JP7526485B2 - Method for pretreating organic waste, method for treating organic waste, and agent for pretreating organic waste - Google Patents

Description

The present invention relates to a method for pretreating organic waste, a method for treating organic waste, and a pretreatment agent for organic waste.

Today, about one-third of the food produced in the world is discarded without being consumed. In Japan alone, 20 million tons of food waste and 100 million tons of organic industrial waste are generated annually, which has become a major social issue. At the same time, in order to secure feed for fish and livestock, overfishing and resource-intensive agricultural production are taking place to the point that they are distorting the Earth's ecosystem. Furthermore, the organic waste generated during these processes is ultimately disposed of by ethanol/methane fermentation or thermal incineration, which is a source of greenhouse gases that cause global warming.

The realization of a truly sustainable, recycling-oriented society that prevents global warming is a challenge that must be addressed on a global scale in order for humanity to survive, and the problem of disposing of organic waste, which amounts to hundreds of megatons per year in major countries alone, can be considered one example of this.

However, currently, effective and economical resource recovery technology for organic waste has not been fully established, and there is no recycling technology that does not require fossil fuels. To solve this problem, attention has been focused on detritivorous insects that can grow by feeding on organic waste such as food waste and manure, and progress has been made in developing a method for decomposing and recycling organic waste using one type of insect, the soldier fly (see, for example, Patent Document 1). The grown soldier fly is effective as a high-protein, high-fat feed for livestock, and there is hope for industrialization as a recycling technology that requires almost no fossil fuels.

Currently, black soldier flies are mass-produced in large breeding equipment where food is placed in flat metal trays to raise the larvae. In the recycling business, food waste such as food scraps, agricultural residues, and livestock manure are used as food, and the black soldier flies are raised in open containers to improve work efficiency and promote evaporation of water.
Therefore, food waste such as raw garbage, agricultural residues, and livestock manure generate terrible odors due to the proliferation of bacteria. At recycling plants, it is necessary to take measures against the odors generated by these feed and decomposition products, but this is not easy to do because it is an open system without a lid. Also, in terms of the working environment for breeding workers, it is necessary to develop breeding techniques that do not generate odors.

JP 2004-181379 A

The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a method for pretreating organic waste, a method for treating organic waste, and a pretreatment agent for organic waste that can suppress the generation of odors caused by organic waste.

The inventors discovered that the odor generation from organic waste can be suppressed by adding the intestinal flora of black soldier fly larvae or a processed product thereof to the organic waste before treating it with black soldier fly larvae, leading to the completion of the present invention.

That is, the present invention includes the following aspects.
[1] A method for pretreating organic waste, comprising adding an intestinal bacterial flora of black soldier fly larvae or a treated product thereof to organic waste.
[2] The pretreatment method according to [1], wherein the pretreatment is to suppress odor generation from organic waste.
[3] The pretreatment method according to [1] or [2], wherein the intestinal bacterial flora of black soldier fly larvae or a treated product thereof is excreta of black soldier fly larvae or a treated product of the excreta.
[4] The pretreatment method according to [3], wherein the excrement is feces.
[5] The pretreatment method according to any one of [1] to [4], wherein the intestinal bacterial flora of the black soldier fly larvae contains at least one type of bacteria selected from Gram-positive bacteria and Proteobacteria.
[6] A method for treating organic waste, comprising raising black soldier fly larvae and feeding them with a pretreated organic waste product that has been treated by the pretreatment method according to any one of [1] to [5].
[7] The treatment method according to [6], wherein the pretreatment is to suppress odor generation from organic waste.
[8] The treatment method according to [6] or [7], wherein the intestinal bacterial flora of black soldier fly larvae or a treated product thereof is excretion of black soldier fly larvae or a treated product of the excretion.
[9] The method according to [8], wherein the excrement is feces.
[10] The treatment method according to any one of [6] to [9], wherein the intestinal bacterial flora of the black soldier fly larvae contains at least one type of bacteria selected from Gram-positive bacteria and Proteobacteria.
[11] A pretreatment agent for organic waste, comprising the intestinal bacterial flora of black soldier fly larvae or a treated product thereof.
[12] The pretreatment agent according to [11], wherein the pretreatment is to suppress odor generation from organic waste.
[13] The pretreatment agent according to [11] or [12], wherein the intestinal bacterial flora of black soldier fly larvae or a treated product thereof is excreta of black soldier fly larvae or a treated product of the excreta.
[14] The pretreatment agent according to [13], wherein the excrement is feces.
[15] The pretreatment agent according to any one of [11] to [14], wherein the intestinal bacterial flora of the black soldier fly larvae contains at least one type of bacteria selected from Gram-positive bacteria and Proteobacteria.

