334
views
1
recommends
+1 Recommend
0 collections
    9
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Characterization and engineering of a plastic-degrading aromatic polyesterase

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Significance

          Synthetic polymers are ubiquitous in the modern world but pose a global environmental problem. While plastics such as poly(ethylene terephthalate) (PET) are highly versatile, their resistance to natural degradation presents a serious, growing risk to fauna and flora, particularly in marine environments. Here, we have characterized the 3D structure of a newly discovered enzyme that can digest highly crystalline PET, the primary material used in the manufacture of single-use plastic beverage bottles, in some clothing, and in carpets. We engineer this enzyme for improved PET degradation capacity and further demonstrate that it can also degrade an important PET replacement, polyethylene-2,5-furandicarboxylate, providing new opportunities for biobased plastics recycling.

          Abstract

          Poly(ethylene terephthalate) (PET) is one of the most abundantly produced synthetic polymers and is accumulating in the environment at a staggering rate as discarded packaging and textiles. The properties that make PET so useful also endow it with an alarming resistance to biodegradation, likely lasting centuries in the environment. Our collective reliance on PET and other plastics means that this buildup will continue unless solutions are found. Recently, a newly discovered bacterium, Ideonella sakaiensis 201-F6, was shown to exhibit the rare ability to grow on PET as a major carbon and energy source. Central to its PET biodegradation capability is a secreted PETase (PET-digesting enzyme). Here, we present a 0.92 Å resolution X-ray crystal structure of PETase, which reveals features common to both cutinases and lipases. PETase retains the ancestral α/β-hydrolase fold but exhibits a more open active-site cleft than homologous cutinases. By narrowing the binding cleft via mutation of two active-site residues to conserved amino acids in cutinases, we surprisingly observe improved PET degradation, suggesting that PETase is not fully optimized for crystalline PET degradation, despite presumably evolving in a PET-rich environment. Additionally, we show that PETase degrades another semiaromatic polyester, polyethylene-2,5-furandicarboxylate (PEF), which is an emerging, bioderived PET replacement with improved barrier properties. In contrast, PETase does not degrade aliphatic polyesters, suggesting that it is generally an aromatic polyesterase. These findings suggest that additional protein engineering to increase PETase performance is realistic and highlight the need for further developments of structure/activity relationships for biodegradation of synthetic polyesters.

          Related collections

          Most cited references57

          • Record: found
          • Abstract: not found
          • Article: not found

          Polylactic Acid Technology

            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            A microbial polyhydroxyalkanoates (PHA) based bio- and materials industry.

            Biopolyesters polyhydroxyalkanoates (PHA) produced by many bacteria have been investigated by microbiologists, molecular biologists, biochemists, chemical engineers, chemists, polymer experts and medical researchers. PHA applications as bioplastics, fine chemicals, implant biomaterials, medicines and biofuels have been developed and are covered in this critical review. Companies have been established or involved in PHA related R&D as well as large scale production. Recently, bacterial PHA synthesis has been found to be useful for improving robustness of industrial microorganisms and regulating bacterial metabolism, leading to yield improvement on some fermentation products. In addition, amphiphilic proteins related to PHA synthesis including PhaP, PhaZ or PhaC have been found to be useful for achieving protein purification and even specific drug targeting. It has become clear that PHA and its related technologies are forming an industrial value chain ranging from fermentation, materials, energy to medical fields (142 references).
              Bookmark
              • Record: found
              • Abstract: not found
              • Article: not found

              Fungal cellulases.

                Bookmark

                Author and article information

                Journal
                Proc Natl Acad Sci U S A
                Proc. Natl. Acad. Sci. U.S.A
                pnas
                pnas
                PNAS
                Proceedings of the National Academy of Sciences of the United States of America
                National Academy of Sciences
                0027-8424
                1091-6490
                8 May 2018
                17 April 2018
                17 April 2018
                : 115
                : 19
                : E4350-E4357
                Affiliations
                [1] aMolecular Biophysics Laboratories, School of Biological Sciences, Institute of Biological and Biomedical Sciences, University of Portsmouth , Portsmouth PO1 2DY, United Kingdom;
                [2] bBiosciences Center, National Renewable Energy Laboratory , Golden, CO 80401;
                [3] cNational Bioenergy Center, National Renewable Energy Laboratory , Golden, CO 80401;
                [4] dDepartment of Chemistry, University of South Florida , Tampa, FL 33620-5250;
                [5] eInstitute of Chemistry, University of Campinas , Campinas, 13083-970 Sao Paulo, Brazil;
                [6] fDiamond Light Source , Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
                Author notes
                2To whom correspondence may be addressed. Email: hlw@ 123456mail.usf.edu , john.mcgeehan@ 123456port.ac.uk , or gregg.beckham@ 123456nrel.gov .

                Edited by Alexis T. Bell, University of California, Berkeley, CA, and approved March 28, 2018 (received for review October 29, 2017)

                Author contributions: J.E.M. and G.T.B. designed research; H.P.A., M.D.A., B.S.D., N.A.R., F.L.K., R.L.S., B.C.P., G.D., R.D., K.E.O., V.M., A.W., W.E.M., A.A., A.W.T., C.W.J., and H.L.W. performed research; H.P.A., M.D.A., B.S.D., N.A.R., F.L.K., R.L.S., B.C.P., G.D., R.D., K.E.O., V.M., A.W., W.E.M., A.A., M.S.S., M.F.C., A.W.T., C.W.J., H.L.W., J.E.M., and G.T.B. analyzed data; and J.E.M. and G.T.B. wrote the paper with contributions from all authors.

                1H.P.A., M.D.A., B.S.D., N.A.R., and F.L.K. contributed equally to this work.

                Author information
                http://orcid.org/0000-0002-2272-5059
                http://orcid.org/0000-0002-3566-8698
                http://orcid.org/0000-0001-8995-7324
                http://orcid.org/0000-0002-6750-1462
                http://orcid.org/0000-0002-3480-212X
                Article
                201718804
                10.1073/pnas.1718804115
                5948967
                29666242
                d2ae8ce5-04eb-4eb5-9e2f-327a94dba828
                Copyright © 2018 the Author(s). Published by PNAS.

                This open access article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND).

                History
                Page count
                Pages: 8
                Funding
                Funded by: NREL
                Award ID: LDRD
                Funded by: BBSRC
                Award ID: BB/P011918/1
                Funded by: Sao Paulo Research Foundation
                Award ID: #2016/22956-7
                Funded by: US Department of Energy
                Award ID: DE-SC0011297TDD
                Categories
                PNAS Plus
                Biological Sciences
                Biochemistry
                PNAS Plus

                biodegradation,poly(ethylene terephthalate),poly(ethylene furanoate),plastics recycling,cutinase

                Comments

                Comment on this article