Environmental Question #28 [Plastic Eating Microbes]

What do you think about those plastic eating microbes? Can they actually break down plastic, and are the broken down compounds safe? 

Courtesy of Reddit user u/nifsea

Q: What do you think about those plastic eating microbes? Can they actually break down plastic, and are the broken down compounds safe? 

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A:  Plastic digesting microbes might be part of a much broader solution someday, but they won't even come close to solving the whole problem. Honestly it bothers me how sensationalist the headlines surrounding that research is, because while the new microbes are an interesting discovery, they are only capable of digesting one kind of plastic--polyester. The reason why the articles bother me is because they take advantage of the misconception that plastic is just one thing. There are dozens of types of commonly used plastic, and polyester is just one of them. Polyester makes up a sizeable chunk of all plastic waste, so this is nothing to sneeze at, but it is also one of the easiest conventional plastics to digest. Most non-polyester plastics are chemically bonded in such a way that it makes them practically impossible to break down via digestion, so microbes are very unlikely to be the solution to the whole plastic waste problem. The benefit of pyrolysis (which I discuss in the Q&A linked here) is that it's a one-size-fits all solution that works for any plastic, although it is also very expensive. Most likely a complete solution would involve some combination of microbial digestion, pyrolysis, and other solutions that are still under development.

To your question about the safety of microbially degraded polyester, the resulting products are mildly toxic, but I'm not particularly concerned about that part. The microbes used for this are genetically engineered for this purpose anyway, so it isn't hard to imagine that the researchers involved in this work will continue to refine their microbe design so that the digestion products are no longer toxic.