Briefing

An inadvertently-engineered creation discovered by US Department of Energy’s National Renewable Energy Laboratory (NREL) and the UK’s University of Portsmouth may offer a vital solution to the problem of plastic pollution.

The PET-digesting enzyme Ideonella sakaiensis, also known as PETase, was first discovered in 2016 by Yoshida et al., who found the bacterium living in the soil at a recycling plant in Japan that was piled with used bottles. This bacterium was unique as it could use polyethylene terephthalate (PET) as its major carbon and energy source. In other words, these bacteria can simply feed on plastic used to make disposable beverage bottles for survival and growth.

With this discovery, NREL and the University of Portsmouth dedicated a research team to determine the enzyme’s structure. While conducting the research, the team inadvertently created a mutant PETase. “We hoped to determine its structure to aid in protein engineering, but we ended up going a step further and accidentally engineered an enzyme with improved performance at breaking down these plastics,” explained the research team in NREL’s statement.

As compared to the original enzyme, the mutant’s appetite has dramatically increased and the process of feeding has accelerated.

Not only is this new creation more effective than PETase, the differentiating feature lies in its ability to consume another type of plastic, polyethylene furandicarboxylate (PEF). “It is literally drilling holes through the PEF sample. This shows that by using PETase, PEF is even more biodegradable than PET,” said NREL’s Gregg Beckham, one of the leading researchers. This new creation opens a new door to combating the huge quantities of plastic waste entering landfills and accumulating in the ocean.

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