Synthesis of 1-(S)-phenylethanol and ethyl (R)-4-chloro-3-hydroxybutanoate using recombinant Rhodococcus erythropolis alcohol dehydrogenase produced by two yeast species

The ReADH gene of Rhodococcus erythropolis DSM 43297 encoding alcohol dehydrogenase (ReADH) was expressed in the yeast Arxula adeninivorans and Hansenula polymorpha to determine which host accumulated the highest concentration of recombinant alcohol dehydrogenase for the production of enantiometrically pure alcohols. The ReADH gene was fused with a His-tag encoding sequence at its 3′-end and expressed in both yeast species. The recombinant ReADH-6H preparations exhibited small host-strain dependent differences in their pH and temperature optima, thermo-stability and substrate specificity. The recombinant enzymes in combination with a substrate-coupled cofactor regeneration system were used to synthesize 1-(S)-phenylethanol and ethyl (R)-4-chloro-3-hydroxybutanoate. Permeabilized A. adeninivorans whole cell catalysts co-expressing R. erythropolis alcohol dehydrogenase and Bacillus megaterium glucose dehydrogenase, for enzyme-coupled cofactor regeneration, were also used for the synthesis reactions.