초록
The RrADH gene of Rhodococcus ruber coding for (S)-specific alcohol dehydrogenase (RrADH) was overexpressed in the yeast Arxula adeninivorans and used for the synthesis of enantiomerically pure alcohols. The substrates acetophenone, 2,5-hexandione and 2-nonanon used for this synthesis, were reduced by RrADH to produce S-configured alcohols. Regeneration of the cofactor, NADH, was required for the reaction and this was provided by using isopropanol as a second ADH substrate to reduce NAD<SUP>+</SUP> or by cloning the glucose dehydrogenase gene from Bacillus megaterium (BmGDH) into the yeast which regenerated NADH by oxidizing glucose. Expressing both RrADH and BmGDH in the yeast provided a strain that could synthesize 1-(S)-phenylethanol from acetophenone with NADH being regenerated by the oxidation of glucose. Both bioreduction systems led to the synthesis of pure (S) enantiomer of 1-phenylethanol, but only the enzyme coupled approach reduced 40mM acetophenone completely in 150min. 75mg of 98% pure product could be isolated from 20ml. In conclusion the synthesis potential of the RrADH expressed in A. adeninivorans is very promising for 1-(S)-phenylethanol synthesis.