There's a good chance that sometime in the last 24 hours, you've had a drink from a plastic bottle. If you live in the USA, there's about a 31% chance you recycled it (50% if you're in Europe).
Chances are, you've also heard the horror stories about where all those un-recycled bottles are ending up.
Absent a medical miracle, you and I will have departed this Earth within 100 years, and absent another scientific breakthrough, all of those plastic bottles will still be here, creating an even bigger environmental nightmare. The problem has become so bad, it's reported that there are now islands of plastic garbage floating in the world's oceans.
I'm not aware of any breakthroughs to extend human life, but a game-changing solution for plastic bottles may be just around the corner, thanks to an important discovery that was recently reported by Professor John McGeehan at the University of Portsmouth and Dr. Gregg Beckham at the US Department of Energy's National Renewal Energy Laboratory. The researchers have found an enzyme that digests PET – polyethylene terephthalate – a plastic that was first developed, and patented, in the 1940's.
The average consumer will recognize it by the triangle with a number one in it. Broadly speaking, there are seven different types of plastic. PET represents about 8% of worldwide plastic. It is commonly referred to as polyester, and is often found in textiles, some clothing, and some types of packaging. Because PET has excellent water repelling properties, it's a great for packaging soft drinks and water. There's a good chance you've got it on the floor of your home or office, your clothes closet, and even in your refrigerator.
While PET was first developed only about 70 years ago, and wasn't widely used in drinks packaging until the 1970's, evolution has already produced a bacterium that eats PET as food. The bacterium – named Ideonella sakaiensis 201-F6 – was first discovered at a PET industrial recycling facility in Sakai, Japan. The bacterium has developed the amazing ability to break down PET and use it to provide carbon for energy. The reason the bacterium could do this, the researchers found, was because it contained a PET-digesting enzyme named PETase. When you think about it, it's pretty amazing that the PETase enzyme was able to evolve so quickly to develop the capacity to convert PET plastic into energy!
The researchers didn't discover either the bacterium or the PETase enzyme. That was done by other researchers at the Kyoto Institute of Technology and Keio University in Japan.
Professors McGeehan and Beckham built upon the research done in Japan by gaining an understanding of the structure of PETase. They were able to determine the crystal structure of the enzyme using what's called the Long Wavelength Macromolecular Crystallography beamline at a place called Diamond Light Source. It's the only device of its kind in the world.
The researchers were able to get PETase to degrade commercial PET bottles. They also found that PETase was able to degrade another plastic called PEF, a new type of plastic. The nice thing about PEF is that it is bio-based, as opposed to being a petroleum derivative, as are PET and most other plastics. Thus it appears the PETase enzyme will be capable of degrading both traditional PET as well as bio-based PEF.
But in the course of their research, they actually found a way to improve the capacity of PETase to gobble up PET. The researchers acknowledged that their improvement was somewhat serendipitious, but who cares? The end result is a more capable enzyme.
What McGeehan and Beckham have come up with isn't really a solution, at least not yet. That's because, as previously noted, PET represents only about 8% of all plastic. Even if all PET can be recycled using the new process, that still leaves the other 92% of plastic still piling up around the world.
Not only that, but there isn't yet a commercial way to put the PETase to work. It's probably going to take some time for the researchers to come up with a way for the PETase enzyme to gobble up industrial quantities of PET bottles and other forms of PET waste.
But think of the possibilities? The researchers have demonstrated the capacity to improve the digesting capabilities of PETase. They'll likely continue making improvements; and if fortune truly shines, they'll develop a Moore's Law-like improvement in the process, thus truly creating the potential to recycle huge amounts of PET, and PEF when the latter gains commercial scale.
It could be a blessing. But like many blessings, there are some potential downsides. You really don't want to let plastic eating enzymes get into the wrong hands. I can envision the next big prank: putting PETase on your friend's polyester pants or sweater. The clothes you thought you were wearing suddenly start disappearing! Or how about coating it on some other PET surface and watching the surface disappear?
On the positive side, it creates the potential for an entirely new industry - large scale elimination of plastic waste. Recycling is already a pretty big business, but commercialization of the PETase process could dramatically change the environment by providing a way to deal with the 70% of PET containers in the USA - and 50% in Europe - that don't presently get recycled.
Once again, however, don't start celebrating quite yet. That's because even if and when a commercially viable process is developed to get PETase to ingest huge amount of PET waste, there's still the problem of getting the un-recycled waste from the consumer to the PETase "factory".
Someone will have to come up with a viable way to get that "other 70%" recycled, otherwise we'll still have mountains of waste. While people profess a desire to recycle plastic waste, the actual results fall far short of an ideal solution. So even if PETase can be commercialized, that doesn't mean the amount of plastic refuse will decrease much. Needless to say, that requires something other than a scientific or technological breakthrough.
Recycling has always depended upon getting people either to separate out recyclable items and/or to take them to a special location. Some people do, and some people don't. Even then, sometimes it's just hard to recycle.
So why not turn the entire model around? Instead of asking people to take their waste to a recycling center, why not bring the recycling center to them? The new discovery about PETase creates the potential for portable, personal PET recycling. Why not create a consumer-sized box filled with PETase? Just put your PET bottles in the unit and let the PETase feast on the waste? Make it easy! Commercial and industrial sized units could also be built to handle larger quantities.
And then there's still the problem of the "islands of plastic" in the ocean. Someone needs to develop a "floating factory". That may sound crazy, but not that crazy. After all, just as there are "factory ships" that do industrial scale fishing on the high seas, why not a ffloating recycling ship filled with PETase? The PETase could feast upon the plastic waste, then turn the waste into energy that could be sold back on land. If the economics work out, there's a potential new business.
Crazy? Maybe so. The more important question though is, is it crazy enough? What the scientists have come up with is certainly a promising first step, so now they need to take the next step and create both a solution to the "islands of plastic" nightmare, as well as a business of the future.
