title: A new arylesterase from Pseudomonas pseudoalcaligenes can hydrolyze ionic phthalic polyesters.
abstract: Extracellular enzymes are assumed to be responsible for the initial and rate limiting step in biodegradation of polymers. Mainly enzymes with aliphatic esters as their natural substrates (e.g. lipase, cutinases) have until now been evaluated for polyester hydrolysis studies. However, the potential of enzymes with aromatic esters as their natural substrates (e.g. arylesterases) have been neglected although many types of polyester today contain aromatic moieties. Consequently, in order to elucidate biodegradation of phthalic polyesters in aquatic systems, a novel arylesterase (PpEst) was investigated related to hydrolysis of ionic phthalic polyesters. The hydrolysis of various ionic phthalic polyesters by PpEst was mechanistically studied. The polyester building blocks (terephthalic acid (TA), 5-sulfoisophthalic acid (NaSIP) and alkyl or ether diols) were systematically varied to investigate the impact on hydrolysis. PpEst effectively hydrolyzed all 14 synthetized ionic phthalic polyesters as indicated by released TA. However, no NaSIP was detected indicating that PpEst has a limited capacity to cleave bonds in close vicinity to the ionic monomer NaSIP. The systematic study indicated that increasing water solubility and hydrophilicity significantly enhanced hydrolysis. A higher release of TA was seen with increasing NaSIP ratio while up to 20 times more TA was released when alkyl diols were replaced by ether diol analogues. In contrast, cyclic and branched diols had a negative effect on hydrolysis when compared to linear diols. PpEst also revealed a linear release of TA over seven days for ether containing polyesters, indicating a very stable enzyme.
authors.affiliation: ACIB - Austrian Centre of Industrial Biotechnology GmbH, Konrad Lorenz Strasse 20, 3430 Tulln an der Donau, Austria.
authors.forename: Karolina
authors.initials: K
authors.lastname: Haernvall
authors.affiliation: ACIB - Austrian Centre of Industrial Biotechnology GmbH, Konrad Lorenz Strasse 20, 3430 Tulln an der Donau, Austria.
authors.forename: Sabine
authors.initials: S
authors.lastname: Zitzenbacher
authors.affiliation: BASF SE, Carl-Bosch-Strasse 38, 67056 Ludwigshafen am Rhein, Germany.
authors.forename: Motonori
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: BASF SE, Carl-Bosch-Strasse 38, 67056 Ludwigshafen am Rhein, Germany.
authors.forename: Michael Bernhard
authors.initials: MB
authors.lastname: Schick
authors.affiliation: ACIB - Austrian Centre of Industrial Biotechnology GmbH, Konrad Lorenz Strasse 20, 3430 Tulln an der Donau, Austria. Electronic address: doris.ribitsch@acib.at.
authors.forename: Doris
authors.initials: D
authors.lastname: Ribitsch
authors.affiliation: ACIB - Austrian Centre of Industrial Biotechnology GmbH, Konrad Lorenz Strasse 20, 3430 Tulln an der Donau, Austria; BOKU - University of Natural Resources and Life Sciences, Institute for Environmental Biotechnology, Konrad Lorenz Strasse 20, 3430 Tulln an der Donau, Austria.
authors.forename: Georg M
authors.initials: GM
authors.lastname: Guebitz
mesh_terms: D063566:Biodegradable Plastics; D001673:Biodegradation, Environmental; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D015964:Gene Expression Regulation, Bacterial; D006868:Hydrolysis; D007477:Ions; D010795:Phthalic Acids / Q000378:metabolism*; D011091:Polyesters / Q000737:chemistry / Q000378:metabolism*; D011108:Polymers / Q000737:chemistry / Q000378:metabolism*; D044205:Pseudomonas pseudoalcaligenes / Q000201:enzymology* / Q000235:genetics
chemical_list: D063566:Biodegradable Plastics; D007477:Ions; D010795:Phthalic Acids; D011091:Polyesters; D011108:Polymers; C011363:terephthalic acid; C549093:5-sulfoisophthalic acid; D002265:Carboxylic Ester Hydrolases; C019734:arylesterase
keywords: Aromatic polyester; Biodegradation; Mechanistic study; Paraoxonase; Sulfonated polymer