title: Effect of Tris, MOPS, and phosphate buffers on the hydrolysis of polyethylene terephthalate films by polyester hydrolases.
abstract: The enzymatic degradation of polyethylene terephthalate (PET) occurs at mild reaction conditions and may find applications in environmentally friendly plastic waste recycling processes. The hydrolytic activity of the homologous polyester hydrolases LC cutinase (LCC) from a compost metagenome and TfCut2 from Thermobifida fusca KW3 against PET films was strongly influenced by the reaction medium buffers tris(hydroxymethyl)aminomethane (Tris), 3-(N-morpholino)propanesulfonic acid (MOPS), and sodium phosphate. LCC showed the highest initial hydrolysis rate of PET films in 0.2 m Tris, while the rate of TfCut2 was 2.1-fold lower at this buffer concentration. At a Tris concentration of 1 m, the hydrolysis rate of LCC decreased by more than 90% and of TfCut2 by about 80%. In 0.2 m MOPS or sodium phosphate buffer, no significant differences in the maximum initial hydrolysis rates of PET films by both enzymes were detected. When the concentration of MOPS was increased to 1 m, the hydrolysis rate of LCC decreased by about 90%. The activity of TfCut2 remained low compared to the increasing hydrolysis rates observed at higher concentrations of sodium phosphate buffer. In contrast, the activity of LCC did not change at different concentrations of this buffer. An inhibition study suggested a competitive inhibition of TfCut2 and LCC by Tris and MOPS. Molecular docking showed that Tris and MOPS interfered with the binding of the polymeric substrate in a groove located at the protein surface. A comparison of the K i values and the average binding energies indicated MOPS as the stronger inhibitor of the both enzymes.
authors.affiliation: Department of Microbiology and Bioprocess Technology Institute of Biochemistry Leipzig University Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: Schmidt
authors.affiliation: Department of Microbiology and Bioprocess Technology Institute of Biochemistry Leipzig University Germany.
authors.forename: Ren
authors.initials: R
authors.lastname: Wei
authors.affiliation: Department of Microbiology and Bioprocess Technology Institute of Biochemistry Leipzig University Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Oeser
authors.affiliation: Department of Microbiology and Bioprocess Technology Institute of Biochemistry Leipzig University Germany.
authors.forename: Matheus Regis
authors.initials: MR
authors.lastname: Belisário-Ferrari
authors.affiliation: Department of Microbiology and Bioprocess Technology Institute of Biochemistry Leipzig University Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Barth
authors.affiliation: Department of Microbiology and Bioprocess Technology Institute of Biochemistry Leipzig University Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Then
authors.affiliation: Department of Microbiology and Bioprocess Technology Institute of Biochemistry Leipzig University Germany.
authors.forename: Wolfgang
authors.identifier: 0000-0002-5730-6663
authors.initials: W
authors.lastname: Zimmermann
keywords: 3‐(N‐morpholino)propanesulfonic acid; Tris; biocatalysis; inhibition; polyester hydrolase; polyethylene terephthalate