JUL 10, 2018 2:48 PM PDT

Newly Found Enzyme can Help Turn Plant Waste to Plastic

WRITTEN BY: Carmen Leitch

As the amount of trash in the world grows, scientists are searching for innovative ways to get rid of it. Now, researchers have discovered a family of enzymes that can open up new avenues for converting plant waste into desirable products like nylon, fuel or plastics. This team has already announced the improvement of an enzyme that can break down plastic and may help us find environmentally-friendly ways to dispose of plastic trash; that research is described in the video. 

These enzymes can work to degrade lignin, a primary part of plants that scientists have been trying to efficiently digest for a long time. In nature, the molecule acts as a scaffold, helps defend against pathogens, and aids in water distribution. The findings have been reported in the journal Nature Communications by a team of researchers including Professor John McGeehan of the University of Portsmouth, Dr. Gregg Beckham of the US Department of Energy's National Renewable Energy Laboratory (NREL) and others. The researchers have expertise in a variety of fields including synthetic biology, quantum chemistry, and molecular dynamics.
"We have assembled an international team for the discovery and engineering of naturally occurring enzymes. Enzymes are biological catalysts that can perform incredible reactions, breaking down some of our toughest natural and man-made polymers,” explained Professor McGeehan, Director of the Institute of Biological and Biomedical Sciences in the School of Biological Sciences at Portsmouth.

"To protect their sugar-containing cellulose, plants have evolved a fascinatingly complicated material called lignin that only a small selection of fungi and bacteria can tackle. However, lignin represents a vast potential source of sustainable chemicals, so if we can find a way to extract and use those building blocks, we can create great things,” he added.

The team broke through a bottleneck in the lignin-degradation process. Now, it can be used to make new stuff. "It's an amazing material," McGeehan said, "cellulose and lignin are among the most abundant biopolymers on earth. The success of plants is largely due to the clever mixture of these polymers to create lignocellulose, a material that is challenging to digest."

Building block of plants: Lignin is seen here stained red in a cross-section of plant cells from an oak tree. / Credit: Berkshire Community College Bioscience Image Library

This enzyme family may help us break our dependence on fossil fuels by providing a new way to make consumables. 

"There is a long-standing phrase - you can make anything out of lignin except money - but by harnessing the power of enzymes, this is set to change. Using advanced techniques, from X-ray crystallography at the Diamond Light Source synchrotron to advanced computer modeling, we have been able to understand the detailed workings of a brand new enzyme system,” said first author Sam Mallinson, a graduate student in structural biology at the University of Portsmouth.

This new enzyme isn’t picky; it has the ability to work on many different chemicals, making it a ‘promiscuous’ enzyme.

"This new cytochrome P450 enzyme can degrade a lot of different lignin-based substrates. That's good because it means it can then be engineered to be a specialist for a specific molecule and we can evolve it further to push it in a certain direction,” Beckham noted. "We now have one of the most well-known, versatile, engineerable and evolvable classes of enzymes ready to go as a foothold for biotechnology to move forward and make the enzyme better."


Sources: AAAS/Eurekalert! Via University of Portsmouth, Nature Communications

About the Author
Bachelor's (BA/BS/Other)
Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
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