Construction of artificial multicellular systems and their applications in waste biomass treatment

Abstract

The present invention relates to the field of fermentation degradation technology, and specifically to the construction of an artificial multicellular system and its application in waste biomass. The main role in the artificial multicellular system is played by a composite bacterial agent prepared by mixing Bacillus thuringiensis ZJB19165 and Bacillus licheniformis ZJB19163. These two strains are strains with high degradation activity on the main components of fruit and vegetable wastes, which are screened according to the characteristics of the components of fruit and vegetable wastes. The present invention utilizes the synergistic effect of microorganisms in the degradation process of organic matter to develop an artificial multicellular system suitable for the treatment needs of fruit and vegetable wastes, significantly improves the degradation effect and the stability of the process, and realizes the rapid and harmless treatment of fruit and vegetable wastes.

Description

Technical Field

[0001] The present invention relates to the technical field of fermentation degradation, and in particular to the construction of an artificial multicellular system and its application in waste biomass treatment. Background Art

[0002] Fruit and vegetable waste primarily refers to the waste generated by fruits, vegetables, and other foods during market circulation. Like public restaurant waste and household kitchen waste, fruit and vegetable waste is a biodegradable organic waste component of municipal solid waste. Currently, fruit and vegetable waste accounts for a growing proportion of municipal solid waste. The large-scale generation and accumulation of fruit and vegetable waste poses a serious threat to farmland, water bodies, fruit and vegetable distribution markets, and other human settlements, becoming a significant source of pollution. One of the characteristics of fruit and vegetable waste is its diverse sources. Leaves, roots, stems, and fruits produced during vegetable production, processing, transportation, and unsold goods can all contribute to this waste. Untreated fruit and vegetable waste can be dumped into waterways, or the leachate generated by the accumulation and decomposition of vegetable waste can enter water bodies with rainwater, causing water pollution. Vegetable waste has a high moisture content, high volatile solids content, and is easily biodegradable. During stacking, storage, and transportation, it generates foul-smelling gases, causing varying degrees of atmospheric pollution. It can also harbor mosquitoes and flies, spread bacteria, and affect environmental hygiene and human health. Some farmers spray herbicides after harvesting some of the produce, causing the remaining vegetables to wilt. This increases pesticide residues in the soil and poses a high risk of contamination. Due to a lack of effective and scientific treatment methods, nearly 100 million tons of fruit and vegetable waste are discarded in my country each year. The vast majority of this waste is not repurposed and is discarded as garbage or released into the environment. This low utilization rate not only has a range of environmental impacts, but also requires appropriate treatment of fruit and vegetable waste.

[0003] Currently, microbial degradation technologies are commonly used to degrade fruit and vegetable waste. However, due to the high moisture content and low nutrient content of fruit and vegetable waste, conventional treatment methods struggle to achieve complete fermentation. Consequently, many existing microbial degradation technologies using a single bacterial species struggle to achieve comprehensive treatment of perishable waste. Furthermore, single-strain systems are limited in the types of substrates they can utilize, resulting in low substrate utilization efficiency and poor stability when used on complex fruit and vegetable waste. Summary of the Invention

[0004] This invention aims to overcome the drawbacks of existing technologies, such as the difficulty of using a single bacterial strain to completely degrade fruit and vegetable waste and the complex treatment process. It provides a method for constructing an artificial multicellular system and its application in waste biomass treatment to overcome these drawbacks. Based on the compositional characteristics of fruit and vegetable waste, this invention screens and obtains bacterial strains with high degradation activity against the main components of fruit and vegetable waste. By leveraging the synergistic effects of microorganisms in the organic matter degradation process, this invention develops an artificial multicellular system suitable for fruit and vegetable waste treatment. This system significantly improves the degradation efficiency and process stability, achieving rapid and harmless treatment of fruit and vegetable waste.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] An artificial multicellular system comprising Bacillus thuringlensis ZJB19165 and Bacillus licheniformis ZJB19163;

[0007] The Bacillus thuringlensis ZJB19165 is deposited in the China Center for Type Culture Collection with the deposit number CCTCC M2020015;

[0008] The Bacillus licheniformis ZJB19163 is deposited in the China Center for Type Culture Collection with a deposit number of CCTCC NO: M2020014.

