterized in that The preparation method of the cabbage leaf extract is: The first step is to mix clean and dry cabbage leaves with deionized water and grind them in an ice bath to obtain a slurry, and then ultrasonically vibrate the slurry at 60-80 Hz for 15-20 minutes at 50-65° C., then adjust the pH to 7.5-8, and stand for 5-10 minutes to obtain a crude extract; The second step is to centrifuge the crude extract, filter it through a nanofiltration membrane to obtain an extract fine solution, and spray-dry the extract fine solution to obtain the cabbage leaf extract.

3. The microbial culture medium prepared from plant waste according to claim 2, It is characterized in that In the first step, the cabbage leaves are waste generated during the processing or transportation of cabbage.

4. The microbial culture medium prepared from plant waste according to claim 2, It is characterized in that In the second step, the crude extract is centrifuged for 15-20 minutes.

5. The microbial culture medium prepared from plant waste according to claim 2, It is characterized in that In the second step, the pore size of the nanofiltration membrane is 5000D.

6. The microbial culture medium prepared from plant waste according to claim 1, It is characterized in that The inorganic salt is any one or more of sodium chloride, potassium phosphate, sodium phosphate and magnesium sulfate.

7. The microbial culture medium prepared from plant waste according to claim 1, It is characterized in that The preparation method of the microbial culture medium is: Step 1, the cabbage leaf extract, inorganic salt and water are mixed uniformly in a weight ratio of 3:1:(10-15), and then water is added to make the weight ratio of the three to be 3:1:(40-50) to obtain a culture solution; Step 2: sterilize the culture solution to obtain the microbial culture medium.

8. The microbial culture medium prepared from plant waste according to claim 7, It is characterized in that The sterilization methods include ultraviolet sterilization, chemical sterilization, filtration sterilization and high-pressure steam sterilization.

9. The microbial culture medium prepared from plant waste according to claim 7, It is characterized in that The microbial culture medium is used for culturing bacteria or fungi.

10. The microbial culture medium prepared from plant waste according to claim 9, It is characterized in that The bacteria include any one of lactic acid streptococci, bifidobacteria and Helicobacter pylori.

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