Can Serendipitous Discoveries Save Mankind from Itself? The Case of Plastic-Digesting Enzymes and Bacteria

As a further chapter in my occasional highlight of serendipitous discoveries, teams of scientists from the UK and the U.S. discovered and evolved in Japan an enzyme that can degrade plastic by assisting a bacterium with digesting PET plastics. Ongoing further research promises to put a relatively cheap end to worldwide plastic pollution by recycling it sustainably. As it stands today, PET plastics can survive hundreds of years in the environment and have turned into an increasingly serious and mushrooming burden to major countries and large oceanic regions. Researchers from the University of Portsmouth, UK and the Renewable Energy Laboratory at the U.S. Department of Energy have now discovered, and published in PNAS, a potential solution to this blight by studying and tuning the structure of a natural enzyme that developed on its own in a Japanese waste recycling center. Initial research found that the PETase enzyme assists a bacterium, Ideonella sakaiensis 201-F6, with breaking down or digesting PET plastics. The enzyme structure was then optimized by bioengineering by adding some amino acids. This optimization process resulted in random changes to PETase’s activities and ultimately indeed an altered enzyme that turned out to be significantly more effective than its natural form. The same team now continues to explore the enzyme further to see if PET plastics can be degraded on an industrial scale, and if so, with what side effects. It is entirely possible, indeed likely, that the next few years will yield industrially viable processes to disassemble PET and possibly other plastics back into their original organic building blocks to set in motion a sustainable chain of recycling. Independent scientists not directly involved in this research consider this biodegradability approach clearly promising despite the obvious concerns that the development of the enzyme as possible solution against pollution is still at too early a stage to render a meaningful assessment possible. And that may well be true, but it is also secondary: enzymes are non-toxic, biodegradable and capable of being produced in large quantities by microorganisms, and there is great potential for using enzyme technology to solve society's growing waste and landfill problem by degrading at least some of today’s most commonly used plastics. Even as it may still be necessary to await further developments intended to improve the enzyme, this discovery brings sustainable recycling of plastics within striking distance.