Can a plastic-devouring super-enzyme eat one of the planet’s biggest problems for breakfast?
The evidence is undeniable and ever-mounting: plastic waste is a major threat to the planet. As the pressure to find creative solutions has increased over the past decade, research dollars from companies and research institutions have mounted as well. From bots crawling along the seafloor collecting waste to biodegradable packaging made from plants, unique approaches to the problem have emerged, each a small but significant step in the fight for sustainability. Now, a team at The University of Texas at Austin is making waves with an important discovery that could change the future of plastic–and recycling–altogether.
In April of 2022, a research group led by Dr. Hal Alper published an article in the journal Nature. Their discovery: an enzyme variant that changes the breakdown time of common plastics found in consumer products like food and beverage packaging, carpet, and textiles as well as materials used in life sciences, reducing it from centuries to 24 hours.
Plastics breakdown time-lapse courtesy of The University of Texas at Austin
The lab’s findings were the result of a highly collaborative approach to a completely different original challenge: sustainable solutions for biomanufacturing. The team–with backgrounds in synthetic biology, chemical engineering, and artificial intelligence–was particularly interested in the problem of engineering-produced polyethylene terephthalate (PET) waste. Compared to microorganisms, plastic is extremely new, so they looked to biology for answers. After Alper’s team observed that some organisms can slowly colonize on plastic and dismantle it, their research revealed the function to be driven by enzymes.
Armed with their discovery, Alper and team turned to machine-learning algorithms to identify enzymes with desirable properties and eventually used their findings to create a functional, active, stable, and tolerant PETase compound, or FAST-PETase. A super-enzyme with the power to completely reuse plastic waste already in the environment, Alper compares its mechanism to deconstructing a necklace made from a heap of beads. The enzyme acts as a pair of scissors, releasing plastic monomers from their chain structure and returning them to a heap. The monomers themselves are unchanged and can be used again, in another plastic polymer chain. The enzyme is “extraordinarily active and outpaces pretty much everything out there,” Alper says. “It degrades pretty much every post-consumer PET plastic waste we throw at it.”
The enzyme separates different strings of polymers rather than melting and mixing all types together as in traditional recycling, resulting in a technically reused material identical to the original. Highly malleable, it is essentially virgin PET. “We're able to regenerate that same performance it had from the beginning,” Alper says. “You can break it back down, build it back up, and you have that original single use element once again.”
Alper points out that FAST-PETase also eliminates a major conundrum in environmental clean-up: temperature. The current industrial processes used to break down plastic generate extremely high temperatures and use a lot of energy, actually contributing to global warming. With Alper’s enzyme, plastic only needs to be melted in an ambient temperature for activation, tackling one environmental issue without exacerbating another. “This requirement is where our tech has a huge advantage in the future,” he says.
For the team, that future includes the challenges of scaling up as well as studying the enzyme’s effect on other types of plastics. Multiple-stream products that combine different polymers will be most challenging, as each “layer” has its own properties and structures that degrade differently. Whatever comes next, Alper is committed to applying the PET-eating enzyme to increasingly complex plastic waste products, progressing towards the goal of a truly circular plastic economy.
In January, Cytiva donated $50 000 to The University of Texas at Austin and the Laboratory for Cellular and Metabolic Engineering group headed up by Dr Hal Alper to support this research into the enzymatic degradation of polyethylene terephthalate (PET) plastics. Our commitment to sustainability and funding academia research was well matched with his team’s efforts.
Tune in to the Discovery Matters podcast for a deep dive with Dr. Alper on this important discovery and what it means for sustainability in the race against time.