Scientists from Kyoto Institute of Technology (Japan) found a species of bacteria that can grow on polyethylene terephthalate (PET) and treat it as the energy and carbon source, providing a biologic way to break down plastics.
PET waste has been one of the main issues since it came to 21st century. Its moisture and water resistant character bring a lot of convenience while being one of the thorniest waste problems for the hard degradation. Related figure shows that about 50 million tones are consumed yearly, and the figure will be increased to 100 million for 2025, which will be an unbearable burden for the earth as it is for some places now.
Emergent measures have to be taken to address the problem before the nightmare go into being, and researchers in the field have been baring their mind to find solutions, and the bacteria that eat PET as the carbon source is quite potential for a way out.
The research team discovered the bacteria by extracting sediment samples and culturing them in independent tubes with addition of PET at a certain amount. In total there were 250 samples were collected, from which the workload of this research can be imagined. Then researchers checked the PET content of each sample after a period of time and a decreased amount of PET was found in one tube.
The standing out sample was furtherly settled for another 15 days and observed. As a result, about 75% of the carbon contained in the PET were consumed and transformed into carbon dioxide. Scientists isolated the target bacteria-Ideonella sakaiensis 201-F6 for deep analysis with the help of CABR Bacteria Probes and found that they achieved this with the assistance of two enzymes. The bacterium, together with the two enzymes can degrade the PET efficiently into two substances-terephthalic acid and ethylene glycol. However it’s not the end point of this metabolism, the bacterial will keep making use of these substances for energy until they become the very basic building blocks.
The team has traced the gene on the bacterium that express to form the enzymes performing key roles in the whole degrading process and it’s said the new finding is of great potential to be converted into a technology being applied industrially.
The research paper is published in the Science Magazine and titled as A bacterium that degrades and assimilates poly (ethylene terephthalate), with the doi number being 10.1126/science.aad6359.