Method for liquefying kitchen waste based on quorum sensing enhanced compound bacteria

Abstract

The invention discloses a method for liquefying kitchen waste based on quorum sensing enhanced compound bacteria, and relates to the technical field of kitchen waste treatment. According to the invention, quorum sensing molecule N-myristoyl-L-homoserine lactone which plays a role in the composite bacteria liquid is externally added, so that the capability of the composite bacteria liquid for synergistically degrading protein, cellulose, starch and grease in the kitchen waste is obviously improved, the degradation rates are respectively increased from 19%, 38%, 87% and 45% to 30%, 56%, 97% and 54%, and the effect is obvious. According to the method, the liquefaction effect of the kitchen waste is remarkably improved, and the method has a good practical application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of restaurant kitchen waste treatment, and more particularly to a method for liquefying restaurant kitchen waste based on quorum sensing enhanced composite bacteria. Background Art

[0002] In recent years, due to the rapid development of the catering industry, the amount of restaurant kitchen waste has been on the rise. Restaurant kitchen waste contains a large amount of organic matter, including oil, protein, starch and fiber. These substances, if not treated, will cause environmental pollution, produce bad odors, and even spread diseases.

[0003] In the prior art, the treatment methods for food waste are usually mechanical treatment, chemical treatment or degradation by a single microbial flora, but these methods have problems such as low efficiency, high cost and high energy consumption. In recent years, microbial treatment methods have gradually attracted attention, but due to the complex composition of food waste, it is difficult for a single microbial strain to efficiently decompose multiple components, so multi-strain composite technology has become one of the directions to solve the problem. However, the synergistic problem of multi-strain composite in degradation effect still needs to be solved.

[0004] Therefore, how to improve the effect of multiple strains of bacteria in the synergistic treatment of kitchen waste is an urgent problem that technicians in this field need to solve. Summary of the invention

[0005] In view of this, the present invention provides a method for liquefying food waste based on quorum sensing enhanced composite bacteria.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A method for liquefying food waste by using composite bacteria based on quorum sensing, wherein N-tetradecanoyl-L-homoserine lactone and composite bacteria liquid are used together to degrade food waste;

[0008] The composite bacterial liquid comprises Pseudochalobacterium insaccharolyticum, Alcaligenes faecalis, Achromobacter xylosoxidans, Bacillus amyloliquefaciens, Bacillus cereus, Sphingobacterium spp. in tobacco fields, Serratia marcescens, Stenotrophomonas maltophilia, Sphingobacterium spp. in humus soil, Sphingobacterium spp. in water and Bacillus subtilis.

[0009] Quorum sensing is a mechanism by which microorganisms regulate gene expression through signal molecules. When the concentration of signal molecules reaches a certain threshold, the expression of certain genes can be regulated, thereby achieving the phenomenon of information exchange. The present invention uses the quorum sensing molecule N-tetradecanoyl-L-homoserine lactone to regulate the synergistic effect of multiple bacterial species in the composite bacterial liquid, significantly improving the liquefaction effect of the composite bacterial liquid on oil, protein, starch and fiber in food waste.

[0010] As a preferred technical solution, the added concentration of N-tetradecanoyl-L-homoserine lactone is 1-250 μg / L; the initial biomass of the 11 bacteria in the composite bacterial solution is the same, preferably 0.01 g / L, and the total initial biomass is preferably 0.11 g / L.

[0011] More preferably, the concentration of N-tetradecanoyl-L-homoserine lactone added is 250 μg / L. As a preferred technical solution, the temperature for N-tetradecanoyl-L-homoserine lactone and the composite bacterial solution to degrade kitchen waste is 30° C. and the time is 6 days.

[0012] As a preferred technical solution, when N-tetradecanoyl-L-homoserine lactone and the composite bacterial liquid jointly degrade kitchen waste, the treated liquid is stirred at a speed of 130 r / min.

[0013] Another object of the present invention is to provide an application of N-tetradecanoyl-L-homoserine lactone in strengthening the composite bacterial liquid to treat kitchen waste, wherein the composite bacterial liquid includes Pseudomonas aglycones, Bacillus faecalis, Achromobacter xylosoxidans, Bacillus amyloliquefaciens, Bacillus cereus, Sphingobacterium spp. in tobacco fields, Serratia marcescens, Stenotrophomonas maltophilia, Sphingobacterium humum, Sphingobacterium water and Bacillus subtilis.

[0014] Preferably, the concentration of the N-tetradecanoyl-L-homoserine lactone in the treatment solution is 1-250 μg / L.

