Last month, I wrote about the fingerprint-like uniqueness of the gut microbiome and an episode of the TV series Scorpion in which one character’s gut flora saved the day. Coincidentally, the topic I chose for this month’s editorial — plastic waste — was the subject of another Scorpion episode.
In the Critical Issues article on pp. 22–29, Jeffrey Seay and his coauthors discuss some of the issues the chemical process industries (CPI) and society face with regard to waste plastic. They explain that a major hurdle to creating a circular plastics economy is the huge number of plastics formulations on the market — literally thousands, each with a unique, often proprietary, blend of additives, which makes sorting, separating, and recycling them challenging.
In the Scorpion episode, the National Oceanic and Atmospheric Administration (NOAA) hired the team of geniuses to clean up the Great Pacific Garbage Patch. Their plan was to spray a binding agent onto the floating trash to harden it into a solid mass that they could walk on, and then scatter waxworms across the garbage, “because they can eat and digest plastic, rendering it nontoxic.”
The ability of worms to biodegrade plastics was discovered several years ago by accident. Federica Bertocchini, a research scientist at the Spanish National Research Council and an amateur beekeeper, noticed that honeycomb panels stored in her house were covered with worms that were eating the leftover honey and wax from her bees. She removed the worms and put them in a plastic bag. After she finished cleaning the panels, she returned to the room where she had left the worms, and “they were everywhere. They had escaped from the bag even though it was closed … the bag was full of holes.” In subsequent experiments, about a hundred waxworms were exposed to a plastic bag from a supermarket; holes started to appear after 40 minutes, and after 12 hr the bag’s mass was reduced by 92 mg. And, the waxworms did not just ingest the plastic — they also chemically transformed the polyethylene into ethylene glycol.
Engineers at Stanford have found that mealworms can subsist on a diet of polystyrene, including Styrofoam, which is difficult to decompose because of its molecular structure. The mealworms each ate 34–39 mg of Styrofoam per day, converting about half of it into carbon dioxide (as they would any food) and, within 24 hr, excreting the bulk of the remaining plastic as biodegraded fragments that look like tiny rabbit droppings. In more recent tests, mealworms successfully digested Styrofoam that contained the flame retardant hexabromocyclododecane (HBCD).
But cultivating massive amounts of such plastic-eating worms is likely not a viable solution to our plastic woes. Addressing our plastic waste problem will require action by all of us. Producers will need to design for circularity, researchers must develop new and innovative recycling technologies and biobased/biodegradable plastic blends, and governments must create science-based and forward-thinking policies. Consumers will need to drive these changes by demanding recycled plastics in our packaging, making compromises regarding the types and formulations of plastics that are available to us, and rethinking our relationship with single-use plastics.
Cynthia F. Mascone, Editor-in-Chief
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