White is not the base color of the earth!

As my country's urbanization and modernization levels continue to improve, people's demand for disposable products is also increasing.

Plastic bags have won the favor of consumers with their advantages of low cost, light weight and good waterproof performance, and have become the main force in disposable products. They can be seen everywhere in supermarkets and vegetable markets.

However, while plastic bags bring convenience to people, they also bring a century-old problem to mankind - plastic degradation!

Plastic is a man-made product that did not exist in nature, so there are no organisms that can decompose plastic. This has led to a serious consequence: the speed at which people produce plastic is much faster than its natural degradation rate. The accumulated waste plastics impact people's vision, affect people's emotions, damage the ecological environment, and threaten the lives and health of people and other organisms.

Based on the powerful functions of microorganisms, microorganisms have quickly become a new force in the treatment of white pollution since the beginning of the millennium.

It is generally believed that the biodegradation process mainly includes two steps. The first step is that microorganisms release enzymes such as hydrolases to specifically bind to receptors on the surface of plastics, hydrolyzing them into fatty acids or lipids with a molecular weight of less than 500 Daltons (molecular weight unit); the second step is that the small molecular acids or lipids generated in the previous process enter the microorganisms and participate in their physiological metabolism, and then decompose into water and carbon dioxide, and provide energy for cells.

A team at Tianjin University has developed a mixed bacterial system that can be used to efficiently degrade plastics. The mixed bacterial system is highly efficient and stable. The general process of degradation is that some bacteria in the system work first to degrade plastic macromolecules into small molecules that can be used later, and other bacteria then absorb or convert these small molecules into substances that are harmless to the environment. Experiments have shown that the mixed bacterial system can completely degrade some common plastics in life, such as polyethylene terephthalate (PET) [1].

Researchers at the University of Manchester in the UK buried polyurethane plastics in fertile soil and found that as the plastics continued to degrade, the number of microorganisms such as fungi in the soil continued to increase, indicating that some fungi in the soil can use polyurethane plastics as metabolic raw materials [1].

Sun Chaomin's research group at the Institute of Oceanology, Chinese Academy of Sciences, has made great achievements in the study of marine microorganisms. In 2021, the research group discovered for the first time a marine microbial community that can effectively degrade plastic waste. Later, the research group discovered and cultivated an "upgraded version" of marine microorganisms that can not only effectively degrade a variety of plastics, but also degrade them faster, degrading some plastics into fragments within two weeks [2].

The efforts of the researchers have given the world hope for solving the problem of white pollution, but we still need to unify our thinking and develop the habit of using less, not using, and recycling disposable products. I believe that in the near future, the problem of white pollution can be completely solved, and future generations can still have this blue planet.

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