Composition for increasing plant growth and biomass, comprising fecal extract of mealworms fed with expanded polystyrene as active ingredient, and use thereof

Abstract

The present invention relates to: a composition for increasing plant growth and biomass, the composition comprising, as an active ingredient, a fecal extract of mealworms fed with expanded polystyrene; and a use thereof. The fecal extract of mealworms in the present invention has the excellent effect of promoting plant growth and biomass, and thus can be effectively used as an active ingredient of a composition for increasing plant growth and biomass, a fertilizer composition, or a soil conditioner.

Description

Composition for plant growth and biomass increase comprising fecal extract of mealworms that have ingested expanded polystyrene as an active ingredient and uses thereof

[0001] The present invention relates to a composition for plant growth and biomass increase comprising a fecal extract of mealworms that have consumed expanded polystyrene as an active ingredient, and to the use thereof.

[0002] Styrofoam is a brand name for expanded polystyrene. Because it is 98% air by volume, it is lightweight and has good thermal insulation properties, so it is widely used as packaging, cushioning, or thermal insulation material. However, since it does not decompose, tens of millions of styrofoams remain abandoned on Earth, becoming a source of pollution for soil and rivers.

[0003] Recently, as various attempts have been made to overcome the recalcitrant nature of plastic, it has been revealed that mealworms can decompose plastic. Mealworms, the larvae of the brown mealworm (*Tenebrio molitor*), are the only insects discovered to date capable of digesting styrofoam. Furthermore, two studies conducted by Stanford University in 2015 and 2020 have proven that mealworms that have decomposed styrofoam are safe from the presence of endocrine disruptors in their bodies.

[0004] It has long been a known fact that insects and birds gnaw on or peck at plastic. While studies have frequently been published claiming that certain microorganisms decompose plastic, strictly speaking, their decomposition was either physical or incomplete chemical. They would either break down large plastic fragments into fine powder or decompose only a portion, leaving the remaining plastic components intact. In contrast, mealworms have demonstrated the ability to break down Styrofoam—which typically does not decompose properly even over long periods—in a short time, and into harmless components completely different from the original Styrofoam. Based on approximately 3 million mealworms, 1 kg of Styrofoam can be organically decomposed within 24 hours. Upon consuming the Styrofoam, the mealworms convert half of it into carbon dioxide and excrete the remainder in their feces. Since the excreted feces do not contain the environmentally polluting components of Styrofoam, it is safe to use for crop cultivation.

[0005] Meanwhile, Korean Published Patent No. 2024-0107618 discloses a "fermented composition for promoting plant growth comprising a mealworm vermicompost mixture and a method for manufacturing the same," and Korean Published Patent No. 2023-0058772 discloses a "method for promoting plant growth by co-rearing mealworms," ​​but there is no description of the composition for plant growth and biomass increase comprising a fecal extract of mealworms that have consumed expanded polystyrene as an active ingredient according to the present invention, nor of the use thereof.

[0006] The present invention was derived from the above requirements. The inventors mixed the feces of mealworms that had ingested styrofoam with water or an aqueous solution of 0.1 to 2 N potassium hydroxide (KOH), extracted the mixture at 121°C for 30 minutes, and then centrifuged the supernatant to obtain a solution. They then added 6 M HCl with a pH of 1 to 3 to the supernatant and precipitated it, recovering only the supernatant. Furthermore, they confirmed that the hot water extract of the mealworm feces or the aqueous solution extract of potassium hydroxide contained humic acid-like substances at 12.6% and 38.8%, respectively. By treating plants with the hot water extract of the mealworm feces or the aqueous solution extract of potassium hydroxide and confirming that the growth condition was similar or superior compared to a group treated with general nutrient solution or commercial humic acid, the present invention was completed.

[0007] To solve the above problem, the present invention provides a composition for plant growth and biomass increase comprising, as an active ingredient, a fecal extract of a mealworm that has consumed expanded polystyrene.

[0008] In addition, the present invention provides a method for increasing plant growth and biomass, comprising the step of treating a plant, a plant seed, or plant planting soil with the composition for increasing plant growth and biomass.

[0009] In addition, the present invention provides a fertilizer composition for plant growth and biomass increase comprising a fecal extract of mealworms that have consumed expanded polystyrene as an active ingredient.

