Complex microbial inoculant and application of complex microbial inoculant in degrading kitchen waste in cooperation with hermetia illucens

Abstract

The invention provides a complex microbial inoculant and application of the complex microbial inoculant in degradation of kitchen waste in cooperation with hermetia illucens, belongs to the technical field of microorganism application, and provides bacillus subtilis LH-Pika23. The bacillus subtilis LH-Pika23 independently treats the kitchen waste and can remarkably remove odor in the kitchen waste. The complex microbial inoculant obtained by compounding the bacillus subtilis LH-Pika23 and the casei paracasei TDM-2 widens the variety of treatable substrates, and is higher in odor removal rate and more stable and lasting in odor removal effect. The complex microbial inoculant provided by the invention cooperates with the hermetia illucens to treat the kitchen waste, so that the bioconversion efficiency of the hermetia illucens is improved, and meanwhile, the complex microbial inoculant also has a remarkable deodorization effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of microbial agents, and particularly relates to a compound microbial agent and its application in synergistically degrading food waste with black soldier flies. Background Art

[0002] In recent years, with the rapid development of industries such as tourism and catering, factors such as daily life, catering consumption, food processing links, and consumption habits have jointly promoted the formation of food waste. The treatment and disposal of food waste have received extensive attention. Food waste is the food processing leftovers, edible residues (swill), and waste edible oils generated in activities such as households, food service, institutional catering, and food processing. It is characterized by high moisture content (80% - 95%), high organic matter (such as protein, fat, starch, etc.), and high salt content. The organic matter in food waste undergoes anaerobic fermentation by microorganisms to form various odorous harmful gases, which become the main body of malodorous substances. Among them, ammonia (NH3) and hydrogen sulfide (H2S) are the most abundant gases. Short-term exposure can cause acute poisoning, and long-term exposure may increase the risk of chronic diseases. How to effectively and environmentally reduce and reuse food waste is a current challenge.

[0003] Currently, the main methods for treating malodorous gases cover three categories: physical, chemical, and biological. Physical methods include masking, dilution and diffusion, etc. The principle is to capture odor substances in micropores using adsorbents such as activated carbon. However, this adsorption process often makes it difficult for the adsorbent to release the adsorbed substances, and it is prone to blockage, thereby making the adsorbent unable to be recycled and may also cause secondary pollution problems in the environment. Catalytic combustion is another method that crosses physical and chemical fields. Its characteristics are low energy consumption and simple operation. However, the drawback is that the equipment structure is complex, the selection of catalysts is quite challenging, and the phenomenon of catalyst poisoning needs to be strictly prevented. Chemical methods use oxidants such as potassium permanganate, ozone, sulfur dioxide, etc., as well as reducing agents such as sodium borohydride and sodium sulfite, or acid-base agents to eliminate the odor source. Although it has a certain effect, it is often not thorough enough, has a short persistence, and may have certain side effects on the environment. In contrast, microbial deodorization technology uses the physiological and metabolic activities of microorganisms to decompose malodorous substances to achieve the deodorization goal. This method not only does not cause secondary pollution but also has many advantages such as high efficiency, safety, non-toxicity, and harmlessness. However, it is difficult to achieve good deodorization effects with a single strain alone.

[0004] Hermetia illucens, as an efficient bioconversion insect, shows significant potential in the field of food waste treatment. Its larvae can rapidly degrade organic matter (such as starch, fat, and protein) by feeding, convert the waste into high-value insect body protein (with a crude protein content of 40%-50%) and insect manure organic fertilizer (containing nitrogen, phosphorus, potassium, and humic acid), while reducing carbon emissions and secondary pollution. Currently, due to its advantages such as no need for complex pretreatment, adaptability to high-moisture / high-oil waste, and short treatment cycle (5-7 days), the Hermetia illucens treatment technology has established large-scale breeding bases in many places at home and abroad and is gradually applied to communities, catering enterprises, and waste treatment plants. However, the current single application of Hermetia illucens still needs to improve the biological conversion rate. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a compound bacterial agent and its application in synergizing with Hermetia illucens for degrading food waste.

[0006] The compound bacterial agent provided by the present invention has a very obvious deodorization effect on food waste. After 10 days of application, the removal rates of ammonia and hydrogen sulfide can reach more than 95%. The two bacteria in the compound bacterial agent cooperate synergistically to play a role, broaden the types of substrates that can be treated, and the deodorization effect is significantly better than that of a single strain, with a more stable and lasting effect.

