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Can caterpillars that eat plastic save the world?

Caterpillars that consume polyethylene and break it down may serve as inspiration for new industrial tools

Dong caterpillars, like the one in the picture, are able to gnaw and break down plastic. Image: Federica Bertocchini, Paolo Bombelli, and Chris Howe.
Dong caterpillars, like the one in the picture, are able to gnaw and break down plastic. Image: Federica Bertocchini, Paolo Bombelli, and Chris Howe.

By Matthew Sadka, the article is published with the approval of Scientific American Israel and the Ort Israel network 19.09.2017

Humans produce more than 300 million tons of plastic every year. Almost half of this amount ends up as waste in landfills, and about 12 million tons pollute the oceans. So far no practical way to get rid of this polluting plastic waste has been found, but new research reveals that the answer may lie in the stomachs of some hungry caterpillars.

Researchers in Spain and England recently discovered that the larvae of The great Dong Moth able to disassemble efficiently Polyethylene, a material that makes up about 40% of all plastic produced. The researchers placed one hundred Dong larvae on a commercial polyethylene shopping bag for twelve hours, and the larvae ate and decomposed about ninety-two milligrams - about 3% of the bag. To make sure that the decomposition of the polyethylene was not caused solely by the chewing action of the larvae, the researchers crushed some larvae into a mash and spread it on plastic sheets. After about fourteen hours, the sheets lost about 13% of their mass - apparently due to decomposition by enzymes from the larvae's stomachs.

When the researchers examined the decomposed plastic sheets, they also found tiny amounts of ethylene glycol, a product of polyethylene decomposition, which taught them about true biodegradation. These findings Were published Last year in the journal Current Biology.

One of the authors of the article, the biological one Federica Bertuccini from the Spanish Institute of Biomedicine and Biotechnology in Cantabria, says that the larvae's ability to break down their main food - bee dung - is what allows them to break down plastic as well. According to her, "The dong is a complex mixture of molecules, but the carbon-carbon chemical bond, which is the basic bond in polyethylene, is also found there. The dong caterpillar has developed a mechanism to dissolve this bond."

According to Jennifer Debruin, a microbiologist from the University of Tennessee who was not involved in the research, it is not surprising that an organism has developed the ability to break down polyethylene, but the exciting finding in this study compared to previous studies is the speed of the biological breakdown. The next step, according to Debruin, is to accurately identify the cause of the dissolution. Is it an enzyme produced by the larva itself, or by the bacteria in its digestive system? Bertuccini agrees and hopes that her team's findings will one day help harness the enzyme to break down the plastic found in landfills and oceans. However, she envisions an industrial process of using this chemical, and not just a need to "scatter millions of larvae on the plastic."

More of the topic in Hayadan:

3 תגובות

  1. In the article it is stated that the decomposition product is ethylene glycol, from which PET is mainly produced (86%) - the material from which plastic bottles are produced, 7% is used as an antifreeze agent in engines,
    The rest is used, among other things, in the production of shoe polishes, vaccines and more...

  2. The question is what are the decomposition products, and if no more harmful substance is created than the decomposed plastic.
    If the material is harmless, how can it be used?

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