[0010] In addition, the present invention provides a soil conditioner for plant growth and biomass increase comprising a fecal extract of mealworms that have consumed expanded polystyrene as an active ingredient.

[0011] The hot water extract or potassium hydroxide aqueous solution extract of mealworm feces that have ingested expanded polystyrene (styrofoam) according to the present invention has excellent effects in promoting plant growth and biomass, and can be usefully used as an active ingredient in compositions for increasing plant growth and biomass, fertilizer compositions, or soil conditioners.

[0012] Figure 1 is a process for preparing a hot water extract or a potassium hydroxide (KOH) aqueous extract of mealworm feces that have ingested styrofoam according to the present invention.

[0013] Figure 2 is a physicochemical test report confirming the content of humic acid-like substances in the hot water extract or potassium hydroxide aqueous extract of mealworm feces that have ingested styrofoam according to the present invention.

[0014] Figure 3 shows the results of measuring the ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) assay and total phenolic content for the hot water extract or potassium hydroxide aqueous extract of mealworm feces that ingested styrofoam according to the present invention and commercial humic acid. The total phenolic content was expressed as Gallic acid equivalent (GAE mg / L) using gallic acid as a standard substance.

[0015] Figure 4 is a photograph of the potassium hydroxide aqueous extract of mealworm feces that have ingested styrofoam according to the present invention, observed after treating lettuce (Lactuca sativa).

[0016] To achieve the objective of the present invention, the present invention provides a composition for plant growth and biomass increase comprising, as an active ingredient, a fecal extract of a mealworm that has ingested expanded polystyrene.

[0017] The term "biomass" in the present invention refers to the dry weight or fresh weight of a plant. Unless otherwise defined, biomass may include, but is not limited to, all parts of a plant, such as sprout biomass (all parts of the plant above ground), leaf biomass, and root biomass. The term "dry weight" refers to the weight of a plant that has been dried to remove moisture from the majority of its cells. The term "fresh weight" refers to the weight of a plant that has not been dried. Biomass can be measured by biomass measurement methods known in the art.

[0018] In this specification, the term "expandable polystyrene" means "styrofoam," which is a resource-saving material composed of 98% air and 2% resin by volume. In this specification, the term "expandable polystyrene" may be used interchangeably with "styrofoam."

[0019] In this specification, the term "mealworm" refers to the larva of the brown mealworm, scientifically known as Tenebrio molitor, belonging to the family Tenebrionidae of the order Coleoptera.

[0020] In the composition for plant growth and biomass increase according to the present invention, the extract may be prepared by mixing the feces of mealworms that have consumed expanded polystyrene with water or an aqueous solution of potassium hydroxide (KOH), extracting at a high temperature, centrifuging the supernatant, and then applying acidic conditions to obtain the supernatant; preferably, the extract may be prepared by mixing the feces of mealworms that have consumed expanded polystyrene with water or an aqueous solution of potassium hydroxide (0.1-2N), extracting at 101-143°C for 10-70 minutes, centrifuging the supernatant, adding hydrochloric acid (HCl) with a pH of 1-3 to the supernatant, and precipitating to obtain the supernatant; more preferably, the extract may be prepared by mixing the feces of mealworms that have consumed expanded polystyrene with water or an aqueous solution of potassium hydroxide (KOH), extracting at 121°C for 30 minutes, and then centrifuging It may be prepared by adding hydrochloric acid with a pH of 1 or 3 to the obtained supernatant and precipitating it to obtain the supernatant, but is not limited thereto.

[0021] In the composition for plant growth and biomass increase of the present invention, applying acidic conditions to the supernatant is intended to remove styrofoam from the excrement and to separate and purify humic acid to a high purity.

[0022] In the composition for plant growth and biomass increase of the present invention, the plant may be a dicotyledonous plant such as lettuce, potato, eggplant, tobacco, chili pepper, tomato, burdock, crown daisy, balloon flower, spinach, Swiss chard, sweet potato, celery, carrot, water celery, parsley, napa cabbage, cabbage, mustard greens, watermelon, Korean melon, cucumber, pumpkin, gourd, strawberry, soybean, mung bean, kidney bean, pea, etc., or a monocotyledonous plant such as rice, barley, wheat, rye, corn, sugarcane, oat, onion, etc., preferably a dicotyledonous plant, and more preferably lettuce.

