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Gewählte Publikation:

Ribitsch, D; Heumann, S; Trotscha, E; Acero, EH; Greimel, K; Leber, R; Birner-Gruenberger, R; Deller, S; Eiteljoerg, I; Remler, P; Weber, T; Siegert, P; Maurer, KH; Donelli, I; Freddi, G; Schwab, H; Guebitz, GM.
(2011): Hydrolysis of Polyethyleneterephthalate by p-Nitrobenzylesterase from Bacillus subtilis
BIOTECHNOL PROGR. 2011; 27(4): 951-960. FullText FullText_BOKU

From a screening on agar plates with bis(benzoyloxyethyl) terephthalate (3PET), a Bacillus subtilis p-nitrobenzylesterase (BsEstB) was isolated and demonstrated to hydrolyze polyethyleneterephthalate (PET). PET-hydrolase active strains produced clearing zones and led to the release of the 3PET hydrolysis products terephthalic acid (TA), benzoic acid (BA), 2-hydroxyethyl benzoate (HEB), and mono-(2-hydroxyethyl) terephthalate (MHET) in 3PET supplemented liquid cultures. The 3PET-hydrolase was isolated from non-denaturating polyacrylamide gels using fluorescein diacetate (FDA) and identified as BsEstB by LC-MS/MS analysis. BsEstB was expressed in Escherichia coli with C-terminally fused StrepTag II for purification. The tagged enzyme had a molecular mass of 55.2 kDa and a specific activity of 77 U/mg on p-nitrophenyl acetate and 108 U/mg on p-nitrophenyl butyrate. BsEstB was most active at 40 degrees C and pH 7.0 and stable for several days at pH 7.0 and 37 degrees C while the half-life times decreased to 3 days at 40 degrees C and only 6 h at 45 degrees C. From 3PET, BsEstB released TA, MHET, and BA, but neither bis(2-hydroxyethyl) terephthalate (BHET) nor hydroxyethylbenzoate (HEB). The k(cat) values decreased with increasing complexity of the substrate from 6 and 8 (s-1) for p-nitrophenyl-acetate (4NPA) and p-nitrophenyl-butyrate (4NPB), respectively, to 0.14 (s-1) for bis(2-hydroxyethyl) terephthalate (BHET). The enzyme hydrolyzed PET films releasing TA and MHET with a concomitant decrease of the water-contact angle (WCA) from 68.2 degrees +/- 1.7 degrees to 62.6 degrees +/- 1.1 degrees due to formation of novel hydroxyl and carboxyl groups. These data correlated with a fluorescence emission intensity increase seen for the enzyme treated sample after derivatization with 2-(bromomethyl)naphthalene. (C) 2011 American Institute of Chemical Engineers Biotechnol. Prog., 27: 951-960, 2011
Autor*innen der BOKU Wien:
Greimel Katrin
Gübitz Georg
Herrero Acero Enrique
Ribitsch Doris
Find related publications in this database (using NML MeSH Indexing)
Bacillus subtilis/enzymology*
Carboxylic Ester Hydrolases/metabolism*
Polyethylene Terephthalates/metabolism*

Find related publications in this database (Keywords)
poly(ethylene terephthalate)
Bacillus subtilis
enzymatic degradation

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