[0007] On the other hand, the compound bacterial agent provided by the present invention synergizes with Hermetia illucens to treat food waste, which can improve the biological conversion efficiency of Hermetia illucens and also has a significant deodorization effect.

[0008] The present invention provides a Bacillus subtilis LH-Pika23, and the preservation number is CCTCC M 2025439.

[0009] The present invention provides the application of the Bacillus subtilis LH-Pika23 in degrading food waste.

[0010] The present invention provides the application of the Bacillus subtilis LH-Pika23 in degrading the odor of food waste.

[0011] Preferably, the odor includes ammonia and hydrogen sulfide.

[0012] The present invention provides a compound bacterial agent, including the Bacillus subtilis LH-Pika23 and Lactobacillus paracasei TDM-2; the quantity ratio of the Bacillus subtilis LH-Pika23 to the Lactobacillus paracasei TDM-2 is (0.5-1.5):(0.5-1.5).

[0013] Preferably, the compound bacterium agent is a liquid bacterium agent; the viable bacteria concentration of Bacillus subtilis LH-Pika23 in the compound bacterium agent is 10 8 ~10 9 CFU / mL, and the viable bacteria concentration of Lactobacillus paracasei TDM-2 in the compound bacterium agent is 10 8 ~10 9 CFU / mL.

[0014] The present invention provides the application of the compound bacterium agent in degrading kitchen waste.

[0015] The present invention provides the application of the compound bacterium agent in degrading the odor of kitchen waste.

[0016] The present invention provides a method for degrading kitchen waste by microorganisms cooperating with black soldier flies, comprising the following steps:

[0017] Mix the microorganisms, black soldier flies and kitchen waste to degrade the kitchen waste;

[0018] The microorganisms are the compound bacterium agent described above.

[0019] Preferably, the mass ratio of the microorganisms, black soldier flies and kitchen waste is (3-7):1:(100-300).

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] First of all, the present invention provides a Bacillus subtilis LH-Pika23. When the Bacillus subtilis LH-Pika23 is used to treat kitchen waste alone, it can significantly remove the odor in the kitchen waste; the removal rate of ammonia reaches 82.5%, and the removal rate of hydrogen sulfide reaches 99.5%. The Bacillus subtilis LH-Pika23 can be applied to the treatment of kitchen waste with remarkable effects.

[0022] In addition, the present invention provides a compound bacterium agent, comprising the Bacillus subtilis LH-Pika23 and Lactobacillus paracasei TDM-2; the two bacteria in the compound bacterium agent cooperate with each other to play a role, broaden the types of substrates that can be treated, and the deodorization effect is significantly better than that of a single strain. The removal rate of ammonia reaches 95.2%, and the removal rate of hydrogen sulfide reaches 99.8%. The deodorization effect is more stable and more lasting.

[0023] Furthermore, the present invention provides a method for degrading kitchen waste by microorganisms cooperating with black soldier flies. When the compound bacterium agent and black soldier flies are used to cooperate in treating kitchen waste, while improving the biological conversion efficiency of black soldier flies, it also has a remarkable deodorization effect. According to the records of the examples, after adding the compound bacterium agent, the biological conversion rate of black soldier flies increased by 45.9% compared with the control group. Brief Description of the Drawings

[0024] Figure 1 It is a colony morphology diagram after culturing on an appropriate culture medium plate for 24 h. On the left is Lactobacillus paracasei TDM-2, and on the right is Bacillus subtilis LH-Pika23;

[0025] Figure 2 It is a comparison of the efficiency of different treatments on the absorption and transformation of food waste by black soldier fly larvae.

[0026] Biological Deposit Description

[0027] Bacillus subtilis LH-Pika23 is deposited in the China Center for Type Culture Collection, with the deposit number CCTCC NO.M 2025439, the deposit date being March 11, 2025, and the deposit address being Wuhan University, Wuhan, China.

[0028] Lacticaseibacillus paracasei TDM-2 is deposited in the General Microbiology Center of the China Committee for Culture Collection of Microorganisms, with the deposit number CGMCC No.26579, the deposit date being February 20, 2023, and the deposit address being No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. Detailed Description of the Invention

[0029] The present invention provides a Bacillus subtilis LH-Pika23, with the deposit number CCTCC M 2025439.

