Cells of Candida utilis for in vitro (R)-phenylacetylcarbinol production in an aqueous/octanol two-phase reactor.
(R)-Phenylacetylcarbinol (PAC), a pharmaceutical precursor, was produced from benzaldehyde and pyruvate by pyruvate decarboxylase (PDC) of Candida utilis in an aqueous/organic two-phase emulsion reactor. When the partially purified enzyme in this previously established in vitro process was replaced with C. utilis cells and the temperature was increased from 4 to 21 degrees C, a screen of several 1-alcohols (C4-C9) confirmed the suitability of 1-octanol as the organic phase. Benzyl alcohol, the major by-product in the commercial in vivo conversion of benzaldehyde and sugar to PAC by Saccharomyces cerevisiae, was not formed. With a phase volume ratio of 1:1 and 5.6 g C. utilis l-1 (PDC activity 2.5 U ml-1), PAC levels of 103 g l-1 in the octanol phase and 12.8 g l-1 in the aqueous phase were produced in 15 h at 21 degrees C. In comparison to our previously published process with partially purified PDC in an aqueous/octanol emulsion at 4 degrees C, PAC was produced at a 4-times increased specific rate (1.54 versus 0.39 mg U-1 h-1) with simplified catalyst production and reduced cooling cost. Compared to traditional in vivo whole cell PAC production, the yield on benzaldehyde was 26% higher, the product concentration increased 3.9-fold (or 6.9-fold based on the organic phase), the productivity improved 3.1-fold (3.9 g l-1 h-1) and the catalyst was 6.9-fold more efficient (PAC/dry cell mass 10.3 g g-1).
Rosche
Bettina
B
School of Biotechnology and Biomolecular Sciences, University of New South Wales, NSW 2052, Sydney, Australia. b.rosche@unsw.edu.au
Breuer
Michael
M
Hauer
Bernhard
B
Rogers
Peter L
PL
D000096:Acetone / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism; D001547:Benzaldehydes / Q000378:metabolism; D019149:Bioreactors / Q000382:microbiology*; D001711:Biotransformation; D002175:Candida / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D005947:Glucose / Q000493:pharmacokinetics; D019850:Heptanol / Q000737:chemistry / Q000494:pharmacology; D000442:Octanols / Q000737:chemistry / Q000494:pharmacology; D019289:Pyruvic Acid / Q000378:metabolism
D001547:Benzaldehydes; D000442:Octanols; D000096:Acetone; D019289:Pyruvic Acid; D019850:Heptanol; C035293:1-hydroxy-1-phenyl-2-propanone; D005947:Glucose; C032175:benzaldehyde