Preparation of Enantiomerically Pure (S)-(-)-1-(1′-naphthyl)-ethanol by the Fungus Alternaria alternata

(S)-(-)-1-(1-napthyl)-ethanol (S-NE) is an important intermediate for the preparation of mevinic acid analogs, which is used for the treatment of hyperlipidemia. The objectives of the study were to isolate a microorganism that could effectively reduce 1-acetonaphthone (1-ACN) to S-NE, to determine the influence that the physicochemical parameters would have on the reduction by the isolated microorganism, and to attempt large-scale studies with the microorganism. Over the years fungi have been considered a promising biocatalyst and it has been presumed that many fungal species have not been isolated and therefore the current study focused on possible isolation of these microorganisms. A total of 72 fungal isolates were screened for their ability to reduce 1-ACN to its corresponding alcohol. The isolate, EBK-62, identified as Alternaria alternata, was found to be the most successful at reducing the ketone to the corresponding alcohol in the submerged culture. The reaction conditions were systematically optimized for the reducing agent A. alternata EBK-62, which showed high stereospecificity and good conversion for the reduction. The preparative scale study was carried out in a 2L bioreactor and a total of 4.9g of S-NE in optically pure form (>99% enantiomeric excess) was produced in 48h. Chirality 28:669-673, 2016. (c) 2016 Wiley Periodicals, Inc.