[0030] In the present invention, the Bacillus subtilis LH-Pika23 is isolated from the intestine of plateau pikas. Its colonies are dirty white, convex on the surface, with rough wrinkles, and uneven edges.

[0031] The Bacillus subtilis LH-Pika23 of the present invention can rapidly consume free oxygen in the environment, promote the growth of lactic acid bacteria, and produce organic acids such as lactic acid, reducing the pH value of the environment and indirectly inhibiting the growth of other harmful bacteria. The cells of Bacillus subtilis LH-Pika23 can synthesize digestive enzymes by themselves, such as protease, amylase, lipase, cellulase, etc. These enzymes have a certain decomposition effect on organic matter and a certain purification effect on the environment.

[0032] The culture method of the Bacillus subtilis LH-Pika23 of the present invention is not particularly limited, and a conventional Bacillus subtilis culture method in the art can be used. In the specific implementation process of the present invention, it is preferably activated and cultured using an LB solid medium and an LB liquid medium.

[0033] The present invention also provides the application of the Bacillus subtilis LH-Pika23 in degrading food waste.

[0034] The present invention provides the application of the Bacillus subtilis LH-Pika23 in degrading the odor of food waste. In the present invention, the odor preferably includes ammonia and hydrogen sulfide. The removal rate of ammonia by the Bacillus subtilis LH-Pika23 of the present invention reaches 82.5%, and the removal rate of hydrogen sulfide reaches 99.5%. The Bacillus subtilis LH-Pika23 can be applied to food waste treatment with remarkable effects.

[0035] The present invention also provides a compound bacterium agent, which includes the Bacillus subtilis LH-Pika23 and Lactiplantibacillus paracasei TDM-2; the quantity ratio of the Bacillus subtilis LH-Pika23 to the Lactiplantibacillus paracasei TDM-2 is (0.5-1.5):(0.5-1.5).

[0036] In the present invention, the Lactiplantibacillus paracasei TDM-2, Lacticaseibacillus paracasei TDM-2, is separated from milk, is milky white, round, convex, with a smooth and raised surface, and has a neat edge. The preservation number is CGMCC No. 26579; in the present invention, the Lactiplantibacillus paracasei TDM-2 will secrete nisin and produce organic acids during the growth process, and these metabolites have significant antibacterial effects and can effectively inhibit the growth of harmful bacteria, thereby reducing the generation of malodorous substances.

[0037] In the present invention, the compound bacterium agent is preferably a liquid bacterium agent; the concentration of the Bacillus subtilis LH-Pika23 in the compound bacterium agent is preferably 10 8 ~10 9 CFU / mL, and the concentration of the Lactiplantibacillus paracasei TDM-2 in the compound bacterium agent is preferably 10 8 ~10 9 CFU / mL.

[0038] In the present invention, the preparation method of the compound bacterium agent comprises the following steps: 1) activating and culturing Bacillus subtilis LH-Pika23 to obtain the fermentation broth of Bacillus subtilis LH-Pika23; activating and culturing Lactobacillus paracasei TDM-2 to obtain the fermentation broth of Lactobacillus paracasei TDM-2, 2) respectively collecting the cells of Bacillus subtilis LH-Pika23 and Lactobacillus paracasei TDM-2 from the two fermentation broths, redissolving with a culture medium, and mixing to obtain the compound bacterium agent.

[0039] In the present invention, Bacillus subtilis LH-Pika23 is preferably activated with an LB solid medium and then cultured with an LB liquid medium. The temperature of the culture is preferably 36-38°C, the time of the culture is 20-28 h, the culture process is accompanied by oscillation, and the rotation speed of the oscillation is preferably 150-200 rpm. In the present invention, the OD 600 of the fermentation broth of Bacillus subtilis LH-Pika23 is preferably 0.6-1.2, more preferably 0.8-1.0. The viable bacteria concentration of the fermentation broth of Bacillus subtilis LH-Pika23 is preferably 10 8 to 10 9 CFU / mL.

[0040] In the present invention, Lactobacillus paracasei TDM-2 is preferably activated with an MRS solid medium and then cultured with an MRS liquid medium. The temperature of the culture is preferably 36-38°C, the time of the culture is 20-28 h, the culture process is accompanied by oscillation, and the rotation speed of the oscillation is preferably 150-200 rpm. In the present invention, the OD 600 of the fermentation broth of Lactobacillus paracasei TDM-2 is preferably 0.6-1.2, more preferably 0.8-1.0. The viable bacteria concentration of the fermentation broth of Lactobacillus paracasei TDM-2 is preferably 10 8 to 10 9 CFU / mL.

