title: Enzymatic (R)-phenylacetylcarbinol production in a benzaldehyde emulsion system with Candida utilis cells.
abstract: Recent progress in enzymatic (R)-phenylacetylcarbinol (PAC) production has established the need for low cost and efficient biocatalyst preparation. Pyruvate decarboxylase (PDC) added in the form of Candida utilis cells showed higher stability towards benzaldehyde and temperature in comparison with partially purified preparations. In the presence of 50 mM benzaldehyde and at 4 degrees C, a half-life of 228 h was estimated for PDC added as C. utilis cells, in comparison with 24 h for the partially purified preparation. Increasing the temperature from 4 to 21 degrees C for PAC production with C. utilis cells resulted in similar final PAC levels of 39 and 43 g l(-1) (258 and 289 mM), respectively, from initial 300 mM benzaldehyde and 364 mM pyruvate. The overall volumetric productivity was enhanced 2.8-fold, which reflected the 60% shorter reaction time at the higher temperature. Enantiomeric excess values of 98 and 94% for R-PAC were obtained at 4 and 21 degrees C, respectively, and benzyl alcohol (a potential by-product from benzaldehyde) was not formed.
authors.affiliation: School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia.
authors.forename: Gernalia
authors.initials: G
authors.lastname: Satianegara
authors.forename: Michael
authors.initials: M
authors.lastname: Breuer
authors.forename: Bernhard
authors.initials: B
authors.lastname: Hauer
authors.forename: Peter L
authors.initials: PL
authors.lastname: Rogers
authors.forename: Bettina
authors.initials: B
authors.lastname: Rosche
mesh_terms: D000096:Acetone / Q000031:analogs & derivatives* / Q000378:metabolism; D001547:Benzaldehydes; D002175:Candida / Q000166:cytology* / Q000201:enzymology*; D004795:Enzyme Stability; D007700:Kinetics; D011767:Pyruvate Decarboxylase / Q000302:isolation & purification* / Q000378:metabolism*; D019289:Pyruvic Acid / Q000378:metabolism; D013696:Temperature
chemical_list: D001547:Benzaldehydes; D000096:Acetone; D019289:Pyruvic Acid; C035293:1-hydroxy-1-phenyl-2-propanone; D011767:Pyruvate Decarboxylase; C032175:benzaldehyde