Method for the preparation of chiral alpha haloalkanoic acids

Method of selectively hydrolyzing the S-enantiomer of an alpha haloalkanoic acid according to formula I,

• wherein X is a halogen and
• R is an alkyl chain of 1 to 6 carbon atoms, wherein that said alkyl chain can be straight or branched at carbon atoms γ or δ,
• comprising
• providing a racemate of the R-enantiomer and the S-enantiomer of said alpha haloalkanoic acid,
• providing a polypeptide having dehalogenase activity comprising an amino acid sequence as set forth in SEQ ID NO. 1 or SEQ ID NO. 4 or a sequence with at least 80% sequence identity to either of said sequences,
• reacting the racemate for 1-8 hours, wherein
• the pH is in the range of 9-10 and the temperature is in the range of 15-35° C. for the polypeptide with dehalogenase activity comprising an amino acid sequence as set forth in SEQ ID NO. 1 or a sequence with at least 80% sequence identity to said sequence or
• the pH is in the range of 9-10 and the temperature is in the range of 55-65° C. for the polypeptide with dehalogenase activity comprising an amino acid sequence as set forth in SEQ ID NO. 4 or a sequence with at least 80% sequence identity to said sequence.
• and wherein an enantiomeric excess of the R-enantiomer of between 90.0 and 99.9% is reached after 1-8 hours.