[0009] Compared to single-bacteria systems, artificial multicellular systems contain diverse bacterial species, providing diverse catalytic environments for the various enzymes involved in biodegradation pathways. Furthermore, artificial multicellular systems can rationally allocate the pathways and functions involved in different organic matter degradation processes, reducing the metabolic burden on individual bacterial species and enabling each species to develop distinct substrate utilization preferences. This eliminates interference from a single cell utilizing multiple substrates and improves overall substrate utilization.

[0010] Before the preparation of the compound bacterial agent began, a series of experiments were conducted to screen out the strains that are most conducive to the degradation of fruit and vegetable waste.

[0011] It is known that the organic matter in fruit and vegetable waste is primarily composed of protein, starch, and cellulose; therefore, the primary goal of the screening process was to identify strains with highly active amylases, proteases, and cellulases. Ultimately, experimental results showed that Bacillus thuringiensis ZJB19165 and Bacillus licheniformis ZJB19163 exhibited the highest amylase, protease, and cellulase activities among the 87 strains screened.

[0012] Simulated degradation experiments were conducted on fruit and vegetable waste using either Bacillus thuringiensis ZJB19165 or Bacillus licheniformis ZJB19163 alone, a mixture of the two, and no other strains. The results showed that both strains effectively degraded fruit and vegetable waste, and that when inoculated together, the two strains significantly promoted degradation, with the total weight loss rate consistently higher than when inoculated with a single strain, indicating that the two strains can synergistically degrade fruit and vegetable waste.

[0013] Furthermore, when the artificial multicellular system was compared with two commercially available agents commonly used for degrading fruits and vegetables, the total weight loss rate of the artificial multicellular system constructed by the present invention reached 84.53%, while the total weight loss rate of commercial agent A was 77.08%, and the total weight loss rate of commercial agent B was 76.39%. This data strongly demonstrates that the artificial multicellular system constructed by the present invention can replace long-used commercial agents for large-scale production and application, which is of great practical significance. Furthermore, stability tests on the artificial multicellular system revealed its strong stability.

[0014] Preferably, the artificial multicellular system further comprises wheat straw or corn cobs for fixing the bacterial agent.

[0015] Wheat straw or corn cobs are added to fix the inoculum for easy storage and transportation. Without wheat straw or corn cobs, the inoculum can still degrade normally.

[0016] Preferably, based on the weight of wet cells, the mass ratio of Bacillus thuringiensis ZJB19165 to Bacillus licheniformis ZJB19163 is 1:(0.5-2); the mass ratio of the total cell mass of Bacillus thuringiensis ZJB19165 and Bacillus licheniformis ZJB19163 to the mass of wheat straw or corn cobs is 1:(1-2).

[0017] Application of an artificial multicellular system in the degradation of fruit and vegetable waste.

[0018] A method for degrading fruit and vegetable wastes comprises adding the artificial multicellular system to the fruit and vegetable wastes to be degraded for fermentation degradation.

[0019] Preferably, the method comprises the following steps: mixing fruit and vegetable waste, an artificial multicellular system and a filler and adding the mixture into a fermentation bin; controlling the temperature in the fermentation bin, ventilating the mixture and stirring the mixture intermittently until primary degradation is completed; after the primary degradation is completed, adding fruit and vegetable waste for secondary degradation until the fermentation bin is full and the fermentation degradation is terminated.

[0020] More specifically, fermentation degradation is carried out in stages within the fermentation chamber. Crushed fruit and vegetable waste and a compound inoculant are placed in the fermentation chamber, a filler is added, and the temperature is maintained at 40°C. Ventilation and intermittent stirring are maintained for 12 hours. The temperature is then adjusted to 50°C, and stirring is continued for another 12 hours, completing one cycle of degradation. After completing one cycle of degradation, no inoculant is added, and a second cycle of crushed fruit and vegetable waste continues under the same conditions, until the chamber is nearly overflowing.

