Microbial reduction of 1-acetonapthone: a highly efficient process for multigram synthesis of S(−)-1-(1′-napthyl) ethanol

1-Acetonaphthone was incubated with the resting cells of Geotrichum candidum, Candida parapsilosis, Yarrowia lipolytica and Rhizopus arrhizus at 28 °C for its transformation. The first two microorganisms have shown excellent results leading to the product S(−)-1-(1′-napthyl) ethanol in high yield with selectivity above 99 and 98% in the case of G. candidum and C. parapsilosis, respectively. The pH of the medium, substrate concentration and time of incubation were optimised for the maximum conversion. Adsorbent resin (XAD-7) was used for controlling cell toxicity, substrate and product inhibition. The optimum ratio of substrate: resin was found to be 1:2 for maximum yield with excellent selectivity. Subsequently, a method for the preparative bioreduction (2 g) of acetonapthone was developed by adsorbing the substrate on the resin.