title: Discovery of Polyesterases from Moss-Associated Microorganisms.
abstract: The growing pollution of the environment with plastic debris is a global threat which urgently requires biotechnological solutions. Enzymatic recycling not only prevents pollution but also would allow recovery of valuable building blocks. Therefore, we explored the existence of microbial polyesterases in microbial communities associated with the Sphagnum magellanicum moss, a key species within unexploited bog ecosystems. This resulted in the identification of six novel esterases, which were isolated, cloned, and heterologously expressed in Escherichia coli The esterases were found to hydrolyze the copolyester poly(butylene adipate-co-butylene terephthalate) (PBAT) and the oligomeric model substrate bis[4-(benzoyloxy)butyl] terephthalate (BaBTaBBa). Two promising polyesterase candidates, EstB3 and EstC7, which clustered in family VIII of bacterial lipolytic enzymes, were purified and characterized using the soluble esterase substrate p-nitrophenyl butyrate (Kmvalues of 46.5 and 3.4 μM, temperature optima of 48°C and 50°C, and pH optima of 7.0 and 8.5, respectively). In particular, EstC7 showed outstanding activity and a strong preference for hydrolysis of the aromatic ester bond in PBAT. Our study highlights the potential of plant-associated microbiomes from extreme natural ecosystems as a source for novel hydrolytic enzymes hydrolyzing polymeric compounds.
  
  
  
  In this study, we describe the discovery and analysis of new enzymes from microbial communities associated with plants (moss). The recovered enzymes show the ability to hydrolyze not only common esterase substrates but also the synthetic polyester poly(butylene adipate-co-butylene terephthalate), which is a common material employed in biodegradable plastics. The widespread use of such synthetic polyesters in industry and society requires the development of new sustainable technological solutions for their recycling. The discovered enzymes have the potential to be used as catalysts for selective recovery of valuable building blocks from this material.
authors.affiliation: Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria christina.mueller@tugraz.at.|ACIB GmbH, Graz, Austria.
authors.forename: Christina Andrea
authors.initials: CA
authors.lastname: Müller
authors.affiliation: ACIB GmbH, Tulln an der Donau, Austria.
authors.forename: Veronika
authors.initials: V
authors.lastname: Perz
authors.affiliation: Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria.|ACIB GmbH, Graz, Austria.
authors.forename: Christoph
authors.initials: C
authors.lastname: Provasnek
authors.affiliation: Institute of Environmental Biotechnology, University of Natural Resources and Life Sciences, Tulln an der Donau, Austria.
authors.forename: Felice
authors.initials: F
authors.lastname: Quartinello
authors.affiliation: ACIB GmbH, Tulln an der Donau, Austria.|Institute of Environmental Biotechnology, University of Natural Resources and Life Sciences, Tulln an der Donau, Austria.
authors.forename: Georg M
authors.initials: GM
authors.lastname: Guebitz
authors.affiliation: Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Berg
mesh_terms: D001419:Bacteria / Q000201:enzymology*; D002087:Butyrates / Q000378:metabolism; D004950:Esterases / Q000235:genetics* / Q000378:metabolism*; D006868:Hydrolysis; D064307:Microbiota / Q000235:genetics / Q000502:physiology; D011091:Polyesters / Q000378:metabolism*; D044003:Sphagnopsida / Q000382:microbiology*
chemical_list: D002087:Butyrates; D011091:Polyesters; C488797:poly(butylene adipate-co-butylene terephthalate); C033592:4-nitrophenyl butyrate; D004950:Esterases
keywords: enzyme discovery; esterases; functional metagenomics; plant-associated microbiomes; polymer hydrolysis