[0021] The advantage of staged degradation is that it can be processed immediately according to the generation of waste, and the utilization of the degradation bin is more reasonable, avoiding the problem of the degradation bin capacity being too small to accommodate the waste when it is put in at one time.

[0022] Intermittent stirring is a fermentation condition where the mixture is stirred for a period of time and then rested for a period of time, such as stirring for 15 to 30 minutes and then resting for 5 to 10 minutes. The actual stirring time can be considered as the time when the bacteria and waste begin to come into contact and ferment.

[0023] Preferably, the filler is any one of wheat straw, sawdust, and corn cob.

[0024] The function of filler is to adjust the C / N ratio and moisture content.

[0025] Generally speaking, microorganisms need to absorb 1g of nitrogen for every 25g of organic carbon they consume. If the C / N ratio is too high, microbial growth will be slow, and organic matter decomposition will be slow. If the C / N ratio is too low, excess nitrogen will be released as ammonia, emitting an unpleasant odor. Sawdust is typically used as a filler to adjust both the C / N ratio and the moisture content. Excessive moisture can cause anaerobic fermentation, resulting in an unpleasant odor.

[0026] Preferably, the mass ratio of the filler to the fruit and vegetable waste is 1:(2-10).

[0027] Preferably, the mass ratio of the added amount of the artificial multicellular system to the fruit and vegetable waste is (1-10):150.

[0028] Preferably, the fermentation time is not less than 12 hours.

[0029] The overall operation time of degradation may include the static time of intermittent stirring, and the fermentation time of no less than 12 hours must be ensured in the overall operation time. Too little fermentation time will lead to low degradation efficiency.

[0030] Therefore, the present invention has the following beneficial effects:

[0031] (1) The main mixed bacteria in the artificial multicellular system constructed by the present invention are Bacillus thuringiensis ZJB19165 and Bacillus licheniformis ZJB19163, which are obtained by screening and contain highly active amylase, protease, and cellulase. They have better degradation capabilities for the main components of fruit and vegetable waste (starch, protein, cellulose) than conventional commercially available fruit and vegetable degradation agents and have great application value.

[0032] (2) The present invention uses staged degradation to achieve complete degradation of fruit and vegetable waste, which has the advantage of being able to process waste immediately according to its generation, making more reasonable use of the degradation bin;

[0033] (3) The artificial multicellular system constructed by the present invention has strong stability and does not require the addition of bacterial agents during degradation, which can achieve rapid harmless and low-cost treatment of fruit and vegetable waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The graph shows the degradation rate of starch, protein and cellulose by the strain in liquid culture medium;

[0035] Figure 2 This is a diagram showing the weight reduction effect of the strain on fruit and vegetable waste. DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below generally represent only a portion of the present invention, rather than all of the embodiments. Therefore, all other embodiments derived by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0037]

Preparation before the test

[0038] 1. Screening and identification of strains capable of degrading the main components of fruit and vegetable waste

[0039] (1) Determine the species of the strain obtained by screening

[0040] Organic matter in fruit and vegetable waste is primarily composed of protein, starch, and cellulose. Therefore, the ultimate goal of strain screening is to identify strains with high activity of protease, amylase, and cellulase. The following analysis focuses on characterizing the degradation effects of the selected strains on these three main substances.

[0041] 2 g of fresh soil sample was taken from the soil sample near the Yuxiu Restaurant of Zhejiang University of Technology and suspended in sterile water, shaken at 30°C and 150 rpm for 30 minutes. The suspension was diluted with sterile water in a gradient of 10 -4 , 10-5 , 10 -6 , 10 -7 , 10 -8 , 10 -9 200 μL of each bacterial suspension was inoculated onto an agar plate and incubated in a 37°C incubator for 24 hours. Representative colonies were selected and repeatedly streaked until distinct single colonies were isolated. The agar plates used were Luria-Bertani (LB) solid medium (1% peptone, 0.5% yeast extract, 1% NaCl, and 2% agar).

