Immobilization of Phenylalanine Ammonia-Lyase on Single-Walled Carbon Nanotubes for Stereoselective Biotransformations in Batch and Continuous-Flow Modes

Judith H Bartha-Vári; Monica I Toşa; Florin-Dan Irimie; Diána Weiser; Zoltán Boros; Beáta G Vértessy; Csaba Paizs; László Poppe

doi:10.1002/cctc.201402894

Immobilization of Phenylalanine Ammonia-Lyase on Single-Walled Carbon Nanotubes for Stereoselective Biotransformations in Batch and Continuous-Flow Modes

ChemCatChem. 2015 Apr 7;7(7):1122-1128. doi: 10.1002/cctc.201402894. Epub 2015 Mar 12.

Authors

Judith H Bartha-Vári¹, Monica I Toşa¹, Florin-Dan Irimie¹, Diána Weiser², Zoltán Boros³, Beáta G Vértessy⁴, Csaba Paizs¹, László Poppe³

Affiliations

¹ Biocatalysis and Biotransformation Research Group, Babeş-Bolyai University of Cluj-Napoca, Arany János str. 11, 400028 Cluj-Napoca (Romania).
² Department of Organic Chemistry and Technology, Budapest University of Technology and Economics, Műegyetem rkp. 3, 1111 Budapest (Hungary).
³ Department of Organic Chemistry and Technology, Budapest University of Technology and Economics, Műegyetem rkp. 3, 1111 Budapest (Hungary); SynBiocat Ltd, Lázár deák u 4/1, 1173 Budapest (Hungary).
⁴ Department of Biotechnology and Food Sciences, Budapest University of Technology and Economics, Szt. Gellért tér 4, 1111 Budapest (Hungary); Institute of Enzymology, Research Centre for Natural Sciences of Hungarian Academy of Sciences, Magyar tudósok krt. 2, 1117 Budapest (Hungary).

Abstract

Carboxylated single-walled carbon nanotubes (SwCNT_COOH) were used as a support for the covalent immobilization of phenylalanine ammonia-lyase (PAL) from parsley by two different methods. The nanostructured biocatalysts (SwCNT_COOH-PAL^I and SwCNT_COOH-PAL^II) with low diffusional limitation were tested in the batch-mode kinetic resolution of racemic 2-amino-3-(thiophen-2-yl)propanoic acid (1) to yield a mixture of (R)-1 and (E)-3-(thiophen-2-yl)acrylic acid (2) and in ammonia addition to 2 to yield enantiopure (S)-1. SwCNT_COOH-PAL^II was a stable biocatalyst (>90 % of the original activity remained after six cycles with 1 and after three cycles in 6 m NH₃ with 2). The study of ammonia addition to 2 in a continuous-flow microreactor filled with SwCNT_COOH-PAL^II (2 m NH₃, pH 10.0, 15 bar) between 30-80 °C indicated no significant loss of activity over 72 h up to 60 °C. SwCNT_COOH-PAL^II in the continuous-flow system at 30 °C was more productive (specific reaction rate, r_flow=2.39 μmol min^-1 g^-1) than in the batch reaction (r_batch=1.34 μmol min^-1 g^-1).

Keywords: biotransformations; enzyme catalysis; immobilization; nanotubes; supported catalysts.