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NPE2018 Show Daily - Thursday

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THURSDAY N PE 2 018 M AY 10 TH Researchers Discover Plasঞc-Eaঞng Enzyme By Heather Caliendo Plascs Technology NREL's Bryon Donohoe and Nic Rorrer punch out coupon samples from a PET bole to test how effecঞvely the PETase enzyme digests plasঞc. They and Gregg Beckham are among the internaঞonal team of researchers who are working to fur- ther improve the enzyme to allow it to be used industrially to break down plasঞcs in a fracঞon of the ঞme. New research claims that an enzyme can break down ubiq- uitous plasঞc boles made of PET in what could eventually revoluঞonize recycling. This breakthrough in enzyme research was led by the U.S. Department of Energy's Naঞonal Renew- able Energy Laboratory (NREL) and the United Kingdom's Uni- versity of Portsmouth. While working to solve the crystal structure of PETase—a recently discovered enzyme that digests PET—the team inad- vertently engineered an enzyme to be even beer at degrad- ing the man-made substance. Although the improvement is modest, this unanঞcipated discovery suggests that there is much more room to further improve these enzymes, moving scienঞsts closer to solving the problem of an ever-growing amount of discarded plasঞcs, the researchers stated. The paper, "Characterizaঞon and engineering of a plas- ঞc-degrading aromaঞc polyesterase," was published in the Proceedings of the Naঞonal Academy of Sciences (PNAS). The lead authors from the research team—NREL's Gregg Beckham, University of Portsmouth's John McGeehan, and Lee Wood- cock from the University of South Florida—were aempঞng to understand how PETase evolved from likely working on natu- ral substances to digesঞng syntheঞc materials when the dis- covery was made. To begin experiments, the research team wanted to find out exactly how effecঞve PETase was at digesঞng PET. NREL Se- nior Scienঞst Bryon Donohoe and postdoctoral researcher Nic Rorrer tested PETase by taking samples of PET from the soda boles in Beckham's office and ran an experiment with PETase. "A[er just 96 hours you can see clearly via electron microscopy that the PETase is degrading PET," Donohoe says. "And this test is using real examples of what is found in the oceans and landfills." "We originally set out to determine how this enzyme evolved from breaking down cuঞn—the waxy substance on the surface of plants—with cuঞnase, to degrading syntheঞc PET with PETase," says Beckham. "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 plasঞcs. What we've learned is that PETase is not yet fully opঞmized to de- grade PET—and now that we've shown this, it's ঞme to apply the tools of protein engineering and evoluঞon to conঞnue to improve it." NREL and the University of Portsmouth collaborated close- ly with a mulঞdisciplinary research team at the Diamond Light Source in the UK, a large synchrotron that uses intense beams of X-rays 10 billion ঞmes brighter than the sun to act as a microscope powerful enough to see individual atoms. Using their beamline I23, an ultra-high-resoluঞon 3D model of the PETase enzyme was generated in a reported exquisite detail. With help from the computaঞonal modeling scienঞsts at the University of South Florida and the University of Campi- nas in Brazil, the team discovered that PETase looks very simi- lar to a cuঞnase, but it has some unusual surface features and a much more open acঞve site. These differences indicated that PETase must have evolved in a PET-containing environ- ment to enable the enzyme to degrade PET. To test that hy- pothesis, the researchers mutated the PETase acঞve site to make it more like a cuঞnase. And this is where the unexpected happened. "Surprisingly, we found that the PETase mutant outperforms the wild-type PETase in degrading PET," says Rorrer. "Understanding how PET binds in the PETase catalyঞc site using computaঞonal While working to solve the crystal structure of PETase—a recently dis- covered enzyme that digests PET— the team inadvertently engineered an enzyme to be even beer at degrading the man-made substance. tools helped illuminate the reasons for this improved performance. Given these results, it's clear that significant potenঞal remains for im- proving its acঞvity further." Another significant aspect of the research: the discovery that PETase can also degrade polyethylene furandicarboxylate, or PEF, a bio- based subsঞtute for PET plasঞcs. The en- hanced oxygen barrier properঞes of PEF could lead to its widespread use in boles, the re- searchers stated. The team's goal is to use their findings to conঞnue to improve the new enzymes to break down these plasঞcs, but in a fracঞon of the ঞme. 81 A M E R I M O L D E X P O . C O M REGISTER NOW! PRESENTED BY: BUSINESS DEVELOPMENT OPPORTUNITIES for mold builders and mold buyers EXHIBIT HALL featuring machine tools, mold components, tooling, materials, software, more AMERIMOLD TECH TALKS on designing, machining, maintaining molds BOOTH SALES ARE OPEN Sales@amerimold.com CO-LOCATED WITH: Novi, MI | June 13-14, 2018 OVER MOLDING COMPOSITES

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