[0042] The genomic DNA of the strain was extracted using the FastDNATM Spin Kit for Soil and used as a template for PCR amplification. The bacterial universal primers were:

[0043] 27F: 5'-AGAGTTTTGATCCTGGCTCA-3',

[0044] 1492R: 5'-AAGGAGGTGATCCAGCCGCA-3'.

[0045] The products were sequenced by Qingke Biotechnology Co., Ltd. The obtained DNA sequences were entered into GenBank and compared with all sequences in the database using the Blast program to determine the species of the strains obtained by screening.

[0046] (2) Screening of strains

[0047] A total of 87 strains were screened. Initial screening was performed using the clearing zone method. All screened strains were inoculated onto agar media containing starch, fat, protein, and cellulose. Clearing zones surrounding colonies were used as indicators of degradation activity. Ten strains with the largest clearing zone diameters in each culture medium were selected for rescreening, and the isolated single strain was inoculated into LB medium. Cultures were incubated at 37°C for 24 hours. The fermentation broth was centrifuged at 8000 rpm for 10 minutes, and the supernatant was assayed for amylase, protease, and cellulase activities. Amylase and cellulase activities were determined using the DNS method, with 1 μg of reducing sugar produced per minute per mL of enzyme solution (unit of activity, expressed in U / mL). Protease activity was determined using the Folin-phenol method, with 1 μg of tyrosine produced per minute per mL of enzyme solution (unit of activity, expressed in U / mL). The reaction temperature was 40°C, and the pH was 7.0.

[0048] Table 1 Comparison of bacterial activity

[0049] strain Amylase activity (U) Protease activity (U) Cellulase activity (U) Bacillus thuringiensis 818.6 605 9.9 Bacillus licheniformis 262.5 1027 10.1 Bacillus subtilis 237.6 475.2 5.4 Streptococcus liquefaciens 223.5 577.4 1.133

[0050] Finally, one Bacillus thuringiensis and one Bacillus licheniformis were screened from the 24 strains, and they were named and preserved respectively. Bacillus thuringiensis ZJB19165 (Bacillus thuringlensis), with the preservation number CCTCCM2020015, was preserved in the China Center for Type Culture Collection; Bacillus licheniformis ZJB19163 (Bacillus subtilis), with the preservation number CCTCC M2021188, was preserved in the China Center for Type Culture Collection.

[0051] 2. Determination of organic matter degradation rate by Bacillus thuringiensis ZJB19165 and Bacillus licheniformis ZJB19163 at different temperatures

[0052] The isolated Bacillus thuringiensis ZJB19165 and Bacillus licheniformis ZJB19163 were inoculated into starch degradation medium, protein degradation medium, and cellulose degradation medium as a single strain or a mixed strain, and cultured at 20°C, 30°C, 40°C, 50°C, and 60°C for three days, respectively, to measure the degradation rate of the corresponding organic matter. The starch degradation medium composition is: peptone 10.0g / L, soluble starch 10.0g / L, beef extract 5.0g / L, NaCl 5.0g / L, pH 7.0-7.2. The protein degradation medium composition is: skim milk powder 10g / L, peptone 10.0g / L, beef extract 5.0g / L, MgSO4·7H2O 0.2g / L, pH 7.0-7.2. The cellulose degradation medium consists of 10.0 g / L peptone, 5.0 g / L beef extract, 0.5 g / L K₂HPO₄, 0.25 g / L MgSO₄, and 1 g / L wheat straw. All culture media, except the protein selection medium, were sterilized at 121°C for 20 min. Protein medium sterilization conditions included sterilizing skim milk powder at 115°C for 20 min, and all other culture media at 121°C for 20 min.

