Method for degrading waste plastic by using champion larva
By feeding larvae of the nine dragonfly under mild conditions to degrade plastic, the problems of high energy consumption and limited effectiveness of traditional methods have been solved, achieving a highly efficient and environmentally friendly plastic mineralization effect.
Patent Information
- Application Number
- CN202511177819.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-21
- Publication Date
- 2025-11-21
AI Technical Summary
Existing technologies are unable to efficiently and completely degrade plastics under mild conditions. Traditional methods are energy-intensive, costly, or have limited effectiveness. Microbial screening cycles are long and difficult to scale up.
By using larvae of the worm to pretreat waste plastics, and then raising them under specific conditions, the mineralization of plastics is promoted by controlling the temperature, humidity, and light environment, taking advantage of their efficient ability to degrade plastics.
The larvae of the nine-dragon worm can efficiently degrade plastic under mild conditions, with a removal rate of 50.19%-55.26% and a survival rate of over 85%. The residual plastic produced is easily degraded by the environment, and the degradation effect is significantly better than that of other insects.
Smart Images
Figure CN120984663A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of solid waste treatment technology, and in particular to a method for degrading waste plastics using the worm. Background Technology
[0002] Plastic pollution has become a global environmental problem. Traditional polyolefin materials such as polyethylene (PE), polypropylene (PP), and polystyrene (PS) have extremely stable chemical structures and can take hundreds of years to degrade naturally. "White pollution" has caused irreversible damage to marine ecosystems, soil microenvironments, and the human food chain.
[0003] Traditional degradation technologies include photo / oxygen degradation, industrial composting, chemical catalytic cracking, and microbial degradation. Photo / oxygen degradation relies on ultraviolet light or high temperatures, requiring large energy inputs and only breaking down plastics into microplastics, not completely mineralizing them. Industrial composting requires specialized equipment, resulting in high transportation and sorting costs. Chemical catalytic cracking has harsh reaction conditions, complex products, and high energy consumption. Microbial degradation involves long strain screening cycles and is difficult to scale up.
[0004] In recent years, the technology of insect degradation of plastics has gradually attracted attention. However, research on insects with the ability to degrade plastics is limited, and the types of plastics that can be degraded are also limited. A new approach that can efficiently and completely degrade or mineralize polyolefin plastics under mild conditions urgently needs further research and development. Summary of the Invention
[0005] The purpose of this invention is to address the technical deficiencies in the existing technology by providing a method for the degradation of waste plastics by the cricket.
[0006] The technical solution adopted to achieve the purpose of this invention is:
[0007] A method for degrading waste plastics using the cricket insect, comprising the following steps:
[0008] Step 1, waste plastic pretreatment: Crush the waste plastic, then soak it in the palatability enhancer, and dry it for later use;
[0009] Step 2: Starve the larvae of the Kowloon worm. The larvae have a stronger diet and metabolic capacity than the adults, while the adults prefer to choose nutrient-rich natural food and have a low willingness to actively feed on plastic.
[0010] Step 3: Place the waste plastic pretreated in Step 1 and the larvae of the nine-dragon worm after starvation treatment in Step 2 into a rearing box or rearing container for rearing. During the rearing process, the larvae of the nine-dragon worm feed on the waste plastic, which degrades or mineralizes it.
[0011] In the above technical solution, during step 1, the size of the waste plastic during crushing is no more than 2cm.
[0012] In the above technical solution, in step 1, the palatability enhancer is fruit juice, and the palatability enhancer includes 0-3 wt% energy substances, 0-4 wt% carbohydrates, and 0-1 wt% sodium, wherein the energy substances include sugars.
[0013] In the above technical solution, the soaking time in step 1 is 18-24 hours.
[0014] In the above technical solution, in step 2, the larvae of the Kowloon worm are 2-3 weeks old.
[0015] In the above technical solution, the starvation treatment time in step 2 is 36-48 hours.
