Apr 09, 2020 11:15:00

An enzyme that will decompose nearly 1 ton of PET bottles in 10 hours and enable recycling will be developed

An enzyme has been developed that can degrade

polyethylene terephthalate (PET), which is used for materials such as PET bottles and clothing, overwhelmingly in a short time. Unlike PET-degrading enzymes that have been discovered so far, they can be applied to recycling.

An engineered PET depolymerase to break down and recycle plastic bottles | Nature
https://www.nature.com/articles/s41586-020-2149-4

Newly engineered enzyme can break down plastic to raw materials | Ars Technica
https://arstechnica.com/science/2020/04/researchers-engineer-enzyme-to-break-down-plastic-bottles/

Scientists create mutant enzyme that recycles plastic bottles in hours | Environment | The Guardian
https://www.theguardian.com/environment/2020/apr/08/scientists-create-mutant-enzyme-that-recycles-plastic-bottles-in-hours

A study published in 2019 estimates that between 359 million tonnes of plastic produced annually worldwide, 150 million to 200 million tonnes are accumulating in landfills or the natural environment It has been. Among them, about 70 million tons of PET are produced annually around the world, but since they hardly decompose naturally, there is an environmental problem such as residual PET bottles and other garbage affecting the ecosystem.

This is not the first discovery of an enzyme that can hydrolyze PET. ' Petase ' has been found in bacteria ' Ideonella sakaiensis ' found in a sample collected at a recycling plant in Sakai City, Osaka Prefecture.

It turns out that an enzyme that can degrade PET bottles was accidentally created in the experimental facility-gigazine

However, degradation by petase takes time, and after the decomposition, it becomes unrecyclable, so the goal of 'reducing PET production' cannot be achieved. Then, Calbios , a major French plastics manufacturer, investigated 100,000 kinds of microorganisms found in compost in 2012. He announced that he had mutated the enzyme found there based on the research data on the PET degradation pathway and developed a new enzyme that degrades PET in a short time and makes it more recyclable.

In order to decompose PET, it is necessary to dissolve it to some extent, but there was a problem that conventional enzymes lose their activity at a temperature of about 65 ° C. However, the enzyme developed by Calbios showed stable activity at 72 ° C and was able to rapidly degrade PET. The research team reports that the new enzyme can degrade 90% of a 1-ton plastic bottle in less than 10 hours, and has succeeded in reproducing the plastic bottle from the degraded material.

Alan Marty, Calbios Chief Science Officer and Professor of Biology at the University of Toulouse, said, `` The microorganisms discovered in 2012 were completely forgotten, but I found that they gave the best results. '' Commenting.

The production cost of the enzyme is about 4% of the cost of producing a new plastic bottle, and Calbios has already signed a contract to produce this enzyme on a large scale with biotechnology company Novozymes. Since decomposition requires heating, the production cost of PET bottles recycled using this enzyme is absolutely higher than the production cost of new PET bottles, but Calbios CEO Martin Stefan said, Recycled PET is also sold at a low price while being of low quality. '

`` Reducing plastic usage is one way to solve the waste problem, '' said Stephen, `` While plastic has brought much value to society such as food, medicine, transportation, etc. What we know is that the problem is with plastic waste disposal. Since about half of plastic ends up in the environment and landfills, increasing the amount of plastic waste collected is key. ' .