Reaction and strain engineering for improved stereo-selective whole-cell reduction of a bicyclic diketone

Summary, in English

Reduction of bicyclo[2.2.2]octane-2,6-dione to (1R, 4S, 6S)-6-hydroxy-bicyclo[2.2.2]octane-2-one by whole cells of Saccharomyces cerevisiae was improved using an engineered recombinant strain and process design. The substrate inhibition followed a Han-Levenspiel model showing an effective concentration window between 12 and 22 g/l, in which the activity was kept above 95%. Yeast growth stage, substrate concentration and a stable pH were shown to be important parameters for effective conversion. The over-expression of the reductase gene YDR368w significantly improved diastereoselectivity compared to previously reported results. Using strain TMB4110 expressing YDR368w in batch reduction with pH control, complete conversion of 40 g/l (290 mM) substrate was achieved with 97% diastereomeric excess (de) and >99 enantiomeric excess (ee), allowing isolation of the optically pure ketoalcohol in 84% yield.

• Författare: Ted Johanson; Magnus Carlquist; Cecilia Olsson; Andreas Rudolf; Torbjörn Frejd; Marie-Francoise Gorwa-Grauslund
• Avdelning/ar: Teknisk mikrobiologi; Centrum för analys och syntes; Avdelningen för kemiteknik
• Publiceringsår: 2008
• Språk: Engelska
• Sidor: 1111-1118
• Publikation/Tidskrift/Serie: Applied Microbiology and Biotechnology
• Volym: 77
• Issue: 5
• Länkar: http://dx.doi.org/10.1007/s00253-007-1240-1
• Dokumenttyp: Artikel i tidskrift
• Förlag: Springer
• Ämne: Chemical Sciences; Industrial Biotechnology; Organic Chemistry
• Nyckelord: Whole-cell - Bioreduction - Reductase - Yeast - Dicarbonyl - Process optimisation - Toxicity - Substrate inhibition - Diastereoselectivity
• Status: Published
• ISBN/ISSN/Övrigt: ISSN: 1432-0614