If you read carefully, they're conceiving of an enzyme that works above 158º that will provide more like-to-like plastic compatibility and speed up the recycling process. This enzyme is not going to eat your car or your plastic body parts! It's also not something you can plop in the ocean to eliminate the 2x-Texas-sized garbage dump: (https://www.usatoday.com/story/tech/science/2018/03/22/great-pacific-garbage-patch-grows/446405002/)

Like irresponsible children we made a big mess and this IS commendable progress, I suppose, but it will likely take millions of years for planet Earth to fully recover from human nescience.