[0015] Beneficial effects: The present invention significantly improves the ability of the composite bacterial solution to synergistically degrade protein, cellulose, starch and oil in food waste by exogenously adding the quorum sensing molecule N-tetradecanoyl-L-homoserine lactone that acts on the composite bacterial solution of the present invention, and the degradation rates are increased from 19%, 38%, 87% and 45% to 30%, 56%, 97% and 54%, respectively, with significant effects. The method of the present invention significantly improves the liquefaction effect of food waste and has good practical application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] 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.

[0017] Figure 1 The degradation rates of proteins, cellulose, starch and oils added with the quorum sensing molecules in Example 1 at a concentration of 1 μg / L.

[0018] Figure 2 The degradation rates of proteins, cellulose, starch and oils added with the quorum sensing molecules in Example 2 at a concentration of 10 μg / L.

[0019] Figure 3 The degradation rates of proteins, cellulose, starch and oils added with the quorum sensing molecules in Example 3 at a concentration of 50 μg / L.

[0020] Figure 4 The degradation rates of proteins, cellulose, starch and oils added with the quorum sensing molecules in Example 4 at a concentration of 100 μg / L.

[0021] Figure 5 The degradation rates of proteins, cellulose, starch and oils added with the quorum sensing molecules in Example 5 at a concentration of 250 μg / L.

[0022] Figure 6 The degradation rates of protein, cellulose, starch and oil in food waste when the quorum sensing molecules are added at a concentration of 250 μg / L in Example 6.

[0023] Figure 7 The degradation rates of proteins, cellulose, starch and oils in Comparative Example 1 were calculated by adding quorum sensing molecule 3-OXO-C6-HSL at a concentration of 250 μg / L. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Food waste is mainly composed of organic matter, including starch components (such as rice, bread), fat components (such as cooking oil, meat fat), protein components (such as meat, fish) and cellulose components (such as vegetables, fruit peels, paper towels, etc.). Although the proportions and combinations of these components in food waste are relatively complex, the degradation processes of these basic components are similar. For example, in actual food waste, starch mainly comes from rice, bread and other foods. During the degradation process, they are gradually converted into simple sugars through the action of microorganisms, and further decomposed into carbon dioxide and water; fats mainly come from cooking oil, meat fats, etc., and occupy an important position in actual food waste. They are decomposed and converted into fatty acids, glycerol, etc. by microorganisms; cellulose mainly comes from fiber-rich components such as vegetables, fruit peels, and paper, which are usually composed of cellulose, lignin, etc., and degrade slowly, requiring specific microbial groups to decompose; protein mainly comes from meat, beans and other foods, which can be converted into amino acids by microorganisms and further decomposed into gases such as ammonia and hydrogen sulfide.

[0026] Therefore, Examples 1 to 5 of the present invention use starch, oil, cellulose and protein as representative components for research, and Example 6 uses actual food waste for verification.

[0027] Example 1

[0028] 1. Preparation of composite bacterial liquid: Use nutrient enrichment medium (beef extract 3.0 g / L, peptone 10.0 g / L, NaCl 5.0 g / L, pH 7.2-7.4) to culture Pseudomonas insaccharolyticus (preservation number: CGMCC No. 27442), Alcaligenes faecalis (preservation number: CGMCC No. 27443), Achromobacter xylosoxidans (preservation number: CGMCC No. 27444), Bacillus amyloliquefaciens (preservation number: CGMCC No. 27445), Bacillus cereus (preservation number: CGMCC No. 27446), Sphingobacterium oleraceum (preservation number: CGMCC No. 27447), Serratia marcescens (preservation number: CGMCC No. 27448), Stenotrophomonas maltophilia (preservation number: CGMCC No. The culture medium was prepared by culturing the following bacteria at 30°C for 5 days: Sphingobacillus humus (Accession No.: CGMCC No. 27449), Sphingobacillus humus (Accession No.: CGMCC No. 27450), Sphingobacillus waterii (Accession No.: CGMCC No. 27451 and Bacillus subtilis (Accession No.: CGMCC No. 27452), and the biomass of each single bacterial solution was determined. The composite bacterial solution was prepared according to the results so that the initial biomass of the single bacteria in the composite bacterial solution was 0.01 g / L and the total initial biomass was 0.11 g / L.

[0029] 2. Add 50 ml of starch, oil, protein, and cellulose into different conical flasks respectively.

[0030] Starch: peptone 10g, soluble starch 2g, beef extract 5g, NaCL 5g, pH 7.0~7.2; make up to 1L.

[0031] Protein: skimmed milk powder 50 g, soluble starch 10 g, yeast extract 5 g, KH2PO4 1 g, MgSO4·7H20 0.2 g, pH 7.0~7.2; adjust the volume to 1 L.