[0016] In the above technical solution, in step 3, the mass ratio of pretreated waste plastic to starved larvae is (0.10-0.15):(21-24). Preferably, each gram of pretreated waste plastic is degraded or mineralized by 250-300 larvae.
[0017] In the above technical solution, in step 3, the rearing temperature is 25±1℃ and the rearing humidity is 75±5%.
[0018] In the above technical solution, in step 3, the side wall of the breeding box or breeding cage is covered with a light-blocking layer, the top of the breeding box or breeding cage is provided with a breathable net, the bottom is a screening net, and a frass collection box is provided below the screening net.
[0019] In the above technical solution, in step 3, the material of the waste plastic is PS, LDPE, PP or PLA / PBAT.
[0020] Compared with the prior art, the beneficial effects of the present invention are:
[0021] 1. This invention is the first to discover the plastic degradation ability of Kowloon larvae, which has both environmental protection and medicinal value, providing a new solution for the biodegradation of plastic waste.
[0022] 2. After the larvae of the nine dragonfly ingested four types of plastics, the residual plastics were mostly fragmented with a particle size of around 100 micrometers. The smaller the particle size, the easier they were to degrade in the environment.
[0023] 3. The average daily consumption of PS, LDPE, PP, and PLA / PBAT by the larvae of the Kowloon worm was 7.28, 3.30, 2.83, and 1.87 mg / g, respectively, with a removal rate of 50.19%-55.26% and a survival rate of over 85%. Attached Figure Description
[0024] Figure 1This is a schematic diagram of the automatic separation device for larvae and frass in this invention.
[0025] Figure 2 This is a structural diagram of the mouthparts of the larvae of the nine dragon insect used in this invention.
[0026] Figure 3 The particle size ranges of the four plastics in the excrement of the larvae of the nine dragonfly in this invention are shown.
[0027] Figure 4 This is a comparison chart of the average daily consumption of four types of plastics by the larvae of the nine dragon insect in this invention.
[0028] Figure 5 This is a survival rate curve of Kochia scoparia larvae fed with different foods in this invention.
[0029] Figure 6 This is a bar chart showing the removal effect of the larvae of the nine dragon insect on four types of plastics in this invention.
[0030] Figure 7 The residual plastic in insect excrement in this invention 13 C isotope characteristic value variation diagram. Detailed Implementation
[0031] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
[0032] Example 1
[0033] A method for degrading waste plastics using the cricket insect, comprising the following steps:
[0034] Step 1, Pre-treatment of waste plastics:
[0035] In this embodiment, the waste plastics selected are foam board (polystyrene, PS), pearl cotton (low-density polyethylene, LDPE), disposable masks (polypropylene, PP), and biodegradable bags (polylactic acid / polybutylene terephthalate, PLA / PBAT).
[0036] The waste plastic was cut into 2×2cm pieces. To enhance its absorption of waste plastic, it was soaked in fruit juice (composition: 3% energy substances, 4% carbohydrates, 1% sodium) for 24 hours, dried at 60°C to constant weight, and the initial mass was accurately weighed (accuracy: ±0.1mg).
[0037] Step 2: Starve the larvae of the nine-dragon worm:
[0038] The larvae of the nine dragon worm were starved for 48 hours, and their excrement was separated by passing them through a 500μm sieve. The larvae skin, dead worms and pupae were removed, and 300 healthy larvae were selected.
[0039] Step 3: Place the pretreated waste plastic from Step 1 and the starved larvae from Step 2 into a rearing box for rearing. During the rearing process, the larvae feed on the waste plastic, which degrades or mineralizes it.
[0040] like Figure 1 As shown, the top side wall of the breeding box is equipped with a breathable mesh, the bottom is a sieve mesh, and below the sieve mesh is a frass collection box. The sieve mesh has a pore size of ≤500μm, and the side walls of the breeding box are covered with kraft paper to simulate the natural habitat.
[0041] Maintain a temperature of 25±1℃ and a humidity of 75±5% in the enclosure; replenish water daily to maintain a constant humidity.
