Extracts of 7 yeast were examined regarding their potential for production of (R)-phenylacetylcarbinol [(R)-PAC], which is the chiral precursor in the manufacture of the pharmaceuticals ephedrine and pseudoephedrine. Benzaldehyde and pyruvate were transformed at a scale of 1.2 ml into PAC by cell-free extracts of all selected strains, covering the broad taxonomic spectrum of Zygomycota and Basidiomycota. Highest final PAC concentrations were obtained with the extracts of Hansenulla polymorphs and B.lambicus. [78-84 mM (11.7-12.6 g/l) PAC within 20 h from initial substrate concentrations of 100 mM benzaldehyde and 150 mM pyruvate]. (R)-PAC was in about90-93% enantiomeric excess. Hansenulla polymorphs had the advantage of faster growth than B.lambicus. Hansenulla polymorpha were used as an example in a biotransformation process based on whole cells and benzaldehyde and glucose as substrates. The substrate pyruvate was generated through the fungal fermentation of glucose. Only 19 mM PAC (2.9 g/l) was produced within8 h from 80 mM benzaldehyde, with evidence of significant benzyl alcohol production.

Keywords : Bioconversion, Hansenulla polymorpha, Brettanomyces lambicus, (R)-Phenylacetylcarbinol