The present invention provides a method for pretreating organic waste, a method for treating organic waste, and a pretreatment agent for organic waste that can suppress the generation of odors caused by organic waste.

FIG. 1 is a diagram showing an outline of a method for pretreating organic waste using black soldier fly larvae and a method for treating organic waste. FIG. 2 is a graph showing the amount of methyl disulfide generated in the control area and the treatment area in Example 1.

[Method for pre-treatment of organic waste]
The organic waste pretreatment method of the present invention is characterized in that the intestinal bacterial flora of black soldier fly larvae or a processed product thereof is added to organic waste. The organic waste pretreatment method of the present invention can suppress the generation of odors arising from organic waste. There are no particular limitations on the odors arising from organic waste, but examples include specific malodorous components, as well as mold odors and fecal odors. Specific examples of odors generated from organic waste include ammonia, methyl mercaptan, hydrogen sulfide, methyl sulfide, methyl disulfide, trimethylamine, acetaldehyde, propionaldehyde, normal butyraldehyde, isobutyraldehyde, normal valeraldehyde, isovaleraldehyde, isobutanol, ethyl acetate, methyl isobutyl ketone, toluene, styrene, xylene, propionic acid, normal butyric acid, normal valeric acid, isovaleric acid, diacetyl, skatole, indole, methanethiol, dimethyl trisulfide, tribromoanisole, trichloroanisole, diosmin, 2-nonenal, and pyridine.
In the present invention, the intestinal bacterial flora of black soldier fly larvae is not particularly limited as long as it contains one or more intestinal bacteria living in the intestine of black soldier fly larvae, and examples thereof include feces of black soldier fly larvae, excreta such as digested matter of black soldier fly larvae, crushed black soldier fly larvae, etc. Examples of the intestinal bacteria of black soldier fly larvae include bacteria such as gram-positive bacteria and proteobacteria. Examples of gram-positive bacteria include bacteria belonging to the genus Bacillus, Clostridium, Enterococcus, Atopostipes, Lactobacillus, Tissierella, etc. Examples of proteobacteria include bacteria belonging to the genus Ignatzschineria, Morganella, Providencia, etc.

Examples of the processed intestinal bacterial flora of black soldier fly larvae include feces of the black soldier fly larvae, excretions such as digested matter of the black soldier fly larvae, dried products of crushed black soldier fly larvae, and supernatants obtained by suspending the dried products in aqueous media, etc. Examples of the aqueous media include water, physiological saline, various buffer solutions, etc.
The treated intestinal flora of black soldier fly larvae may contain antibacterial proteins or decomposition enzymes derived from black soldier fly larvae. By containing antibacterial proteins or decomposition enzymes derived from black soldier fly larvae, the pretreatment effect of the present invention can be improved. For example, by containing the antibacterial proteins or decomposition enzymes in the treated intestinal flora of black soldier fly larvae, the effect of suppressing the generation of odors generated from organic waste can be improved. Examples of the decomposition enzymes include proteases and pectinases. Examples of the antibacterial proteins include defensins, attacins, diptericins, cecropins, drosocins, and the like.

In the present invention, the method for adding the intestinal flora of black soldier fly larvae or a processed product thereof to organic waste is not particularly limited, and examples thereof include a method of directly adding black soldier fly larvae feces to organic waste, and a method of suspending black soldier fly larvae feces in water and spraying the resulting supernatant onto the organic waste.