[0042] This embodiment includes six experimental groups: jujube group, starvation control group, foam group (PS), pearl cotton group (LDPE), mask group (PP), and biodegradable bag group (PLA / PBAT), with each group repeated three times.
[0043] Each breeding box in each experiment contained 300 larvae of the worm *Ichthyophthirius multifiliis*. The jujube group contained 5g of jujubes, the starvation control group contained no food, and the foam group (PS), pearl cotton group (LDPE), mask group (PP), and biodegradable bag group (PLA / PBAT) contained 0.1g of PS, LDPE, PP, and PLA / PBAT obtained in step 1, respectively. During the experiment, jujubes and waste plastic were added in a timely manner to ensure that the worm larvae had a sufficient food source.
[0044] Test Example 1
[0045] like Figure 2 As shown, the mouthparts of the Kowloon worm larvae are approximately 300 micrometers in diameter. The claw-like structures (mandibles) on the mouthparts are well-developed and hard, used for cutting or grinding plastic. The serrated structures (dentae) inside the mouthparts enable efficient chewing and grinding of plastic. Figure 3 As shown, after the larvae of the nine-lobed worm ingested four types of plastic, the incompletely mineralized residual plastic was excreted with their feces. The particle size of most of these residual plastics was around 100 micrometers, appearing as fragments. These residual plastics are chemically less stable than the original plastics and degrade more readily in the environment. Furthermore, due to the small mouthparts of the nine-lobed worm larvae, compared to other insects that degrade plastics, the nine-lobed worm exhibits a more significant degree of plastic fragmentation, resulting in smaller fragments that degrade more easily in the environment.
[0046] Insect excrement was collected every 3 days and frozen at -80°C for digestion and use in test case 3. The amount of plastic consumed was recorded daily. Figure 4 ) and larval survival rate ( Figure 5 ),Depend on Figure 4It can be seen that the average daily consumption of the four types of plastics by the larvae of the nine-lobed worm was 7.28 mg / g (PS), 3.30 mg / g (LDPE), 2.83 mg / g (PP), and 1.87 mg / g (PLA / PBAT), respectively. Comparative experiments under the same conditions verified that the average daily consumption of the four types of plastics by the larvae of the yellow mealworm was 6.00 mg / g (PS), 2.38 mg / g (LDPE), 2.62 mg / g (PP), and 1.51 mg / g (PLA / PBAT), respectively. Figure 5 It is evident that the survival rate of worm larvae fed with different types of waste plastics was not significantly different from that of larvae fed with jujubes, proving that worm larvae can maintain normal life activities for a short period of time even when plastic is the only food source.
[0047] Test Example 2
[0048] After 10 days of feeding, the remaining plastic mass was weighed, and the consumed mass was recorded as W. 消耗 After the insect excrement is dissolved, the remaining plastic mass is weighed and recorded as W. 残余塑料， Calculate the removal rate (the portion completely mineralized into water and carbon dioxide) using the following formula.
[0049]
[0050] W 消耗 This indicates the mass of plastic consumed by the nine-dragon worm; W 残余塑料 This indicates the mass of residual plastic in insect excrement.
[0051] Depend on Figure 6 It can be seen that within 10 days, the removal rates of the four plastics by the larvae of the worm were 55.3% ± 2.2% (PS), 50.2% ± 1.6% (LDPE), 51.4% ± 1.0% (PP), and 53.5% ± 2.3% (PLA / PBAT), respectively.
[0052] Test Example 3
[0053] Insect droppings characteristics:
[0054] 1g of insect excrement was digested using 50mL of 30% hydrogen peroxide at a constant temperature of 50℃ for 48 hours. The remaining plastic fragments were collected and... 13 Changes in C isotope characteristic values verified the degradation of plastic in the intestines of Kochia scoparia larvae.
