Resource recovery method for strengthening rapid enzyme hydrolysis of kitchen waste and synchronously producing solid organic fertilizer and denitrification carbon source

Abstract

The invention belongs to the technical field of kitchen waste treatment, and particularly relates to a resource recovery method for strengthening rapid enzyme hydrolysis of kitchen waste and synchronously producing a solid organic fertilizer and a denitrification carbon source. Alkaline substances (namely plant ash and biochar) are added in the enzyme hydrolysis process of the kitchen waste, hydrolysate with high organic matter concentration and excellent storage performance is produced and directly used as a denitrification carbon source, and corresponding hydrolysis residues have high nutrient content and can be directly converted into ecological organic fertilizer. Based on a self-made bio-enzyme preparation technology, alkaline substances are doped into a kitchen waste hydrolysis system, the purpose of efficient resource recovery of kitchen waste is expected to be achieved, and the effect of treating waste with waste is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of kitchen waste treatment, and particularly relates to a resource recovery method for strengthening rapid enzymatic hydrolysis of kitchen waste and synchronously producing solid organic fertilizer and denitrification carbon source. Background Art

[0002] Kitchen waste is mainly composed of rice, noodles, meat, fruits and vegetables. In addition, it is mixed with a small amount of impurities such as paper, metal, bone, wood and plastic. It is the main component of urban solid waste. Its output has increased year by year with economic growth and residents' consumption level. As a considerable amount of organic solid waste, improper handling of kitchen waste can easily breed mosquitoes, emit odors, and spread viruses and bacteria, causing adverse effects on environmental hygiene. Kitchen waste is composed of various organic macromolecules and has significant resource attributes. As a new, green and efficient pretreatment hydrolysis technology, bioenzyme preparations are crucial for the efficient hydrolysis and resource recovery of kitchen waste.

[0003] CN202110170591.7 discloses a method for treating food waste using a homemade biological composite hydrolase, which can achieve rapid hydrolysis of food waste within 8 hours, the hydrolyzate can be used for anaerobic digestion to produce biogas, and the hydrolysis residue can be used as a solid fertilizer. Through the synchronous resource conversion of the hydrolyzate and the hydrolysis residue, the full resource disposal of food waste is achieved, which helps food waste to move towards a new stage of zero solid discharge. CN202310374816.X discloses a method for rapid composting of food waste using a biological enzyme preparation. This method not only shortens the composting cycle, but also improves the quality of organic fertilizer and reduces secondary pollution. CN202111264786.4 discloses a method for treating wastewater sludge using a homemade composite hydrolase, and the generated hydrolyzate can be converted into methane through anaerobic digestion. CN202110170591.7 discloses a method for treating food waste using a homemade composite hydrolase. The produced hydrolyzed solids can be directly used as organic fertilizer, while the hydrolyzate rich in small molecular organic matter can be quickly (3 days) converted into biomethane through anaerobic digestion, ultimately achieving zero solid emissions.

[0004] Although homemade composite hydrolase has the advantages of high hydrolysis efficiency and strong economic potential in the treatment of kitchen waste, the produced hydrolyzate is very easy to acidify and deteriorate, and the storage performance is poor, which significantly limits the application potential of the hydrolyzate as a high-purity organic carbon source product. In addition, the current disclosed technology mainly utilizes anaerobic digestion technology to further recycle the hydrolyzate, which takes several days, and the produced biogas needs to be further purified and concentrated before it can be put into use. The biogas produced by the corresponding anaerobic digestion is difficult to handle and expensive, which further reduces the resource value of the hydrolyzate. Secondly, the hydrolysis residue is weakly acidic, and when it is used as an agricultural fertilizer, it is easy to cause a series of negative ecological effects (such as soil acidification and compaction), which greatly reduces the economic benefits of this technology. Summary of the invention

[0005] In view of this, the present invention aims to improve the problem of easy deterioration and corruption of kitchen waste hydrolyzate and to address the low efficiency of current kitchen waste resource recovery technology. The present invention provides a resource recovery method for strengthening the rapid enzymatic hydrolysis of kitchen waste and simultaneously producing solid organic fertilizer and denitrification carbon source, so as to improve the resource conversion efficiency and economic benefits of kitchen waste.