The amount of the intestinal flora of black soldier fly larvae or a processed product thereof added is preferably 0.1 to 90% by mass, more preferably 0.1 to 80% by mass, even more preferably 0.1 to 70% by mass, and particularly preferably 0.1 to 60% by mass, based on the total mass of the organic waste, and is, for example, 0.1 to 50% by mass, 0.1 to 40% by mass, 0.1 to 30% by mass, 0.1 to 20% by mass, 0.1 to 10% by mass, 1 to 50% by mass, 1 to 40% by mass, 1-30% by mass, 1-20% by mass, 1-10% by mass, 5-90% by mass, 5-80% by mass, 5-70% by mass, 5-60% by mass, 5-50% by mass, 5-40% by mass, 5-30% by mass, 5-20% by mass, 5-10% by mass, 10-90% by mass, 10-80% by mass, 10-70% by mass, 10-60% by mass , 10-50% by mass, 10-40% by mass, 10-30% by mass, 10-20% by mass, etc.

An outline of the organic waste pretreatment method of the present invention and the organic waste treatment method of the present invention is shown in Figure 1. Specific examples of the organic waste pretreatment method of the present invention include a method including the following steps (a) to (d) (Figure 1 a to c).
(a) rearing black soldier fly larvae;
(b) harvesting the intestinal bacterial flora of black soldier fly larvae or a processed product thereof; and (c) adding and mixing the intestinal bacterial flora of black soldier fly larvae or a processed product thereof obtained in the step (b) with organic waste, and treating the organic waste with the intestinal bacteria of black soldier fly larvae or a processed product thereof.

In step (a), the method for rearing black soldier fly larvae is not particularly limited. For example, a black soldier fly rearing tank is installed, organic waste or crushed material thereof is introduced into the black soldier fly rearing tank, adult black soldier flies are reared in the black soldier fly rearing tank, and eggs laid by the adult black soldier flies in the organic waste are hatched to produce black soldier fly larvae. For example, in FIG. 1, black soldier fly larvae can be reared in a larva rearing tank by feeding them organic waste or crushed material thereof as food. The temperature at which black soldier fly larvae are reared is preferably 20 to 40°C, more preferably 25 to 30°C.

In step (b), the intestinal bacterial flora of black soldier fly larvae or a processed product thereof can be collected by, for example, sieving the residue and feces of black soldier fly larvae after they have eaten the organic waste, and the black soldier fly larvae, obtained in a rearing tank for the black soldier fly larvae, and collecting the residue and feces of the black soldier fly larvae after they have eaten the organic waste. The residue and feces of the black soldier fly larvae after they have eaten the organic waste may or may not be separated, but it is preferable not to separate them because this shortens the process.

In the step (c), the organic waste is not particularly limited, and examples thereof include food waste, soybean residue generated during tofu production, animal feces, etc. It is preferable to use the organic waste that has been crushed and mixed.
In step (c), the intestinal bacterial flora of black soldier fly larvae obtained in step (b) or a processed product thereof can be added to the organic waste by, for example, directly adding the feces of black soldier fly larvae obtained in step (b) or the residue of the organic waste containing the feces to the organic waste, or by drying the feces of black soldier fly larvae or the residue of the organic waste containing the feces obtained in step (b) and adding it to the organic waste.

Also, the feces of the black soldier fly larvae obtained in step (b) or the residue of the organic waste containing the feces or the dried matter thereof may be suspended in an aqueous medium, and the resulting supernatant may be added to the organic waste. Examples of the aqueous medium include those mentioned above.

The treated organic waste obtained in step (c) can be remixed as is with the organic waste used to rear the soldier fly larvae in step (a). By repeating this cycle of steps (a) to (c), the organic waste can be efficiently treated by the soldier fly larvae while preventing the organic waste from decaying and generating odors.

The organic waste pretreatment method of the present invention can suppress the generation of odors from organic waste. The odors from organic waste can be collected, for example, in a collection tube or carrier, and measured using a measuring device such as a gas chromatography mass spectrometer. The odors can also be evaluated by sensory tests conducted by a panel.

[Method of treating organic waste]
The organic waste treatment method of the present invention is characterized in that the organic waste treated by the organic waste pretreatment method is fed to black soldier fly larvae as food. The organic waste treatment method of the present invention makes it possible to treat the organic waste with black soldier fly larvae while suppressing the generation of odors from the organic waste.

Specific examples of the organic waste treatment method of the present invention include a method including the following steps (d) to (f) (d to f in Figure 1).

