An enzyme that rapidly breaks down plastic
A new enzyme created in the lab can reduce the time it takes to break down plastic from thousands of years to days or even hours, and then recycle it by reassembling it. A study published in Nature by researchers at the University of Texas at Austin shows how the use of this enzyme, called FAST-PETase, can dramatically reduce the time it takes for plastic to break down.
PET, or polyethylene terephthalate, is one of the most common plastic components used in plastic packaging and accounts for about 12% of global waste. Considering also that about 6 million barrels of oil are used every day to produce plastic bags, bottles and other plastic objects, a process that promotes the rapid decomposition of plastic would both reduce the carbon footprint of the plastic industry and limit pollution.
The team of researchers who developed the enzyme believes it could be used to clean up sites contaminated by plastic pollution, as it can decompose within a week and, in some circumstances, within 24 hours.
Chemical engineer Al Alper, director of the research, believes that the possibilities of using this process are endless, regardless of the type of industry involved, because this technique would allow companies to reduce their waste and at the same time anticipate and implement an in-house recycling process without having to resort to external service providers and transport to recycling sites.
The FAST-PETase enzyme was created by taking a naturally occurring PET-degrading enzyme and modifying it through machine learning to act on five mutations that allow it to break down plastic more quickly. The researchers were then able to repolymerize the plastic through chemical reactions to allow the creation of new products.
The feasibility of the process was verified by testing 51 post-use consumer plastic containers, five different polyester fibers, PET and water bottles. The FAST-PETase enzyme was found to be effective with temperatures below 50˚C, which Al Alper says is a definite advantage because the enzyme can be used at room temperature, especially outdoors at polluted sites.
Currently, the solutions to reduce the plastic stockpile are landfilling, with a long decomposition time, or burning which is expensive and harmful to health and the environment. The use of such an enzyme, adaptable to different industries, according to the researchers, would be an environmental and technological breakthrough because it combines processes from artificial intelligence with machine learning, synthetic biology and chemistry.