In recent years, scientists have been concerned with the global problem of plastic pollution of water and soil. That is why the discovery that certain bacteria can break down plastic has become particularly important. However, for a long time it was not clear how they do this. A researcher from Leiden University (Netherlands) has analysed how different types of bacteria interact with plastic waste.

The scientist analyzed 96 strains of actinobacteria – streptomycetes. He used the bacterial collection kept at Leiden University. Researchers usually use it to develop drugs, but a scientific group led by Jo-Anne Verschoor (Jo-Anne Verschoor) decided to see if they could recycle plastic.

PET is one of the most common types of plastic used in the pharmaceutical and food industries, mechanical engineering, electrical engineering and everyday life.

As a result, it turned out that almost 18% of them were able to separate polyethylene terephthalate (PET) and its oligomer bis(2-hydroxyethyl)terephthalate (BGET). Moreover, Vershur discovered that bacteria help to decompose much more plastic if they are stimulated. According to the authors of the article, microorganisms only start to act when they are “hungry”.

“At one point, we literally ‘fed’ bacteria the smallest particles of plastic and observed how the lack of food affected the speed at which PET and BHT were processed,” said Jo-Ann Verschoor.

Biologists also discovered that three types of LIPA esterase enzymes help bacteria in this regard: ScLIPA, S2LIPA and S92LIPA. During the experiments, scientists removed the bacteria Streptomyces coelicolor The gene responsible for the ScLIPA enzyme. This resulted in a reduction in the degradation of BHET.

At the same time, overexpression (activation) of genes encoding all variants of LIPA significantly increased the degradation of BHT. Scientists also found that bacteria “work” most effectively at a temperature of about 25 degrees Celsius and a pH of 7.

Thanks to this research, the diversity of microorganisms that can process plastic has increased significantly. Some global companies have already adopted this method and are using microorganisms and their enzymes to decompose various types of plastic. The study was published in the journal Communication Biology.