[0041] After obtaining the two fermentation broths, the two fermentation broths are centrifuged separately, and the bacterial cells are collected; the rotation speed of the centrifugation is preferably 5000-7000 rpm, more preferably 5500-6500 rpm; the time of the centrifugation is preferably 15-25 min, more preferably 18-22 min, and most preferably 20 min. After obtaining the bacterial cells in the present invention, Bacillus subtilis LH-Pika23 is redissolved with LB liquid medium, and Lactobacillus paracasei TDM-2 is redissolved with MRS liquid medium. Then the redissolved Bacillus subtilis LH-Pika23 and Lactobacillus paracasei TDM-2 are mixed to obtain a compound microbial agent; the quantity ratio of the mixed Bacillus subtilis LH-Pika23 and Lactobacillus paracasei TDM-2 is preferably (0.5-1.5):(0.5-1.5), further preferably (0.8-1.2):(0.8-1.2), and most preferably 1:1. In the present invention, the concentration of Bacillus subtilis LH-Pika23 in the compound microbial agent is preferably 10 8 ~10 9 CFU / mL, and the concentration of Lactobacillus paracasei TDM-2 in the compound microbial agent is preferably 10 8 ~10 9 CFU / mL.

[0042] The present invention provides the application of the compound microbial agent in degrading kitchen waste.

[0043] The present invention provides the application of the compound microbial agent in degrading the odor of kitchen waste.

[0044] In the present invention, the two kinds of bacteria in the compound microbial agent cooperate synergistically to play a role, broaden the types of substrates that can be treated, and the deodorization effect is significantly better than that of a single strain. The removal rate of ammonia reaches 95.2%, and the removal rate of hydrogen sulfide reaches 99.8%. The deodorization effect is more stable.

[0045] The present invention also provides a method for degrading kitchen waste by microorganisms cooperating with black soldier flies, comprising the following steps: mixing microorganisms, black soldier flies and kitchen waste to carry out the degradation of kitchen waste; the microorganisms are the compound microbial agent.

[0046] In the present invention, the mass ratio of the microorganisms, black soldier flies and kitchen waste is preferably (3-7):1:(100-300), further preferably (4-6):1:(150-250), and still further preferably 5:1:(180-220). In the present invention, the black soldier flies are preferably 4-6-day-old black soldier flies. In the present invention, the degradation time of the kitchen waste is preferably 8-15 days, more preferably 9-12 days.

[0047] In the present invention, the black soldier fly, as an efficient biotransformation insect, provides a new idea for urban waste treatment and environmental protection by using the black soldier fly in combination with a composite microbial agent to treat food waste.

[0048] The composite microbial agent provided by the present invention degrades malodorous substances through the physiological and metabolic activities of microorganisms to achieve the purpose of deodorization. At the same time, the microbial agent can improve the intestinal microbial flora of black soldier fly larvae, promote the efficient degradation of food waste by black soldier flies, effectively avoid the local anaerobic environment caused by garbage accumulation, and thus realize the source control and resource utilization of odor (such as insect body protein, organic fertilizer), combining environmental protection and economy.

[0049] In addition, both of the two microorganisms in the composite microbial agent provided by the present invention are probiotics. After ingestion, they enter the host (black soldier fly) body. By improving the function of the host intestinal microbial flora, they can enhance the health level, immune ability and other physiological characteristics of the host. The composite microbial agent of the present invention can also improve the digestibility and flavor of food waste to a certain extent, which is beneficial to increasing the feeding tendency and absorption and transformation of black soldier flies.

[0050] The technical solutions provided by the present invention will be described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0051] Strain:

[0052] Lacticaseibacillus paracasei TDM-2, with the preservation number of CGMCC No. 26579

[0053] Bacillus subtilis LH-Pika23 is preserved in the China Center for Type Culture Collection, with the preservation number of CCTCC M 2025439.

