title: Scale-up and intensification of (S)-1-(2-chlorophenyl)ethanol bioproduction: economic evaluation of whole cell-catalyzed reduction of o-chloroacetophenone.
abstract: Escherichia coli cells co-expressing genes coding for Candida tenuis xylose reductase and Candida boidinii formate dehydrogenase were used for the bioreduction of o-chloroacetophenone with in situ coenzyme recycling. The product, (S)-1-(2-chlorophenyl)ethanol, is a key chiral intermediate in the synthesis of polo-like kinase 1 inhibitors, a new class of chemotherapeutic drugs. Production of the alcohol in multi-gram scale requires intensification and scale-up of the biocatalyst production, biotransformation, and downstream processing. Cell cultivation in a 6.9-L bioreactor led to a more than tenfold increase in cell concentration compared to shaken flask cultivation. The resultant cells were used in conversions of 300 mM substrate to (S)-1-(2-chlorophenyl)ethanol (e.e. >99.9%) in high yield (96%). Results obtained in a reaction volume of 500 mL were identical to biotransformations carried out in 1 mL (analytical) and 15 mL (preparative) scale. Optimization of product isolation based on hexane extraction yielded 86% isolated product. Biotransformation and extraction were accomplished in a stirred tank reactor equipped with pH and temperature control. The developed process lowered production costs by 80% and enabled (S)-1-(2-chlorophenyl)ethanol production within previously defined economic boundaries. A simple and efficient way to synthesize (S)-1-(2-chlorophenyl)ethanol in an isolated amount of 20 g product per reaction batch was demonstrated.
authors.affiliation: Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 12/1, 8010 Graz, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Eixelsberger
authors.forename: John M
authors.initials: JM
authors.lastname: Woodley
authors.forename: Bernd
authors.initials: B
authors.lastname: Nidetzky
authors.forename: Regina
authors.initials: R
authors.lastname: Kratzer
mesh_terms: D000438:Alcohols / Q000378:metabolism*; D000449:Aldehyde Reductase / Q000235:genetics / Q000378:metabolism*; D001709:Biotechnology / Q000379:methods; D001711:Biotransformation; D002175:Candida / Q000201:enzymology / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D005560:Formate Dehydrogenases / Q000235:genetics / Q000378:metabolism*; D060847:Metabolic Engineering / Q000379:methods*; D010084:Oxidation-Reduction; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D002721:omega-Chloroacetophenone / Q000378:metabolism*
chemical_list: D000438:Alcohols; D011994:Recombinant Proteins; D002721:omega-Chloroacetophenone; D000449:Aldehyde Reductase; D005560:Formate Dehydrogenases