title: Continuous asymmetric ketone reduction processes with recombinant Escherichia coli.
abstract: The reduction of methyl acetoacetate was carried out in continuously operated biotransformation processes catalyzed by recombinant Escherichia coli cells expressing an alcohol dehydrogenase from Lactobacillus brevis. Three different cell types were applied as biocatalysts in three different cofactor regeneration approaches. Both processes with enzyme-coupled cofactor regeneration catalyzed by formate dehydrogenase or glucose dehydrogenase are characterized by a rapid deactivation of the biocatalyst. By contrast the processes with substrate-coupled cofactor regeneration by alcohol dehydrogenase catalyzed oxidation of 2-propanol could be run over a period of 7 weeks with exceedingly high substrate and cosubstrate concentrations of up to 2.5 and 2.8 mol L(-1), respectively. Even under these extreme conditions, the applied biocatalyst showed a good stability with only marginal leakage of intracellular cofactors.
authors.affiliation: Institut für Biotechnologie 2, Forschungszentrum Jülich, 52425 Jülich, Germany.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Schroer
authors.forename: Ursula
authors.initials: U
authors.lastname: Mackfeld
authors.forename: Ivy Ai Wei
authors.initials: IA
authors.lastname: Tan
authors.forename: Christian
authors.initials: C
authors.lastname: Wandrey
authors.forename: Florian
authors.initials: F
authors.lastname: Heuser
authors.forename: Stephanie
authors.initials: S
authors.lastname: Bringer-Meyer
authors.forename: Andrea
authors.initials: A
authors.lastname: Weckbecker
authors.forename: Werner
authors.initials: W
authors.lastname: Hummel
authors.forename: Thomas
authors.initials: T
authors.lastname: Daussmann
authors.forename: Rupert
authors.initials: R
authors.lastname: Pfaller
authors.forename: Andreas
authors.initials: A
authors.lastname: Liese
authors.forename: Stephan
authors.initials: S
authors.lastname: Lütz
mesh_terms: D000090:Acetoacetates / Q000378:metabolism; D019149:Bioreactors; D001711:Biotransformation; D004274:DNA, Recombinant; D004926:Escherichia coli / Q000378:metabolism*; D005560:Formate Dehydrogenases; D005948:Glucose Dehydrogenases; D007659:Ketones / Q000378:metabolism*