[0054] Culture medium:

[0055] TSB medium: 17.0 g of tryptone, 3.0 g of soy peptone, 5.0 g of sodium chloride, 2.5 g of dipotassium hydrogen phosphate, 2.5 g of glucose, 1000 ml of distilled water;

[0056] TSA medium: 15.0 g of tryptone, 5.0 g of soy peptone, 5.0 g of sodium chloride, 15.0 g of agar powder;

[0057] Beef extract peptone solid medium: 5.0 g of beef extract powder, 10.0 g of peptone, 5.0 g of sodium chloride, 15.0 g of agar powder;

[0058] Beef extract peptone liquid medium: 5.0 g of beef extract powder, 10.0 g of peptone, 5.0 g of sodium chloride;

[0059] LB solid medium: 10.0 g of tryptone, 5.0 g of yeast extract, 10.0 g of NaCl, 15.0 g of agar, 1000 ml of distilled water;

[0060] LB liquid medium: 10.0 g of peptone, 5.0 g of yeast extract, 10.0 g of NaCl, 1000 ml of distilled water;

[0061] MRS solid medium: 10 g of peptone, 10 g of beef extract powder, 1 mL of Tween 80, 1.16 g of dipotassium hydrogen phosphate, 5 g of yeast extract powder, 0.05 g of magnesium sulfate, 2 g of ammonium citrate, 20 g of glucose, 0.03 g of manganese sulfate, 3.02 g of sodium acetate, 14 g of agar, 1000 mL of water, pH 6.2 ± 0.2;

[0062] MRS liquid medium: 10 g of peptone, 10 g of beef extract powder, 1 mL of Tween 80, 1.16 g of dipotassium hydrogen phosphate, 5 g of yeast extract powder, 0.05 g of magnesium sulfate, 2 g of ammonium citrate, 20 g of glucose, 0.03 g of manganese sulfate, 3.02 g of sodium acetate, 1000 mL of water, pH 6.2 ± 0.2.

[0063] Example 1

[0064] Isolation and identification of Bacillus subtilis LH-Pika23

[0065] Bacillus subtilis can consume oxygen during growth and reproduction, thus inhibiting Enterobacter and Enterococcus while facilitating the growth and reproduction of anaerobic Lactobacillus, and further being beneficial to deodorization in cooperation with lactic acid bacteria.

[0066] Step 1: Isolation of Bacillus subtilis LH-Pika23

[0067] TSA culture conditions

[0068] Inoculate the TSB medium containing pika intestinal contents by streaking on the TSA medium, place it in a constant temperature incubator at 37 °C for 24 h, then pick a single colony and continue streaking culture. The single colony culture time is 18 - 24 h (because some strains grow fast and some grow slow), and repeat streaking 3 times. Inoculate the single colony into the TSB medium and culture it in a shaker at 37 °C and 180 rpm for 24 h.

[0069] Beef extract peptone medium

[0070] Inoculate the TSB medium containing the intestinal contents of pikas by streaking on a peptone beef extract medium, and incubate it in a constant temperature incubator at 37°C for 24 h. Then pick a single colony and continue streaking for cultivation. The single colony cultivation time is 18 - 24 h (because some strains grow fast and some grow slow), and repeat streaking 3 times. Inoculate the single colony into a peptone beef extract liquid medium and incubate it on a shaker at 37°C and 180 rpm for 24 h.

[0071] Step 2: Identification of Bacillus subtilis LH-Pika23 strain

[0072] Clone the 16S rDNA sequence of LH-Pika23 (PCR primers: 27F and 1492R) and perform first-generation sequencing on this 16S rRNA sequence. Compare the sequencing results in Genbank by BLAST to determine the phylogenetic and evolutionary status of LH-Pika23. LH-Pika23 was further identified as Bacillus subtilis among Bacillus

[0073] Example 2

[0074] Preparation of compound microbial agent

[0075] Step 1: Inoculate and activate Bacillus subtilis LH-Pika23 by streaking on an LB solid culture plate.

[0076] Inoculate and activate Lactobacillus paracasei TDM-2 by streaking on an MRS solid culture plate.

[0077] Take the above-activated strains and use the plate coating method to test the antagonistic effects of each strain in the compound microbial agent. The results show that there is no antagonistic effect between the strains in pairs.

[0078] Step 2: Use an inoculation loop to pick out the single colonies on the plate. Inoculate Bacillus subtilis LH-Pika23 into an LB liquid medium after high-temperature sterilization (121°C, 20 min); inoculate Lactobacillus paracasei TDM-2 into an MRS liquid medium after high-temperature sterilization (121°C, 20 min), and culture them separately.

[0079] Step 3: Culture Lactobacillus paracasei TDM-2 at 37°C and 180 rpm for 24 h. Culture Bacillus subtilis LH-Pika23 at 37°C and 180 rpm for 24 h.