[0053] The results are summarized in Figure 1 In, observe Figure 1 As can be seen, at fermentation temperatures between 20°C and 60°C, the degradation rates of starch, protein, and cellulose all initially increased with increasing temperature, reaching a peak before decreasing. However, starch peaked at 30°C, while protein and cellulose peaked at 40°C. Overall, the best degradation rate was achieved at 40°C, while a relatively good degradation rate was observed at 30°C to 50°C.

[0054] [Example]

[0055] Example 1

[0056] (1) Activate the frozen glycerol tubes of the two strains using LB medium. Streak the tubes separately and incubate at 37°C for 12 hours. The medium used for activation is LB solid medium.

[0057] (2) The activated Bacillus thuringiensis and Bacillus licheniformis were inoculated into LB medium, cultured at 37°C with shaking for 24 h, and centrifuged at 8000 rpm for 10 min to obtain wet cells of Bacillus thuringiensis and Bacillus licheniformis.

[0058] (3) The wet cells of Bacillus thuringiensis and Bacillus licheniformis were mixed at a mass ratio of 1:1, and then inoculated into a shake flask containing crushed fruit and vegetable waste at a mass ratio of 1%. The mixture was shaken and cultured at 40°C. The cells were weighed every 12 hours to determine the weight loss rate.

[0059] Comparative Example 1

[0060] The difference is that Bacillus thuringiensis is inoculated into the shake flask containing the crushed fruit and vegetable waste at a mass ratio of 1%, and the rest is the same as Example 1.

[0061] Comparative Example 2

[0062] The difference is that the wet cells of Bacillus licheniformis are inoculated into the shaking bottle containing the crushed fruit and vegetable waste at a mass ratio of 1%, and the rest is the same as in Example 1.

[0063] Comparative Example 3

[0064] No bacteria were added, and the rest was the same as in Example 1.

[0065] The test results of Example 1 and Comparative Examples 1 to 3 are summarized as follows: Figure 2 In the experiment, compared with the blank control, both strains can effectively degrade fruit and vegetable waste, and when the two strains are inoculated together, they obviously promote the degradation of fruit and vegetable waste. The total weight loss rate is always higher than the weight loss rate when a single strain is inoculated, indicating that the two strains can synergistically degrade fruit and vegetable waste.

[0066] It is worth noting that when cultured under oscillation at 30 / 50℃, the weight loss rate of the mixed strains still remained at an optimal level, which is consistent with the experimental results of the organic matter degradation rate determination of Bacillus thuringiensis ZJB19165 and Bacillus licheniformis ZJB19163 at different temperatures; and the weight loss effect at 50℃ is better than that at 30℃, which is because the system removes water faster at 50℃.

[0067] Example 2

[0068] (1) Use LB medium to activate the two frozen strains. Streak the glycerol tubes separately and culture them at 37°C for 12 hours to activate the strains.

[0069] (2) Pick well-growing colonies into a shake flask containing 100 mL of LB and culture at 200 rpm at 37°C for 48 hours to obtain seed solutions of Bacillus thuringiensis and Bacillus licheniformis. Transfer the seed solutions into a 2 L shake flask containing 800 mL of LB and culture at 200 rpm at 37°C for 48 hours. Centrifuge at 8000 rpm for 10 minutes to obtain wet cells of the two strains.

[0070] (3) The wet cells of Bacillus thuringiensis and Bacillus licheniformis were mixed at a mass ratio of 1:0.5, and then mixed with wheat straw at a ratio of 1:1 of total cell mass. The composite microbial agent was obtained after natural drying at 37°C and stored at 4°C. The number of viable cells in the final product was ≥10 9 CFU / mL.

[0071] (4) Take 100 g of the compound bacterial agent of (3) and add it into the degradation treatment machine, add 1.5 kg of crushed fruit and vegetable waste, and add 750 g of wheat straw to adjust the moisture content, and run for 15 hours.

[0072] Example 3

[0073] (1) Use LB medium to activate the two frozen strains. Streak the glycerol tubes separately and culture them at 37°C for 12 hours to activate the strains.

