In an effort to prepare 3,4-methylene-dioxyphenyl-(S)-isopropanol from 3,4-methylene-dioxyphenylacetone, an initial screen of microbes indicated that Candida famata could catalyze this reaction efficiently at low substrate concentration. A dilute, large-scale process was developed to provide experimental material for the chemical synthesis to be explored. However, the productivity number of this process [0.134 g product (g wet weight cells)(-1) day(-1) was too low to be practical. C. famata was also extremely sensitive to concentrations of both the ketone and the alcohol greater than 2 g/l. A more extensive screen of yeast and fungi revealed that Zygosacchmomyces rouxii was more tolerant to higher substrate concentrations and had a higher productivity number [0.8 g (g wet weight cells)(-1) day(-1)]. These characteristics suggested that Z. rouxii could be used in a large-scale process at high substrate concentrations.