[0080] Step 4: After the cultivation in Step 3, use a spectrophotometer to measure the absorbance of the bacterial solution at a wavelength of 600 nm, and keep the OD 600 value between 0.6 - 1.2 to make the viable bacteria concentration reach 10 8 ~10 9CFU / mL, and the fermentation is ended.

[0081] Step 5: After the fermentation is completed, centrifuge at 6000 rpm for 20 min, discard the supernatant, and obtain solid bacterial cells. Resuspend the bacterial cells of each strain after centrifugation with the corresponding sterilized liquid medium, and mix Bacillus subtilis and Lactobacillus paracasei according to the ratio of the final colony counts (the final viable cell concentrations of both bacteria are 10 8 CFU / ml) to obtain a compound bacterial agent.

[0082] Example 3

[0083] Deodorization effect test of the compound bacterial agent

[0084] Test grouping:

[0085] Test group 1: Add 1 kg of kitchen waste (obtained from the school cafeteria) to a plastic box with dimensions of 20×19 cm, use a meat grinder to make it into a homogeneous slurry, add 20 mL of the bacterial liquid of activated Bacillus subtilis LH-Pika23 (the viable cell concentration is 10 8 CFU / ml) according to an inoculation amount of 2%, mix evenly, and add 5 g of 5-day-old black soldier fly larvae.

[0086] Test group 2: Add 1 kg of kitchen waste (obtained from the school cafeteria) to a plastic box with dimensions of 20×19 cm, use a meat grinder to make it into a homogeneous slurry, add 20 mL of the bacterial liquid of activated Lactobacillus paracasei TDM-2 (the viable cell concentration is 10 8 CFU / ml) according to an inoculation amount of 2%, mix evenly, and add 5 g of 5-day-old black soldier fly larvae.

[0087] Test group 3: Add 1 kg of kitchen waste (obtained from the school cafeteria) to a plastic box with dimensions of 20×19 cm, use a meat grinder to make it into a homogeneous slurry, add 20 mL of the compound bacterial agent prepared in Example 3 (the viable cell concentrations are 10 8 CFU / ml) according to an inoculation amount of 2%, mix evenly, and add 5 g of 5-day-old black soldier fly larvae.

[0088] Control group: Add 1 kg of kitchen waste (obtained from the school cafeteria) to a plastic box with dimensions of 20×19 cm, use a meat grinder to make it into a homogeneous slurry, add 20 mL of sterile water according to an inoculation amount of 2%, mix evenly, and add 5 g of 5-day-old black soldier fly larvae. Each test is set with three replicates.

[0089] Treatment settings: Seal with plastic wrap, insert an air bag at one end to control the flow rate, insert a gas collection bag at the other end for gas collection, and use a multi-functional composite gas detector (YF-900A, Shenzhen Yifan Technology) to measure the odor value 2 h after adding the bacterial liquid, and measure the odor value at the same time the next day. The whole process lasts for 10 days. The test results are shown in Table 1:

[0090] Table 1 Comparison of deodorization effects during the process of black soldier fly absorbing and converting food waste under different treatments

[0091] Treatment Ammonia removal rate (%) Hydrogen sulfide removal rate (%) Control group 56.6 99.4 Experimental group 1 82.5 99.5 Experimental group 2 75.2 99.0 Experimental group 3 95.2 99.8

[0092] Table 2 NH₃ emissions (unit: ppm) during the process of black soldier fly absorbing and converting food waste under different treatments

[0093]

[0094] Table 3 H₂S emissions (unit: ppm) during the process of black soldier fly absorbing and converting food waste under different treatments

[0095]

[0096] As can be seen from the above table, after adding the compound microbial agent to the food waste, during the continuous 10-day measurement period, the contents of NH₃ and H₂S both decreased significantly, and the removal rates were 95.2% and 99.8% respectively, which were lower than those of the blank control treatment and the single-strain reagent, indicating that the microbial deodorant of the present invention not only has a strong deodorization effect but also has a good long-term effect.

[0097] Example 4

[0098] Biological conversion efficiency of food waste by adding compound microbial agent

[0099] By adding specific microbial agents, various enzymes can be secreted to assist the black soldier fly in decomposing macromolecular substances into small molecular substances that are easy to absorb, thereby improving the conversion rate of the black soldier fly to the substrate. It can also enhance the vitality of the black soldier fly and improve its adaptability to the environment. The biological conversion rate reflects the amount of dry matter in the food waste converted into the dry matter of the black soldier fly larvae.