[0006] Specifically, the present invention produces a hydrolyzate with a high organic matter concentration and excellent storage performance by adding alkaline substances (i.e., wood ash and biochar) during the enzymatic hydrolysis of kitchen waste, which is directly used as a denitrification carbon source, and the corresponding hydrolyzate residue has a high nutrient content and can be directly converted into ecological organic fertilizer.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A resource recovery method for strengthening rapid enzymatic hydrolysis of kitchen waste and simultaneously producing solid organic fertilizer and denitrification carbon source, the method specifically comprising the following steps:

[0009] (1) Production of bio-enzyme preparations

[0010] (2) adjusting the moisture content of the collected food waste to 75-85% by tap water, mixing the bioenzyme preparation and the alkaline substance with the food waste, and performing heating and hydrolysis treatment to obtain a food waste hydrolyzate;

[0011] (3) separating the food waste hydrolyzate obtained in step (2), filtering the liquid product to obtain a hydrolyzate, which can be directly used as a substitute for commercial carbon source for denitrification; and converting the solid residue into solid biofertilizer after drying for agricultural production.

[0012] It is worth noting that the filtering method in this application is not specifically limited, which may include filtering with rapid filter paper or 0.5-1.0 micron solid-liquid separation bags, and filter membranes; and, the stirring and centrifugal process conditions during the hydrolysis process are not specifically limited, as long as they meet / achieve the technical purpose.

[0013] Furthermore, the present application can effectively inhibit the conversion of small molecular organic acids in the hydrolyzate by adding alkaline substances (i.e., biochar and wood ash) during the hydrolysis process, thereby alleviating the over-acidification and deterioration of the hydrolyzate. After the addition of alkaline substances, the high-concentration liquid organic carbon source produced after 2-12 hours of rapid enzymatic hydrolysis has good storage performance and high bioavailability. It can replace commercial carbon sources and be directly used in biological denitrification processes. Compared with anaerobic digestion technology, the treatment cycle is shorter and the resource recovery efficiency is higher. In addition, the introduction of biochar and wood ash helps to increase the nutrient content (nitrogen, phosphorus and potassium) of the hydrolysis residue, and then convert it into a high-efficiency ecological organic fertilizer. The hydrolyzate and hydrolysis residue produced by the present application have significant economic value, and the overall process does not generate secondary waste, which helps to promote the zero solid emission disposal of food waste.

[0014] Optionally, in step (1), the production operation of the bioenzyme preparation is as follows:

[0015] The deoiled and impurity-removed food waste is inoculated with Aspergillus awamori, and a bioenzyme preparation is obtained through solid-state fermentation. The specific method for preparing the bioenzyme preparation is as follows: 3-5% dry mass ratio of biochar is added to food waste with a moisture content of 70-80%, and the mixture is fully mixed and then sterilized by high pressure; Aspergillus awamori is inoculated into the food waste that has been sterilized by high pressure, and the mixture is cultured in an incubator for 5-8 days to obtain a fermentation product with high saccharifying enzyme activity, i.e., a bioenzyme preparation.

[0016] Optionally, in step (2), the hydrolysis time is 2-12 hours and the hydrolysis temperature is 60°C.

[0017] Furthermore, the alkaline substance is at least one of biochar and wood ash. In order to give full play to the alkaline conditioning effect of the alkaline substance in the hydrolysis process, the alkaline substance must be fully ground before use to increase the specific surface area of ​​the material, and then used after passing through a 0.1-2 mm sieve; during hydrolysis, the mixing ratios of the biological enzyme preparation, the alkaline substance and the food waste are 3-5% and 3-45% (by dry weight), respectively.

[0018] Optionally, in step (3), the drying temperature is 50-80° C. and the drying time is 4-12 hours.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention is based on the technology of homemade bio-enzyme preparations and adds alkaline substances into the enzymatic hydrolysis system of kitchen waste, which is expected to achieve the purpose of efficient resource recovery of kitchen waste and achieve the effect of "treating waste with waste".

