Environmental-throttling plastics, typically required centuries to degrade in just a few hours to days, can be broken down by an enzyme sequence created by engineers and scientists at The University of Texas at Austin.
This breakthrough, published today in Nature, might help resolve one of the world''s most pressing environmental problems: what to do with the billions of tons of plastic waste piling up in landfills and polluting our natural lands and water. It has the potential to supercharge recycling on a large scale, which would allow major industries to reduce their environmental effects by recovering and reusing plastics at the molecular level.
According to Hal Alper, a professor at the McKetta Department of Chemical Engineering at UT Austin, the possibilities of leverage this leading-edge recycling process are endless. This also provides corporations from all sectors the opportunity to take a lead in recycling their goods. Through these more sustainable enzyme approaches, we can begin to envision a true circular plastics economy.
Polyethylene terephthalate (PET), a significant polymer found in most consumer goods, including cookie containers, soda bottles, fruit and salad packaging, and several fibers and textiles. It represents 12% of all global waste.
In some instances, the enzyme could complete a circular process of dividing down the plastic into smaller pieces (depolymerization) and then chemically putting it back together (repolymerization). In some cases, these plastics can be completely broken down to monomers in just 24 hours.
Researchers at the Cockrell School of Engineering and the College of Natural Sciences used a machine learning technique to develop novel mutations to a natural enzyme called PETase, which permits bacteria to degrade PET plastics. The study predicts which mutations in these enzymes would accomplish the goal of quickly depolymerizing post-consumer waste plastic at low temperatures.
The researchers demonstrated the effectiveness of the enzyme, which they call FAST-PETase (functional, active, stable, and tolerant PETase) through this process.
According to Andrew Ellington, a professor at the Center for Systems and Synthetic Biology, who led the development of the machine learning model, this study demonstrate the power of reuniting different disciplines, from synthetic biology to chemical engineering to artificial intelligence.
Recycling is the most promising method to reduce plastic waste. Yet worldwide, less than 10% of all plastic has been recycled. Unlike throwing it in a landfill, it is more costly and energy-intensive and sends harmful gases into the air. Other alternative industrial processes include very energy-intensive glycolysis and/or methanolysis.
Biological solutions consume much less energy. For example, research on enzymes for plastic recycling has increased in recent years. However, nobody had ever been able to determine how to make enzymes that would operate efficiently at low temperatures to be both portable and affordable at large industrial scale. FAST-PETase can perform the process at less than 50 degrees Celsius.
The team intends to expand enzyme production to prepare for an industrial and environmental application. The researchers have submitted a patent application for the technology and are employing several methods. However, environmental remediation is an important possibility.
An enzyme that can function in the environment at ambient temperatures is crucial to environmental cleanup practices, according to Alper.