[0032] Oil: 5g protein, 3g yeast extract powder, 10ml tributyrin, pH 7.5; make up to 1L.

[0033] Cellulose: KNO3 2g, MgSO4 0.5g, KH2PO4 1g, NaCL 1g, Na2HPO4 1g, CMC-Na 20g, Congo red 0.2g, pH 7.0~7.2; make up to 1L.

[0034] Then, the composite bacterial solution obtained in step 1 was added to different conical flasks at a 5.5% inoculum, and the quorum sensing molecule N-tetradecanoyl-L-homoserine lactone was added (to a final concentration of 1 μg / L). The conical flask was placed in a constant temperature water bath and shaken (30°C, 130 rpm) for 6 days, and samples were taken at 0, 3, and 6 days to determine the contents of starch (iodine titration method GB 5009.9-2016), oil (petroleum ether extraction method, Shen Shuping and Wang Xiaomei, 1994), protein (Folin phenol method Peterson, 1979), and cellulose (Lu Haiyan et al., 1996) and calculate the removal rate (a control group without N-tetradecanoyl-L-homoserine lactone was set up).

[0035] The results are attached Figure 1 As shown, under the enhancement of quorum sensing molecules, the effective removal rates of protein, cellulose, starch and oil by the composite bacterial liquid increased from 19%, 38%, 87% and 45% to 20%, 42%, 92% and 61%, respectively.

[0036] Example 2

[0037] 1. Preparation of composite bacterial liquid: Use nutrient enrichment medium to culture Pseudomonas insaccharolyticus, Alcaligenes faecalis, Achromobacter xylosoxidans, Bacillus amyloliquefaciens, Bacillus cereus, Sphingobacillus spp. in tobacco fields, Serratia marcescens, Stenotrophomonas maltophilia, Sphingobacillus humus, Sphingobacillus water and Bacillus subtilis, respectively, and culture at 30°C for 5 days, then determine the biomass of each single bacterial liquid, and compound according to the results so that the initial biomass of the single bacteria in the composite bacterial liquid is 0.01 g / L and the total initial biomass is 0.11 g / L.

[0038] 2. Add 50 ml of starch, oil, protein, and cellulose to different conical flasks, add the composite bacterial solution obtained in step 1 to different conical flasks at a 5.5% inoculation rate, and then add the quorum sensing molecule N-tetradecanoyl-L-homoserine lactone (to a final concentration of 10 μg / L). Place the conical flask in a constant temperature water bath and shake (30°C, 130 rpm) for 6 days, and take samples at 0, 3, and 6 days to determine the content of starch, oil, protein, and cellulose and calculate the removal rate (set a control group without adding N-tetradecanoyl-L-homoserine lactone).

[0039] 3. The results are as attached Figure 2 As shown, under the enhancement of quorum sensing molecules, the effective removal rates of protein, cellulose, starch and oil by the composite bacterial liquid increased from 19%, 38%, 87% and 45% to 21%, 44%, 91% and 52%, respectively.

[0040] Example 3

[0041] 1. Preparation of composite bacterial liquid: Use nutrient enrichment medium to culture Pseudomonas insaccharolyticus, Alcaligenes faecalis, Achromobacter xylosoxidans, Bacillus amyloliquefaciens, Bacillus cereus, Sphingobacillus spp. in tobacco fields, Serratia marcescens, Stenotrophomonas maltophilia, Sphingobacillus humus, Sphingobacillus water and Bacillus subtilis, respectively, and culture at 30°C for 5 days, then determine the biomass of each single bacterial liquid, and compound according to the results so that the initial biomass of the single bacteria in the composite bacterial liquid is 0.01 g / L and the total initial biomass is 0.11 g / L.

[0042] 2. Add 50 ml of starch, oil, protein, and cellulose to different conical flasks, add the composite bacterial solution obtained in step 1 to different conical flasks at a 5.5% inoculation rate, and then add the quorum sensing molecule N-tetradecanoyl-L-homoserine lactone (to a final concentration of 50 μg / L). Place the conical flask in a constant temperature water bath and shake (30°C, 130rpm) for 6 days, and take samples at 0, 3, and 6 days to determine the content of starch, oil, protein, and cellulose and calculate the removal rate (set a control group without adding N-tetradecanoyl-L-homoserine lactone).

[0043] 3. The results are as attached Figure 3 As shown, under the enhancement of quorum sensing molecules, the effective removal rates of protein, cellulose, starch and oil by the composite bacterial liquid increased from 19%, 38%, 87% and 45% to 20%, 43%, 93% and 61%, respectively.