(d) feeding the organic waste treated by the pretreatment method for organic waste to black soldier fly larvae, and treating the organic waste treated by the pretreatment method;
(e) separating the black soldier fly larvae and the organic waste residue from the treated organic waste obtained in the step (d); and
(f) A step of drying the organic waste residue obtained in the step (d).

In the step (d), the organic waste treated by the organic waste pretreatment method may be remixed with the organic waste used in rearing black soldier fly larvae in the step (a) of the pretreatment step. The method of rearing black soldier fly larvae is the same as that described in the step (a) of the organic waste pretreatment method.

In step (e), the method for separating the black soldier fly larvae from the organic waste residue is not particularly limited as long as it is a method that can separate the black soldier fly larvae from the organic waste residue, but an example of such a method is to sieve the black soldier fly larvae and the organic waste residue to separate them.

In the step (f), the method for drying the organic waste residue is not particularly limited, but examples thereof include natural drying, hot air drying, and drying under reduced pressure. The step (f) may include a step of molding the dried product after drying the organic waste residue, if necessary. Examples of molding methods include injection molding, extrusion molding, vacuum molding, and compression molding.

[Pretreatment agent for organic waste]
The pretreatment agent for organic waste of the present invention contains the intestinal bacterial flora of black soldier fly larvae or a treated product thereof. The pretreatment agent for organic waste of the present invention can suppress the generation of odors arising from organic waste.

In the present invention, the intestinal flora of black soldier fly larvae is not particularly limited as long as it contains one or more types of intestinal bacteria living in the intestine of black soldier fly larvae, and examples thereof include feces of black soldier fly larvae, excreta such as digested matter of black soldier fly larvae, crushed black soldier fly larvae, etc. Examples of the intestinal bacteria of black soldier fly larvae include bacteria such as gram-positive bacteria and proteobacteria. Examples of gram-positive bacteria include bacteria belonging to the genera Bacillus, Clostridium, Enterococcus, Atopostipes, Lactobacillus, and Tissierella. Examples of proteobacteria include bacteria belonging to the genera Ignatzschineria, Morganella, and Providencia.

Examples of the processed intestinal bacterial flora of black soldier fly larvae include feces of the black soldier fly larvae, excretions such as digested matter of the black soldier fly larvae, dried products of crushed black soldier fly larvae, and supernatants obtained by suspending the dried products in aqueous media, etc. Examples of the aqueous media include water, physiological saline, various buffer solutions, etc.
The treated intestinal flora of black soldier fly larvae may contain an antibacterial protein or decomposition enzyme derived from black soldier fly larvae. By containing an antibacterial protein or decomposition enzyme derived from black soldier fly larvae, the pretreatment effect of the present invention can be improved. For example, by containing the antibacterial protein or decomposition enzyme in the treated intestinal flora of black soldier fly larvae, the effect of suppressing the generation of odor generated from organic waste can be improved. Examples of the decomposition enzyme and the antibacterial protein include those described above.

The content of the intestinal bacterial flora of black soldier fly larvae or a processed product thereof contained in the pretreatment agent for organic waste of the present invention is preferably 1 to 90% by mass, more preferably 1 to 80% by mass, even more preferably 1 to 70% by mass, and particularly preferably 1 to 60% by mass, based on the total mass of the pretreatment agent, and may be, for example, 1 to 50% by mass, 1 to 40% by mass, 1 to 30% by mass, 1 to 20% by mass, 1 to 10% by mass, 5 to 90% by mass, 5 to 80% by mass, 5 to 70% by mass, 5 to 60% by mass, 5 to 50% by mass, 5 to 40% by mass, 5 to 30% by mass, 5 to 20% by mass, 5 to 10% by mass, 10 to 90% by mass, 10 to 80% by mass, 10 to 70% by mass, 10 to 60% by mass, 10 to 50% by mass, 10 to 40% by mass, 10 to 30% by mass, 10 to 20% by mass, etc.

The pretreatment agent for organic waste of the present invention may contain other additives in addition to the intestinal flora of black soldier fly larvae or a processed product thereof. Examples of the additives include preservatives, excipients, colorants, antioxidants, etc.

The present invention will now be described in more detail with reference to examples, but the present invention is not limited to the following examples.