[0023] The present invention also provides a method for increasing plant growth and biomass, comprising the step of treating a plant, a plant seed, or plant planting soil with the composition for increasing plant growth and biomass.

[0024] The method for increasing the growth and biomass of the plant according to the present invention may be performed by immersing the plant in the composition for increasing the growth and biomass of the plant, or by drenching, i.e., spraying. In the case of the immersion method, the composition may be poured into the soil surrounding the plant or seeds may be immersed in the composition, but is not limited thereto.

[0025] The present invention also provides a fertilizer composition for plant growth and biomass increase comprising, as an active ingredient, a fecal extract of mealworms that have consumed expanded polystyrene.

[0026] The term 'fertilizer' in the present invention refers to any substance that supplies one or more of the elements necessary for a plant to grow normally, and may be classified into organic fertilizers (composed of decomposable plant / animal materials) and inorganic fertilizers (composed of chemical and inorganic materials), etc.

[0027] The fertilizer composition according to the present invention may be formulated into various forms such as liquid, powder, pellets, or granules of suitable size using a general formulation machine, but is not limited thereto. The fertilizer composition of the present invention formulated as described above may be used as is, or dried by air drying at room temperature, freeze-drying, or high-temperature drying methods. For the liquid fertilizer composition to be properly used by farmers, it must not precipitate within a pH range suitable for use on crops. This requires selecting the mixing ratio by considering the pH and solubility of the raw materials used.

[0028] The present invention also provides a soil conditioner for plant growth and biomass increase comprising, as an active ingredient, a fecal extract of mealworms that have consumed expanded polystyrene.

[0029] In the present invention, the term 'soil conditioner' refers to a substance used to increase productivity by improving the physicochemical properties of the soil to suit plant growth, and the soil conditioner may be used alone as the black excrement extract of super mealworms that have ingested styrofoam according to the present invention, or mixed with one or more selected from the group consisting of conventional chemical fertilizers, bentonite, zeolite, vermiculite, ammonium, lime salt, rice straw, barley straw, and wild grass, but is not limited thereto.

[0030]

[0031] The present invention will be explained in detail below through examples. However, the following examples are merely illustrative of the present invention, and the scope of the present invention is not limited to the following examples.

[0032]

[0033] Preparation Example 1. Preparation of fecal extract from mealworms that ingested styrofoam

[0034] 5 g of feces from mealworms (owned by MCE) used for styrofoam decomposition was mixed with 50 ml of distilled water or 50 ml of 0.1N, 0.5N, 1N, or 2N aqueous potassium hydroxide solution, extracted in an autoclave at 121°C for 30 minutes, and centrifuged to obtain the supernatant. Then, acidic conditions adjusted to pH 1 or pH 3 with a 6M aqueous hydrochloric acid solution were applied to the obtained supernatant, and precipitation was performed to obtain only the supernatant excluding the pellet, thereby preparing a hot water extract or an aqueous potassium hydroxide extract of mealworm feces that consumed styrofoam (Fig. 1).

[0035]

[0036] Example 1. Results of measuring humic acid content in the mealworm fecal extract of the present invention

[0037] To determine the content of humic acid-like substances contained in the hot water extract and 0.5N potassium hydroxide aqueous solution extract of mealworm feces that ingested the above-mentioned styrofoam, the test was repeated twice and the average value was calculated.

[0038] As a result, it was confirmed that the humic acid-like substance in the hot water extract of mealworm feces was contained at 12.6%, and the humic acid-like substance in the 0.5N potassium hydroxide aqueous extract of mealworm feces was contained at 38.8% (Fig. 2).

[0039] Humic acid similarity was evaluated by antioxidant activity, total phenolic content, and size-exclusion chromatography. Specifically, to evaluate antioxidant activity, an ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) assay was performed, and it was confirmed that the ABTS radical scavenging activity of the hot water extract and potassium hydroxide aqueous extract of the mealworm feces of the present invention was similar to or higher than that of commercial humic acid (Fig. 3A). In addition, the total phenolic content was measured, and since phenolic components were present in the hot water extract and potassium hydroxide aqueous extract of the mealworm feces of the present invention, it was determined that the extract of the mealworm feces contains humic acid-like substances (Fig. 3B).

[0040]

[0041] Example 2. Analysis of the characteristics of the mealworm fecal extract of the present invention

[0042] The plant growth-promoting effect, ABTS radical scavenging ability, total phenol content, extraction amount (yield), and detection of microstyrene were confirmed for the fecal extract of mealworms that ingested styrofoam according to the present invention.

