Here we go. I read this book in the 70s.

«The breakthrough, spurred by the discovery of plastic-eating bugs at a Japanese dump, could help solve the global plastic pollution crisis»

Source: https://www.theguardian.com/environment/2018/apr/16/scientists-accidentally-create-mutant-enzyme-that-eats-plastic-bottles

https://www.goodreads.com/book/show/2368220.Mutant_59