Enantioselective reduction of flavanone and oxidation of cis- and trans-flavan-4-ol by selected yeast cultures
作者:Tomasz Janeczko、Monika Dymarska、Monika Siepka、Radosław Gniłka、Agnieszka Leśniak、Jarosław Popłoński、Edyta Kostrzewa-Susłow
DOI:10.1016/j.molcatb.2014.08.006
日期:2014.11
This research investigated stereochemistry of reduction of racemic flavanone and a concurrent competitive process of oxidation, taking place in cultures of live yeast strains. The results obtained gave us information about capability of tested biocatalysts for enantioselective (with respect to both substrate and product) reduction of flavanone and for enantioselective oxidation of the resulting cis- and trans-flavan-4-ols. As a result of our experiments we obtained (2S,4S)-cis-flavan-4-ol with 43% of conversion and 96% of enantiomeric excess, and (2R,4S)-trans-flavan-4-ol with 41% of conversion and ee > 99% in the culture of Rhodotorula rubra; (2S,4S)-cis-flavan-4-ol (43%, ee = 96%) along with (2R,4R)-cis-flavan-4-ol (44%, ee = 61%) in the culture of Zygosaccharomyces bailii KCh 907. Additionally, some of the tested strains demonstrated an excellent capability for enantioselective oxidation of (+/-)-cis-flavan-4-ol and (+/-)-trans-flavan-4-ol, obtained by chemical synthesis. A one-day biotransformation in the culture of Candida parapsilosis KCh 909 afforded (S)-flavanone (ee = 93%) as 49% of the reaction mixture and 49% of unreacted (2R,4R)-cis-flavan-4-ol with ee = 97%. Racemic trans-flavan-4-ol was effectively oxidized in the culture of Yarrowia lipolytica KCh 71 - after a three-day biotransformation the reaction mixture contained 52% of (R)-flavanone (ee = 85%) and 48% of (2R,45)-trans-flavan-4-ol with a high enantiomeric excess (ee = 93%). (C) 2014 Elsevier B.V. All rights reserved.