Enantioselective synthesis of (S)-phenylephrine by whole cells of recombinant Escherichia coli expressing the amino alcohol dehydrogenase gene from Rhodococcus erythropolis BCRC 10909

(R)-phenylephrine [(R)-PE] is an alpha(1)-adrenergic receptor agonist that is widely used in over-the-counter drugs to treat the common cold. We found that Rhodococcus erythropolis BCRC 10909 can convert detectable level of 1-(3-hydroxyphenyl)-2-(methylamino) ethanone (HPMAE) to (S)-PE by high performance liquid chromatography tandem mass spectrometry analysis. An amino alcohol dehydrogenase gene (RE_AADH) which possesses the ability to convert HPMAE to (S)-PE was then isolated from R. erythropolis BCRC 10909 and expressed in Escherichia coli NovaBlue. The purified RE_AADH, tagged with 6x His, had a molecular mass of approximately 30 kDa and exhibited a specific activity of 0.19 mu U/mg to HPMAE in the presence of NADPH, indicating this enzyme could be categorized as NADP(+)-dependent short-chain dehydrogenase reductase. E. coli NovaBlue cell expressing the RE_AADH gene was able to convert HPMAE to (S)-PE with more than 99% enantiomeric excess (ee), 78% yield and a productivity of 3.9 mmol (S)-PE/L h in 12 h at 30 degrees C and pH 7. The (S)-PE, recovered from reaction mixture by precipitation at pH 11.3, could be converted to (R)-PE (ee >99%) by Walden inversion reaction. This is the first reported biocatalytic process for the production of (S)-PE from HPMAE. (C) 2010 Elsevier Ltd. All rights reserved.