[0021] (1) The total NPK content of the solid ecological organic fertilizer produced by this method is higher than the requirement of 4.0% of the National Standard for Organic Biofertilizers in China (NY / T525-2021). On the other hand, the pH and heavy metal content are also within the range specified by NY / T525-2021. Therefore, the ecological organic fertilizer produced by this method can be used as a safe and high-quality agricultural fertilizer.

[0022] (2) The hydrolyzate prepared by this method is mainly composed of glucose, has excellent storage performance and high bioavailability, and can be directly used as a supplementary carbon source for the biological denitrification process of a sewage treatment plant, thus having significant commercial prospects.

[0023] (3) The solid ecological organic fertilizer prepared by the method can promote the root growth of crops, and the fertilizer performance is completely comparable to that of commercial organic fertilizers. By using the fertilizer to replace commercial fertilizers, the consumption of commercial fertilizers can be effectively saved, thereby reducing the carbon emissions of fertilizer production.

[0024] The kitchen waste treatment and resource utilization ideas proposed in this method not only create considerable economic benefits, but also have significant carbon emission reduction potential, and are both economically and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0026] Figure 1 This is a comparison chart of denitrification performance driven by different carbon sources.

[0027] Figure 2 This is a comparison chart of the growth of Chinese cabbage. DETAILED DESCRIPTION

[0028] 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.

[0029] The word "embodiment" used here as an "exemplary" does not necessarily mean that any embodiment described is superior to or better than other embodiments. Unless otherwise specified, the performance index tests in the embodiments of this application are performed using conventional test methods in the art. It should be understood that the terms described in this application are only used to describe specific implementation methods and are not used to limit the content disclosed in this application.

[0030] Unless otherwise specified, the technical and scientific terms used in this document have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs; other experimental methods and technical means not specifically specified in this application refer to experimental methods and technical means commonly used by ordinary technicians in this field.

[0031] In order to better illustrate the content of the present application, numerous specific details are provided in the specific examples below. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In the embodiments, some methods, means, instruments, equipment, etc. well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present application.

[0032] Under the premise of no conflict, the technical features disclosed in the embodiments of the present application can be combined arbitrarily, and the resulting technical solutions belong to the contents disclosed in the embodiments of the present application.

[0033] The invention discloses a resource recovery method for strengthening rapid enzymatic hydrolysis of kitchen waste and synchronously producing solid organic fertilizer and denitrification carbon source.

[0034] In order to further demonstrate the beneficial effects of the present invention and to better understand the present invention, the following implementation test examples are used to further illustrate the technical features of the device and its application disclosed in the present invention, but they should not be understood as limitations of the present invention. Other improvements made by those skilled in the art based on the above invention content without creative work are also considered to fall within the scope of protection of the present invention.

[0035] Test Example 1

[0036] In order to verify the effect of adding biochar to enhance the enzyme production of bio-enzyme preparations proposed in this application, in Experimental Example 1, food waste was added with biochar and used as a substrate for in-situ preparation of bio-enzyme preparations. After 8 days of fermentation and cultivation, the saccharifying enzyme activity of the bio-enzyme preparation was detected.

[0037] The method for preparing the bio-enzyme in this test example comprises the following steps:

[0038] The collected food waste was pre-degreased and cleaned, and the moisture content was adjusted to 70-80%. Then, different mass proportions of biochar were added to the food waste, mixed thoroughly, and sterilized by high pressure. Aspergillus awamori spore suspension was inoculated into the food waste after high pressure sterilization, and the spore concentration was 10 per gram of dry weight of food waste. 6 Then, the inoculated food waste is placed in an incubator and cultured for 5-8 days to obtain a fermentation product (i.e., a bioenzyme preparation) with high saccharifying enzyme activity.