[0074] (2) Pick well-growing colonies into a shake flask containing 100 mL of LB and culture at 200 rpm at 37°C for 48 hours to obtain seed solutions of Bacillus thuringiensis and Bacillus licheniformis. Transfer the seed solutions into a 2 L shake flask containing 800 mL of LB and culture at 200 rpm at 37°C for 48 hours. Centrifuge at 8000 rpm for 10 minutes to obtain wet cells of the two strains.

[0075] (3) The wet cells of Bacillus thuringiensis and Bacillus licheniformis were mixed at a mass ratio of 1:1, and then mixed with corn cobs at a ratio of 1:2 of the total cell mass. The composite microbial agent was obtained after natural drying at 37°C and stored at 4°C. The number of viable cells in the final product was ≥10 9 CFU / mL.

[0076] (4) Take 100 g of the compound bacterial agent of (3) and add it into the degradation treatment machine, add 1 kg of crushed fruit and vegetable waste, add 200 g of sawdust to adjust the moisture, and run for 24 hours.

[0077] Example 4

[0078] (1) Use LB medium to activate the two frozen strains. Streak the glycerol tubes separately and culture them at 37°C for 12 hours to activate the strains.

[0079] (2) Pick well-growing colonies into a shake flask containing 100 mL of LB and culture at 200 rpm at 37°C for 48 hours to obtain seed solutions of Bacillus thuringiensis and Bacillus licheniformis. Transfer the seed solutions into a 2 L shake flask containing 800 mL of LB and culture at 200 rpm at 37°C for 48 hours. Centrifuge at 8000 rpm for 10 minutes to obtain wet cells of the two strains.

[0080] (3) The wet cells of Bacillus thuringiensis and Bacillus licheniformis were mixed at a mass ratio of 1:2, and then mixed with wheat straw at a ratio of 1:1.5 of total cell mass. The composite microbial agent was obtained after natural drying at 37°C and stored at 4°C. The number of viable cells in the final product was ≥10 9 CFU / mL.

[0081] (4) Take 10 g of the compound bacterial agent of (3) and add it into the degradation treatment machine, add 1.5 kg of crushed fruit and vegetable waste, add 300 g of corn cobs to adjust the moisture, and run for 48 hours.

[0082] Comparative Example 4

[0083] In the degradation processor, 1 kg of crushed fruit and vegetable waste and 200 g of sawdust were added simultaneously to adjust the moisture content and the machine was run for 24 hours.

[0084] Comparative Example 5

[0085] In the degradation processor, 100 g of commercially available microbial agent A (a conventional microbial agent for degrading fruits and vegetables), 1 kg of crushed fruit and vegetable waste, and 200 g of sawdust were added simultaneously to adjust the moisture content, and the machine was run for 24 hours.

[0086] Comparative Example 6

[0087] In the degradation processor, 100 g of commercially available microbial agent B (a conventional microbial agent for degrading fruits and vegetables), 1 kg of crushed fruit and vegetable waste, and 200 g of sawdust were added simultaneously to adjust the moisture content, and the machine was run for 24 hours.

[0088] The degradation conditions in Examples 2 to 4 and Comparative Examples 4 to 6 were observed, and the starch degradation rate, protein degradation rate, cellulose degradation rate and total weight loss rate of each system were measured. The relevant results are shown in Table 2.

[0089] Table 2 Comparison of degradation ability of each system

[0090] Starch degradation rate Protein degradation rate Cellulose degradation rate Total weight loss rate Example 2 51.78％ 50.63％ 35.77％ 81.21％％ Example 3 53.45％ 56.21％ 40.25％ 84.53％ Example 4 46.35％ 51.46％ 31.87％ 80.35％％ Comparative Example 4 4.15％ 7.45％ 1.21％ 71.05％ Comparative Example 5 33.57％ 30.89％ 12.33％ 77.08％ Comparative Example 6 22.41％ 35.47％ 15.22％ 76.39％

[0091] The test results in Table 2 show that without inoculation, the organic matter in the fruit and vegetable waste was essentially not degraded. The degradation effect of the mixed inoculant was better than that of the two commercially available inoculants, and the best degradation effect was achieved when the mass ratio of Bacillus thuringiensis to Bacillus licheniformis was 1:1.

