TAMPA, Fla. – It started as a study intended to gain a greater understanding of how a newly discovered enzyme evolved from breaking down natural products to man-made materials. But through this research, scientists unintentionally mutated the enzyme, strengthening its ability to degrade polyethylene terephthalate (PET), commonly found in plastics. This conclusion published in theProceedings of the National Academy of Sciences (PNAS) follows computational modeling conducted at the University of South Florida (USF) in Tampa.
“We used our computer models to see how PETase ‘bites’ on plastic pieces,” said co-author H. Lee Woodcock, PhD, associate professor of chemistry at USF. “It’s like seeing for the first time how scissors cut paper, but the ‘scissors’ are a biological enzyme and the ‘paper’ is the billions of tons of plastic circulating for hundreds of years in the environment. From modeling the engineered PETase enzyme, we found it’s like having sharper scissors, giving us hope.”
The enzyme PETase was isolated from a bacterium found in a Japanese recycling plant in 2016. After its discovery, researchers at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL), the University of Portsmouth and USF led a joint interdisciplinary effort to understand how PETase works. During their investigation, they inadvertently improved the activity of PETse and USF led the charge in better understanding this improved activity.
Biochemistry is truly amazing. What we are talking about here is the need to break one really strong molecular bond in the plastic polymer, now with PETase we can do that," said co-author USF graduate student Fiona Kearns. "It's been an honor to be some of the first people to understand this incredible enzyme. When we look at this enzyme, we're looking at the future of plastic recycling."
"Being from the beautiful Pacific Northwest, growing up with the mountains and forests, I have a special affinity for the environment,” said co-author USF graduate student Ben Pollard. “With this research, we are saving the environment with biology and that’s really special to me.”
Pollard will help further improve the enzyme and target other plastics through his upcoming fellowship with NREL. He, Dr. Woodcock and their colleagues are confident PETase could eventually be used to completely recycle plastics, helping reduce our dependence on petroleum, which is currently required to create new plastics.