[0039] The experimental parameters and results of each group are shown in Table 1:

[0040] Table 1 Experimental parameters and results

[0041]

[0042] As shown in Table 1, compared with experimental group 1, the saccharifying enzyme activities of experimental group 2, experimental group 3, experimental group 4 and experimental group 5 increased by 20.96%, 29.5%, 27.95% and 1.8%, respectively. With the increase of the amount of biochar added, the enzyme activity of the corresponding bioenzyme preparation was improved. This shows that the addition of biochar proposed in this application helps to improve the enzyme activity of the bioenzyme preparation. After adding biochar and solid-state fermentation culture, a bioenzyme preparation with higher saccharifying enzyme activity can be obtained.

[0043] Test Example 2

[0044] In order to verify the effect of adding alkaline substances to strengthen the enzymatic hydrolysis of food waste and the simultaneous production of hydrolyzate and hydrolyzate residue proposed in this application, the food waste was hydrolyzed using Test Example 2, and then the properties of the hydrolyzate and hydrolyzate residue of each experimental group were tested. The food waste used in the test example was collected from food residues generated during the daily operation of a university cafeteria. The food waste hydrolysis method in this test example includes the following steps:

[0045] (1) Aspergillus awamori spore suspension was inoculated into food waste (water content 70%) that had been degreased and sterilized at high pressure (sterilization temperature 121°C, sterilization for 30 min) to a spore concentration of 10 / g of food waste. 6 The inoculated kitchen waste was spread on a flat plate, cultured in a solid fermentation tank at 50% saturated oxygen, 70% saturated humidity and 30°C for 8 days, and 3% mass proportion of biochar was added to prepare a bioenzyme preparation. The saccharification enzyme activity per gram of dry weight of the product was determined to be 163.21U;

[0046] (2) The food waste was hydrolyzed in a hydrolysis tank to verify the hydrolysis efficiency of the food waste after adding alkaline substances. In the hydrolysis experiment, 12 experimental groups were set up, and the experimental parameters of each group are shown in Table 2.

[0047] Table 2 Experimental parameter design

[0048]

[0049] The hydrolysis experiment process is as follows:

[0050] The moisture content of the food waste was adjusted to 75-85%, and 100g of food waste was added to each group. Then, bioenzyme preparation was added at a ratio of 3-5% of the dry weight of the food waste, and different proportions of biochar or plant ash were added at the same time. The ash is derived from the combustion of agricultural straw. During the hydrolysis process, the hydrolysis temperature is 60°C and the hydrolysis treatment lasts for 2- 12 h. The hydrolyzate and hydrolysis residue in the hydrolysis product were then separated. The hydrolyzate was filtered with a 0.45 μm filter, sterilized at high pressure (sterilization temperature 121°C, sterilization time 30 min) and stored at 4°C. The hydrolysis residue was dried (drying temperature 50°C, drying time 12 h) as solid biofertilizer.

[0051] The components and properties of the hydrolyzates and hydrolysis residues in each group in Table 2 were tested and analyzed, and the results are shown in Tables 3, 4 and 5.

[0052] As shown in Table 3, the hydrolyzate produced by each experimental group contains a large amount of glucose, which indicates that the food waste hydrolyzate has excellent bioavailability potential. The organic matter in the hydrolyzate is mainly composed of easily biodegradable organic matter (protein and glucose, etc.), which has high bioavailability and has the potential to be used as a supplementary carbon source for the denitrification process.

[0053] Table 3 Hydrolyzate composition

[0054] Serial number Glucose content (g / L) Experimental Group 1 106.25 Experimental Group 2 79.22 Experimental Group 3 112.73 Experimental Group 4 91.77 Experimental Group 5 42.59 Experimental Group 6 117.86 Experimental Group 7 52.34 Experimental Group 8 98.54 Experimental Group 9 87.32 Experimental Group 10 81.45 Experimental Group 11 71.24 Experimental Group 12 35.14 Experimental Group 13 108.32 Experimental Group 14 110.42 Experimental Group 15 103.15

[0055] The results in Table 4 show that during the 14-day storage period, the hydrolyzate produced by experimental group 1 (without alkaline substances) was the most acidic, while the pH of the hydrolyzate produced by experimental groups 2-7 was significantly higher than that of experimental group 1. The alkaline substances added during the hydrolysis will continuously release alkaline substances into the hydrolysis system, extending the storage performance of the hydrolyzate. This shows that the addition of alkaline substances can effectively delay the excessive acidification of the hydrolyzate, improve the economic value of the hydrolyzate as a carbon source product, and thus enhance the application potential of the hydrolyzate as a denitrification carbon source.

