Caterpillars eating polyethylene. Scientists have discovered caterpillars that eat plastic bags

Scientists have found a caterpillar that recycles polyethylene. How she does it, no one knows.

IN scientific journal Current Biology reported that wax moth caterpillars can apparently digest polyethylene. And not just chew and remove from the body naturally, and processed into other substances. Scientists had known similar organisms before, but they all process polyethylene very slowly. And a hundred wax moth caterpillars can cope with 92 milligrams of polyethylene in 12 hours.

Polyethylene is one of the most common types of plastic and is used mainly for packaging. Every year, about a trillion plastic bags are used worldwide and their disposal represents a serious problem. So, in countries European Union only a quarter of plastic bags are recycled, 36 percent are incinerated, and people simply throw away the remaining bags, thereby damaging the environment.

Wax moth larva (Galleria mellonella)

It was previously believed that polyethylene was not biodegradable because it did not occur in nature. Nevertheless, scientists have more than once found organisms capable of processing it. Thus, it turned out that the mold fungi Penicillium simplicissimum are able to partially utilize polyethylene pre-treated with nitric acid within three months. Later, reports emerged that the bacteria Nocardia asteroides “eats” plastic in four to seven months, and bacteria living in the intestines of the Indian moth (Plodia interpunctella) can decompose 100 milligrams of polyethylene in eight weeks. The authors of a new study found that the larvae of the wax moth Galleria mellonella can utilize polyethylene even faster, within a few hours.

During the experiment, after the larvae were left alone with a plastic bag, the first holes began to appear in it after 40 minutes. In 12 hours, 100 larvae ate about 100 milligrams of plastic. To understand how the worms digested the plastic, scientists crushed several larvae in a mortar and spread the resulting paste plastic film and left her for several hours. The researchers analyzed the “treated” polyethylene using Fourier transform infrared spectroscopy. In the spectrogram, in addition to the peaks characteristic of polyethylene, a peak corresponding to ethylene glycol appeared.

In subsequent experiments, scientists found that the caterpillars are capable of completely recycling polyethylene. This is due to the presence of a special enzyme in their bodies, which is either produced by the caterpillars themselves or by bacteria in their digestive system.

Experts believe that caterpillars developed the ability to process polyethylene by analogy with the mechanisms for processing wax in beehives. Now they hope to finally isolate the substance that produces the desired effect, and then try to synthesize it artificially.

“This discovery could help get rid of the huge amount of waste that accumulates in landfills and in the ocean,” one of the study’s authors, Professor Paolo Bombelli at the University of Cambridge, told France-Presse. Polyethylene poses a serious environmental problem because it decomposes very slowly in natural conditions.

But has no one thought about what these multiplied caterpillars will eat when they gobble up all the garbage? Will they eat the polyethylene we need like Colorado beetles eat potatoes?

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MOSCOW, April 25 - RIA Novosti. Caterpillars of the common wax moth, which eat wax in bee hives, have been shown to be able to eat and digest polyethylene and other types of plastic, allowing them to be used for waste disposal, according to a paper published in the journal Current Biology.

"We found out that caterpillars common insects, a large wax moth, can decompose one of the most resistant and chemically resistant plastics - polyethylene. We plan to adapt them to save the Earth's oceans and rivers from pollution by particles of these materials. This, however, does not mean that you can now litter anywhere,” said Federica Bertocchini from the University of Cantabria in Santander (Spain).

Today, approximately 300 million tons of plastic waste end up in landfills every year. most of which is not decomposed by soil microbes and remains almost untouched for tens and even hundreds of years. Many plastic particles end up in the world's oceans, where they penetrate the stomachs of fish and birds and often cause their death.

Over the past two years, scientists have discovered several species of insects whose larvae appear to be able to solve this problem. For example, two years ago Chinese biologists discovered that favorite dish Many visitors to Chinese restaurants - mealworm caterpillars - can eat polystyrene foam, PET and some other types of plastic. The discovery of bacteria in their intestines that can degrade plastic has provided the first hope for quickly clearing the Earth of trash.

As Bertocchini says, she accidentally managed to find " natural enemy" for the strongest and most common plastic - polyethylene, caring for bees in your garden.

When she looked at the bag a couple of hours later, she saw that the caterpillars did not give up, but “continued the banquet” and began to eat not wax, but polyethylene. Such strange appetites of insects interested Bertocchini, and she checked whether moth larvae could actually feed on plastic by observing their behavior in the laboratory.

It turned out that this is indeed the case, and that moths can eat polyethylene at a record speed - in half a day, about a hundred caterpillars ate almost 100 milligrams of the bag, which is thousands of times more speed decomposition of plastic with the help of bacteria and other insects.

As scientists suggest, the caterpillars' body apparently produces a special enzyme that breaks the bonds between the links of polymer molecules and converts them into ethylene glycol, an alcohol toxic to humans. Similar bonds are present in the polymer molecules that make up beeswax, which may explain why moth caterpillars are so active in eating plastic.

While Bertocchini and her colleagues don't know which molecules are involved in this process, they plan to unlock the caterpillars' secrets soon. If this can be done, then a synthetic version of their enzymes can be used to process plastic waste and cleanse the Earth's biosphere of anthropogenic pollution.

MOSCOW, April 25 - RIA Novosti. Caterpillars of the common wax moth, which eat wax in bee hives, have been shown to be able to eat and digest polyethylene and other types of plastic, allowing them to be used for waste disposal, according to a paper published in the journal Current Biology.

“We found that the caterpillars of common insects, the great wax moth, can decompose one of the most persistent and chemically strong plastics - polyethylene. We plan to adapt them to save the oceans and rivers of the Earth from pollution by particles of these materials. This, however, does not mean that Now you can litter anywhere,” said Federica Bertocchini from the University of Cantabria in Santander (Spain).