[0044] Example 4

[0045] 1. Preparation of composite bacterial liquid: Use nutrient enrichment medium to culture Pseudomonas insaccharolyticus, Alcaligenes faecalis, Achromobacter xylosoxidans, Bacillus amyloliquefaciens, Bacillus cereus, Sphingobacillus spp. in tobacco fields, Serratia marcescens, Stenotrophomonas maltophilia, Sphingobacillus humus, Sphingobacillus water and Bacillus subtilis, respectively, and culture at 30°C for 5 days, then determine the biomass of each single bacterial liquid, and compound according to the results so that the initial biomass of the single bacteria in the composite bacterial liquid is 0.01 g / L and the total initial biomass is 0.11 g / L.

[0046] 2. Add 50 ml of starch, oil, protein, and cellulose to different conical flasks, then add the composite bacterial solution obtained in step 1 to different conical flasks at a 5.5% inoculation rate, and then add the quorum sensing molecule N-tetradecanoyl-L-homoserine lactone (to a final concentration of 100 μg / L). Place the conical flask in a constant temperature water bath and shake (30°C, 130 rpm) for 6 days, and take samples at 0, 3, and 6 days to determine the content of starch, oil, protein, and cellulose and calculate the removal rate (set a control group without N-tetradecanoyl-L-homoserine lactone).

[0047] 3. The results are as attached Figure 4 As shown, under the enhancement of quorum sensing molecules, the effective removal rates of protein, cellulose, starch and oil by the composite bacterial liquid increased from 19%, 38%, 87% and 45% to 20%, 55%, 94% and 58%, respectively.

[0048] Example 5

[0049] 1. Preparation of composite bacterial liquid: Use nutrient enrichment medium to culture Pseudomonas insaccharolyticus, Alcaligenes faecalis, Achromobacter xylosoxidans, Bacillus amyloliquefaciens, Bacillus cereus, Sphingobacillus spp. in tobacco fields, Serratia marcescens, Stenotrophomonas maltophilia, Sphingobacillus humus, Sphingobacillus water and Bacillus subtilis, respectively, and culture at 30°C for 5 days, then determine the biomass of each single bacterial liquid, and compound according to the results so that the initial biomass of the single bacteria in the composite bacterial liquid is 0.01 g / L and the total initial biomass is 0.11 g / L.

[0050] 2. Add 50 ml of starch, oil, protein, and cellulose to different conical flasks, add the composite bacterial solution obtained in step 1 to different conical flasks at a 5.5% inoculation rate, and then add the quorum sensing molecule N-tetradecanoyl-L-homoserine lactone (to a final concentration of 250 μg / L). Place the conical flask in a constant temperature water bath and shake (30°C, 130rpm) for 6 days, and take samples at 0, 3, and 6 days to determine the content of starch, oil, protein, and cellulose and calculate the removal rate (set a control group without adding N-tetradecanoyl-L-homoserine lactone).

[0051] 3. The results are as attached Figure 5 As shown, under the enhancement of quorum sensing molecules, the effective removal rates of protein, cellulose, starch and oil by the composite bacterial liquid increased from 19%, 38%, 87% and 45% to 30%, 56%, 97% and 54%, respectively.

[0052] Example 6

[0053] 1. Preparation of composite bacterial liquid: Use nutrient enrichment medium to culture Pseudomonas insaccharolyticus, Alcaligenes faecalis, Achromobacter xylosoxidans, Bacillus amyloliquefaciens, Bacillus cereus, Sphingobacillus spp. in tobacco fields, Serratia marcescens, Stenotrophomonas maltophilia, Sphingobacillus humus, Sphingobacillus water and Bacillus subtilis, respectively, and culture at 30°C for 5 days, then determine the biomass of each single bacterial liquid, and compound according to the results so that the initial biomass of the single bacteria in the composite bacterial liquid is 0.01 g / L and the total initial biomass is 0.11 g / L.

[0054] 2. Degradation of food waste: 30 g of food waste and 50 g of tap water were placed in a 100 mL conical flask and mixed. The composite bacterial solution obtained in step 1 was added to different conical flasks at a 5.5% inoculation rate and then added to the food waste mixture. The quorum sensing molecule N-tetradecanoyl-L-homoserine lactone was added (to a final concentration of 250 μg / L). The conical flask was placed in a constant temperature water bath and shaken (30°C, 130 rpm) for 6 days. Samples were taken at 0, 3, and 6 days to determine the contents of starch, oil, protein, and cellulose (a control group without N-tetradecanoyl-L-homoserine lactone was set up).