[0043] First, the growth status of lettuce (Lactuca sativa) was observed after treating it with the 0.5N potassium hydroxide aqueous extract of mealworm feces that had consumed styrofoam according to the present invention. The general nutrient solution treatment group, the commercial humic acid treatment group, and the potassium hydroxide aqueous extract of mealworm feces treatment group according to the present invention were treated in equal amounts.

[0044] As a result, it was confirmed that the growth status of lettuce was superior in the commercial humic acid treatment group and the potassium hydroxide aqueous extract of mealworm feces of the present invention compared to the general nutrient solution treatment group (Fig. 4). Through the above results, it was found that the potassium hydroxide aqueous extract of mealworm feces that consumed styrofoam according to the present invention can be used to promote plant growth in place of commercial humic acid.

[0045] In addition, when the fresh weight was measured after treating lettuce (Lactuca sativa) with the hot water extract of mealworm feces that had consumed styrofoam or with 0.1N, 1N, and 2N aqueous potassium hydroxide extracts of the present invention, it was confirmed that the fresh weight increased significantly when treated with the extract of the present invention compared to the untreated control group, and was nearly the same or increased compared to commercial humic acid (Table 1).

[0046] Analysis of the characteristics of the mealworm fecal extract of the present invention Crop growth promotion (%)* ABTS radical scavenging ability (%)* Total phenolic content (%)* Extraction amount (%)** Microstyrene detection status*** Agricultural / Commercial Humic Acid 100% 100% 100% Not applicable Not applicable Untreated 63% 0% 0% Not applicable Not applicable Distilled water / pH 195% 170% 123% 20% Not detected Distilled water / pH 398% 200% 178% 17% Not detected Distilled water / No acid treatment**** 80% 140% 135% 17% Detected 1 N / No acid treatment**** 82% 133% 125% 33% Detected 0.1 N / pH 196% 230% 145% 10% Not detected 0.1 N / pH 3103%300%170%8%Not Detected 1 N / pH 1105%170%200%18%Not Detected 1 N / pH 384%180%210%15%Not Detected 2 N / pH 193%200%230%24%Not Detected 2 N / pH 3101%220%180%22%Not Detected

[0047] *: Expresses the degree of increase or decrease in fresh weight as a percentage based on the result of commercial agricultural humic acid (100%).

[0048] **: The solid content of the precipitated pellets or supernatant is expressed as a percentage based on 100% by weight of the total mealworm feces used in the preparation of the extract.

[0049] ***: Acid treatment, and the recovered pellets were separated into particles by density separation after oxidation of organic matter with hydrogen peroxide and analyzed by IR (infrared spectroscopy).

[0050] ****: Use the supernatant obtained by centrifugation before acid treatment.

[0051]

[0052] In addition, as shown in Table 1 above, the hot water extract or 0.1N, 1N, and 2N potassium hydroxide aqueous solution extract of mealworm feces that ingested styrofoam according to the present invention showed significantly increased ABTS radical scavenging ability and total phenol content compared to the commercial humic acid treatment group, and it was confirmed that no microstyrofoam was detected when acidic conditions were applied to the supernatant obtained by centrifugation.

Claims

1. A composition for plant growth and biomass increase comprising, as an active ingredient, a fecal extract of a mealworm that has ingested expanded polystyrene.

2. A composition for plant growth and biomass increase according to claim 1, characterized in that the extract is prepared by mixing mealworm feces that have consumed expanded polystyrene with water or an aqueous solution of potassium hydroxide (KOH), extracting at a high temperature, centrifuging the supernatant, and then applying acidic conditions to the supernatant to obtain the supernatant.

3. A method for increasing plant growth and biomass, comprising the step of treating a plant, plant seeds, or plant planting soil with the composition of claim 1 or 2.

4. A fertilizer composition for plant growth and biomass increase comprising, as an active ingredient, a fecal extract of mealworms that have consumed expanded polystyrene.

5. A fertilizer composition for plant growth and biomass increase according to claim 4, characterized in that the fertilizer composition is formulated in the form of a liquid, powder, pellets, or granules.

6. A soil conditioner for plant growth and biomass increase containing, as an active ingredient, fecal extract of mealworms that have ingested expanded polystyrene.

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