Today, approximately 300 million tons of plastic waste end up in Earth's landfills every year, most of which is not decomposed by soil microbes and remains almost untouched for tens or even hundreds of years. Many plastic particles end up in the world's oceans, where they penetrate the stomachs of fish and birds and often cause their death.

Over the past two years, scientists have discovered several species of insects whose larvae appear to be able to solve this problem. For example, two years ago, Chinese biologists discovered that the favorite dish of many visitors to Chinese restaurants - mealworm caterpillars - can eat polystyrene foam, PET and some other types of plastic. The discovery of bacteria in their intestines that can degrade plastic has provided the first hope for quickly clearing the Earth of trash.

As Bertocchini says, she accidentally managed to find a “natural enemy” for the strongest and most common plastic - polyethylene, while caring for bees in her garden.

When she looked at the bag a couple of hours later, she saw that the caterpillars did not give up, but “continued the banquet” and began to eat not wax, but polyethylene. Such strange appetites of insects interested Bertocchini, and she checked whether moth larvae could actually feed on plastic by observing their behavior in the laboratory.

It turned out that this is indeed the case, and that moths can eat polyethylene at a record speed - in half a day, about a hundred caterpillars ate almost 100 milligrams of the bag, which is thousands of times faster than the rate of plastic decomposition with the help of bacteria and other insects.

As scientists suggest, the caterpillars' body apparently produces a special enzyme that breaks the bonds between the links of polymer molecules and converts them into ethylene glycol, an alcohol toxic to humans. Similar bonds are present in the polymer molecules that make up beeswax, which may explain why moth caterpillars are so active in eating plastic.

While Bertocchini and her colleagues don't know which molecules are involved in this process, they plan to unlock the caterpillars' secrets soon. If this can be done, then a synthetic version of their enzymes can be used to process plastic waste and cleanse the Earth's biosphere of anthropogenic pollution.

Biologists have made a big discovery. Turns out, regular caterpillars, which are often bred as fish bait, have much more valuable property. They can recycle polyethylene, one of the most durable and commonly used types of plastic, which litters landfills and the world's oceans everywhere. Polyethylene and polypropylene account for 92% of global plastic production, including 40% of polyethylene. Every year people use and throw away trillion plastic bags.

These caterpillars are the larvae of the common insect Galleria mellonella (great wax moth). The animal is considered a pest because it lays larvae in honey bee hives. There, the caterpillars feed on honey, pollen and wax (hence the name moth), damaging everything around them: honeycombs, brood, honey reserves, bee bread, frames and insulating material of the hives. But still, these harmful caterpillars found useful application. Instead of wax, they can be fed plastic waste.

Plastic is one of the most dangerous materials in terms of littering the planet. In terms of the combination of prevalence and duration of natural decomposition, it has almost no equal. For comparison, paper decomposes in nature from one month to three years, clothes made of wool - one year, clothes made of natural fabrics - two to three years, can- 10 years, but normal plastic bag decomposes in 100-200 years. Among all types of waste, polyethylene is second only to aluminum cans(500 years), disposable diapers (300-500 years) and glass bottles (more than 1000 years).

Over the past 50 years, plastic production has grown exponentially. In the EU countries, despite all efforts to recycling waste, up to 38% of plastic ends up in landfills, the rest is recycled (26%) or incinerated (36%). When burned or buried in a landfill, polyethylene creates a serious burden on environment Therefore, scientists are intensively searching for acceptable ways to harmlessly degrade plastic. Using great wax moth caterpillars is one great option.

Scientists estimate that the rate of polyethylene biodegradation by wax moth caterpillars is much higher than that of plastic-eating bacteria reported last year. Those bacteria could eat 0.13 mg per day, and the caterpillars devour the material literally before our eyes. In the photo above you can see that we made 10 caterpillars with the bag in just 30 minutes.

Federica Bertocini contacted colleagues from the Department of Biochemistry at the University of Cambridge - and together they set up an experiment for a while. About a hundred caterpillars were placed in a regular plastic bag from a British supermarket. Holes in the bag began to appear after 40 minutes, and after 12 hours the mass of plastic had decreased by 92 mg!

Scientists have yet to study the details of the biodegradation of wax and plastic, but it appears that the caterpillars in both cases break down the same chemical bonds between molecules (CH²−CH²) in the substance. According to the chemical formula and its properties, wax is a polymer, something like “natural plastic”, and its structure is not much different from polyethylene.

Scientists carried out spectroscopic analysis and checked how the caterpillars break down chemical bonds in polyethylene. They found that the result of processing is ethylene glycol, a dihydric alcohol, the simplest representative of polyols. The analysis proved that the holes in the plastic bag are not the result of simple mechanical chewing of the material, but that there is actually a chemical reaction and biodegradation of the material. To be 100% sure of this, biologists conducted a scientific experiment: they crushed caterpillars into puree and mixed it with plastic bags. The result was identical - part of the plastic disappeared. This is the most convincing evidence that caterpillars do not just eat plastic, but digest it into ethylene glycol. Chemical reaction occurs somewhere in the animal's digestive tract - these may be salivary glands or symbiotic bacteria in the esophagus. The corresponding enzyme has not yet been identified.

Lead author scientific work Paolo Bombelli is confident that if a chemical process is carried out using a single enzyme, then it is quite possible to reproduce this process using biochemical methods on a large scale. "This discovery could be important means to get rid of polyethylene waste accumulated in landfills and in the ocean,” he says.

The scientific work was published on April 24, 2017 in the journal Current Biology.

In an experiment with bacteria, a film of 1 cm² of Ideonella sakaiensis bacteria processed 0.13 mg of polyethylene terephthalate (PET) per day.