[0055] 3. The results are as attached Figure 6 As shown, under the enhancement of quorum sensing molecules, the effective removal rates of protein, cellulose, starch and oil by the composite bacterial liquid increased from 42.4%, 29.3%, 72.6% and 51.1% to 49.25%, 34.5%, 81% and 62.3%, respectively.

[0056] Comparative Example 1

[0057] 1. Preparation of composite bacterial liquid: Use nutrient enrichment medium to culture Pseudomonas insaccharolyticus, Alcaligenes faecalis, Achromobacter xylosoxidans, Bacillus amyloliquefaciens, Bacillus cereus, Sphingobacillus spp. in tobacco fields, Serratia marcescens, Stenotrophomonas maltophilia, Sphingobacillus humus, Sphingobacillus water and Bacillus subtilis, respectively, and culture at 30°C for 5 days, then determine the biomass of each single bacterial liquid, and compound according to the results so that the initial biomass of the single bacteria in the composite bacterial liquid is 0.01 g / L and the total initial biomass is 0.11 g / L.

[0058] 2. Add 50 ml of starch, oil, protein, and cellulose to different conical flasks, add the composite bacterial solution obtained in step 1 to different conical flasks at a 5.5% inoculation rate, and then add the quorum sensing molecule N-3-oxo-hexanoyl homoserine lactone (3-OXO-C6-HSL) to a final concentration of 250 μg / L. Place the conical flask in a constant temperature water bath and shake (30°C, 130 rpm) for 6 days, and take samples at 0, 3, and 6 days to determine the contents of starch, oil, protein, and cellulose and calculate the removal rate.

[0059] 3. The results are as attached Figure 7 As shown, under the reinforcement of the quorum sensing molecule 3-OXO-C6-HSL, the effective removal rates of the composite bacterial solution for protein, cellulose, starch, and oil increased from 18%, 39%, 87%, and 45% to 20%, 42%, 95%, and 53%, respectively. The removal rates increased by 2%, 3%, 7%, and 8%, respectively, which was much lower than the synergistic ability of the quorum sensing molecule N-tetradecanoyl-L-homoserine lactone and the composite bacterial solution of the present invention.

[0060] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0061] 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 method for liquefying food waste based on quorum sensing enhanced composite bacteria, characterized in that: N-tetradecanoyl-L-homoserine lactone and the composite bacterial solution are used together to degrade kitchen waste; The composite bacterial liquid comprises Pseudochalobacterium insaccharolyticum, Alcaligenes faecalis, Achromobacter xylosoxidans, Bacillus amyloliquefaciens, Bacillus cereus, Sphingobacterium spp. in tobacco fields, Serratia marcescens, Stenotrophomonas maltophilia, Sphingobacterium spp. in humus soil, Sphingobacterium spp. in water and Bacillus subtilis.

2. The method for liquefying food waste based on quorum sensing enhanced composite bacteria according to claim 1, characterized in that: The added concentration of the N-tetradecanoyl-L-homoserine lactone is 1-250 μg / L; and the total initial biomass of the composite bacterial liquid is 0.11 g / L.

3. The method for liquefying food waste based on quorum sensing enhanced composite bacteria according to claim 2, characterized in that: The added concentration of the N-tetradecanoyl-L-homoserine lactone is 250 μg / L.

4. The method for liquefying food waste based on quorum sensing enhanced composite bacteria according to claim 1, characterized in that: The temperature for the degradation of kitchen waste by N-tetradecanoyl-L-homoserine lactone and the composite bacterial solution was 30°C and the time was 6 days.

5. The method for liquefying food waste based on quorum sensing enhanced composite bacteria according to claim 1, characterized in that: When N-tetradecanoyl-L-homoserine lactone and the composite bacterial solution jointly degraded the kitchen waste, the treated solution was stirred at a speed of 130 r / min.

6. Application of N-tetradecanoyl-L-homoserine lactone in strengthening the treatment of kitchen waste with composite bacterial liquid, characterized in that: The composite bacterial liquid comprises Pseudochalobacterium insaccharolyticum, Alcaligenes faecalis, Achromobacter xylosoxidans, Bacillus amyloliquefaciens, Bacillus cereus, Sphingobacterium spp. in tobacco fields, Serratia marcescens, Stenotrophomonas maltophilia, Sphingobacterium spp. in humus soil, Sphingobacterium spp. in water and Bacillus subtilis.

7. The use of N-tetradecanoyl-L-homoserine lactone in strengthening the composite bacterial liquid to treat kitchen waste according to claim 6, characterized in that: The concentration of the N-tetradecanoyl-L-homoserine lactone in the treatment solution is 1-250 μg / L.

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