[0092] Observing the data for Comparative Examples 4-6 in Table 2, we can see that the total weight loss rate after adding a commercially available microbial agent increased by 6% compared to the total weight loss rate when no microbial agent was added. Furthermore, when the artificial multicellular system was used for degradation, the total weight loss rate reached 84.53%, a significant increase of 7-8% compared to existing commercial microbial agents. This demonstrates that the artificial multicellular system constructed by the present invention has significant application advantages.

[0093]

Stability test

[0094] (1) The composite microbial agent was used in a high-temperature continuous biodegradation experiment on fruit and vegetable waste. 200 g of the composite microbial agent from Example 1 was added to a waste degradation processor, along with 1 kg of crushed fruit and vegetable waste and 200 g of sawdust to adjust the moisture content. The temperature was adjusted to 40°C and the reaction was stirred for 12 hours. The temperature was then adjusted to 50°C and the reaction was stirred for another 12 hours to complete one cycle of degradation.

[0095] (2) After completing one round of degradation, crushed fruit and vegetable waste was added for a second round of degradation under the same conditions until the degradation chamber was close to overflowing (10 days). Approximately 80% of the material was removed from the degradation chamber and fruit and vegetable waste was added for further degradation. The fruit and vegetable waste degradation experiment was carried out for a total of 18 days.

[0096] Table 3 Effect of degradation cycle on degradation effect

[0097] Degradation cycle Average starch degradation rate Average protein degradation rate Average cellulose degradation rate Total weight loss rate 0-10 days 76.05％ 73.36％ 51.28％ 87.35％ 11-18day 78.17％ 70.24％ 44.51％ 85.01％

[0098] From the data in the above table, we can see that the degradation efficiency of the bacterial agent after 10 days is equivalent to that after 11 to 18 days; and no bacterial agent was added during the period of 11 to 18 days, which proves that the bacterial agent has good stability.

Claims

1. A method for degrading fruit and vegetable waste, characterized in that: After mixing fruit and vegetable waste, the artificial multicellular system and the filler, the mixture is added to the fermentation bin, the temperature is controlled at 40°C, ventilation and intermittent stirring are carried out for 12 hours, and then the temperature is adjusted to 50°C, and the stirring reaction is continued for 12 hours to complete one round of degradation. After completing one round of degradation, fruit and vegetable waste is continued to be added for a second round of degradation until the fermentation bin is full and the fermentation degradation ends. The artificial multicellular system consists of Bacillus thuringlensis ZJB19165, Bacillus licheniformis ZJB19163 and a fixative; the mass ratio of Bacillus thuringlensis ZJB19165 to Bacillus licheniformis ZJB19163 is 1:(0.5-2) based on the weight of the wet cells; the Bacillus thuringlensis ZJB19165 is deposited in the China Center for Type Culture Collection with a deposit number of CCTCCNO: M2020015; the Bacillus licheniformis ZJB19163 is deposited in the China Center for Type Culture Collection with a deposit number of CCTCCNO: M2020014; and the fixative is wheat straw or corn cob.

2. The method for degrading fruit and vegetable waste according to claim 1, characterized in that: The mass ratio of the total bacterial mass of the Bacillus thuringiensis ZJB19165 and the Bacillus licheniformis ZJB19163 to the mass of the wheat straw or corn cob is 1:(1-2).

3. The method for degrading fruit and vegetable waste according to claim 1, characterized in that: The filler is any one of wheat straw, sawdust and corn cob.

4. A method for degrading fruit and vegetable waste according to claim 1 or 3, characterized in that: The mass ratio of the filler to the fruit and vegetable waste is 1:(2-10).

5. The method for degrading fruit and vegetable waste according to claim 1, characterized in that: The mass ratio of the added amount of the artificial multicellular system to the fruit and vegetable waste is (1-10):150.

Images