![]() It is fast for what it is, but it still takes days to break down PET and the reactions have to occur at very high temperatures. LCC is good, they say, but it has limitations. Since the discovery of LCC, researchers like Sonnendecker have been looking for new PET-eating enzymes in nature. Instead, LCC recognizes PET plastic as a naturally occurring substance and eats it like it would a natural polymer. Scientists working on LCC have found that the enzyme does not differentiate between natural polymers and synthetic polymers - the latter being plastic. LCC was a major breakthrough because it showed that PETase, a component of LCC, can be used to degrade PET plastic when it is combined with another enzyme known as an esterase.Įsterase enzymes are used to break chemical bonds in a process called hydrolysis. Scientists have been trying to find enzymes that will do that for decades and in 2012 they found LCC, or "leaf-branch compost cutinase." The second way is to force the plastic to degrade. This is what a grape container looks like after it's been treated with the enzyme PHL7 - the white particles are leftover terephthalic acid and ethylene glycol, chemicals that can be used to create brand new PET rather than a lower quality version Image: Clare Roth/DW There are two ways to look at solving this problem: The first is to stop production of all PET plastic.īut the material is so common that even if companies stopped producing it immediately, there would still be millions of empty soft drink bottles - or tote bags fashioned from those bottles - lying around for thousands of years. So, a lot of PET is eventually fashioned into products like carpets and - yes - an exorbitant number of tote bags that end up in landfill sites. But the quality of the plastic weakens with each cycle. It can be refashioned into new products - it's not hard to create a tote bag from recycled water bottles, for example. Like nuclear waste or a nasty comment to your partner, once PET plastic is created, it never really goes away. PET plastic is everyoneĪlthough PET plastic can be recycled, it does not biodegrade. "Apparently, you go to nature and there are going to be enzymes that do this everywhere," said Howe. Howe, who also studies PET degradation but was not involved in the Leipzig research, appeared to be amazed by the study published in Chemistry Europe. "I would have thought you'd need to sample from hundreds of different sites before you'd find one of these enzymes," said Graham Howe, an enzymologist at Queens University in Ontario, Canada. And they found it was true: PHL7 was faster. To ensure their discovery wasn't a fluke, Sonnendecker's team compared PHL7 to LCC, with both enzymes degrading multiple plastic containers. ![]() PHL7 appears to 'eat' PET plastic times faster than LCC, a standard enzyme used in PET plastic-eating experiments today. To test the rate at which the seven enzymes broke down PET, Sonnendecker and his team added a mixture of water, a phosphate buffer, which is often used to detect bacteria, for example, and the new enzyme to seven individual test tubes Image: Clare Roth/DW After adding the mixture to the test tubes, the team added tiny slivers of PET plastic to each container to see how quickly it took to degrade Image: Clare Roth/DW Two enzymes 'eat' plastic: PHL7 vs. The PHL7 enzyme disintegrated an entire piece of plastic in less than a day. It was only the second dump they had rummaged through and they thought PET-eating enzymes were rare.īut in one of the samples, they found an enzyme, or polyester hydrolase, called PHL7. The scientists weren't expecting much when they brought the samples back to the lab, said Sonnendecker when DW visited their Leipzig University laboratory. It is commonly used for bottled water and groceries like grapes. They were hunting for proteins that would eat PET plastic - the most highly produced plastic in the world. While scavenging through a compost heap at a Leipzig cemetery, Christian Sonnendecker and his research team found seven enzymes they had never seen before. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |