In 1933, a chemical plant in Britain inadvertently developed polyethylene, which was the first time that human beings synthesized a compound material that could be used in industry. In 1965, Sten Gustav Turing, an engineer of Celloplast Company in Sweden, designed and developed the first integrated polyethylene plastic bag and applied for related patents. Since then, plastic bags have become a ubiquitous product on the earth, and they have found traces of plastics all over the world, from the deepest part of the seabed to the peak of Mount Everest to the polar ice sheet.
The original intention of Stern Gustav Turing's invention of plastic bags is that compared with paper bags, plastic bags are not easy to be damaged due to moisture, and can be reused, thus reducing tree felling. However, contrary to expectations, it is estimated that more than half of plastic bags have not achieved the original design intention of "reuse", and many plastic bags are randomly discarded in nature. According to the statistics of the United Nations, the annual output of plastic bags in the world now reaches one trillion. The white pollution caused by plastic bags has brought severe challenges to the fragile environment of human beings. How to solve the white pollution caused by plastic bags has always been a subject that scientists have been studying.
At present, the most common plastic material in the world is polyethylene terephthalate (PET), which is widely used in clothing, bottled water and food packaging. However, it takes hundreds of years for PET to be decomposed under natural conditions, which will cause incalculable damage to the environment. Recently, however, a research team in Japan discovered a new type of bacteria that loves to "eat" PET-"Sakamoto Osaka".
"Sakamoto Osaka" was discovered by accident when a research team led by Kohei Oda of Kyoto University of Arts and Crafts and Kenji Miyamoto of Keio University collected sediment samples contaminated by PET near a garbage collection facility in Sakai, Japan.
Sakamoto osaka is very important for degrading PET plastics. Before this bacterium, no organism has been found that can degrade PET as the main carbon and energy. As a recycling and bioremediation method, the appearance of Sakamoto osaka makes "biodegradation of PET" possible.
so, how does morinda osaka digest PET?
There are two enzymes involved in the decomposition of PET in this bacterium.
In this way, PET will return to its original monomer, and bacteria will further decompose it, and finally return to the element cycle of nature in the form of carbon dioxide and water, from which bacteria can obtain energy for survival.
Although the bacteria decompose PET very slowly, scientists have found that after some genetic engineering modification, the decomposition speed of bacteria can be doubled. At present, the National Renewable Energy Laboratory (NREL) of the University of Portsmouth, UK, is re-studying the fungus in Osaka. The research team used synchrotron to study the atomic structure of PET hydrolase and MHET hydrolase. With the help of synchrotron, the research team obtained the 3D structure of these two enzymes and the interaction between them. Subsequently, the research team connected the bacteria's PET hydrolase and MHET hydrolase in a physical way, which increased the efficiency of the bacteria to decompose PET by 6 times.
However, there is still a long way to go before the fungus in Osaka can be put into practical use. What we urgently need to solve now is how to realize mass production and how to apply it in the future. I believe that through the efforts of scientists and the use of genetic engineering in the future, we will certainly find a way to make PET decompose faster.
Written at the end:
Although the microbes and enzymes discovered this time can really help human beings solve the plastic pollution problem we are facing in the future, human beings should not regard it as the final solution. The most scientific way to solve plastic pollution should be to reduce the use of plastics, scientifically coordinate the use of various materials in the future, and protect the global environment, which is our primary goal.
this article is a selected work submitted by the first children's popular science essay contest in Zhengzhou
Author: Jiang Dandan
The opinions only represent the author himself, and do not represent his own position.