[0056] Table 4 Hydrolyzate composition

[0057]

[0058] As shown in Table 5, the total NPK content of the solid ecological organic fertilizer produced by experimental group 4 (5% plant ash and 5% biochar synergistic addition group) is 5.61%, which is higher than the 4.0% requirement of the national standard for organic fertilizer (NY / T·525-2021). In addition, the seed germination index of experimental group 4 is higher than that of experimental group 1 (without alkaline substances), which indicates that the solid ecological organic fertilizer added with alkaline substances has a better fertilizer effect.

[0059] Table 5 Properties of solid biological fertilizer

[0060]

[0061] The kitchen waste hydrolyzate produced by the present application is mainly composed of high-concentration biodegradable organic matter, and has great potential in replacing commercial glucose. In order to illustrate the application potential of the hydrolyzate, the hydrolyzate obtained after adding different plant ashes and biochar was used to conduct a denitrification experiment, and commercial glucose was used as a control to verify the application potential of the hydrolyzate as a denitrification carbon source. Various data were monitored during the denitrification experiment. The experimental design is shown in Table 6.

[0062] Table 6 Denitrification experimental parameters

[0063]

[0064] like Figure 1 As shown in the figure, under the action of denitrifying bacteria, nitrate nitrogen in each group was quickly removed, and the removal trend of nitrate nitrogen in experimental groups 2, 3, 4 and 5 was similar to that in experimental group 1, which showed that the denitrifying bacteria could better utilize the organic matter in the hydrolyzate of food waste for nitrogen metabolism, thereby achieving a good denitrification effect. This proves that the hydrolyzate has the potential to replace commercial glucose as a carbon source for denitrification.

[0065] The first-order kinetic fitting was performed on the nitrate nitrogen removal process of each group in Table 6 above, and the rate constant k of each group was obtained by analysis, as shown in Table 7. The larger the k value, the more advantageous the nitrate nitrogen removal process is in terms of kinetics. The analysis results showed that the hydrolyzate produced by experimental group 4 had the largest k value, followed by experimental group 5 and experimental group 3. This shows that the hydrolyzate produced by adding alkaline substances (wood ash or biochar) has good biological utilization potential and can be used as a carbon source for biological denitrification processes, reducing the consumption of commercial carbon sources and creating economic benefits.

[0066] Table 7 Nitrate nitrogen removal kinetic analysis results

[0067]

[0068]

[0069] Test Example 3

[0070] In order to verify the fertilizer effect of the hydrolyzed residue produced by adding alkaline substances to strengthen the enzymatic hydrolysis of food waste and the simultaneous production of hydrolyzed residues proposed in the present application, a planting experiment was used to conduct research in the test example.

[0071] The preparation parameters of the hydrolyzed residue used in the experiment are shown in Table 8. During the enzymatic hydrolysis of the food waste, different mass ratios of plant ash were added. After 12 hours of hydrolysis, the hydrolyzed residue was separated by centrifugation and converted into solid biofertilizer under different drying parameters for planting experiments. The hydrolysis parameters and methods of the food waste were consistent with those in Experimental Example 2.

[0072] The planting experiment used pakchoi as the experimental object. Before the planting experiment, each 4L planting pot was filled with soil, and then pakchoi seeds were sown for cultivation. On the 14th day after sowing, 2 pakchoi seedlings were randomly selected for transplanting, and 2 pakchoi were placed in every 4 pots. Each experimental group was cultivated for 18 consecutive days until harvested on the 32nd day. Each planting pot was fed with biological fertilizers produced by experimental groups 1, 2 and 3, respectively, and experimental group 1 was fed with commercial fertilizers as a control. The entire experiment was fertilized twice. The first time was on the 16th day after sowing, and 3g of solid biological fertilizer was applied to each experimental group. The second time was on the 23rd day after sowing, and 1.2g of solid biological fertilizer was applied to each experimental group. On the 36th day after sowing, the pakchoi of all experimental groups were harvested, and the growth parameters of the pakchoi were recorded.

