The Ministry of Science and ICT on Jan. 3 said Kyungpook National University professor Kim Kyung-jin and the research team of the food and bio company CJ Cheiljedang have developed the world's best-quality PET (polyethylene terephthalate) depolymerase, an enzyme that dissolves the plastic PET. (iclickart) *[Unauthorized reproduction and redistribution of the above photo is strictly prohibited under copyright laws and regulations.]

By Lee Jihae

A domestic research team has developed the world's best performing enzyme that dissolves plastic.

This will enable the recycling of even contaminated plastics, leading to expectations of innovation in the chemical industry.

The Ministry of Science and ICT on Jan. 3 said Kyungpook National University professor Kim Kyung-jin and the research team of food and bio company CJ Cheiljedang developed the world's best-performing PET (polyethylene terephthalate) depolymerase, an enzyme that dissolves the plastic material PET.

The study appeared on Jan. 3 in the global academic journal Science.

The team focused on biological recycling, in which bio enzymes mediate the decomposition of plastic similar to the same process of a tree decaying in a natural environment. The result was a high-quality bio enzyme that biologically dissolves PET, which is used in a range of items like plastic bottles, clothing, packaging cups and car mats.

The ministry said the bio enzyme selectively reacts with PET and forms pure reactants, hardly polluting the environment in the dissolution process and maintaining high quality of the recycled material.

Most plastics are used as intermediate products after going through mechanical recycling that requires label removal, crushing, cleaning and reprocessing into raw materials after waste sorting and collection. Their poor quality, however, means the recycled products end up incinerated or buried in landfills.

Another method to reuse plastics is chemical recycling, which uses chemical enzymes to melt PET with heat or dissolve it with solvents to make raw materials. But this is also not a viable alternative given its negative impact on the environment.

To solve these problems, the team proposed an activity map of bio enzymes containing microorganisms and discovered the bio enzyme Kubu-P. Based on the high potential of Kubu-P, the researchers developed through enzymatic engineering KubuM12, a stronger and more effective bio enzyme.

Displaying the world's best performance, KubuM12 dissolves 45% of 1 kg of PET into 0.58 g in an hour and over 90% of it in eight hours.

"This research is significant in showing the great potential of nature," Kim said. "Innovation is coming in the use of bio enzymes for a range of chemical industries."

jihlee08@korea.kr