Oceans subject to plastic pollution
According to National Geographic, in recent years scientists have discovered an animal called a wax worm, a small bug that can eat plastic, but it is not known whether this small animal can help humans solve the problem of white pollution.
About 300 million tons of plastic waste are generated around the world each year, and because plastic cannot be degraded, it can be seen in every corner of the planet. There is a team of scientists in Europe who seem to have found a solution to the problem, and they found that an ordinary insect can bite a big hole in a plastic shopping bag in 40 minutes.
Wei-Min Wu, an environmental engineer at Stanford University, said: "This finding is a milestone in the study of plastic degradation. ”
The bug was first discovered by Federica Bertocchini, a biologist at the University of Cantabria in Spain, who discovered the possibility two years ago while cleaning her backyard. She threw the wax worms that lived in the hive into the plastic bag, and an hour later she found that the larvae inside had bitten out many small holes in the plastic bag. Although she was not an entomologist, she could guess what was going on.
Wax worms, as the name suggests, are small meat worms that feed on wax on honeycombs. Plastics are similar to wax on honeycombs, consisting of long chains of carbon atoms that aggregate, while wax and polyethylene plastics also have a similar carbon structure. Since these insects eat wax, they may secrete a molecular particle capable of breaking down wax or plastic.
Bertocini set up a team to study how wax worms devour plastic bags. They found that each worm could eat an average of 2.2 holes per hour, and 100 worms ate 92 milligrams a day, at which rate 100 worms could only break down 5.5 grams of plastic bags a month.
In order to improve the rate of degradation, they stirred the dead worms into a liquid and put them in plastic bags to observe, and found that the liquid larvae can also erode the plastic, which shows that the enzymes on the worms or the bacteria they carry have the ability to break down the plastic. This enzyme can break down polyethylene into glycol, and Bertocini hopes to accurately identify this enzyme in future studies.
Uwe Bornscheuer, a biochemist at the University of Greifswald in Germany, said: "Scientists have been looking at ways to biodegrade plastics for decades, and plastic pollution is still a big problem." ”
In 2014, Wu Weimin of Stanford University and colleagues found that the gut bacteria in another wax worm also have the effect of breaking down polyethylene. A 2016 study reported that enzymes that could break down polyethylene plastic were isolated in a group of bacteria. Wu Weimin said: "There may be other types of worms that can degrade plastics. ”
Tracy Mincer, a marine biologist at the Woods Hole Oceanographic Institute, says the only way to tackle plastic pollution is to reduce the production of new polyethylene products while increasing recycling of old plastic products. She said: Polyethylene is a high-quality resin, which can be continuously upgraded to develop new polyethylene products, and the raw material price of polyethylene is close to $500 per ton driven by demand. Biodegradation technology cannot solve the widespread pollution caused by the flooding of polyethylene from the current point of view.