Production of (R)-3-Amino-3-phenylpropionic Acid and (S)-3-Amino-3-phenylpropionic Acid from (R,S)-N-Acetyl-3-amino-3-phenylpropionic Acid Using Microorganisms Having Enantiomer-Specific Amidohydrolyzing Activity

Abstract

(R)-3-Amino-3-phenylpropionic acid ((R)-β-Phe) and (S)-3-amino-3-phenylpropionic acid ((S)-β-Phe) are key compounds on account of their use as intermediates in synthesizing pharmaceuticals. Enantiomerically pure non-natural amino acids are generally prepared by enzymatic resolution of the racemic N-acetyl form, but despite the intense efforts this method could not be used for preparing enantiomerically pure β-Phe, because the effective enzyme had not been found. Therefore, screening for microorganisms capable of amidohydrolyzing (R,S)-N-acetyl-3-amino-3-phenylpropionic acid ((R,S)-N-Ac-β-Phe) in an enantiomer-specific manner was performed.
A microorganism having (R)-enantiomer-specific amidohydrolyzing activity and another having both (R)-enantiomer- and (S)-enantiomer-specific amidohydrolyzing activities were obtained from soil samples. Using 16S rDNA analysis, the former organism was identified as Variovorax sp., and the latter as Burkholderia sp. Using these organisms, enantiomerically pure (R)-β-Phe (>99.5% ee) and (S)-β-Phe (>99.5% ee) with a high molar conversion yield (67%–96%) were obtained from the racemic substrate.