[Example 1]
In a glass tube containing 10 mL of organic waste, 3 g of soybean pulp was placed as organic waste, and 0.3 g (10% by mass) of the residue of organic waste (residues 1 to 4) containing the feces of black soldier fly larvae that had already been decomposed by black soldier fly larvae was added to the tube. This was used as a treatment group, and a control group was used without the residue and only soybean pulp. After incubation at 25°C for 7 days, the gas phase of the glass tube was collected with an autosampler (MPS, GERSTEL), concentrated four times with a thermal desorption device (TDU-2, CIS 4 Cooled Injection System, GERSTEL), and then introduced into a gas chromatography mass spectrometer (GC-MS, GC 7890A/MS 5977B MSD, Agilent technologies). The liner with concentrated odorous components in the gas phase was heated to 250°C at a temperature increase rate of 12°C/sec, and the temperature was maintained for 10 minutes before being introduced into the GC-MS. The GC-MS was equipped with a DB-5MS UI (length 30 m x diameter 0.25 mm x film thickness 0.25 μm, manufactured by Agilent Technologies), and the initial temperature was maintained at 40°C for 3 minutes, heated to 150°C at 10°C/min, and heated from 150°C to 280°C at 20°C/min, and maintained for 5 minutes.
Mass spectrum was obtained by ionization at 70 eV using EI method, and fragment ions from m/z 29 to m/z 400 were obtained. The obtained fragment ions were compared with a library (NIST17) to identify odorous components. Among odorous components, the amount of methyl disulfide, designated as a specific odorous substance by the Offensive Odor Prevention Law, was compared between the treated and control areas based on the GC/MS peak area. The results are shown in Figure 2.
As shown in Figure 2, compared to the control area, the generation of methyl disulfide was suppressed in the treatment areas to which Residues 1 to 4 were added. In particular, the suppression effect was remarkable in Residues 2 and 4.
These results confirmed that the odor generated from organic waste can be suppressed by pretreating the organic waste with the bacterial flora of black soldier fly larvae or a processed product thereof.

The present invention provides a method for pretreating organic waste, a method for treating organic waste, and a pretreatment agent for organic waste.

Claims (15)

A method for pretreating organic waste, comprising adding an intestinal bacterial flora of black soldier fly larvae or a processed product thereof to the organic waste before the organic waste is treated . The pretreatment method according to claim 1, wherein the pretreatment is to suppress odor generation from organic waste. The pretreatment method according to claim 1 or 2, wherein the intestinal bacterial flora of black soldier fly larvae or a processed product thereof is excreta of black soldier fly larvae or a processed product of the excreta. The pretreatment method according to claim 3, wherein the waste is feces. The pretreatment method according to any one of claims 1 to 4, wherein the intestinal flora of the soldier fly larvae contains at least one type of bacteria selected from Gram-positive bacteria and Proteobacteria. A method for treating organic waste, comprising feeding black soldier fly larvae with the pretreated organic waste treated by the pretreatment method according to any one of claims 1 to 5 as food. The treatment method according to claim 6, wherein the pretreatment is to suppress odor generation from organic waste. The treatment method according to claim 6 or 7, wherein the intestinal bacterial flora of black soldier fly larvae or a processed product thereof is excreta of black soldier fly larvae or a processed product of the excreta. The treatment method according to claim 8, wherein the waste is feces. The treatment method according to any one of claims 6 to 9, wherein the intestinal flora of the soldier fly larvae contains at least one type of bacteria selected from Gram-positive bacteria and Proteobacteria. A pretreatment agent for organic waste containing the intestinal flora of black soldier fly larvae or a processed product thereof. The pretreatment agent according to claim 11, wherein the pretreatment is to suppress odor generation from organic waste. The pretreatment agent according to claim 11 or 12, wherein the intestinal bacterial flora of black soldier fly larvae or a processed product thereof is excreta of black soldier fly larvae or a processed product of the excreta. The pretreatment agent according to claim 13, wherein the excrement is feces. The pretreatment agent according to any one of claims 11 to 14, wherein the intestinal flora of the soldier fly larvae contains at least one type of bacteria selected from Gram-positive bacteria and Proteobacteria.

Images