title: Fully integrated L-phenylalanine separation and concentration using reactive-extraction with liquid-liquid centrifuges in a fed-batch process with E. coli.
abstract: A novel in situ product recovery (ISPR) approach for the (fully) integrated separation of L-phenylalanine (L-phe) from a 20 l fed-batch process with the recombinant L-tyrosine auxotrophic strain E. coli F-4/pF81 is presented. The strain was rationally constructed for the production of the aromatic amino acid. Glucose and tyrosine control is used. A reactive extraction system consisting of kerosene, the cation-selective carrier D(2)EHPA and sulphuric acid, all circulating in liquid-liquid centrifuges, is applied for the on-line L-phe separation from cell- and protein-free permeate. Permeate is drained off from the bioreactor bypass. Using the novel ISPR approach, a significantly extended product formation period at 0.25 mmol/(g*h) together with a reduced by-product formation and a 28% relative glucose/L-phe yield increase is observed. Thus, the ISPR approach is superior to the reference non-ISPR process and even offers extraction rates approximately three times higher than the published membrane-based process.
authors.affiliation: Institute of Biotechnology, Forschungszentrum Jülich GmbH, 52425 Juelich, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Rüffer
authors.forename: U
authors.initials: U
authors.lastname: Heidersdorf
authors.forename: I
authors.initials: I
authors.lastname: Kretzers
authors.forename: G A
authors.initials: GA
authors.lastname: Sprenger
authors.forename: L
authors.initials: L
authors.lastname: Raeven
authors.forename: R
authors.initials: R
authors.lastname: Takors
mesh_terms: D002499:Centrifugation, Density Gradient / Q000295:instrumentation* / Q000379:methods; D005591:Chemical Fractionation / Q000379:methods*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D010649:Phenylalanine / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification; D018511:Systems Integration
chemical_list: D011994:Recombinant Proteins; D010649:Phenylalanine