Stereoselective hydration of (RS)-phenylglycine nitrile by new whole cell biocatalysts
- Publication Type
- Journal contribution (peer reviewed)
- Authors
- Hensel, M., Lutz-Wahl, S., Fischer, L.
- Year of publication
- 2002
- Published in
- Tetrahedron: Asymmetry
- Band/Volume
- 13(24)/
- DOI
- 10.1016/S0957-4166(02)00751-6
- Page (from - to)
- nnb
Five new bacterial isolates with stereoselective nitrile hydratase activity against (RS)-2-phenylpropionitrile and (RS)-phenylglycine nitrile were investigated. The permeabilized whole cell isolates selectively hydrate the (S)-enantiomer of phenylglycine nitrile with E values of 1.2-5.4. One isolate, which was identified as Pantoea endophytica, produced pure (S)-phenylglycine (>99% ee) as a result of hydrolysis of (S)-phenylglycine amide by an (S)-specific amidase. Surprisingly, in the hydrolysis of (RS)-phenylglycine nitrile, it was found that the (R)-amide was accumulated in excess (21% ee) despite the nitrile hydratase produced by Pantoea endophytica was (S)-selective. The synthesis of pure (R)-phenylglycine (>99% ee) was achieved in time course studies using another Pantoea sp. with (R)-selective amidase. In the case of Nocardioides sp. the intermediate product, (S)-phenylglycine amide, could be produced (52% ee) without its subsequent hydrolysis into the acid due to the apparent absence of any amidase activity.