Two years ago, Japanese scientists made headlines when they announced they had found a bacteria capable of eating polyethylene terephthalate (PET). And now, there are more breakthroughs to report.
At the time, this was a major discovery. Previously, some fungi had been found that can break down PET, but bacteria are much easier than fungi to use in industrial applications. After two years, how close are we to actually seeing this bacteria used to recycle our plastics? Scientists have been hard at work with this bacteria and its enzymes to figure out how to speed up the process, since it was far too slow for any bio-recycling application — that is, using some type of biological element, such as bacteria and enzymes, to break down waste.
Commercial Application of Bacteria
Bio-recycling is the process by which plant and food waste is turned into compost; however, in this specific application, it’s plastic that is broken down into its basic chemicals. As teams from the U.S., UK, Brazil, Korea and China published and shared their research, they’ve made a couple of important discoveries.
The first is the protein in the enzymes works particularly well at 30 degrees Celsius (86 degrees Fahrenheit), perfect for a bio-recycling application. The second discovery is that by making slight modifications to the enzymes’ chemical properties, scientists were able to make modest improvements in how quickly the enzyme broke down PET. Why are these discoveries important? Well, if scientists can accelerate the process of breakdown, this could become a profitable way to recycle plastics, something that is actually getting more challenging in the U.S. right now.
Other enzymes are already used in industrial applications, such as in the production of biofuels, an article in The Guardian noted. After considerable work from scientists, these enzymes now work up to 1,000 times faster than they used to. Hopefully, over the next few years, researchers will make similar progress with this bacteria. If they do, we could see our first bio-recycling facility that recycles plastics.
How It Works
Most PET bottles, when recycled, are turned into fibers for clothing or other textiles. Recently, a few companies have started recycling PET back into plastic bottles, which is an improvement.
By using bacteria in the recycling process, rather than shredding PET into flakes, the bacteria will actually break down the PET back into its chemicals. Those chemicals can then be used to create all-new plastic bottles. This would be complete, end-to-end recycling.
This bacteria produces two enzymes when it’s in an environment surrounded by PET. Scientists were able to find the gene in the bacteria DNA that controls the production of the enzymes. With that information, they were then able to manufacture the enzymes without the bacteria and show that it could break down PET.
Future Implications
While the discovery of this bacteria and its enzymes, along with the progress in optimizing its breakdown capabilities, is fantastic, we should still continue to reduce our own consumption of plastic.
This is particularly important right now, as the recycling industry is in the midst of some major changes. As China limits what materials can be imported, we’re seeing a reduction in recycling options here in the U.S. While we’ll find solutions in the long run — such as this bacteria — the next few years may be challenging as cities try to adapt to restricted recycling options.