[0055] Plastics are primarily derived from fossil fuels, and their carbon isotopic composition is similar to that of ancient plant carbon, δ 13 The C value is typically -30‰ to -22‰ (leaning towards negative). When microorganisms or insects degrade plastics, their enzymes preferentially utilize those containing light isotopes (…). 12 C). Therefore, undegraded residual plastic will accumulate. 13C, leading to its δ 13 The C value shifts towards a positive bias (i.e., δ) 13 (C increases).
[0056] 100 mg of residual plastic was weighed and its carbon isotope ratio was analyzed using isotope ratio mass spectrometry. δ 13 The C value was calibrated using the international carbon isotope standard PeeDeeBelemnite (PDB) to meet quality control requirements. The instrument measures δ. 13 The precision of C is ±0.10‰. The calculation formula is as follows:
[0057]
[0058] ( 13 C / 12 C) 样品 It was measured through test samples. 13 C / 12 C) 标准 That is the standard value.
[0059] like Figure 7 As shown, the δ values of PS, PE, PP, and PLA / PBAT polyplastics in insect excrement are calculated using the above formulas. 13 The C value increased significantly compared to the original polymer. 13 Change in C isotope characteristic value (Δδ) 13 C) are 1.70, 1.81, 1.60 and 1.34 respectively.
[0060] The above description is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for degrading waste plastics using the nine-dragon insect, characterized in that, Includes the following steps: Step 1, waste plastic pretreatment: Crush the waste plastic, then soak it in the palatability enhancer, and dry it for later use; Step 2: Starve the larvae of the Kowloon worm. The larvae have a stronger diet and metabolic capacity than the adults, while the adults prefer to choose nutrient-rich natural food and have a low willingness to actively feed on plastic. Step 3: Place the waste plastic pretreated in Step 1 and the larvae of the nine-dragon worm after starvation treatment in Step 2 into a rearing box or rearing container for rearing. During the rearing process, the larvae of the nine-dragon worm feed on the waste plastic, which degrades or mineralizes it.
2. The method for degrading waste plastics using *Amanita muscaria* as described in claim 1, characterized in that... In step 1, when the waste plastic is crushed, its size shall not exceed 2cm.
3. The method for degrading waste plastics using *Amanita muscaria* as described in claim 1, characterized in that... In step 1, the palatability enhancer is fruit juice, and the palatability enhancer includes 0-3 wt% energy substances, 0-4 wt% carbohydrates, and 0-1 wt% sodium, wherein the energy substances include sugars.
4. The method for degrading waste plastics using *Amanita muscaria* as described in claim 1, characterized in that... In step 1, the soaking time is 18-24 hours.
5. The method for degrading waste plastics using *Amanita muscaria* as described in claim 1, characterized in that... In step 2, the larvae of the Kowloon worm are 2-3 weeks old.
6. The method for degrading waste plastics using *Amanita muscaria* as described in claim 1, characterized in that... In step 2, the starvation treatment time is 36-48 hours.
7. The method for degrading waste plastics using *Amanita muscaria* as described in claim 1, characterized in that... In step 3, the mass ratio of the pretreated waste plastic to the starved larvae of the nine dragons is (0.10-0.15):(21-24). Preferably, each gram of pretreated waste plastic is degraded or mineralized by 250-300 nine dragons larvae.
8. The method for degrading waste plastics using *Amanita muscaria* as described in claim 1, characterized in that... In step 3, the rearing temperature is 25±1℃ and the rearing humidity is 75±5%.
9. The method for degrading waste plastics using *Amanita muscaria* as described in claim 1, characterized in that... In step 3, the side walls of the breeding box or enclosure are covered with a light-blocking layer, the top of the breeding box or enclosure is provided with a breathable mesh, the bottom is a sieve mesh, and a frass collection box is provided below the sieve mesh.
10. The method for degrading waste plastics using *Amanita muscaria* as described in claim 1, characterized in that, In step 3, the waste plastic is made of PS, LDPE, PP, or PLA / PBAT.