[0073] Table 8 Solid biofertilizer preparation parameter design

[0074]

[0075] Figure 2 The growth status of Chinese cabbage on the 15th, 24th and 36th day after sowing. It can be found that with the increase of the amount of wood ash added, the growth of Chinese cabbage is getting better.

[0076] It can be seen from Table 9 that compared with commercial solid fertilizers, the solid biofertilizer produced by adding wood ash can more effectively promote the growth of Chinese cabbage, and the corresponding growth height and weight are higher. This proves that the solid biofertilizer produced by the present application has excellent fertilizer efficiency and can be used as an ideal substitute for commercial fertilizers in agricultural production, thereby creating economic benefits.

[0077] Table 9 Comparison of physical properties of harvested Chinese cabbage

[0078]

[0079] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A resource recovery method for enhancing rapid enzymatic hydrolysis of kitchen waste and simultaneously producing solid organic fertilizer and denitrification carbon source, characterized in that: The method specifically comprises the following steps: (1) Production of bio-enzyme preparations (2) adjusting the moisture content of the collected food waste, mixing the bio-enzyme preparation and the alkaline substance with the food waste, heating and hydrolyzing the mixture, and obtaining a food waste hydrolyzate; (3) separating the food waste hydrolyzate obtained in step (2), filtering the liquid product to obtain a hydrolyzate, which can be directly used as a substitute for commercial carbon sources for denitrification; and converting the solid residue into solid biofertilizer after drying for use in agricultural production.

2. The resource recovery method for enhancing rapid enzymatic hydrolysis of kitchen waste and simultaneously producing solid organic fertilizer and denitrification carbon source according to claim 1, characterized in that: In step (1), the production operation of the bioenzyme preparation is as follows: The deoiled and impurity-removed food waste is inoculated with Aspergillus awamori, and a bioenzyme preparation is obtained through solid-state fermentation. The specific method for preparing the bioenzyme preparation is as follows: biochar is added to the food waste, and the mixture is sterilized under high pressure; Aspergillus awamori is inoculated into the food waste, and the mixture is cultured in an incubator for 5-8 days, so that a fermentation product with high saccharifying enzyme activity, i.e., a bioenzyme preparation, can be obtained.

3. The resource recovery method for enhancing rapid enzymatic hydrolysis of kitchen waste and simultaneously producing solid organic fertilizer and denitrification carbon source according to claim 2, characterized in that: The mass ratio of the added biochar to the kitchen waste is 3-5%, and the moisture content of the kitchen waste used for inoculation is 70-80%.

4. The resource recovery method for enhancing rapid enzymatic hydrolysis of kitchen waste and simultaneously producing solid organic fertilizer and denitrification carbon source according to claim 1, characterized in that: In step (2), the moisture content of the collected food waste is adjusted to 75-85%, the hydrolysis time is 2-12 hours, and the hydrolysis temperature is 60°C.

5. The resource recovery method for enhancing rapid enzymatic hydrolysis of kitchen waste and simultaneously producing solid organic fertilizer and denitrification carbon source according to claim 1 or 4, characterized in that: The alkaline substance is at least one of biochar and wood ash; and the alkaline substance must be ground and passed through a 0.1-2 mm sieve before use.

6. The resource recovery method for enhancing rapid enzymatic hydrolysis of kitchen waste and simultaneously producing solid organic fertilizer and denitrification carbon source according to claim 5, characterized in that: In step (2), during hydrolysis, the mixing ratios of the bio-enzyme preparation, the alkaline substance and the food waste are 3-5% and 3-45% respectively (based on dry weight).

7. The resource recovery method for enhancing rapid enzymatic hydrolysis of kitchen waste and simultaneously producing solid organic fertilizer and denitrification carbon source according to claim 1 or 6, characterized in that: The drying temperature is 50-80°C and the drying time is 4-12 hours.

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