Science and Technology Daily News (Reporter Wang Jiangao Reporter Wang Min) Hazardous Materials on April 25, the international academic journal reported the latest research results of Sun Chaomin and his team under the Institute of Oceanology of the Chinese Academy of Sciences, which for the first time identified Marine microbial flora and enzymes that can effectively degrade polyethylene terephthalate (PET) and polyethylene (PE) plastics. It provides an important theoretical basis and candidate materials for obtaining plastic degrading microorganisms and functional enzymes, and the development of biodegradable plastic waste biological products, and is expected to break through the bottleneck of degradation of difficult to degrade plastic polyethylene.

Sun Chaomin's research team has collected thousands of plastic wastes from offshore Qingdao since 2016. After extensive screening, it was found that a bacterial community was attached to a plastic waste, which has obvious colonizing and degrading ability on the surface of plastics (PET and PE). The bacterial community maintained good growth ability in the medium containing plastic waste, which is supposed to obtain additional energy sources through the degradation of plastic. Through quantitative analysis of bacterial composition and abundance, it was found that there were 5 types of bacteria as the dominant population. Combined with culture technology, pure culture strains of the above 5 types of bacteria were successfully obtained, and 3 of them had obvious ability to degrade plastics. The 3 strains were combined according to a certain proportion to successfully obtain a stable coexistence and significant degradation of PET and PE plastic waste flora, the flora especially likes to degrade PE plastic, PE can be degraded into fragments within two weeks.

The researchers then combined infrared spectroscopy, gel permeation chromatography, X-ray diffraction, high performance liquid chromatography and mass spectrometry to prove that the above bacteria can effectively degrade PET and PE plastics. Macrotranscriptomic technology was used to analyze the process of the bacteria colonizing the plastic surface by forming biofilms and secreting enzymes to degrade the plastic as an energy source. And then screen a number of candidate enzymes that may be involved in the degradation of PET and PE plastics, and finally combine in vitro expression technology to obtain a number of enzymes that can significantly degrade PE plastics within 24 hours.

Plastic Industry Video