Miracle Solutions and Healthy Skepticism - Don Loepp
I've seen some promising headlines lately for technologies that hint at miracle solutions for the plastics industries' solid waste woes.
But I can't help but pick them apart. I'm afraid that hype can mask some pretty significant question marks. For example, this week's story that scientists at the U.S. Department of Energy's National Renewable Energy Laboratory and the University of Portsmouth have tweaked a bacterium's enzyme to improve its ability to degrade PET.
The media reaction to this was amazingly positive. Maybe it was a response to all the negative headlines about plastics centered around Earth Day. This had both a "science saves the day" and a "man bites dog" angle.
Most of the headlines were similar to this one from CNN.com: "Scientists hope new enzyme will 'eat' plastic pollution." That story, and many others, made a connection between the enzyme and plastics marine pollution.
But hold on. No one is suggesting that scientists release huge quantities of the mutant enzyme into the world's oceans to clean up the Great Pacific Garbage Patch.
The researchers don't want that at all.
"All scientists should be hesitant to introduce foreign organisms into the environment; there would be big problems for ecosystems," H. Lee Woodcock, an associate professor at the University of South Florida, told Plastics News' Michael Lauzon.
Don't get me wrong: Having an enzyme that can degrade PET into terephthalic acid and ethylene glycol is potentially great. There are several well-known methods for breaking down PET into monomers, but they're expensive because they require a lot of energy. This could be a lower-cost way to recycle PET back into brand-new, virgin-quality resin.
But let's keep this in mind: The big issue with PET recycling isn't a technological barrier or even a litter problem.
PET bottles are easy to recycle, and there's a big market for them — never mind what you've heard about China's National Fence.
The big problem with PET bottles is that people don't put them all in their recycling bins. And fortunately for us, we know how to solve the problem because there are systems set up all over the world that work. They're called bottle deposits.
That said, if the researchers who harnessed Ideonella sakaiensis can teach it to degrade other sorts of harder-to-recycle plastics, that could be a real breakthrough. It would be a huge plus if it could break down a batch of mixed plastics, including multilayer films and pouches. Those are the real recycling headaches.
The ultimate goal should be a technology that will allow consumers to recycle all plastics. I hope this is a big step on that path.
Disclaimer: Echemi reserves the right of final explanation and revision for all the information.