[0100] The test groups in this example were consistent with those in Example 3. The dry weights of the waste and the black soldier fly were measured at the beginning and end respectively, and the conversion rate was calculated according to the formula:

[0101] Conversion rate of food waste treatment residue = increased mass of larvae (dry weight) / (mass of food waste residue before conversion (dry weight) - mass of food waste treatment residue after conversion (dry weight)) × 100%.

[0102] The test results are as Figure 2As shown in the figure, by comparing the various groups of experiments, it can be seen that adding microbial inoculants can effectively improve the biological conversion rate of black soldier flies compared to the control group. The biological conversion rate of the group added with the compound microbial inoculant is relatively high, reaching 65.67%, which is higher than that of the control group (45%) and the group added with single-strain inoculants (Bacillus subtilis LH-Pika23: 44.87%). This shows that adding the compound microbial inoculant is beneficial to the efficiency of black soldier flies in absorbing and converting food waste, and can achieve the purpose of promoting the biological conversion of food waste by black soldier flies while maximizing resource utilization.

[0103] Example 5

[0104] Evaluation of the small-scale amplification test effect in the waste treatment plant

[0105] Step 1: Prepare the compound microbial inoculant according to the steps of Example 2.

[0106] Step 2: Put 75 g of 10-day-old black soldier fly larvae hatched into a rectangular feeding box with a volume of 40 L. Put 15 kg of evenly crushed food waste into each feeding box. Add sterile water as the control group and the compound inoculant as the experimental group according to a dose of 2%. Set three replicates for each group of experiments. Seal the feeding box for 2 h before measurement, and use a multi-functional compound gas detector (YF-900A, Shenzhen Yifan Technology Co., Ltd.) to measure the odor value. Measure the odor value at the same time the next day. The whole process takes about 3 days. The test results are shown in Table 2.

[0107] Table 2 Comparison of the deodorization effect during the process of black soldier flies absorbing and converting food waste

[0108]

[0109] It can be seen from the results that after applying the compound inoculant of the present invention, the removal rates of NH3 and H2S both increase significantly, reaching 81.8% and 72.1% respectively, which are higher than those of the control treatment (NH3 removal rate 40.0%, H2S removal rate 40.1%). This shows that developing and producing the compound inoculant of the present invention for deodorizing food waste has broad popularization and utilization value.

[0110] From the above examples, it can be seen that the compound inoculant provided by the present invention has a very obvious deodorization effect on food waste. When cooperating with black soldier flies to treat food waste, while improving the biological conversion efficiency of black soldier flies, it also has a significant deodorization effect.

[0111] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A Bacillus subtilis LH-Pika23, characterized in that, The preservation number is CCTCC M 2025439.

2. Use of Bacillus subtilis LH-Pika23 as claimed in claim 1 in the degradation of food waste.

3. Use of Bacillus subtilis LH-Pika23 as claimed in claim 1 in the degradation of odors from food waste.

4. The application according to claim 3, characterized in that, The odors include ammonia and hydrogen sulfide.

5. A composite microbial agent, characterized in that, Comprising the Bacillus subtilis LH-Pika23 as claimed in claim 1 and Lactobacillus paracasei TDM-2; the quantity ratio of the Bacillus subtilis LH-Pika23 to the Lactobacillus paracasei TDM-2 is (0.5 - 1.5):(0.5 - 1.5).

6. The compound bacterial agent according to claim 5, wherein The composite bacterial agent is a liquid bacterial agent; the viable bacteria concentration of Bacillus subtilis LH-Pika23 in the composite bacterial agent is 10 8 ~10 9 CFU / mL, and the viable bacteria concentration of Lactobacillus paracasei TDM-2 in the composite bacterial agent is 10 8 ~10 9 CFU / mL.

7. Use of the composite bacterial agent as claimed in claim 5 or 6 in the degradation of food waste.

8. Use of the composite bacterial agent as claimed in claim 5 or 6 in the degradation of odors from food waste.

9. A method for the degradation of food waste by microorganisms in cooperation with black soldier flies, characterized in that, Comprising the following steps: Mixing the microorganism, black soldier fly larvae with food waste for the degradation of food waste; The microorganism is the composite bacterial agent as claimed in claim 4.

10. The method according to claim 9, wherein The mass ratio of the microorganism, black soldier fly larvae to food waste is (3 - 7):1:(100 - 300).

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