In earth's battle with pollution caused by hard-to-degrade plastics, the tiny living things have demonstrated mighty power.
Following the encouraging discovery of little worms that eat polystyrene and polyethylene last year, now researchers have found bacteria that can break down and metabolize PET.
According to a recent study published in the March 11 issue of the journal Science from the American Association for the Advancement of Science, a team of Japanese researchers discovered a new species of bacteria called Ideonella sakaiensis 201-F6, which breaks down PET bottles by using two enzymes to hydrolyze PET and a primary reaction intermediate, eventually yielding basic building blocks for growth.
This amazing bacterium apparently lived at a plastic bottle recycling site in Osaka, Japan, and was screened out in an extensive study of 250 samples of plastic debris collected there. Ideonella sakaiensis is said to be able to break down PET in just six weeks, compared to the 450 years it takes to decompose plastic beverage bottles in the nature — a number estimated by the U.S. National Park Service.
The microbe produces two enzymes, PETase and MHETase, which break down PET and yield chemicals that serve as food to the bacteria. “When grown on PET, this strain produces two enzymes capable of hydrolyzing PET and the reaction intermediate, mono(2-hydroxyethyl) terephthalic acid. Both enzymes are required to enzymatically convert PET efficiently into its two environmentally benign monomers, terephthalic acid and ethylene glycol,” the authors said.
Like other scientific discoveries in the lab, the findings will need further examination to determine how effective role Ideonella sakaiensis can play in the cleanup of plastic pollution.
To me, what's truly amazing is the nature's ability to adapt to human impact on the earth — including a synthetic creation like PET that has only existed for about 70 years. Hopefully, nature will empower us to protect the environment and take advantage of polymer materials at the same time.
